Add some external dependencies.

extern/EtcLib/CMakeLists.txt

@@ -0,0 +1,24 @@
+# Copyright 2015 The Etc2Comp Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+project(EtcLib)
+include_directories(./Etc)
+include_directories(./EtcCodec)
+
+file(GLOB SOURCES
+	${PROJECT_SOURCE_DIR}/Etc/*.h
+	${PROJECT_SOURCE_DIR}/EtcCodec/*.h
+	${PROJECT_SOURCE_DIR}/Etc/*.cpp
+	${PROJECT_SOURCE_DIR}/EtcCodec/*.cpp)
+ADD_LIBRARY(EtcLib ${SOURCES})

extern/EtcLib/Etc/Etc.cpp

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "EtcConfig.h"
+#include "Etc.h"
+
+#include <string.h>
+
+namespace Etc
+{
+	// ----------------------------------------------------------------------------------------------------
+	// C-style inteface to the encoder
+	//
+	void Encode(float *a_pafSourceRGBA,
+				unsigned int a_uiSourceWidth, 
+				unsigned int a_uiSourceHeight,
+				Image::Format a_format,
+				ErrorMetric a_eErrMetric,
+				float a_fEffort,
+				unsigned int a_uiJobs,
+				unsigned int a_uiMaxJobs,
+				unsigned char **a_ppaucEncodingBits,
+				unsigned int *a_puiEncodingBitsBytes,
+				unsigned int *a_puiExtendedWidth,
+				unsigned int *a_puiExtendedHeight, 
+				int *a_piEncodingTime_ms, bool a_bVerboseOutput)
+	{
+
+		Image image(a_pafSourceRGBA, a_uiSourceWidth,
+					a_uiSourceHeight,
+					a_eErrMetric);
+		image.m_bVerboseOutput = a_bVerboseOutput;
+		image.Encode(a_format, a_eErrMetric, a_fEffort, a_uiJobs, a_uiMaxJobs);
+
+		*a_ppaucEncodingBits = image.GetEncodingBits();
+		*a_puiEncodingBitsBytes = image.GetEncodingBitsBytes();
+		*a_puiExtendedWidth = image.GetExtendedWidth();
+		*a_puiExtendedHeight = image.GetExtendedHeight();
+		*a_piEncodingTime_ms = image.GetEncodingTimeMs();
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+
+}

extern/EtcLib/Etc/Etc.h

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "EtcConfig.h"
+#include "EtcImage.h"
+#include "EtcColor.h"
+#include "EtcErrorMetric.h"
+
+#define ETCCOMP_MIN_EFFORT_LEVEL (0.0f)
+#define ETCCOMP_DEFAULT_EFFORT_LEVEL (40.0f)
+#define ETCCOMP_MAX_EFFORT_LEVEL (100.0f)
+
+namespace Etc
+{
+	class Block4x4EncodingBits;
+
+	// C-style inteface to the encoder
+	void Encode(float *a_pafSourceRGBA,
+				unsigned int a_uiSourceWidth,
+				unsigned int a_uiSourceHeight,
+				Image::Format a_format,
+				ErrorMetric a_eErrMetric,
+				float a_fEffort,
+				unsigned int a_uiJobs,
+				unsigned int a_uimaxJobs,
+				unsigned char **a_ppaucEncodingBits,
+				unsigned int *a_puiEncodingBitsBytes,
+				unsigned int *a_puiExtendedWidth,
+				unsigned int *a_puiExtendedHeight,
+				int *a_piEncodingTime_ms, bool a_bVerboseOutput = false);
+
+}

extern/EtcLib/Etc/EtcColor.h

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <math.h>
+
+namespace Etc
+{
+
+	inline float LogToLinear(float a_fLog)
+	{
+		static const float ALPHA = 0.055f;
+		static const float ONE_PLUS_ALPHA = 1.0f + ALPHA;
+
+		if (a_fLog <= 0.04045f)
+		{
+			return a_fLog / 12.92f;
+		}
+		else
+		{
+			return powf((a_fLog + ALPHA) / ONE_PLUS_ALPHA, 2.4f);
+		}
+	}
+
+	inline float LinearToLog(float &a_fLinear)
+	{
+		static const float ALPHA = 0.055f;
+		static const float ONE_PLUS_ALPHA = 1.0f + ALPHA;
+
+		if (a_fLinear <= 0.0031308f)
+		{
+			return 12.92f * a_fLinear;
+		}
+		else
+		{
+			return ONE_PLUS_ALPHA * powf(a_fLinear, (1.0f/2.4f)) - ALPHA;
+		}
+	}
+
+	class ColorR8G8B8A8
+	{
+	public:
+
+		unsigned char ucR;
+		unsigned char ucG;
+		unsigned char ucB;
+		unsigned char ucA;
+
+	};
+}

extern/EtcLib/Etc/EtcColorFloatRGBA.h

@@ -0,0 +1,321 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "EtcConfig.h"
+#include "EtcColor.h"
+
+#include <math.h>
+
+namespace Etc
+{
+
+	class ColorFloatRGBA
+    {
+    public:
+
+		ColorFloatRGBA(void)
+        {
+            fR = fG = fB = fA = 0.0f;
+        }
+
+		ColorFloatRGBA(float a_fR, float a_fG, float a_fB, float a_fA)
+        {
+            fR = a_fR;
+            fG = a_fG;
+            fB = a_fB;
+            fA = a_fA;
+        }
+
+		inline ColorFloatRGBA operator+(ColorFloatRGBA& a_rfrgba)
+		{
+			ColorFloatRGBA frgba;
+			frgba.fR = fR + a_rfrgba.fR;
+			frgba.fG = fG + a_rfrgba.fG;
+			frgba.fB = fB + a_rfrgba.fB;
+			frgba.fA = fA + a_rfrgba.fA;
+			return frgba;
+		}
+
+		inline ColorFloatRGBA operator+(float a_f)
+		{
+			ColorFloatRGBA frgba;
+			frgba.fR = fR + a_f;
+			frgba.fG = fG + a_f;
+			frgba.fB = fB + a_f;
+			frgba.fA = fA;
+			return frgba;
+		}
+
+		inline ColorFloatRGBA operator-(float a_f)
+		{
+			ColorFloatRGBA frgba;
+			frgba.fR = fR - a_f;
+			frgba.fG = fG - a_f;
+			frgba.fB = fB - a_f;
+			frgba.fA = fA;
+			return frgba;
+		}
+
+		inline ColorFloatRGBA operator-(ColorFloatRGBA& a_rfrgba)
+		{
+			ColorFloatRGBA frgba;
+			frgba.fR = fR - a_rfrgba.fR;
+			frgba.fG = fG - a_rfrgba.fG;
+			frgba.fB = fB - a_rfrgba.fB;
+			frgba.fA = fA - a_rfrgba.fA;
+			return frgba;
+		}
+
+		inline ColorFloatRGBA operator*(float a_f)
+		{
+			ColorFloatRGBA frgba;
+			frgba.fR = fR * a_f;
+			frgba.fG = fG * a_f;
+			frgba.fB = fB * a_f;
+			frgba.fA = fA;
+
+			return frgba;
+		}
+
+		inline ColorFloatRGBA ScaleRGB(float a_f)
+		{
+			ColorFloatRGBA frgba;
+			frgba.fR = a_f * fR;
+			frgba.fG = a_f * fG;
+			frgba.fB = a_f * fB;
+			frgba.fA = fA;
+
+			return frgba;
+		}
+
+		inline ColorFloatRGBA RoundRGB(void)
+		{
+			ColorFloatRGBA frgba;
+			frgba.fR = roundf(fR);
+			frgba.fG = roundf(fG);
+			frgba.fB = roundf(fB);
+
+			return frgba;
+		}
+
+		inline ColorFloatRGBA ToLinear()
+		{
+			ColorFloatRGBA frgbaLinear;
+			frgbaLinear.fR = LogToLinear(fR);
+			frgbaLinear.fG = LogToLinear(fG);
+			frgbaLinear.fB = LogToLinear(fB);
+			frgbaLinear.fA = fA;
+
+			return frgbaLinear;
+		}
+
+		inline ColorFloatRGBA ToLog(void)
+		{
+			ColorFloatRGBA frgbaLog;
+			frgbaLog.fR = LinearToLog(fR);
+			frgbaLog.fG = LinearToLog(fG);
+			frgbaLog.fB = LinearToLog(fB);
+			frgbaLog.fA = fA;
+
+			return frgbaLog;
+		}
+
+		inline static ColorFloatRGBA ConvertFromRGBA8(unsigned char a_ucR, 
+			unsigned char a_ucG, unsigned char a_ucB, unsigned char a_ucA)
+		{
+			ColorFloatRGBA frgba;
+
+			frgba.fR = (float)a_ucR / 255.0f;
+			frgba.fG = (float)a_ucG / 255.0f;
+			frgba.fB = (float)a_ucB / 255.0f;
+			frgba.fA = (float)a_ucA / 255.0f;
+
+			return frgba;
+		}
+
+		inline static ColorFloatRGBA ConvertFromRGB4(unsigned char a_ucR4,
+														unsigned char a_ucG4,
+														unsigned char a_ucB4)
+		{
+			ColorFloatRGBA frgba;
+
+			unsigned char ucR8 = (unsigned char)((a_ucR4 << 4) + a_ucR4);
+			unsigned char ucG8 = (unsigned char)((a_ucG4 << 4) + a_ucG4);
+			unsigned char ucB8 = (unsigned char)((a_ucB4 << 4) + a_ucB4);
+
+			frgba.fR = (float)ucR8 / 255.0f;
+			frgba.fG = (float)ucG8 / 255.0f;
+			frgba.fB = (float)ucB8 / 255.0f;
+			frgba.fA = 1.0f;
+
+			return frgba;
+		}
+
+		inline static ColorFloatRGBA ConvertFromRGB5(unsigned char a_ucR5,
+			unsigned char a_ucG5,
+			unsigned char a_ucB5)
+		{
+			ColorFloatRGBA frgba;
+
+			unsigned char ucR8 = (unsigned char)((a_ucR5 << 3) + (a_ucR5 >> 2));
+			unsigned char ucG8 = (unsigned char)((a_ucG5 << 3) + (a_ucG5 >> 2));
+			unsigned char ucB8 = (unsigned char)((a_ucB5 << 3) + (a_ucB5 >> 2));
+
+			frgba.fR = (float)ucR8 / 255.0f;
+			frgba.fG = (float)ucG8 / 255.0f;
+			frgba.fB = (float)ucB8 / 255.0f;
+			frgba.fA = 1.0f;
+
+			return frgba;
+		}
+
+		inline static ColorFloatRGBA ConvertFromR6G7B6(unsigned char a_ucR6,
+			unsigned char a_ucG7,
+			unsigned char a_ucB6)
+		{
+			ColorFloatRGBA frgba;
+
+			unsigned char ucR8 = (unsigned char)((a_ucR6 << 2) + (a_ucR6 >> 4));
+			unsigned char ucG8 = (unsigned char)((a_ucG7 << 1) + (a_ucG7 >> 6));
+			unsigned char ucB8 = (unsigned char)((a_ucB6 << 2) + (a_ucB6 >> 4));
+
+			frgba.fR = (float)ucR8 / 255.0f;
+			frgba.fG = (float)ucG8 / 255.0f;
+			frgba.fB = (float)ucB8 / 255.0f;
+			frgba.fA = 1.0f;
+
+			return frgba;
+		}
+
+		// quantize to 4 bits, expand to 8 bits
+		inline ColorFloatRGBA QuantizeR4G4B4(void) const
+		{
+			ColorFloatRGBA frgba = *this;
+
+			// quantize to 4 bits
+			frgba = frgba.ClampRGB().ScaleRGB(15.0f).RoundRGB();
+			unsigned int uiR4 = (unsigned int)frgba.fR;
+			unsigned int uiG4 = (unsigned int)frgba.fG;
+			unsigned int uiB4 = (unsigned int)frgba.fB;
+
+			// expand to 8 bits
+			frgba.fR = (float) ((uiR4 << 4) + uiR4);
+			frgba.fG = (float) ((uiG4 << 4) + uiG4);
+			frgba.fB = (float) ((uiB4 << 4) + uiB4);
+
+			frgba = frgba.ScaleRGB(1.0f/255.0f);
+
+			return frgba;
+		}
+
+		// quantize to 5 bits, expand to 8 bits
+		inline ColorFloatRGBA QuantizeR5G5B5(void) const
+		{
+			ColorFloatRGBA frgba = *this;
+
+			// quantize to 5 bits
+			frgba = frgba.ClampRGB().ScaleRGB(31.0f).RoundRGB();
+			unsigned int uiR5 = (unsigned int)frgba.fR;
+			unsigned int uiG5 = (unsigned int)frgba.fG;
+			unsigned int uiB5 = (unsigned int)frgba.fB;
+
+			// expand to 8 bits
+			frgba.fR = (float)((uiR5 << 3) + (uiR5 >> 2));
+			frgba.fG = (float)((uiG5 << 3) + (uiG5 >> 2));
+			frgba.fB = (float)((uiB5 << 3) + (uiB5 >> 2));
+
+			frgba = frgba.ScaleRGB(1.0f / 255.0f);
+
+			return frgba;
+		}
+
+		// quantize to 6/7/6 bits, expand to 8 bits
+		inline ColorFloatRGBA QuantizeR6G7B6(void) const
+		{
+			ColorFloatRGBA frgba = *this;
+
+			// quantize to 6/7/6 bits
+			ColorFloatRGBA frgba6 = frgba.ClampRGB().ScaleRGB(63.0f).RoundRGB();
+			ColorFloatRGBA frgba7 = frgba.ClampRGB().ScaleRGB(127.0f).RoundRGB();
+			unsigned int uiR6 = (unsigned int)frgba6.fR;
+			unsigned int uiG7 = (unsigned int)frgba7.fG;
+			unsigned int uiB6 = (unsigned int)frgba6.fB;
+
+			// expand to 8 bits
+			frgba.fR = (float)((uiR6 << 2) + (uiR6 >> 4));
+			frgba.fG = (float)((uiG7 << 1) + (uiG7 >> 6));
+			frgba.fB = (float)((uiB6 << 2) + (uiB6 >> 4));
+
+			frgba = frgba.ScaleRGB(1.0f / 255.0f);
+
+			return frgba;
+		}
+
+		inline ColorFloatRGBA ClampRGB(void)
+		{
+			ColorFloatRGBA frgba = *this;
+			if (frgba.fR < 0.0f) { frgba.fR = 0.0f; }
+			if (frgba.fR > 1.0f) { frgba.fR = 1.0f; }
+			if (frgba.fG < 0.0f) { frgba.fG = 0.0f; }
+			if (frgba.fG > 1.0f) { frgba.fG = 1.0f; }
+			if (frgba.fB < 0.0f) { frgba.fB = 0.0f; }
+			if (frgba.fB > 1.0f) { frgba.fB = 1.0f; }
+
+			return frgba;
+		}
+
+		inline ColorFloatRGBA ClampRGBA(void)
+		{
+			ColorFloatRGBA frgba = *this;
+			if (frgba.fR < 0.0f) { frgba.fR = 0.0f; }
+			if (frgba.fR > 1.0f) { frgba.fR = 1.0f; }
+			if (frgba.fG < 0.0f) { frgba.fG = 0.0f; }
+			if (frgba.fG > 1.0f) { frgba.fG = 1.0f; }
+			if (frgba.fB < 0.0f) { frgba.fB = 0.0f; }
+			if (frgba.fB > 1.0f) { frgba.fB = 1.0f; }
+			if (frgba.fA < 0.0f) { frgba.fA = 0.0f; }
+			if (frgba.fA > 1.0f) { frgba.fA = 1.0f; }
+
+			return frgba;
+		}
+
+		inline int IntRed(float a_fScale)
+		{
+			return (int)roundf(fR * a_fScale);
+		}
+
+		inline int IntGreen(float a_fScale)
+		{
+			return (int)roundf(fG * a_fScale);
+		}
+
+		inline int IntBlue(float a_fScale)
+		{
+			return (int)roundf(fB * a_fScale);
+		}
+
+		inline int IntAlpha(float a_fScale)
+		{
+			return (int)roundf(fA * a_fScale);
+		}
+
+		float	fR, fG, fB, fA;
+    };
+
+}
+

extern/EtcLib/Etc/EtcConfig.h

@@ -0,0 +1,67 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#ifdef _WIN32
+#define ETC_WINDOWS (1)
+#else
+#define ETC_WINDOWS (0)
+#endif
+
+#if __APPLE__
+#define ETC_OSX (1)
+#else
+#define ETC_OSX (0)
+#endif
+
+#if __unix__
+#define ETC_UNIX (1)
+#else
+#define ETC_UNIX (0)
+#endif
+
+
+// short names for common types
+#include <stdint.h>
+typedef int8_t i8;
+typedef int16_t i16;
+typedef int32_t i32;
+typedef int64_t i64;
+
+typedef uint8_t u8;
+typedef uint16_t u16;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+typedef float	f32;
+typedef double	f64;
+
+// Keep asserts enabled in release builds during development
+#undef NDEBUG
+
+// 0=disable. stb_image can be used if you need to compress 
+//other image formats like jpg
+#define USE_STB_IMAGE_LOAD 0	
+
+#if ETC_WINDOWS
+#include <SDKDDKVer.h>
+#define _CRT_SECURE_NO_WARNINGS (1)
+#include <tchar.h>
+#endif
+
+#include <stdio.h>
+

extern/EtcLib/Etc/EtcImage.cpp

@@ -0,0 +1,685 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+EtcImage.cpp
+
+Image is an array of 4x4 blocks that represent the encoding of the source image
+
+*/
+
+#include "EtcConfig.h"
+
+#include <stdlib.h>
+
+#include "EtcImage.h"
+
+#include "Etc.h"
+#include "EtcBlock4x4.h"
+#include "EtcBlock4x4EncodingBits.h"
+#include "EtcSortedBlockList.h"
+
+#if ETC_WINDOWS
+#include <windows.h>
+#endif
+#include <ctime>
+#include <chrono>
+#include <future>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+// fix conflict with Block4x4::AlphaMix
+#ifdef OPAQUE
+#undef OPAQUE
+#endif
+#ifdef TRANSPARENT
+#undef TRANSPARENT
+#endif
+
+namespace Etc
+{
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+	Image::Image(void)
+	{
+		m_encodingStatus = EncodingStatus::SUCCESS;
+		m_warningsToCapture = EncodingStatus::SUCCESS;
+		m_pafrgbaSource = nullptr;
+
+		m_pablock = nullptr;
+
+		m_encodingbitsformat = Block4x4EncodingBits::Format::UNKNOWN;
+		m_uiEncodingBitsBytes = 0;
+		m_paucEncodingBits = nullptr;
+
+		m_format = Format::UNKNOWN;
+		m_iNumOpaquePixels = 0;
+		m_iNumTranslucentPixels = 0;
+		m_iNumTransparentPixels = 0;
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// constructor using source image
+	// used to set state before Encode() is called
+	//
+    Image::Image(float *a_pafSourceRGBA, unsigned int a_uiSourceWidth,
+					unsigned int a_uiSourceHeight, 
+					ErrorMetric a_errormetric)
+	{
+		m_encodingStatus = EncodingStatus::SUCCESS;
+		m_warningsToCapture = EncodingStatus::SUCCESS;
+        m_pafrgbaSource = (ColorFloatRGBA *) a_pafSourceRGBA;
+		m_uiSourceWidth = a_uiSourceWidth;
+		m_uiSourceHeight = a_uiSourceHeight;
+
+		m_uiExtendedWidth = CalcExtendedDimension((unsigned short)m_uiSourceWidth);
+		m_uiExtendedHeight = CalcExtendedDimension((unsigned short)m_uiSourceHeight);
+
+		m_uiBlockColumns = m_uiExtendedWidth >> 2;
+		m_uiBlockRows = m_uiExtendedHeight >> 2;
+
+		m_pablock = new Block4x4[GetNumberOfBlocks()];
+		assert(m_pablock);
+
+		m_format = Format::UNKNOWN;
+
+		m_encodingbitsformat = Block4x4EncodingBits::Format::UNKNOWN;
+		m_uiEncodingBitsBytes = 0;
+		m_paucEncodingBits = nullptr;
+
+		m_errormetric = a_errormetric;
+		m_fEffort = 0.0f;
+
+		m_iEncodeTime_ms = -1;
+
+		m_iNumOpaquePixels = 0;
+		m_iNumTranslucentPixels = 0;
+		m_iNumTransparentPixels = 0;
+		m_bVerboseOutput = false;
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// constructor using encoding bits
+	// recreates encoding state using a previously encoded image
+	//
+	Image::Image(Format a_format,
+					unsigned int a_uiSourceWidth, unsigned int a_uiSourceHeight,
+					unsigned char *a_paucEncidingBits, unsigned int a_uiEncodingBitsBytes,
+					Image *a_pimageSource, ErrorMetric a_errormetric)
+	{
+		m_encodingStatus = EncodingStatus::SUCCESS;
+		m_pafrgbaSource = nullptr;
+		m_uiSourceWidth = a_uiSourceWidth;
+		m_uiSourceHeight = a_uiSourceHeight;
+
+		m_uiExtendedWidth = CalcExtendedDimension((unsigned short)m_uiSourceWidth);
+		m_uiExtendedHeight = CalcExtendedDimension((unsigned short)m_uiSourceHeight);
+
+		m_uiBlockColumns = m_uiExtendedWidth >> 2;
+		m_uiBlockRows = m_uiExtendedHeight >> 2;
+
+		unsigned int uiBlocks = GetNumberOfBlocks();
+
+		m_pablock = new Block4x4[uiBlocks];
+		assert(m_pablock);
+
+		m_format = a_format;
+
+		m_iNumOpaquePixels = 0;
+		m_iNumTranslucentPixels = 0;
+		m_iNumTransparentPixels = 0;
+		
+		m_encodingbitsformat = DetermineEncodingBitsFormat(m_format);
+		if (m_encodingbitsformat == Block4x4EncodingBits::Format::UNKNOWN)
+		{
+			AddToEncodingStatus(ERROR_UNKNOWN_FORMAT);
+			return;
+		}
+		m_uiEncodingBitsBytes = a_uiEncodingBitsBytes;
+		m_paucEncodingBits = a_paucEncidingBits;
+
+		m_errormetric = a_errormetric;
+		m_fEffort = 0.0f;
+		m_bVerboseOutput = false;
+		m_iEncodeTime_ms = -1;
+		
+		unsigned char *paucEncodingBits = m_paucEncodingBits;
+		unsigned int uiEncodingBitsBytesPerBlock = Block4x4EncodingBits::GetBytesPerBlock(m_encodingbitsformat);
+
+		unsigned int uiH = 0;
+		unsigned int uiV = 0;
+		for (unsigned int uiBlock = 0; uiBlock < uiBlocks; uiBlock++)
+		{
+			m_pablock[uiBlock].InitFromEtcEncodingBits(a_format, uiH, uiV, paucEncodingBits, 
+														a_pimageSource, a_errormetric);
+			paucEncodingBits += uiEncodingBitsBytesPerBlock;
+			uiH += 4;
+			if (uiH >= m_uiSourceWidth)
+			{
+				uiH = 0;
+				uiV += 4;
+			}
+		}
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+	Image::~Image(void)
+	{
+		if (m_pablock != nullptr)
+		{
+			delete[] m_pablock;
+			m_pablock = nullptr;
+		}
+
+		/*if (m_paucEncodingBits != nullptr)
+		{
+			delete[] m_paucEncodingBits;
+			m_paucEncodingBits = nullptr;
+		}*/
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// encode an image
+	// create a set of encoding bits that conforms to a_format
+	// find best fit using a_errormetric
+	// explore a range of possible encodings based on a_fEffort (range = [0:100])
+	// speed up process using a_uiJobs as the number of process threads (a_uiJobs must not excede a_uiMaxJobs)
+	//
+	Image::EncodingStatus Image::Encode(Format a_format, ErrorMetric a_errormetric, float a_fEffort, unsigned int a_uiJobs, unsigned int a_uiMaxJobs)
+	{
+
+		auto start = std::chrono::steady_clock::now();
+		
+		m_encodingStatus = EncodingStatus::SUCCESS;
+
+		m_format = a_format;
+		m_errormetric = a_errormetric;
+		m_fEffort = a_fEffort;
+
+		if (m_errormetric < 0 || m_errormetric > ERROR_METRICS)
+		{
+			AddToEncodingStatus(ERROR_UNKNOWN_ERROR_METRIC);
+			return m_encodingStatus;
+		}
+
+		if (m_fEffort < ETCCOMP_MIN_EFFORT_LEVEL)
+		{
+			AddToEncodingStatus(WARNING_EFFORT_OUT_OF_RANGE);
+			m_fEffort = ETCCOMP_MIN_EFFORT_LEVEL;
+		}
+		else if (m_fEffort > ETCCOMP_MAX_EFFORT_LEVEL)
+		{
+			AddToEncodingStatus(WARNING_EFFORT_OUT_OF_RANGE);
+			m_fEffort = ETCCOMP_MAX_EFFORT_LEVEL;
+		}
+		if (a_uiJobs < 1)
+		{
+			a_uiJobs = 1;
+			AddToEncodingStatus(WARNING_JOBS_OUT_OF_RANGE);
+		}
+		else if (a_uiJobs > a_uiMaxJobs)
+		{
+			a_uiJobs = a_uiMaxJobs;
+			AddToEncodingStatus(WARNING_JOBS_OUT_OF_RANGE);
+		}
+
+		m_encodingbitsformat = DetermineEncodingBitsFormat(m_format);
+
+		if (m_encodingbitsformat == Block4x4EncodingBits::Format::UNKNOWN)
+		{
+			AddToEncodingStatus(ERROR_UNKNOWN_FORMAT);
+			return m_encodingStatus;
+		}
+
+		assert(m_paucEncodingBits == nullptr);
+		m_uiEncodingBitsBytes = GetNumberOfBlocks() * Block4x4EncodingBits::GetBytesPerBlock(m_encodingbitsformat);
+		m_paucEncodingBits = new unsigned char[m_uiEncodingBitsBytes];
+
+		InitBlocksAndBlockSorter();
+
+
+		std::future<void> *handle = new std::future<void>[a_uiMaxJobs];
+
+		unsigned int uiNumThreadsNeeded = 0;
+		unsigned int uiUnfinishedBlocks = GetNumberOfBlocks();
+
+		uiNumThreadsNeeded = (uiUnfinishedBlocks < a_uiJobs) ? uiUnfinishedBlocks : a_uiJobs;
+			
+		for (int i = 0; i < (int)uiNumThreadsNeeded - 1; i++)
+		{
+			handle[i] = async(std::launch::async, &Image::RunFirstPass, this, i, uiNumThreadsNeeded);
+		}
+
+		RunFirstPass(uiNumThreadsNeeded - 1, uiNumThreadsNeeded);
+
+		for (int i = 0; i < (int)uiNumThreadsNeeded - 1; i++)
+		{
+			handle[i].get();
+		}
+
+		// perform effort-based encoding
+		if (m_fEffort > ETCCOMP_MIN_EFFORT_LEVEL)
+		{
+			unsigned int uiFinishedBlocks = 0;
+			unsigned int uiTotalEffortBlocks = static_cast<unsigned int>(roundf(0.01f * m_fEffort  * GetNumberOfBlocks()));
+
+			if (m_bVerboseOutput)
+			{
+				printf("effortblocks = %d\n", uiTotalEffortBlocks);
+			}
+			unsigned int uiPass = 0;
+			while (1)
+			{
+				if (m_bVerboseOutput)
+				{
+					uiPass++;
+					printf("pass %u\n", uiPass);
+				}
+				m_psortedblocklist->Sort();
+				uiUnfinishedBlocks = m_psortedblocklist->GetNumberOfSortedBlocks();
+				uiFinishedBlocks = GetNumberOfBlocks() - uiUnfinishedBlocks;
+				if (m_bVerboseOutput)
+				{
+					printf("    %u unfinished blocks\n", uiUnfinishedBlocks);
+					// m_psortedblocklist->Print();
+				}
+
+				
+
+				//stop enocding when we did enough to satify the effort percentage
+				if (uiFinishedBlocks >= uiTotalEffortBlocks)
+				{
+					if (m_bVerboseOutput)
+					{
+						printf("Finished %d Blocks out of %d\n", uiFinishedBlocks, uiTotalEffortBlocks);
+					}
+					break;
+				}
+
+				unsigned int uiIteratedBlocks = 0;
+				unsigned int blocksToIterateThisPass = (uiTotalEffortBlocks - uiFinishedBlocks);
+				uiNumThreadsNeeded = (uiUnfinishedBlocks < a_uiJobs) ? uiUnfinishedBlocks : a_uiJobs;
+
+				if (uiNumThreadsNeeded <= 1)
+				{
+					//since we already how many blocks each thread will process
+					//cap the thread limit to do the proper amount of work, and not more
+					uiIteratedBlocks = IterateThroughWorstBlocks(blocksToIterateThisPass, 0, 1);
+				}
+				else
+				{
+					//we have a lot of work to do, so lets multi thread it
+					std::future<unsigned int> *handleToBlockEncoders = new std::future<unsigned int>[uiNumThreadsNeeded-1];
+
+					for (int i = 0; i < (int)uiNumThreadsNeeded - 1; i++)
+					{
+						handleToBlockEncoders[i] = async(std::launch::async, &Image::IterateThroughWorstBlocks, this, blocksToIterateThisPass, i, uiNumThreadsNeeded);
+					}
+					uiIteratedBlocks = IterateThroughWorstBlocks(blocksToIterateThisPass, uiNumThreadsNeeded - 1, uiNumThreadsNeeded);
+
+					for (int i = 0; i < (int)uiNumThreadsNeeded - 1; i++)
+					{
+						uiIteratedBlocks += handleToBlockEncoders[i].get();
+					}
+
+					delete[] handleToBlockEncoders;
+				}
+
+				if (m_bVerboseOutput)
+				{
+					printf("    %u iterated blocks\n", uiIteratedBlocks);
+				}
+			}
+		}
+
+		// generate Etc2-compatible bit-format 4x4 blocks
+		for (int i = 0; i < (int)a_uiJobs - 1; i++)
+		{
+			handle[i] = async(std::launch::async, &Image::SetEncodingBits, this, i, a_uiJobs);
+		}
+		SetEncodingBits(a_uiJobs - 1, a_uiJobs);
+
+		for (int i = 0; i < (int)a_uiJobs - 1; i++)
+		{
+			handle[i].get();
+		}
+
+		auto end = std::chrono::steady_clock::now();
+		std::chrono::milliseconds elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
+		m_iEncodeTime_ms = (int)elapsed.count();
+
+		delete[] handle;
+		delete m_psortedblocklist;
+		return m_encodingStatus;
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// iterate the encoding thru the blocks with the worst error
+	// stop when a_uiMaxBlocks blocks have been iterated
+	// split the blocks between the process threads using a_uiMultithreadingOffset and a_uiMultithreadingStride
+	//
+	unsigned int Image::IterateThroughWorstBlocks(unsigned int a_uiMaxBlocks, 
+													unsigned int a_uiMultithreadingOffset, 
+													unsigned int a_uiMultithreadingStride)
+	{
+		assert(a_uiMultithreadingStride > 0);
+		unsigned int uiIteratedBlocks = a_uiMultithreadingOffset;
+
+		SortedBlockList::Link *plink = m_psortedblocklist->GetLinkToFirstBlock();
+		for (plink = plink->Advance(a_uiMultithreadingOffset);
+				plink != nullptr;
+				plink = plink->Advance(a_uiMultithreadingStride) )
+		{
+			if (uiIteratedBlocks >= a_uiMaxBlocks)
+			{
+				break;
+			}
+
+			plink->GetBlock()->PerformEncodingIteration(m_fEffort);
+
+			uiIteratedBlocks += a_uiMultithreadingStride;	
+		}
+
+		return uiIteratedBlocks;
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// determine which warnings to check for during Encode() based on encoding format
+	//
+	void Image::FindEncodingWarningTypesForCurFormat()
+	{
+		TrackEncodingWarning(WARNING_ALL_TRANSPARENT_PIXELS);
+		TrackEncodingWarning(WARNING_SOME_RGBA_NOT_0_TO_1);
+		switch (m_format)
+		{
+		case Image::Format::ETC1:
+		case Image::Format::RGB8:
+		case Image::Format::SRGB8:
+			TrackEncodingWarning(WARNING_SOME_NON_OPAQUE_PIXELS);
+			TrackEncodingWarning(WARNING_SOME_TRANSLUCENT_PIXELS);
+			break;
+
+		case Image::Format::RGB8A1:
+		case Image::Format::SRGB8A1:
+			TrackEncodingWarning(WARNING_SOME_TRANSLUCENT_PIXELS);
+			TrackEncodingWarning(WARNING_ALL_OPAQUE_PIXELS);
+			break;
+		case Image::Format::RGBA8:
+		case Image::Format::SRGBA8:
+			TrackEncodingWarning(WARNING_ALL_OPAQUE_PIXELS);
+			break;
+
+		case Image::Format::R11:
+		case Image::Format::SIGNED_R11:
+			TrackEncodingWarning(WARNING_SOME_NON_OPAQUE_PIXELS);
+			TrackEncodingWarning(WARNING_SOME_TRANSLUCENT_PIXELS);
+			TrackEncodingWarning(WARNING_SOME_GREEN_VALUES_ARE_NOT_ZERO);
+			TrackEncodingWarning(WARNING_SOME_BLUE_VALUES_ARE_NOT_ZERO);
+			break;
+
+		case Image::Format::RG11:
+		case Image::Format::SIGNED_RG11:
+			TrackEncodingWarning(WARNING_SOME_NON_OPAQUE_PIXELS);
+			TrackEncodingWarning(WARNING_SOME_TRANSLUCENT_PIXELS);
+			TrackEncodingWarning(WARNING_SOME_BLUE_VALUES_ARE_NOT_ZERO);
+			break;
+		case Image::Format::FORMATS:
+		case Image::Format::UNKNOWN:
+		default:
+			assert(0);
+			break;
+		}
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// examine source pixels to check for warnings
+	//
+	void Image::FindAndSetEncodingWarnings()
+	{
+		int numPixels = (m_uiBlockRows * 4) * (m_uiBlockColumns * 4);
+		if (m_iNumOpaquePixels == numPixels)
+		{
+			AddToEncodingStatusIfSignfigant(Image::EncodingStatus::WARNING_ALL_OPAQUE_PIXELS);
+		}
+		if (m_iNumOpaquePixels < numPixels)
+		{
+			AddToEncodingStatusIfSignfigant(Image::EncodingStatus::WARNING_SOME_NON_OPAQUE_PIXELS);
+		}
+		if (m_iNumTranslucentPixels > 0)
+		{
+			AddToEncodingStatusIfSignfigant(Image::EncodingStatus::WARNING_SOME_TRANSLUCENT_PIXELS);
+		}
+		if (m_iNumTransparentPixels == numPixels)
+		{
+			AddToEncodingStatusIfSignfigant(Image::EncodingStatus::WARNING_ALL_TRANSPARENT_PIXELS);
+		}
+		if (m_numColorValues.fB > 0.0f)
+		{
+			AddToEncodingStatusIfSignfigant(Image::EncodingStatus::WARNING_SOME_BLUE_VALUES_ARE_NOT_ZERO);
+		}
+		if (m_numColorValues.fG > 0.0f) 
+		{
+			AddToEncodingStatusIfSignfigant(Image::EncodingStatus::WARNING_SOME_GREEN_VALUES_ARE_NOT_ZERO);
+		}
+
+		if (m_numOutOfRangeValues.fR > 0.0f || m_numOutOfRangeValues.fG > 0.0f)
+		{
+			AddToEncodingStatusIfSignfigant(Image::EncodingStatus::WARNING_SOME_RGBA_NOT_0_TO_1);
+		}
+		if (m_numOutOfRangeValues.fB > 0.0f || m_numOutOfRangeValues.fA > 0.0f)
+		{
+			AddToEncodingStatusIfSignfigant(Image::EncodingStatus::WARNING_SOME_RGBA_NOT_0_TO_1);
+		}
+	}
+	
+	// ----------------------------------------------------------------------------------------------------
+	// return a string name for a given image format
+	//
+	const char * Image::EncodingFormatToString(Image::Format a_format)
+	{
+		switch (a_format)
+		{
+		case Image::Format::ETC1:
+			return "ETC1";
+		case Image::Format::RGB8:
+			return "RGB8";
+		case Image::Format::SRGB8:
+			return "SRGB8";
+
+		case Image::Format::RGB8A1:
+			return "RGB8A1";
+		case Image::Format::SRGB8A1:
+			return "SRGB8A1";
+		case Image::Format::RGBA8:
+			return "RGBA8";
+		case Image::Format::SRGBA8:
+			return "SRGBA8";
+
+		case Image::Format::R11:
+			return "R11";
+		case Image::Format::SIGNED_R11:
+			return "SIGNED_R11";
+
+		case Image::Format::RG11:
+			return "RG11";
+		case Image::Format::SIGNED_RG11:
+			return "SIGNED_RG11";
+		case Image::Format::FORMATS:
+		case Image::Format::UNKNOWN:
+		default:
+			return "UNKNOWN";
+		}
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// return a string name for the image's format
+	//
+	const char * Image::EncodingFormatToString(void)
+	{
+		return EncodingFormatToString(m_format);
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// init image blocks prior to encoding
+	// init block sorter for subsequent sortings
+	// check for encoding warnings
+	//
+	void Image::InitBlocksAndBlockSorter(void)
+	{
+		
+		FindEncodingWarningTypesForCurFormat();
+
+		// init each block
+		Block4x4 *pblock = m_pablock;
+		unsigned char *paucEncodingBits = m_paucEncodingBits;
+		for (unsigned int uiBlockRow = 0; uiBlockRow < m_uiBlockRows; uiBlockRow++)
+		{
+			unsigned int uiBlockV = uiBlockRow * 4;
+
+			for (unsigned int uiBlockColumn = 0; uiBlockColumn < m_uiBlockColumns; uiBlockColumn++)
+			{
+				unsigned int uiBlockH = uiBlockColumn * 4;
+
+				pblock->InitFromSource(this, uiBlockH, uiBlockV, paucEncodingBits, m_errormetric);
+
+				paucEncodingBits += Block4x4EncodingBits::GetBytesPerBlock(m_encodingbitsformat);
+
+				pblock++;
+			}
+		}
+
+		FindAndSetEncodingWarnings();
+
+		// init block sorter
+		{
+			m_psortedblocklist = new SortedBlockList(GetNumberOfBlocks(), 100);
+
+			for (unsigned int uiBlock = 0; uiBlock < GetNumberOfBlocks(); uiBlock++)
+			{
+				pblock = &m_pablock[uiBlock];
+				m_psortedblocklist->AddBlock(pblock);
+			}
+		}
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// run the first pass of the encoder
+	// the encoder generally finds a reasonable, fast encoding
+	// this is run on all blocks regardless of effort to ensure that all blocks have a valid encoding
+	//
+	void Image::RunFirstPass(unsigned int a_uiMultithreadingOffset, unsigned int a_uiMultithreadingStride)
+	{
+		assert(a_uiMultithreadingStride > 0);
+
+		for (unsigned int uiBlock = a_uiMultithreadingOffset;
+				uiBlock < GetNumberOfBlocks(); 
+				uiBlock += a_uiMultithreadingStride)
+		{
+			Block4x4 *pblock = &m_pablock[uiBlock];
+			pblock->PerformEncodingIteration(m_fEffort);
+		}
+	}
+
+    // ----------------------------------------------------------------------------------------------------
+	// set the encoding bits (for the output file) based on the best encoding for each block
+	//
+	void Image::SetEncodingBits(unsigned int a_uiMultithreadingOffset,
+								unsigned int a_uiMultithreadingStride)
+	{
+		assert(a_uiMultithreadingStride > 0);
+
+		for (unsigned int uiBlock = a_uiMultithreadingOffset; 
+				uiBlock < GetNumberOfBlocks(); 
+				uiBlock += a_uiMultithreadingStride)
+		{
+			Block4x4 *pblock = &m_pablock[uiBlock];
+			pblock->SetEncodingBitsFromEncoding();
+		}
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// return the image error
+	// image error is the sum of all block errors
+	//
+	float Image::GetError(void)
+	{
+		float fError = 0.0f;
+
+		for (unsigned int uiBlock = 0; uiBlock < GetNumberOfBlocks(); uiBlock++)
+		{
+			Block4x4 *pblock = &m_pablock[uiBlock];
+			fError += pblock->GetError();
+		}
+
+		return fError;
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// determine the encoding bits format based on the encoding format
+	// the encoding bits format is a family of bit encodings that are shared across various encoding formats
+	//
+	Block4x4EncodingBits::Format Image::DetermineEncodingBitsFormat(Format a_format)
+	{
+		Block4x4EncodingBits::Format encodingbitsformat;
+
+		// determine encoding bits format from image format
+		switch (a_format)
+		{
+		case Format::ETC1:
+		case Format::RGB8:
+		case Format::SRGB8:
+			encodingbitsformat = Block4x4EncodingBits::Format::RGB8;
+			break;
+
+		case Format::RGBA8:
+		case Format::SRGBA8:
+			encodingbitsformat = Block4x4EncodingBits::Format::RGBA8;
+			break;
+
+		case Format::R11:
+		case Format::SIGNED_R11:
+			encodingbitsformat = Block4x4EncodingBits::Format::R11;
+			break;
+
+		case Format::RG11:
+		case Format::SIGNED_RG11:
+			encodingbitsformat = Block4x4EncodingBits::Format::RG11;
+			break;
+
+		case Format::RGB8A1:
+		case Format::SRGB8A1:
+			encodingbitsformat = Block4x4EncodingBits::Format::RGB8A1;
+			break;
+
+		default:
+			encodingbitsformat = Block4x4EncodingBits::Format::UNKNOWN;
+			break;
+		}
+
+		return encodingbitsformat;
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+
+}	// namespace Etc

extern/EtcLib/Etc/EtcImage.h

@@ -0,0 +1,249 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+//#include "Etc.h"
+#include "EtcColorFloatRGBA.h"
+#include "EtcBlock4x4EncodingBits.h"
+#include "EtcErrorMetric.h"
+
+
+namespace Etc
+{
+	class Block4x4;
+	class EncoderSpec;
+	class SortedBlockList;
+
+    class Image
+    {
+    public:
+
+		//the differnt warning and errors that can come up during encoding
+		enum  EncodingStatus
+		{
+			SUCCESS = 0,
+			//
+			WARNING_THRESHOLD = 1 << 0,
+			//
+			WARNING_EFFORT_OUT_OF_RANGE = 1 << 1,
+			WARNING_JOBS_OUT_OF_RANGE = 1 << 2,
+			WARNING_SOME_NON_OPAQUE_PIXELS = 1 << 3,//just for opaque formats, etc1, rgb8, r11, rg11
+			WARNING_ALL_OPAQUE_PIXELS = 1 << 4,
+			WARNING_ALL_TRANSPARENT_PIXELS = 1 << 5,
+			WARNING_SOME_TRANSLUCENT_PIXELS = 1 << 6,//just for rgb8A1
+			WARNING_SOME_RGBA_NOT_0_TO_1 = 1 << 7,
+			WARNING_SOME_BLUE_VALUES_ARE_NOT_ZERO = 1 << 8,
+			WARNING_SOME_GREEN_VALUES_ARE_NOT_ZERO = 1 << 9,
+			//
+			ERROR_THRESHOLD = 1 << 16,
+			//
+			ERROR_UNKNOWN_FORMAT = 1 << 17,
+			ERROR_UNKNOWN_ERROR_METRIC = 1 << 18,
+			ERROR_ZERO_WIDTH_OR_HEIGHT = 1 << 19,
+			//
+		};
+		
+		enum class Format
+		{
+			UNKNOWN,
+			//
+			ETC1,
+			//
+			// ETC2 formats
+			RGB8,
+			SRGB8,
+			RGBA8,
+			SRGBA8,
+			R11,
+			SIGNED_R11,
+			RG11,
+			SIGNED_RG11,
+			RGB8A1,
+			SRGB8A1,
+			//
+			FORMATS,
+			//
+			DEFAULT = SRGB8
+		};
+
+		// constructor using source image
+        Image(float *a_pafSourceRGBA, unsigned int a_uiSourceWidth,
+				unsigned int a_uiSourceHeight,
+				ErrorMetric a_errormetric);
+
+		// constructor using encoding bits
+		Image(Format a_format, 
+				unsigned int a_uiSourceWidth, unsigned int a_uiSourceHeight,
+				unsigned char *a_paucEncidingBits, unsigned int a_uiEncodingBitsBytes,
+				Image *a_pimageSource,
+				ErrorMetric a_errormetric);
+
+		~Image(void);
+
+		EncodingStatus Encode(Format a_format, ErrorMetric a_errormetric, float a_fEffort, 
+			unsigned int a_uiJobs, unsigned int a_uiMaxJobs);
+
+		inline void AddToEncodingStatus(EncodingStatus a_encStatus)
+		{
+			m_encodingStatus = (EncodingStatus)((unsigned int)m_encodingStatus | (unsigned int)a_encStatus);
+		}
+		
+		inline unsigned int GetSourceWidth(void)
+		{
+			return m_uiSourceWidth;
+		}
+
+		inline unsigned int GetSourceHeight(void)
+		{
+			return m_uiSourceHeight;
+		}
+
+		inline unsigned int GetExtendedWidth(void)
+		{
+			return m_uiExtendedWidth;
+		}
+
+		inline unsigned int GetExtendedHeight(void)
+		{
+			return m_uiExtendedHeight;
+		}
+
+		inline unsigned int GetNumberOfBlocks()
+		{
+			return m_uiBlockColumns * m_uiBlockRows;
+		}
+
+		inline Block4x4 * GetBlocks()
+		{
+			return m_pablock;
+		}
+
+		inline unsigned char * GetEncodingBits(void)
+		{
+			return m_paucEncodingBits;
+		}
+
+		inline unsigned int GetEncodingBitsBytes(void)
+		{
+			return m_uiEncodingBitsBytes;
+		}
+
+		inline int GetEncodingTimeMs(void)
+		{
+			return m_iEncodeTime_ms;
+		}
+
+		float GetError(void);
+
+        inline ColorFloatRGBA * GetSourcePixel(unsigned int a_uiH, unsigned int a_uiV)
+		{
+			if (a_uiH >= m_uiSourceWidth || a_uiV >= m_uiSourceHeight)
+			{
+				return nullptr;
+			}
+
+			return &m_pafrgbaSource[a_uiV*m_uiSourceWidth + a_uiH];
+		}
+
+		inline Format GetFormat(void)
+		{
+			return m_format;
+		}
+
+		static Block4x4EncodingBits::Format DetermineEncodingBitsFormat(Format a_format);
+
+		inline static unsigned short CalcExtendedDimension(unsigned short a_ushOriginalDimension)
+		{
+			return (unsigned short)((a_ushOriginalDimension + 3) & ~3);
+		}
+
+		inline ErrorMetric GetErrorMetric(void)
+		{
+			return m_errormetric;
+		}
+
+		static const char * EncodingFormatToString(Image::Format a_format);
+		const char * EncodingFormatToString(void);
+		//used to get basic information about the image data
+		int m_iNumOpaquePixels;
+		int m_iNumTranslucentPixels;
+		int m_iNumTransparentPixels;
+
+		ColorFloatRGBA m_numColorValues;
+		ColorFloatRGBA m_numOutOfRangeValues;
+
+		bool m_bVerboseOutput;
+	private:
+		//add a warning or error to check for while encoding
+		inline void TrackEncodingWarning(EncodingStatus a_encStatus)
+		{
+			m_warningsToCapture = (EncodingStatus)((unsigned int)m_warningsToCapture | (unsigned int)a_encStatus);
+		}
+
+		//report the warning if it is something we care about for this encoding
+		inline void AddToEncodingStatusIfSignfigant(EncodingStatus a_encStatus)
+		{
+			if ((EncodingStatus)((unsigned int)m_warningsToCapture & (unsigned int)a_encStatus) == a_encStatus)
+			{
+				AddToEncodingStatus(a_encStatus);
+			}
+		}
+
+		Image(void);
+		void FindEncodingWarningTypesForCurFormat();
+		void FindAndSetEncodingWarnings();
+
+		void InitBlocksAndBlockSorter(void);
+
+		void RunFirstPass(unsigned int a_uiMultithreadingOffset, 
+							unsigned int a_uiMultithreadingStride);
+
+		void SetEncodingBits(unsigned int a_uiMultithreadingOffset,
+								unsigned int a_uiMultithreadingStride);
+
+		unsigned int IterateThroughWorstBlocks(unsigned int a_uiMaxBlocks,
+												unsigned int a_uiMultithreadingOffset,
+												unsigned int a_uiMultithreadingStride);
+
+		// inputs
+        ColorFloatRGBA *m_pafrgbaSource;
+		unsigned int m_uiSourceWidth;
+		unsigned int m_uiSourceHeight;
+		unsigned int m_uiExtendedWidth;
+		unsigned int m_uiExtendedHeight;
+		unsigned int m_uiBlockColumns;
+		unsigned int m_uiBlockRows;
+		// intermediate data
+		Block4x4 *m_pablock;
+		// encoding
+		Format m_format;
+		Block4x4EncodingBits::Format m_encodingbitsformat;
+		unsigned int m_uiEncodingBitsBytes;		// for entire image
+		unsigned char *m_paucEncodingBits;
+		ErrorMetric m_errormetric;
+		float m_fEffort;
+		// stats
+		int m_iEncodeTime_ms;
+		
+		SortedBlockList *m_psortedblocklist;
+		//this will hold any warning or errors that happen during encoding
+		EncodingStatus m_encodingStatus;
+		//these will be the warnings we are tracking
+		EncodingStatus m_warningsToCapture;
+	};
+
+} // namespace Etc

extern/EtcLib/Etc/EtcMath.cpp

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "EtcConfig.h"
+#include "EtcMath.h"
+
+namespace Etc
+{
+
+	// ----------------------------------------------------------------------------------------------------
+	// calculate the line that best fits the set of XY points contained in a_afX[] and a_afY[]
+	// use a_fSlope and a_fOffset to define that line
+	//
+	bool Regression(float a_afX[], float a_afY[], unsigned int a_Points,
+					float *a_fSlope, float *a_fOffset)
+	{
+		float fPoints = (float)a_Points;
+
+		float fSumX = 0.0f;
+		float fSumY = 0.0f;
+		float fSumXY = 0.0f;
+		float fSumX2 = 0.0f;
+
+		for (unsigned int uiPoint = 0; uiPoint < a_Points; uiPoint++)
+		{
+			fSumX += a_afX[uiPoint];
+			fSumY += a_afY[uiPoint];
+			fSumXY += a_afX[uiPoint] * a_afY[uiPoint];
+			fSumX2 += a_afX[uiPoint] * a_afX[uiPoint];
+		}
+
+		float fDivisor = fPoints*fSumX2 - fSumX*fSumX;
+
+		// if vertical line
+		if (fDivisor == 0.0f)
+		{
+			*a_fSlope = 0.0f;
+			*a_fOffset = 0.0f;
+			return true;
+		}
+
+		*a_fSlope = (fPoints*fSumXY - fSumX*fSumY) / fDivisor;
+		*a_fOffset = (fSumY - (*a_fSlope)*fSumX) / fPoints;
+
+		return false;
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+
+} // namespace Etc

extern/EtcLib/Etc/EtcMath.h

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <math.h>
+
+namespace Etc
+{
+
+	// ----------------------------------------------------------------------------------------------------
+	// return true if vertical line
+	bool Regression(float a_afX[], float a_afY[], unsigned int a_Points,
+					float *a_fSlope, float *a_fOffset);
+
+	inline float ConvertMSEToPSNR(float a_fMSE)
+	{
+		if (a_fMSE == 0.0f)
+		{
+			return INFINITY;
+		}
+
+		return 10.0f * log10f(1.0f / a_fMSE);
+	}
+
+
+}

extern/EtcLib/EtcCodec/EtcBlock4x4.cpp

@@ -0,0 +1,417 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* 
+EtcBlock4x4.cpp
+
+Implements the state associated with each 4x4 block of pixels in an image
+
+Source images that are not a multiple of 4x4 are extended to fill the Block4x4 using pixels with an 
+alpha of NAN
+
+*/
+
+#include "EtcConfig.h"
+#include "EtcBlock4x4.h"
+
+#include "EtcBlock4x4EncodingBits.h"
+#include "EtcColor.h"
+#include "EtcImage.h"
+#include "EtcColorFloatRGBA.h"
+#include "EtcBlock4x4Encoding_RGB8.h"
+#include "EtcBlock4x4Encoding_RGBA8.h"
+#include "EtcBlock4x4Encoding_RGB8A1.h"
+#include "EtcBlock4x4Encoding_R11.h"
+#include "EtcBlock4x4Encoding_RG11.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+namespace Etc
+{
+	// ETC pixels are scanned vertically.  
+	// this mapping is for when someone wants to scan the ETC pixels horizontally
+	const unsigned int Block4x4::s_auiPixelOrderHScan[PIXELS] = { 0, 4, 8, 12, 1, 5, 9, 13, 2, 6, 10, 14, 3, 7, 11, 15 };
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+	Block4x4::Block4x4(void)
+	{
+		m_pimageSource = nullptr;
+		m_uiSourceH = 0;
+		m_uiSourceV = 0;
+
+		m_sourcealphamix = SourceAlphaMix::UNKNOWN;
+		m_boolBorderPixels = false;
+		m_boolPunchThroughPixels = false;
+
+		m_pencoding = nullptr;
+
+		m_errormetric = ErrorMetric::NUMERIC;
+
+	}
+	Block4x4::~Block4x4()
+	{
+		m_pimageSource = nullptr;
+		if (m_pencoding)
+		{
+			delete m_pencoding;
+			m_pencoding = nullptr;
+		}
+	}
+	// ----------------------------------------------------------------------------------------------------
+	// initialization prior to encoding from a source image
+	// [a_uiSourceH,a_uiSourceV] is the location of the block in a_pimageSource
+	// a_paucEncodingBits is the place to store the final encoding
+	// a_errormetric is used for finding the best encoding
+	//
+	void Block4x4::InitFromSource(Image *a_pimageSource, 
+									unsigned int a_uiSourceH, unsigned int a_uiSourceV,
+									unsigned char *a_paucEncodingBits,
+									ErrorMetric a_errormetric)
+	{
+
+		Block4x4();
+
+		m_pimageSource = a_pimageSource;
+		m_uiSourceH = a_uiSourceH;
+		m_uiSourceV = a_uiSourceV;
+		m_errormetric = a_errormetric;
+
+		SetSourcePixels();
+
+		// set block encoder function
+		switch (m_pimageSource->GetFormat())
+		{
+		case Image::Format::ETC1:
+			m_pencoding = new Block4x4Encoding_ETC1;
+			break;
+
+		case Image::Format::RGB8:
+		case Image::Format::SRGB8:
+			m_pencoding = new Block4x4Encoding_RGB8;
+			break;
+
+		case Image::Format::RGBA8:
+		case Image::Format::SRGBA8:
+			switch (m_sourcealphamix)
+			{
+			case SourceAlphaMix::OPAQUE:
+				m_pencoding = new Block4x4Encoding_RGBA8_Opaque;
+				break;
+
+			case SourceAlphaMix::TRANSPARENT:
+				m_pencoding = new Block4x4Encoding_RGBA8_Transparent;
+				break;
+
+			case SourceAlphaMix::TRANSLUCENT:
+				m_pencoding = new Block4x4Encoding_RGBA8;
+				break;
+
+			default:
+				assert(0);
+				break;
+			}
+			break;
+
+		case Image::Format::RGB8A1:
+		case Image::Format::SRGB8A1:
+			switch (m_sourcealphamix)
+			{
+			case SourceAlphaMix::OPAQUE:
+				m_pencoding = new Block4x4Encoding_RGB8A1_Opaque;
+				break;
+
+			case SourceAlphaMix::TRANSPARENT:
+				m_pencoding = new Block4x4Encoding_RGB8A1_Transparent;
+				break;
+
+			case SourceAlphaMix::TRANSLUCENT:
+				if (m_boolPunchThroughPixels)
+				{
+					m_pencoding = new Block4x4Encoding_RGB8A1;
+				}
+				else
+				{
+					m_pencoding = new Block4x4Encoding_RGB8A1_Opaque;
+				}
+				break;
+
+			default:
+				assert(0);
+				break;
+			}
+			break;
+
+		case Image::Format::R11:
+		case Image::Format::SIGNED_R11:
+			m_pencoding = new Block4x4Encoding_R11;
+			break;
+		case Image::Format::RG11:
+		case Image::Format::SIGNED_RG11:
+			m_pencoding = new Block4x4Encoding_RG11;
+			break;
+		default:
+			assert(0);
+			break;
+		}
+
+		m_pencoding->InitFromSource(this, m_afrgbaSource,
+									a_paucEncodingBits, a_errormetric);
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// initialization of encoding state from a prior encoding using encoding bits
+	// [a_uiSourceH,a_uiSourceV] is the location of the block in a_pimageSource
+	// a_paucEncodingBits is the place to read the prior encoding
+	// a_imageformat is used to determine how to interpret a_paucEncodingBits
+	// a_errormetric was used for the prior encoding
+	//
+	void Block4x4::InitFromEtcEncodingBits(Image::Format a_imageformat,
+											unsigned int a_uiSourceH, unsigned int a_uiSourceV,
+											unsigned char *a_paucEncodingBits,
+											Image *a_pimageSource,
+											ErrorMetric a_errormetric)
+	{
+		Block4x4();
+
+		m_pimageSource = a_pimageSource;
+		m_uiSourceH = a_uiSourceH;
+		m_uiSourceV = a_uiSourceV;
+		m_errormetric = a_errormetric;
+
+		SetSourcePixels();
+
+		// set block encoder function
+		switch (a_imageformat)
+		{
+		case Image::Format::ETC1:
+			m_pencoding = new Block4x4Encoding_ETC1;
+			break;
+
+		case Image::Format::RGB8:
+		case Image::Format::SRGB8:
+			m_pencoding = new Block4x4Encoding_RGB8;
+			break;
+
+		case Image::Format::RGBA8:
+		case Image::Format::SRGBA8:
+			m_pencoding = new Block4x4Encoding_RGBA8;
+			break;
+
+		case Image::Format::RGB8A1:
+		case Image::Format::SRGB8A1:
+			m_pencoding = new Block4x4Encoding_RGB8A1;
+			break;
+
+		case Image::Format::R11:
+		case Image::Format::SIGNED_R11:
+			m_pencoding = new Block4x4Encoding_R11;
+			break;
+		case Image::Format::RG11:
+		case Image::Format::SIGNED_RG11:
+			m_pencoding = new Block4x4Encoding_RG11;
+			break;
+		default:
+			assert(0);
+			break;
+		}
+
+		m_pencoding->InitFromEncodingBits(this, a_paucEncodingBits, m_afrgbaSource,
+										m_pimageSource->GetErrorMetric());
+
+	}
+	
+	// ----------------------------------------------------------------------------------------------------
+	// set source pixels from m_pimageSource
+	// set m_alphamix
+	//
+	void Block4x4::SetSourcePixels(void)
+	{
+
+		Image::Format imageformat = m_pimageSource->GetFormat();
+
+		// alpha census
+		unsigned int uiTransparentSourcePixels = 0;
+		unsigned int uiOpaqueSourcePixels = 0;
+
+		// copy source to consecutive memory locations
+		// convert from image horizontal scan to block vertical scan
+		unsigned int uiPixel = 0;
+		for (unsigned int uiBlockPixelH = 0; uiBlockPixelH < Block4x4::COLUMNS; uiBlockPixelH++)
+		{
+			unsigned int uiSourcePixelH = m_uiSourceH + uiBlockPixelH;
+
+			for (unsigned int uiBlockPixelV = 0; uiBlockPixelV < Block4x4::ROWS; uiBlockPixelV++)
+			{
+				unsigned int uiSourcePixelV = m_uiSourceV + uiBlockPixelV;
+
+                ColorFloatRGBA *pfrgbaSource = m_pimageSource->GetSourcePixel(uiSourcePixelH, uiSourcePixelV);
+
+				// if pixel extends beyond source image because of block padding
+				if (pfrgbaSource == nullptr)
+				{
+					m_afrgbaSource[uiPixel] = ColorFloatRGBA(0.0f, 0.0f, 0.0f, NAN);	// denotes border pixel
+					m_boolBorderPixels = true;
+					uiTransparentSourcePixels++;
+				}
+				else
+				{
+					//get teh current pixel data, and store some of the attributes
+					//before capping values to fit the encoder type
+					
+					m_afrgbaSource[uiPixel] = (*pfrgbaSource).ClampRGBA();
+
+					if (m_afrgbaSource[uiPixel].fA == 1.0f)
+					{
+						m_pimageSource->m_iNumOpaquePixels++;
+					}
+					else if (m_afrgbaSource[uiPixel].fA == 0.0f)
+					{
+						m_pimageSource->m_iNumTransparentPixels++;
+					}
+					else if(m_afrgbaSource[uiPixel].fA > 0.0f && m_afrgbaSource[uiPixel].fA < 1.0f)
+					{
+						m_pimageSource->m_iNumTranslucentPixels++;
+					}
+					else
+					{
+						m_pimageSource->m_numOutOfRangeValues.fA++;
+					}
+
+					if (m_afrgbaSource[uiPixel].fR != 0.0f)
+					{
+						m_pimageSource->m_numColorValues.fR++;
+						//make sure we are getting a float between 0-1
+						if (m_afrgbaSource[uiPixel].fR - 1.0f > 0.0f)
+						{
+							m_pimageSource->m_numOutOfRangeValues.fR++;
+						}
+					}
+
+					if (m_afrgbaSource[uiPixel].fG != 0.0f)
+					{
+						m_pimageSource->m_numColorValues.fG++;
+						if (m_afrgbaSource[uiPixel].fG - 1.0f > 0.0f)
+						{
+							m_pimageSource->m_numOutOfRangeValues.fG++;
+						}
+					}
+					if (m_afrgbaSource[uiPixel].fB != 0.0f)
+					{
+						m_pimageSource->m_numColorValues.fB++;
+						if (m_afrgbaSource[uiPixel].fB - 1.0f > 0.0f)
+						{
+							m_pimageSource->m_numOutOfRangeValues.fB++;
+						}
+					}
+					// for formats with no alpha, set source alpha to 1
+					if (imageformat == Image::Format::ETC1 ||
+						imageformat == Image::Format::RGB8 ||
+						imageformat == Image::Format::SRGB8)
+					{
+						m_afrgbaSource[uiPixel].fA = 1.0f;
+					}
+
+					if (imageformat == Image::Format::R11 ||
+						imageformat == Image::Format::SIGNED_R11)
+					{
+						m_afrgbaSource[uiPixel].fA = 1.0f;
+						m_afrgbaSource[uiPixel].fG = 0.0f;
+						m_afrgbaSource[uiPixel].fB = 0.0f;
+					}
+
+					if (imageformat == Image::Format::RG11 ||
+						imageformat == Image::Format::SIGNED_RG11)
+					{
+						m_afrgbaSource[uiPixel].fA = 1.0f;
+						m_afrgbaSource[uiPixel].fB = 0.0f;
+					}
+
+				
+					// for RGB8A1, set source alpha to 0.0 or 1.0
+					// set punch through flag
+					if (imageformat == Image::Format::RGB8A1 ||
+						imageformat == Image::Format::SRGB8A1)
+					{
+						if (m_afrgbaSource[uiPixel].fA >= 0.5f)
+						{
+							m_afrgbaSource[uiPixel].fA = 1.0f;
+						}
+						else
+						{
+							m_afrgbaSource[uiPixel].fA = 0.0f;
+							m_boolPunchThroughPixels = true;
+						}
+					}
+
+					if (m_afrgbaSource[uiPixel].fA == 1.0f)
+					{
+						uiOpaqueSourcePixels++;
+					}
+					else if (m_afrgbaSource[uiPixel].fA == 0.0f)
+					{
+						uiTransparentSourcePixels++;
+					}
+
+				}
+
+				uiPixel += 1;
+			}
+		}
+
+		if (uiOpaqueSourcePixels == PIXELS)
+		{
+			m_sourcealphamix = SourceAlphaMix::OPAQUE;
+		}
+		else if (uiTransparentSourcePixels == PIXELS)
+		{
+			m_sourcealphamix = SourceAlphaMix::TRANSPARENT;
+		}
+		else
+		{
+			m_sourcealphamix = SourceAlphaMix::TRANSLUCENT;
+		}
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// return a name for the encoding mode
+	//
+	const char * Block4x4::GetEncodingModeName(void)
+	{
+
+		switch (m_pencoding->GetMode())
+		{
+		case Block4x4Encoding::MODE_ETC1:
+			return "ETC1";
+		case Block4x4Encoding::MODE_T:
+			return "T";
+		case Block4x4Encoding::MODE_H:
+			return "H";
+		case Block4x4Encoding::MODE_PLANAR:
+			return "PLANAR";
+		default:
+			return "???";
+		}
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+
+}

extern/EtcLib/EtcCodec/EtcBlock4x4.h

@@ -0,0 +1,172 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "EtcColor.h"
+#include "EtcColorFloatRGBA.h"
+#include "EtcErrorMetric.h"
+#include "EtcImage.h"
+#include "EtcBlock4x4Encoding.h"
+
+namespace Etc
+{
+	class Block4x4EncodingBits;
+
+	class Block4x4
+	{
+	public:
+
+		static const unsigned int ROWS = 4;
+		static const unsigned int COLUMNS = 4;
+		static const unsigned int PIXELS = ROWS * COLUMNS;
+
+		// the alpha mix for a 4x4 block of pixels
+		enum class SourceAlphaMix
+		{
+			UNKNOWN,
+			//
+			OPAQUE,			// all 1.0
+			TRANSPARENT,	// all 0.0 or NAN
+			TRANSLUCENT		// not all opaque or transparent
+		};
+
+		typedef void (Block4x4::*EncoderFunctionPtr)(void);
+
+		Block4x4(void);
+		~Block4x4();
+		void InitFromSource(Image *a_pimageSource,
+							unsigned int a_uiSourceH,
+							unsigned int a_uiSourceV,
+							unsigned char *a_paucEncodingBits,
+							ErrorMetric a_errormetric);
+
+		void InitFromEtcEncodingBits(Image::Format a_imageformat,
+										unsigned int a_uiSourceH,
+										unsigned int a_uiSourceV,
+										unsigned char *a_paucEncodingBits,
+										Image *a_pimageSource,
+										ErrorMetric a_errormetric);
+
+		// return true if final iteration was performed
+		inline void PerformEncodingIteration(float a_fEffort)
+		{
+			m_pencoding->PerformIteration(a_fEffort);
+		}
+
+		inline void SetEncodingBitsFromEncoding(void)
+		{
+			m_pencoding->SetEncodingBits();
+		}
+
+		inline unsigned int GetSourceH(void)
+		{
+			return m_uiSourceH;
+		}
+
+		inline unsigned int GetSourceV(void)
+		{
+			return m_uiSourceV;
+		}
+
+		inline float GetError(void)
+		{
+			return m_pencoding->GetError();
+		}
+
+		static const unsigned int s_auiPixelOrderHScan[PIXELS];
+
+		inline ColorFloatRGBA * GetDecodedColors(void)
+		{
+			return m_pencoding->GetDecodedColors();
+		}
+
+		inline float * GetDecodedAlphas(void)
+		{
+			return m_pencoding->GetDecodedAlphas();
+		}
+
+		inline Block4x4Encoding::Mode GetEncodingMode(void)
+		{
+			return m_pencoding->GetMode();
+		}
+
+		inline bool GetFlip(void)
+		{
+			return m_pencoding->GetFlip();
+		}
+
+		inline bool IsDifferential(void)
+		{
+			return m_pencoding->IsDifferential();
+		}
+
+		inline ColorFloatRGBA * GetSource()
+		{
+			return m_afrgbaSource;
+		}
+
+		inline ErrorMetric GetErrorMetric()
+		{
+			return m_errormetric;
+		}
+
+		const char * GetEncodingModeName(void);
+
+		inline Block4x4Encoding * GetEncoding(void)
+		{
+			return m_pencoding;
+		}
+
+		inline SourceAlphaMix GetSourceAlphaMix(void)
+		{
+			return m_sourcealphamix;
+		}
+
+		inline Image * GetImageSource(void)
+		{
+			return m_pimageSource;
+		}
+
+		inline bool HasBorderPixels(void)
+		{
+			return m_boolBorderPixels;
+		}
+
+		inline bool HasPunchThroughPixels(void)
+		{
+			return m_boolPunchThroughPixels;
+		}
+
+	private:
+
+		void SetSourcePixels(void);
+
+		Image				*m_pimageSource;
+		unsigned int		m_uiSourceH;
+		unsigned int		m_uiSourceV;
+		ErrorMetric			m_errormetric;
+		ColorFloatRGBA		m_afrgbaSource[PIXELS];		// vertical scan
+
+		SourceAlphaMix		m_sourcealphamix;
+		bool				m_boolBorderPixels;			// marked as rgba(NAN, NAN, NAN, NAN)
+		bool				m_boolPunchThroughPixels;	// RGB8A1 or SRGB8A1 with any pixels with alpha < 0.5
+
+		Block4x4Encoding	*m_pencoding;
+
+	};
+
+} // namespace Etc

extern/EtcLib/EtcCodec/EtcBlock4x4Encoding.cpp

@@ -0,0 +1,250 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+EtcBlock4x4Encoding.cpp
+
+Block4x4Encoding is the abstract base class for the different encoders.  Each encoder targets a 
+particular file format (e.g. ETC1, RGB8, RGBA8, R11)
+
+*/
+
+#include "EtcConfig.h"
+#include "EtcBlock4x4Encoding.h"
+
+#include "EtcBlock4x4EncodingBits.h"
+#include "EtcBlock4x4.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+namespace Etc
+{
+	// ----------------------------------------------------------------------------------------------------
+	//
+	const float Block4x4Encoding::LUMA_WEIGHT = 3.0f;
+	const float Block4x4Encoding::CHROMA_BLUE_WEIGHT = 0.5f;
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+	Block4x4Encoding::Block4x4Encoding(void)
+	{
+
+		m_pblockParent = nullptr;
+
+		m_pafrgbaSource = nullptr;
+
+		m_boolBorderPixels = false;
+
+		m_fError = -1.0f;
+
+		m_mode = MODE_UNKNOWN;
+
+		m_uiEncodingIterations = 0;
+		m_boolDone = false;
+
+		for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+		{
+			m_afrgbaDecodedColors[uiPixel] = ColorFloatRGBA(-1.0f, -1.0f, -1.0f, -1.0f);
+			m_afDecodedAlphas[uiPixel] = -1.0f;
+		}
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// initialize the generic encoding for a 4x4 block
+	// a_pblockParent points to the block associated with this encoding
+	// a_errormetric is used to choose the best encoding
+	// init the decoded pixels to -1 to mark them as undefined
+	// init the error to -1 to mark it as undefined
+	//
+	void Block4x4Encoding::Init(Block4x4 *a_pblockParent,
+								ColorFloatRGBA *a_pafrgbaSource,
+								ErrorMetric a_errormetric)
+	{
+
+		m_pblockParent = a_pblockParent;
+
+		m_pafrgbaSource = a_pafrgbaSource;
+
+		m_boolBorderPixels = m_pblockParent->HasBorderPixels();
+
+		m_fError = -1.0f;
+
+		m_uiEncodingIterations = 0;
+
+		m_errormetric = a_errormetric;
+
+		for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+		{
+			m_afrgbaDecodedColors[uiPixel] = ColorFloatRGBA(-1.0f, -1.0f, -1.0f, -1.0f);
+			m_afDecodedAlphas[uiPixel] = -1.0f;
+		}
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// calculate the error for the block by summing the pixel errors
+	//
+	void Block4x4Encoding::CalcBlockError(void)
+	{
+		m_fError = 0.0f;
+
+		for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+		{
+			m_fError += CalcPixelError(m_afrgbaDecodedColors[uiPixel], m_afDecodedAlphas[uiPixel],
+										m_pafrgbaSource[uiPixel]);
+		}
+		
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// calculate the error between the source pixel and the decoded pixel
+	// the error amount is base on the error metric
+	//
+	float Block4x4Encoding::CalcPixelError(ColorFloatRGBA a_frgbaDecodedColor, float a_fDecodedAlpha,
+											ColorFloatRGBA a_frgbaSourcePixel)
+	{
+
+		// if a border pixel
+		if (isnan(a_frgbaSourcePixel.fA))
+		{
+			return 0.0f;
+		}
+
+		if (m_errormetric == ErrorMetric::RGBA)
+		{
+			assert(a_fDecodedAlpha >= 0.0f);
+
+			float fDRed = (a_fDecodedAlpha * a_frgbaDecodedColor.fR) -
+							(a_frgbaSourcePixel.fA * a_frgbaSourcePixel.fR);
+			float fDGreen = (a_fDecodedAlpha * a_frgbaDecodedColor.fG) -
+							(a_frgbaSourcePixel.fA * a_frgbaSourcePixel.fG);
+			float fDBlue = (a_fDecodedAlpha * a_frgbaDecodedColor.fB) -
+							(a_frgbaSourcePixel.fA * a_frgbaSourcePixel.fB);
+
+			float fDAlpha = a_fDecodedAlpha - a_frgbaSourcePixel.fA;
+
+			return fDRed*fDRed + fDGreen*fDGreen + fDBlue*fDBlue + fDAlpha*fDAlpha;
+		}
+		else if (m_errormetric == ErrorMetric::REC709)
+		{
+			assert(a_fDecodedAlpha >= 0.0f);
+
+			float fLuma1 = a_frgbaSourcePixel.fR*0.2126f + a_frgbaSourcePixel.fG*0.7152f + a_frgbaSourcePixel.fB*0.0722f;
+			float fChromaR1 = 0.5f * ((a_frgbaSourcePixel.fR - fLuma1) * (1.0f / (1.0f - 0.2126f)));
+			float fChromaB1 = 0.5f * ((a_frgbaSourcePixel.fB - fLuma1) * (1.0f / (1.0f - 0.0722f)));
+
+			float fLuma2 = a_frgbaDecodedColor.fR*0.2126f +
+							a_frgbaDecodedColor.fG*0.7152f +
+							a_frgbaDecodedColor.fB*0.0722f;
+			float fChromaR2 = 0.5f * ((a_frgbaDecodedColor.fR - fLuma2) * (1.0f / (1.0f - 0.2126f)));
+			float fChromaB2 = 0.5f * ((a_frgbaDecodedColor.fB - fLuma2) * (1.0f / (1.0f - 0.0722f)));
+
+			float fDeltaL = a_frgbaSourcePixel.fA * fLuma1 - a_fDecodedAlpha * fLuma2;
+			float fDeltaCr = a_frgbaSourcePixel.fA * fChromaR1 - a_fDecodedAlpha * fChromaR2;
+			float fDeltaCb = a_frgbaSourcePixel.fA * fChromaB1 - a_fDecodedAlpha * fChromaB2;
+
+			float fDAlpha = a_fDecodedAlpha - a_frgbaSourcePixel.fA;
+
+			// Favor Luma accuracy over Chroma, and Red over Blue 
+			return LUMA_WEIGHT*fDeltaL*fDeltaL +
+					fDeltaCr*fDeltaCr +
+					CHROMA_BLUE_WEIGHT*fDeltaCb*fDeltaCb +
+					fDAlpha*fDAlpha;
+	#if 0
+			float fDRed = a_frgbaDecodedPixel.fR - a_frgbaSourcePixel.fR;
+			float fDGreen = a_frgbaDecodedPixel.fG - a_frgbaSourcePixel.fG;
+			float fDBlue = a_frgbaDecodedPixel.fB - a_frgbaSourcePixel.fB;
+			return 2.0f * 3.0f * fDeltaL * fDeltaL + fDRed*fDRed + fDGreen*fDGreen + fDBlue*fDBlue;
+#endif
+		}
+		else if (m_errormetric == ErrorMetric::NORMALXYZ)
+		{
+			float fDecodedX = 2.0f * a_frgbaDecodedColor.fR - 1.0f;
+			float fDecodedY = 2.0f * a_frgbaDecodedColor.fG - 1.0f;
+			float fDecodedZ = 2.0f * a_frgbaDecodedColor.fB - 1.0f;
+
+			float fDecodedLength = sqrtf(fDecodedX*fDecodedX + fDecodedY*fDecodedY + fDecodedZ*fDecodedZ);
+
+			if (fDecodedLength < 0.5f)
+			{
+				return 1.0f;
+			}
+			else if (fDecodedLength == 0.0f)
+			{
+				fDecodedX = 1.0f;
+				fDecodedY = 0.0f;
+				fDecodedZ = 0.0f;
+			}
+			else
+			{
+				fDecodedX /= fDecodedLength;
+				fDecodedY /= fDecodedLength;
+				fDecodedZ /= fDecodedLength;
+			}
+
+			float fSourceX = 2.0f * a_frgbaSourcePixel.fR - 1.0f;
+			float fSourceY = 2.0f * a_frgbaSourcePixel.fG - 1.0f;
+			float fSourceZ = 2.0f * a_frgbaSourcePixel.fB - 1.0f;
+
+			float fSourceLength = sqrtf(fSourceX*fSourceX + fSourceY*fSourceY + fSourceZ*fSourceZ);
+
+			if (fSourceLength == 0.0f)
+			{
+				fSourceX = 1.0f;
+				fSourceY = 0.0f;
+				fSourceZ = 0.0f;
+			}
+			else
+			{
+				fSourceX /= fSourceLength;
+				fSourceY /= fSourceLength;
+				fSourceZ /= fSourceLength;
+			}
+
+			float fDotProduct = fSourceX*fDecodedX + fSourceY*fDecodedY + fSourceZ*fDecodedZ;
+			float fNormalizedDotProduct = 1.0f - 0.5f * (fDotProduct + 1.0f);
+			float fDotProductError = fNormalizedDotProduct * fNormalizedDotProduct;
+			
+			float fLength2 = fDecodedX*fDecodedX + fDecodedY*fDecodedY + fDecodedZ*fDecodedZ;
+			float fLength2Error = fabsf(1.0f - fLength2);
+
+			float fDeltaW = a_frgbaDecodedColor.fA - a_frgbaSourcePixel.fA;
+			float fErrorW = fDeltaW * fDeltaW;
+
+			return fDotProductError + fLength2Error + fErrorW;
+		}
+		else // ErrorMetric::NUMERIC
+		{
+			assert(a_fDecodedAlpha >= 0.0f);
+
+			float fDX = a_frgbaDecodedColor.fR - a_frgbaSourcePixel.fR;
+			float fDY = a_frgbaDecodedColor.fG - a_frgbaSourcePixel.fG;
+			float fDZ = a_frgbaDecodedColor.fB - a_frgbaSourcePixel.fB;
+			float fDW = a_frgbaDecodedColor.fA - a_frgbaSourcePixel.fA;
+
+			return fDX*fDX + fDY*fDY + fDZ*fDZ + fDW*fDW;
+		}
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+
+} // namespace Etc
+

extern/EtcLib/EtcCodec/EtcBlock4x4Encoding.h

@@ -0,0 +1,148 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "EtcColorFloatRGBA.h"
+
+#include "EtcErrorMetric.h"
+
+#include <assert.h>
+#include <float.h>
+
+namespace Etc
+{
+	class Block4x4;
+
+	// abstract base class for specific encodings
+	class Block4x4Encoding
+	{
+	public:
+
+		static const unsigned int ROWS = 4;
+		static const unsigned int COLUMNS = 4;
+		static const unsigned int PIXELS = ROWS * COLUMNS;
+		static const float LUMA_WEIGHT;
+		static const float CHROMA_BLUE_WEIGHT;
+
+		typedef enum
+		{
+			MODE_UNKNOWN,
+			//
+			MODE_ETC1,
+			MODE_T,
+			MODE_H,
+			MODE_PLANAR,
+			MODE_R11,
+			MODE_RG11,
+			//
+			MODES
+		} Mode;
+
+		Block4x4Encoding(void);
+		//virtual ~Block4x4Encoding(void) =0;
+		virtual ~Block4x4Encoding(void) {}
+		virtual void InitFromSource(Block4x4 *a_pblockParent,
+									ColorFloatRGBA *a_pafrgbaSource,
+
+									unsigned char *a_paucEncodingBits, ErrorMetric a_errormetric) = 0;
+
+		virtual void InitFromEncodingBits(Block4x4 *a_pblockParent,
+											unsigned char *a_paucEncodingBits,
+											ColorFloatRGBA *a_pafrgbaSource,
+
+											ErrorMetric a_errormetric) = 0;
+
+		// perform an iteration of the encoding
+		// the first iteration must generate a complete, valid (if poor) encoding
+		virtual void PerformIteration(float a_fEffort) = 0;
+
+		void CalcBlockError(void);
+
+		inline float GetError(void)
+		{
+			assert(m_fError >= 0.0f);
+
+			return m_fError;
+		}
+
+		inline ColorFloatRGBA * GetDecodedColors(void)
+		{
+			return m_afrgbaDecodedColors;
+		}
+
+		inline float * GetDecodedAlphas(void)
+		{
+			return m_afDecodedAlphas;
+		}
+
+		virtual void SetEncodingBits(void) = 0;
+
+		virtual bool GetFlip(void) = 0;
+
+		virtual bool IsDifferential(void) = 0;
+
+		virtual bool HasSeverelyBentDifferentialColors(void) const = 0;
+
+		inline Mode GetMode(void)
+		{
+			return m_mode;
+		}
+
+		inline bool IsDone(void)
+		{
+			return m_boolDone;
+		}
+
+		inline void SetDoneIfPerfect()
+		{
+			if (GetError() == 0.0f)
+			{
+				m_boolDone = true;
+			}
+		}
+
+		float CalcPixelError(ColorFloatRGBA a_frgbaDecodedColor, float a_fDecodedAlpha,
+								ColorFloatRGBA a_frgbaSourcePixel);
+
+	protected:
+
+		void Init(Block4x4 *a_pblockParent,
+					ColorFloatRGBA *a_pafrgbaSource,
+
+					ErrorMetric a_errormetric);
+
+		Block4x4		*m_pblockParent;
+		ColorFloatRGBA	*m_pafrgbaSource;
+
+		bool			m_boolBorderPixels;				// if block has any border pixels
+
+		ColorFloatRGBA	m_afrgbaDecodedColors[PIXELS];	// decoded RGB components, ignore Alpha
+		float			m_afDecodedAlphas[PIXELS];		// decoded alpha component
+		float			m_fError;						// error for RGBA relative to m_pafrgbaSource
+
+		// intermediate encoding
+		Mode			m_mode;
+
+		unsigned int	m_uiEncodingIterations;
+		bool			m_boolDone;						// all iterations have been done
+		ErrorMetric		m_errormetric;
+
+	private:
+
+	};
+
+} // namespace Etc

extern/EtcLib/EtcCodec/EtcBlock4x4EncodingBits.h

@@ -0,0 +1,315 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <assert.h>
+
+namespace Etc
+{
+
+	// ################################################################################
+	// Block4x4EncodingBits
+	// Base class for Block4x4EncodingBits_XXXX
+	// ################################################################################
+
+	class Block4x4EncodingBits
+	{
+	public:
+
+		enum class Format
+		{
+			UNKNOWN,
+			//
+			RGB8,
+			RGBA8,
+			R11,
+			RG11,
+			RGB8A1,
+			//
+			FORMATS
+		};
+
+		static unsigned int GetBytesPerBlock(Format a_format)
+		{
+			switch (a_format)
+			{
+			case Format::RGB8:
+			case Format::R11:
+			case Format::RGB8A1:
+				return 8;
+				break;
+
+			case Format::RGBA8:
+			case Format::RG11:
+				return 16;
+				break;
+
+			default:
+				return 0;
+				break;
+			}
+
+		}
+
+	};
+
+	// ################################################################################
+	// Block4x4EncodingBits_RGB8
+	// Encoding bits for the RGB portion of ETC1, RGB8, RGB8A1 and RGBA8
+	// ################################################################################
+
+	class Block4x4EncodingBits_RGB8
+	{
+	public:
+
+		static const unsigned int BYTES_PER_BLOCK = 8;
+
+		inline Block4x4EncodingBits_RGB8(void)
+		{
+			assert(sizeof(Block4x4EncodingBits_RGB8) == BYTES_PER_BLOCK);
+
+			for (unsigned int uiByte = 0; uiByte < BYTES_PER_BLOCK; uiByte++)
+			{
+				auc[uiByte] = 0;
+			}
+
+		}
+
+		typedef struct
+		{
+			unsigned red2 : 4;
+			unsigned red1 : 4;
+			//
+			unsigned green2 : 4;
+			unsigned green1 : 4;
+			//
+			unsigned blue2 : 4;
+			unsigned blue1 : 4;
+			//
+			unsigned flip : 1;
+			unsigned diff : 1;
+			unsigned cw2 : 3;
+			unsigned cw1 : 3;
+			//
+			unsigned int selectors;
+		} Individual;
+
+		typedef struct
+		{
+			signed dred2 : 3;
+			unsigned red1 : 5;
+			//
+			signed dgreen2 : 3;
+			unsigned green1 : 5;
+			//
+			signed dblue2 : 3;
+			unsigned blue1 : 5;
+			//
+			unsigned flip : 1;
+			unsigned diff : 1;
+			unsigned cw2 : 3;
+			unsigned cw1 : 3;
+			//
+			unsigned int selectors;
+		} Differential;
+
+		typedef struct
+		{
+			unsigned red1b : 2;
+			unsigned detect2 : 1;
+			unsigned red1a : 2;
+			unsigned detect1 : 3;
+			//
+			unsigned blue1 : 4;
+			unsigned green1 : 4;
+			//
+			unsigned green2 : 4;
+			unsigned red2 : 4;
+			//
+			unsigned db : 1;
+			unsigned diff : 1;
+			unsigned da : 2;
+			unsigned blue2 : 4;
+			//
+			unsigned int selectors;
+		} T;
+
+		typedef struct
+		{
+			unsigned green1a : 3;
+			unsigned red1 : 4;
+			unsigned detect1 : 1;
+			//
+			unsigned blue1b : 2;
+			unsigned detect3 : 1;
+			unsigned blue1a : 1;
+			unsigned green1b : 1;
+			unsigned detect2 : 3;
+			//
+			unsigned green2a : 3;
+			unsigned red2 : 4;
+			unsigned blue1c : 1;
+			//
+			unsigned db : 1;
+			unsigned diff : 1;
+			unsigned da : 1;
+			unsigned blue2 : 4;
+			unsigned green2b : 1;
+			//
+			unsigned int selectors;
+		} H;
+
+		typedef struct
+		{
+			unsigned originGreen1 : 1;
+			unsigned originRed : 6;
+			unsigned detect1 : 1;
+			//
+			unsigned originBlue1 : 1;
+			unsigned originGreen2 : 6;
+			unsigned detect2 : 1;
+			//
+			unsigned originBlue3 : 2;
+			unsigned detect4 : 1;
+			unsigned originBlue2 : 2;
+			unsigned detect3 : 3;
+			//
+			unsigned horizRed2 : 1;
+			unsigned diff : 1;
+			unsigned horizRed1 : 5;
+			unsigned originBlue4 : 1;
+			//
+			unsigned horizBlue1: 1;
+			unsigned horizGreen : 7;
+			//
+			unsigned vertRed1 : 3;
+			unsigned horizBlue2 : 5;
+			//
+			unsigned vertGreen1 : 5;
+			unsigned vertRed2 : 3;
+			//
+			unsigned vertBlue : 6;
+			unsigned vertGreen2 : 2;
+		} Planar;
+
+		union
+		{
+			unsigned char auc[BYTES_PER_BLOCK];
+			unsigned long int ul;
+			Individual individual;
+			Differential differential;
+			T t;
+			H h;
+			Planar planar;
+		};
+
+	};
+
+	// ################################################################################
+	// Block4x4EncodingBits_A8
+	// Encoding bits for the A portion of RGBA8
+	// ################################################################################
+
+	class Block4x4EncodingBits_A8
+	{
+	public:
+
+		static const unsigned int BYTES_PER_BLOCK = 8;
+		static const unsigned int SELECTOR_BYTES = 6;
+
+		typedef struct
+		{
+			unsigned base : 8;
+			unsigned table : 4;
+			unsigned multiplier : 4;
+			unsigned selectors0 : 8;
+			unsigned selectors1 : 8;
+			unsigned selectors2 : 8;
+			unsigned selectors3 : 8;
+			unsigned selectors4 : 8;
+			unsigned selectors5 : 8;
+		} Data;
+
+		Data data;
+
+	};
+
+	// ################################################################################
+	// Block4x4EncodingBits_R11
+	// Encoding bits for the R portion of R11
+	// ################################################################################
+
+	class Block4x4EncodingBits_R11
+	{
+	public:
+
+		static const unsigned int BYTES_PER_BLOCK = 8;
+		static const unsigned int SELECTOR_BYTES = 6;
+
+		typedef struct
+		{
+			unsigned base : 8;
+			unsigned table : 4;
+			unsigned multiplier : 4;
+			unsigned selectors0 : 8;
+			unsigned selectors1 : 8;
+			unsigned selectors2 : 8;
+			unsigned selectors3 : 8;
+			unsigned selectors4 : 8;
+			unsigned selectors5 : 8;
+		} Data;
+
+		Data data;
+
+	};
+
+	class Block4x4EncodingBits_RG11
+	{
+	public:
+
+		static const unsigned int BYTES_PER_BLOCK = 16;
+		static const unsigned int SELECTOR_BYTES = 12;
+
+		typedef struct
+		{
+			//Red portion
+			unsigned baseR : 8;
+			unsigned tableIndexR : 4;
+			unsigned multiplierR : 4;
+			unsigned selectorsR0 : 8;
+			unsigned selectorsR1 : 8;
+			unsigned selectorsR2 : 8;
+			unsigned selectorsR3 : 8;
+			unsigned selectorsR4 : 8;
+			unsigned selectorsR5 : 8;
+			//Green portion
+			unsigned baseG : 8;
+			unsigned tableIndexG : 4;
+			unsigned multiplierG : 4;
+			unsigned selectorsG0 : 8;
+			unsigned selectorsG1 : 8;
+			unsigned selectorsG2 : 8;
+			unsigned selectorsG3 : 8;
+			unsigned selectorsG4 : 8;
+			unsigned selectorsG5 : 8;
+		} Data;
+
+		Data data;
+
+	};
+
+}

extern/EtcLib/EtcCodec/EtcBlock4x4Encoding_ETC1.h

@@ -0,0 +1,186 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "EtcBlock4x4Encoding.h"
+#include "EtcBlock4x4EncodingBits.h"
+#include "EtcDifferentialTrys.h"
+#include "EtcIndividualTrys.h"
+
+namespace Etc
+{
+
+	// base class for Block4x4Encoding_RGB8
+	class Block4x4Encoding_ETC1 : public Block4x4Encoding
+	{
+	public:
+
+		Block4x4Encoding_ETC1(void);
+		virtual ~Block4x4Encoding_ETC1(void);
+
+		virtual void InitFromSource(Block4x4 *a_pblockParent,
+									ColorFloatRGBA *a_pafrgbaSource,
+
+									unsigned char *a_paucEncodingBits,
+									ErrorMetric a_errormetric);
+
+		virtual void InitFromEncodingBits(Block4x4 *a_pblockParent,
+											unsigned char *a_paucEncodingBits,
+											ColorFloatRGBA *a_pafrgbaSource, 
+
+											ErrorMetric a_errormetric);
+
+		virtual void PerformIteration(float a_fEffort);
+
+		inline virtual bool GetFlip(void)
+		{
+			return m_boolFlip;
+		}
+
+		inline virtual bool IsDifferential(void)
+		{
+			return m_boolDiff;
+		}
+
+		virtual void SetEncodingBits(void);
+
+		void Decode(void);
+
+		inline ColorFloatRGBA GetColor1(void) const
+		{
+			return m_frgbaColor1;
+		}
+
+		inline ColorFloatRGBA GetColor2(void) const
+		{
+			return m_frgbaColor2;
+		}
+
+		inline const unsigned int * GetSelectors(void) const
+		{
+			return m_auiSelectors;
+		}
+
+		inline unsigned int GetCW1(void) const
+		{
+			return m_uiCW1;
+		}
+
+		inline unsigned int GetCW2(void) const
+		{
+			return m_uiCW2;
+		}
+
+		inline bool HasSeverelyBentDifferentialColors(void) const
+		{
+			return m_boolSeverelyBentDifferentialColors;
+		}
+
+	protected:
+
+		static const unsigned int s_auiPixelOrderFlip0[PIXELS];
+		static const unsigned int s_auiPixelOrderFlip1[PIXELS];
+		static const unsigned int s_auiPixelOrderHScan[PIXELS];
+
+		static const unsigned int s_auiLeftPixelMapping[8];
+		static const unsigned int s_auiRightPixelMapping[8];
+		static const unsigned int s_auiTopPixelMapping[8];
+		static const unsigned int s_auiBottomPixelMapping[8];
+
+		static const unsigned int SELECTOR_BITS = 2;
+		static const unsigned int SELECTORS = 1 << SELECTOR_BITS;
+
+		static const unsigned int CW_BITS = 3;
+		static const unsigned int CW_RANGES = 1 << CW_BITS;
+
+		static float s_aafCwTable[CW_RANGES][SELECTORS];
+		static unsigned char s_aucDifferentialCwRange[256];
+
+		static const int MAX_DIFFERENTIAL = 3;
+		static const int MIN_DIFFERENTIAL = -4;
+
+		void InitFromEncodingBits_Selectors(void);
+
+		void PerformFirstIteration(void);
+		void CalculateMostLikelyFlip(void);
+
+		void TryDifferential(bool a_boolFlip, unsigned int a_uiRadius,
+								int a_iGrayOffset1, int a_iGrayOffset2);
+		void TryDifferentialHalf(DifferentialTrys::Half *a_phalf);
+
+		void TryIndividual(bool a_boolFlip, unsigned int a_uiRadius);
+		void TryIndividualHalf(IndividualTrys::Half *a_phalf);
+
+		void TryDegenerates1(void);
+		void TryDegenerates2(void);
+		void TryDegenerates3(void);
+		void TryDegenerates4(void);
+
+		void CalculateSelectors();
+		void CalculateHalfOfTheSelectors(unsigned int a_uiHalf,
+											const unsigned int *pauiPixelMapping);
+
+		// calculate the distance2 of r_frgbaPixel from r_frgbaTarget's gray line
+		inline float CalcGrayDistance2(ColorFloatRGBA &r_frgbaPixel, 
+										ColorFloatRGBA &r_frgbaTarget)
+		{
+			float fDeltaGray = ((r_frgbaPixel.fR - r_frgbaTarget.fR) +
+								(r_frgbaPixel.fG - r_frgbaTarget.fG) +
+								(r_frgbaPixel.fB - r_frgbaTarget.fB)) / 3.0f;
+
+			ColorFloatRGBA frgbaPointOnGrayLine = (r_frgbaTarget + fDeltaGray).ClampRGB();
+
+			float fDR = r_frgbaPixel.fR - frgbaPointOnGrayLine.fR;
+			float fDG = r_frgbaPixel.fG - frgbaPointOnGrayLine.fG;
+			float fDB = r_frgbaPixel.fB - frgbaPointOnGrayLine.fB;
+
+			return (fDR*fDR) + (fDG*fDG) + (fDB*fDB);
+		}
+
+		void SetEncodingBits_Selectors(void);
+
+		// intermediate encoding
+		bool			m_boolDiff;
+		bool			m_boolFlip;
+		ColorFloatRGBA	m_frgbaColor1;
+		ColorFloatRGBA	m_frgbaColor2;
+		unsigned int	m_uiCW1;
+		unsigned int	m_uiCW2;
+		unsigned int	m_auiSelectors[PIXELS];
+
+		// state shared between iterations
+		ColorFloatRGBA	m_frgbaSourceAverageLeft;
+		ColorFloatRGBA	m_frgbaSourceAverageRight;
+		ColorFloatRGBA	m_frgbaSourceAverageTop;
+		ColorFloatRGBA	m_frgbaSourceAverageBottom;
+		bool			m_boolMostLikelyFlip;
+
+		// stats
+		float			m_fError1;	// error for Etc1 half 1
+		float			m_fError2;	// error for Etc1 half 2
+		bool			m_boolSeverelyBentDifferentialColors;	// only valid if m_boolDiff;
+
+		// final encoding
+		Block4x4EncodingBits_RGB8 *m_pencodingbitsRGB8;		// or RGB8 portion of Block4x4EncodingBits_RGB8A8
+
+		private:
+
+		void CalculateSourceAverages(void);
+
+	};
+
+} // namespace Etc

extern/EtcLib/EtcCodec/EtcBlock4x4Encoding_R11.cpp

@@ -0,0 +1,429 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+EtcBlock4x4Encoding_R11.cpp
+
+Block4x4Encoding_R11 is the encoder to use when targetting file format R11 and SR11 (signed R11).  
+
+*/
+
+#include "EtcConfig.h"
+#include "EtcBlock4x4Encoding_R11.h"
+
+#include "EtcBlock4x4EncodingBits.h"
+#include "EtcBlock4x4.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <float.h>
+#include <limits>
+
+namespace Etc
+{
+
+	// modifier values to use for R11, SR11, RG11 and SRG11
+	float Block4x4Encoding_R11::s_aafModifierTable[MODIFIER_TABLE_ENTRYS][SELECTORS]
+	{
+		{ -3.0f / 255.0f, -6.0f / 255.0f,  -9.0f / 255.0f, -15.0f / 255.0f, 2.0f / 255.0f, 5.0f / 255.0f, 8.0f / 255.0f, 14.0f / 255.0f },
+		{ -3.0f / 255.0f, -7.0f / 255.0f, -10.0f / 255.0f, -13.0f / 255.0f, 2.0f / 255.0f, 6.0f / 255.0f, 9.0f / 255.0f, 12.0f / 255.0f },
+		{ -2.0f / 255.0f, -5.0f / 255.0f,  -8.0f / 255.0f, -13.0f / 255.0f, 1.0f / 255.0f, 4.0f / 255.0f, 7.0f / 255.0f, 12.0f / 255.0f },
+		{ -2.0f / 255.0f, -4.0f / 255.0f,  -6.0f / 255.0f, -13.0f / 255.0f, 1.0f / 255.0f, 3.0f / 255.0f, 5.0f / 255.0f, 12.0f / 255.0f },
+
+		{ -3.0f / 255.0f, -6.0f / 255.0f,  -8.0f / 255.0f, -12.0f / 255.0f, 2.0f / 255.0f, 5.0f / 255.0f, 7.0f / 255.0f, 11.0f / 255.0f },
+		{ -3.0f / 255.0f, -7.0f / 255.0f,  -9.0f / 255.0f, -11.0f / 255.0f, 2.0f / 255.0f, 6.0f / 255.0f, 8.0f / 255.0f, 10.0f / 255.0f },
+		{ -4.0f / 255.0f, -7.0f / 255.0f,  -8.0f / 255.0f, -11.0f / 255.0f, 3.0f / 255.0f, 6.0f / 255.0f, 7.0f / 255.0f, 10.0f / 255.0f },
+		{ -3.0f / 255.0f, -5.0f / 255.0f,  -8.0f / 255.0f, -11.0f / 255.0f, 2.0f / 255.0f, 4.0f / 255.0f, 7.0f / 255.0f, 10.0f / 255.0f },
+
+		{ -2.0f / 255.0f, -6.0f / 255.0f,  -8.0f / 255.0f, -10.0f / 255.0f, 1.0f / 255.0f, 5.0f / 255.0f, 7.0f / 255.0f,  9.0f / 255.0f },
+		{ -2.0f / 255.0f, -5.0f / 255.0f,  -8.0f / 255.0f, -10.0f / 255.0f, 1.0f / 255.0f, 4.0f / 255.0f, 7.0f / 255.0f,  9.0f / 255.0f },
+		{ -2.0f / 255.0f, -4.0f / 255.0f,  -8.0f / 255.0f, -10.0f / 255.0f, 1.0f / 255.0f, 3.0f / 255.0f, 7.0f / 255.0f,  9.0f / 255.0f },
+		{ -2.0f / 255.0f, -5.0f / 255.0f,  -7.0f / 255.0f, -10.0f / 255.0f, 1.0f / 255.0f, 4.0f / 255.0f, 6.0f / 255.0f,  9.0f / 255.0f },
+
+		{ -3.0f / 255.0f, -4.0f / 255.0f,  -7.0f / 255.0f, -10.0f / 255.0f, 2.0f / 255.0f, 3.0f / 255.0f, 6.0f / 255.0f,  9.0f / 255.0f },
+		{ -1.0f / 255.0f, -2.0f / 255.0f,  -3.0f / 255.0f, -10.0f / 255.0f, 0.0f / 255.0f, 1.0f / 255.0f, 2.0f / 255.0f,  9.0f / 255.0f },
+		{ -4.0f / 255.0f, -6.0f / 255.0f,  -8.0f / 255.0f,  -9.0f / 255.0f, 3.0f / 255.0f, 5.0f / 255.0f, 7.0f / 255.0f,  8.0f / 255.0f },
+		{ -3.0f / 255.0f, -5.0f / 255.0f,  -7.0f / 255.0f,  -9.0f / 255.0f, 2.0f / 255.0f, 4.0f / 255.0f, 6.0f / 255.0f,  8.0f / 255.0f }
+	};
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+	Block4x4Encoding_R11::Block4x4Encoding_R11(void)
+	{
+
+		m_pencodingbitsR11 = nullptr;
+
+	}
+
+	Block4x4Encoding_R11::~Block4x4Encoding_R11(void) {}
+	// ----------------------------------------------------------------------------------------------------
+	// initialization prior to encoding
+	// a_pblockParent points to the block associated with this encoding
+	// a_errormetric is used to choose the best encoding
+	// a_pafrgbaSource points to a 4x4 block subset of the source image
+	// a_paucEncodingBits points to the final encoding bits
+	//
+	void Block4x4Encoding_R11::InitFromSource(Block4x4 *a_pblockParent,
+		ColorFloatRGBA *a_pafrgbaSource,
+		unsigned char *a_paucEncodingBits, ErrorMetric a_errormetric)
+	{
+		Block4x4Encoding::Init(a_pblockParent, a_pafrgbaSource,a_errormetric);
+
+		m_pencodingbitsR11 = (Block4x4EncodingBits_R11 *)a_paucEncodingBits;
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// initialization from the encoding bits of a previous encoding
+	// a_pblockParent points to the block associated with this encoding
+	// a_errormetric is used to choose the best encoding
+	// a_pafrgbaSource points to a 4x4 block subset of the source image
+	// a_paucEncodingBits points to the final encoding bits of a previous encoding
+	//
+	void Block4x4Encoding_R11::InitFromEncodingBits(Block4x4 *a_pblockParent,
+		unsigned char *a_paucEncodingBits,
+		ColorFloatRGBA *a_pafrgbaSource,
+		ErrorMetric a_errormetric)
+	{
+		m_pencodingbitsR11 = (Block4x4EncodingBits_R11 *)a_paucEncodingBits;
+
+		// init RGB portion
+		Block4x4Encoding_RGB8::InitFromEncodingBits(a_pblockParent,
+			(unsigned char *)m_pencodingbitsR11,
+			a_pafrgbaSource,
+			a_errormetric);
+
+		// init R11 portion
+		{
+			m_mode = MODE_R11;
+			if (a_pblockParent->GetImageSource()->GetFormat() == Image::Format::SIGNED_R11 || a_pblockParent->GetImageSource()->GetFormat() == Image::Format::SIGNED_RG11)
+			{
+				m_fRedBase = (float)(signed char)m_pencodingbitsR11->data.base;
+			}
+			else
+			{
+				m_fRedBase = (float)(unsigned char)m_pencodingbitsR11->data.base;
+			}
+			m_fRedMultiplier = (float)m_pencodingbitsR11->data.multiplier;
+			m_uiRedModifierTableIndex = m_pencodingbitsR11->data.table;
+
+			unsigned long long int ulliSelectorBits = 0;
+			ulliSelectorBits |= (unsigned long long int)m_pencodingbitsR11->data.selectors0 << 40;
+			ulliSelectorBits |= (unsigned long long int)m_pencodingbitsR11->data.selectors1 << 32;
+			ulliSelectorBits |= (unsigned long long int)m_pencodingbitsR11->data.selectors2 << 24;
+			ulliSelectorBits |= (unsigned long long int)m_pencodingbitsR11->data.selectors3 << 16;
+			ulliSelectorBits |= (unsigned long long int)m_pencodingbitsR11->data.selectors4 << 8;
+			ulliSelectorBits |= (unsigned long long int)m_pencodingbitsR11->data.selectors5;
+			for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+			{
+				unsigned int uiShift = 45 - (3 * uiPixel);
+				m_auiRedSelectors[uiPixel] = (ulliSelectorBits >> uiShift) & (SELECTORS - 1);
+			}
+
+			// decode the red channel
+			// calc red error
+			for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+			{
+				float fDecodedPixelData = 0.0f;
+				if (a_pblockParent->GetImageSource()->GetFormat() == Image::Format::R11 || a_pblockParent->GetImageSource()->GetFormat() == Image::Format::RG11)
+				{
+					fDecodedPixelData = DecodePixelRed(m_fRedBase, m_fRedMultiplier,
+						m_uiRedModifierTableIndex,
+						m_auiRedSelectors[uiPixel]);
+				}
+				else if (a_pblockParent->GetImageSource()->GetFormat() == Image::Format::SIGNED_R11 || a_pblockParent->GetImageSource()->GetFormat() == Image::Format::SIGNED_RG11)
+				{
+					fDecodedPixelData = DecodePixelRed(m_fRedBase + 128, m_fRedMultiplier,
+						m_uiRedModifierTableIndex,
+						m_auiRedSelectors[uiPixel]);
+				}
+				else
+				{
+					assert(0);
+				}
+				m_afrgbaDecodedColors[uiPixel] = ColorFloatRGBA(fDecodedPixelData, 0.0f, 0.0f, 1.0f);
+			}
+			CalcBlockError();
+		}
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// perform a single encoding iteration
+	// replace the encoding if a better encoding was found
+	// subsequent iterations generally take longer for each iteration
+	// set m_boolDone if encoding is perfect or encoding is finished based on a_fEffort
+	//
+	void Block4x4Encoding_R11::PerformIteration(float a_fEffort)
+	{
+		assert(!m_boolDone);
+		m_mode = MODE_R11;
+
+		switch (m_uiEncodingIterations)
+		{
+		case 0:
+			m_fError = FLT_MAX;
+			m_fRedBlockError = FLT_MAX;		// artificially high value
+			CalculateR11(8, 0.0f, 0.0f);
+			m_fError = m_fRedBlockError;
+			break;
+
+		case 1:
+			CalculateR11(8, 2.0f, 1.0f);
+			m_fError = m_fRedBlockError;
+			if (a_fEffort <= 24.5f)
+			{
+				m_boolDone = true;
+			}
+			break;
+
+		case 2:
+			CalculateR11(8, 12.0f, 1.0f);
+			m_fError = m_fRedBlockError;
+			if (a_fEffort <= 49.5f)
+			{
+				m_boolDone = true;
+			}
+			break;
+
+		case 3:
+			CalculateR11(7, 6.0f, 1.0f);
+			m_fError = m_fRedBlockError;
+			break;
+
+		case 4:
+			CalculateR11(6, 3.0f, 1.0f);
+			m_fError = m_fRedBlockError;
+			break;
+
+		case 5:
+			CalculateR11(5, 1.0f, 0.0f);
+			m_fError = m_fRedBlockError;
+			m_boolDone = true;
+			break;
+
+		default:
+			assert(0);
+			break;
+		}
+
+		m_uiEncodingIterations++;
+		SetDoneIfPerfect();
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// find the best combination of base color, multiplier and selectors
+	//
+	// a_uiSelectorsUsed limits the number of selector combinations to try
+	// a_fBaseRadius limits the range of base colors to try
+	// a_fMultiplierRadius limits the range of multipliers to try
+	//
+	void Block4x4Encoding_R11::CalculateR11(unsigned int a_uiSelectorsUsed, 
+												float a_fBaseRadius, float a_fMultiplierRadius)
+	{
+		// maps from virtual (monotonic) selector to ETC selector
+		static const unsigned int auiVirtualSelectorMap[8] = {3, 2, 1, 0, 4, 5, 6, 7};
+
+		// find min/max red
+		float fMinRed = 1.0f;
+		float fMaxRed = 0.0f;
+		for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+		{
+			// ignore border pixels
+			float fAlpha = m_pafrgbaSource[uiPixel].fA;
+			if (isnan(fAlpha))
+			{
+				continue;
+			}
+
+			float fRed = m_pafrgbaSource[uiPixel].fR;
+
+			if (fRed < fMinRed)
+			{
+				fMinRed = fRed;
+			}
+			if (fRed > fMaxRed)
+			{
+				fMaxRed = fRed;
+			}
+		}
+		assert(fMinRed <= fMaxRed);
+
+		float fRedRange = (fMaxRed - fMinRed);
+
+		// try each modifier table entry							  
+		for (unsigned int uiTableEntry = 0; uiTableEntry < MODIFIER_TABLE_ENTRYS; uiTableEntry++)
+		{
+			for (unsigned int uiMinVirtualSelector = 0; 
+					uiMinVirtualSelector <= (8- a_uiSelectorsUsed); 
+					uiMinVirtualSelector++)
+			{
+				unsigned int uiMaxVirtualSelector = uiMinVirtualSelector + a_uiSelectorsUsed - 1;
+
+				unsigned int uiMinSelector = auiVirtualSelectorMap[uiMinVirtualSelector];
+				unsigned int uiMaxSelector = auiVirtualSelectorMap[uiMaxVirtualSelector];
+
+				float fTableEntryCenter = -s_aafModifierTable[uiTableEntry][uiMinSelector];
+
+				float fTableEntryRange = s_aafModifierTable[uiTableEntry][uiMaxSelector] -
+											s_aafModifierTable[uiTableEntry][uiMinSelector];
+
+				float fCenterRatio = fTableEntryCenter / fTableEntryRange;
+
+				float fCenter = fMinRed + fCenterRatio*fRedRange;
+				fCenter = roundf(255.0f * fCenter) / 255.0f;
+
+				float fMinBase = fCenter - (a_fBaseRadius / 255.0f);
+				if (fMinBase < 0.0f)
+				{
+					fMinBase = 0.0f;
+				}
+
+				float fMaxBase = fCenter + (a_fBaseRadius / 255.0f);
+				if (fMaxBase > 1.0f)
+				{
+					fMaxBase = 1.0f;
+				}
+
+				for (float fBase = fMinBase; fBase <= fMaxBase; fBase += (0.999999f / 255.0f))
+				{
+					float fRangeMultiplier = roundf(fRedRange / fTableEntryRange);
+
+					float fMinMultiplier = fRangeMultiplier - a_fMultiplierRadius;
+					if (fMinMultiplier < 1.0f)
+					{
+						fMinMultiplier = 0.0f;
+					}
+					else if (fMinMultiplier > 15.0f)
+					{
+						fMinMultiplier = 15.0f;
+					}
+
+					float fMaxMultiplier = fRangeMultiplier + a_fMultiplierRadius;
+					if (fMaxMultiplier < 1.0f)
+					{
+						fMaxMultiplier = 1.0f;
+					}
+					else if (fMaxMultiplier > 15.0f)
+					{
+						fMaxMultiplier = 15.0f;
+					}
+
+					for (float fMultiplier = fMinMultiplier; fMultiplier <= fMaxMultiplier; fMultiplier += 1.0f)
+					{
+						// find best selector for each pixel
+						unsigned int auiBestSelectors[PIXELS];
+						float afBestRedError[PIXELS];
+						float afBestPixelRed[PIXELS];
+
+						for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+						{
+							float fBestPixelRedError = FLT_MAX;
+
+							for (unsigned int uiSelector = 0; uiSelector < SELECTORS; uiSelector++)
+							{
+								float fPixelRed = DecodePixelRed(fBase * 255.0f, fMultiplier, uiTableEntry, uiSelector);
+
+								ColorFloatRGBA frgba(fPixelRed, m_pafrgbaSource[uiPixel].fG,0.0f,1.0f);
+
+								float fPixelRedError = CalcPixelError(frgba, 1.0f, m_pafrgbaSource[uiPixel]);
+
+								if (fPixelRedError < fBestPixelRedError)
+								{
+									fBestPixelRedError = fPixelRedError;
+									auiBestSelectors[uiPixel] = uiSelector;
+									afBestRedError[uiPixel] = fBestPixelRedError;
+									afBestPixelRed[uiPixel] = fPixelRed;
+								}
+							}
+						}
+						float fBlockError = 0.0f;  
+						for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+						{
+							fBlockError += afBestRedError[uiPixel];
+						}
+						if (fBlockError < m_fRedBlockError)
+						{
+							m_fRedBlockError = fBlockError;
+
+							if (m_pblockParent->GetImageSource()->GetFormat() == Image::Format::R11 || m_pblockParent->GetImageSource()->GetFormat() == Image::Format::RG11)
+							{
+								m_fRedBase = 255.0f * fBase;
+							}
+							else if (m_pblockParent->GetImageSource()->GetFormat() == Image::Format::SIGNED_R11 || m_pblockParent->GetImageSource()->GetFormat() == Image::Format::SIGNED_RG11)
+							{
+								m_fRedBase = (fBase * 255) - 128;
+							}
+							else
+							{
+								assert(0);
+							}
+							m_fRedMultiplier = fMultiplier;
+							m_uiRedModifierTableIndex = uiTableEntry;
+
+							for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+							{
+								m_auiRedSelectors[uiPixel] = auiBestSelectors[uiPixel];
+								float fBestPixelRed = afBestPixelRed[uiPixel];
+								m_afrgbaDecodedColors[uiPixel] = ColorFloatRGBA(fBestPixelRed, 0.0f, 0.0f, 1.0f);
+								m_afDecodedAlphas[uiPixel] = 1.0f;
+							}
+						}
+					}
+				}
+
+			}
+		}
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// set the encoding bits based on encoding state
+	//
+	void Block4x4Encoding_R11::SetEncodingBits(void)
+	{
+		if (m_pblockParent->GetImageSource()->GetFormat() == Image::Format::R11 || m_pblockParent->GetImageSource()->GetFormat() == Image::Format::RG11)
+		{
+			m_pencodingbitsR11->data.base = (unsigned char)roundf(m_fRedBase);
+		}
+		else if (m_pblockParent->GetImageSource()->GetFormat() == Image::Format::SIGNED_R11 || m_pblockParent->GetImageSource()->GetFormat() == Image::Format::SIGNED_RG11)
+		{
+			m_pencodingbitsR11->data.base = (signed char)roundf(m_fRedBase);
+		}
+		else
+		{
+			assert(0);
+		}
+		m_pencodingbitsR11->data.table = m_uiRedModifierTableIndex;
+		m_pencodingbitsR11->data.multiplier = (unsigned char)roundf(m_fRedMultiplier);
+
+		unsigned long long int ulliSelectorBits = 0;
+		for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+		{
+			unsigned int uiShift = 45 - (3 * uiPixel);
+			ulliSelectorBits |= ((unsigned long long int)m_auiRedSelectors[uiPixel]) << uiShift;
+		}
+
+		m_pencodingbitsR11->data.selectors0 = ulliSelectorBits >> 40;
+		m_pencodingbitsR11->data.selectors1 = ulliSelectorBits >> 32;
+		m_pencodingbitsR11->data.selectors2 = ulliSelectorBits >> 24;
+		m_pencodingbitsR11->data.selectors3 = ulliSelectorBits >> 16;
+		m_pencodingbitsR11->data.selectors4 = ulliSelectorBits >> 8;
+		m_pencodingbitsR11->data.selectors5 = ulliSelectorBits;
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+}

extern/EtcLib/EtcCodec/EtcBlock4x4Encoding_R11.h

@@ -0,0 +1,122 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "EtcBlock4x4Encoding_RGB8.h"
+
+namespace Etc
+{
+	class Block4x4EncodingBits_R11;
+
+	// ################################################################################
+	// Block4x4Encoding_R11
+	// ################################################################################
+
+	class Block4x4Encoding_R11 : public Block4x4Encoding_RGB8
+	{
+	public:
+
+		Block4x4Encoding_R11(void);
+		virtual ~Block4x4Encoding_R11(void);
+
+		virtual void InitFromSource(Block4x4 *a_pblockParent,
+			ColorFloatRGBA *a_pafrgbaSource,
+			unsigned char *a_paucEncodingBits, ErrorMetric a_errormetric);
+
+		virtual void InitFromEncodingBits(Block4x4 *a_pblockParent,
+			unsigned char *a_paucEncodingBits,
+			ColorFloatRGBA *a_pafrgbaSource,
+			ErrorMetric a_errormetric);
+
+		virtual void PerformIteration(float a_fEffort);
+
+		virtual void SetEncodingBits(void);
+
+		inline float GetRedBase(void) const
+		{
+			return m_fRedBase;
+		}
+
+		inline float GetRedMultiplier(void) const
+		{
+			return m_fRedMultiplier;
+		}
+
+		inline int GetRedTableIndex(void) const
+		{
+			return m_uiRedModifierTableIndex;
+		}
+
+		inline const unsigned int * GetRedSelectors(void) const
+		{
+			return m_auiRedSelectors;
+		}
+
+	protected:
+
+		static const unsigned int MODIFIER_TABLE_ENTRYS = 16;
+		static const unsigned int SELECTOR_BITS = 3;
+		static const unsigned int SELECTORS = 1 << SELECTOR_BITS;
+
+		static float s_aafModifierTable[MODIFIER_TABLE_ENTRYS][SELECTORS];
+
+		void CalculateR11(unsigned int a_uiSelectorsUsed, 
+							float a_fBaseRadius, float a_fMultiplierRadius);
+
+		
+
+	
+		inline float DecodePixelRed(float a_fBase, float a_fMultiplier,
+			unsigned int a_uiTableIndex, unsigned int a_uiSelector)
+		{
+			float fMultiplier = a_fMultiplier;
+			if (fMultiplier <= 0.0f)
+			{
+				fMultiplier = 1.0f / 8.0f;
+			}
+
+			float fPixelRed = a_fBase * 8 + 4 +
+				8 * fMultiplier*s_aafModifierTable[a_uiTableIndex][a_uiSelector]*255;
+			fPixelRed /= 2047.0f;
+
+			if (fPixelRed < 0.0f)
+			{
+				fPixelRed = 0.0f;
+			}
+			else if (fPixelRed > 1.0f)
+			{
+				fPixelRed = 1.0f;
+			}
+
+			return fPixelRed;
+		}
+
+		Block4x4EncodingBits_R11 *m_pencodingbitsR11;
+
+		float m_fRedBase;
+		float m_fRedMultiplier;
+		float m_fRedBlockError;
+		unsigned int m_uiRedModifierTableIndex;
+		unsigned int m_auiRedSelectors[PIXELS];
+
+		
+	};
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+
+} // namespace Etc

extern/EtcLib/EtcCodec/EtcBlock4x4Encoding_RG11.cpp

@@ -0,0 +1,447 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+EtcBlock4x4Encoding_RG11.cpp
+
+Block4x4Encoding_RG11 is the encoder to use when targetting file format RG11 and SRG11 (signed RG11).
+
+*/
+
+#include "EtcConfig.h"
+#include "EtcBlock4x4Encoding_RG11.h"
+
+#include "EtcBlock4x4EncodingBits.h"
+#include "EtcBlock4x4.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <float.h>
+#include <limits>
+
+namespace Etc
+{
+	// ----------------------------------------------------------------------------------------------------
+	//
+	Block4x4Encoding_RG11::Block4x4Encoding_RG11(void)
+	{
+		m_pencodingbitsRG11 = nullptr;
+	}
+
+	Block4x4Encoding_RG11::~Block4x4Encoding_RG11(void) {}
+	// ----------------------------------------------------------------------------------------------------
+	// initialization prior to encoding
+	// a_pblockParent points to the block associated with this encoding
+	// a_errormetric is used to choose the best encoding
+	// a_pafrgbaSource points to a 4x4 block subset of the source image
+	// a_paucEncodingBits points to the final encoding bits
+	//
+	void Block4x4Encoding_RG11::InitFromSource(Block4x4 *a_pblockParent,
+		ColorFloatRGBA *a_pafrgbaSource,
+		unsigned char *a_paucEncodingBits, ErrorMetric a_errormetric)
+	{
+		Block4x4Encoding::Init(a_pblockParent, a_pafrgbaSource,a_errormetric);
+
+		m_pencodingbitsRG11 = (Block4x4EncodingBits_RG11 *)a_paucEncodingBits;
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// initialization from the encoding bits of a previous encoding
+	// a_pblockParent points to the block associated with this encoding
+	// a_errormetric is used to choose the best encoding
+	// a_pafrgbaSource points to a 4x4 block subset of the source image
+	// a_paucEncodingBits points to the final encoding bits of a previous encoding
+	//
+	void Block4x4Encoding_RG11::InitFromEncodingBits(Block4x4 *a_pblockParent,
+		unsigned char *a_paucEncodingBits,
+		ColorFloatRGBA *a_pafrgbaSource,
+		ErrorMetric a_errormetric)
+	{
+
+		m_pencodingbitsRG11 = (Block4x4EncodingBits_RG11 *)a_paucEncodingBits;
+
+		// init RGB portion
+		Block4x4Encoding_RGB8::InitFromEncodingBits(a_pblockParent,
+			(unsigned char *)m_pencodingbitsRG11,
+			a_pafrgbaSource,
+			a_errormetric);
+		m_fError = 0.0f;
+
+		{
+			m_mode = MODE_RG11;
+			if (a_pblockParent->GetImageSource()->GetFormat() == Image::Format::SIGNED_RG11)
+			{
+				m_fRedBase = (float)(signed char)m_pencodingbitsRG11->data.baseR;
+				m_fGrnBase = (float)(signed char)m_pencodingbitsRG11->data.baseG;
+			}
+			else
+			{
+				m_fRedBase = (float)(unsigned char)m_pencodingbitsRG11->data.baseR;
+				m_fGrnBase = (float)(unsigned char)m_pencodingbitsRG11->data.baseG;
+			}
+			m_fRedMultiplier = (float)m_pencodingbitsRG11->data.multiplierR;
+			m_fGrnMultiplier = (float)m_pencodingbitsRG11->data.multiplierG;
+			m_uiRedModifierTableIndex = m_pencodingbitsRG11->data.tableIndexR;
+			m_uiGrnModifierTableIndex = m_pencodingbitsRG11->data.tableIndexG;
+
+			unsigned long long int ulliSelectorBitsR = 0;
+			ulliSelectorBitsR |= (unsigned long long int)m_pencodingbitsRG11->data.selectorsR0 << 40;
+			ulliSelectorBitsR |= (unsigned long long int)m_pencodingbitsRG11->data.selectorsR1 << 32;
+			ulliSelectorBitsR |= (unsigned long long int)m_pencodingbitsRG11->data.selectorsR2 << 24;
+			ulliSelectorBitsR |= (unsigned long long int)m_pencodingbitsRG11->data.selectorsR3 << 16;
+			ulliSelectorBitsR |= (unsigned long long int)m_pencodingbitsRG11->data.selectorsR4 << 8;
+			ulliSelectorBitsR |= (unsigned long long int)m_pencodingbitsRG11->data.selectorsR5;
+
+			unsigned long long int ulliSelectorBitsG = 0;
+			ulliSelectorBitsG |= (unsigned long long int)m_pencodingbitsRG11->data.selectorsG0 << 40;
+			ulliSelectorBitsG |= (unsigned long long int)m_pencodingbitsRG11->data.selectorsG1 << 32;
+			ulliSelectorBitsG |= (unsigned long long int)m_pencodingbitsRG11->data.selectorsG2 << 24;
+			ulliSelectorBitsG |= (unsigned long long int)m_pencodingbitsRG11->data.selectorsG3 << 16;
+			ulliSelectorBitsG |= (unsigned long long int)m_pencodingbitsRG11->data.selectorsG4 << 8;
+			ulliSelectorBitsG |= (unsigned long long int)m_pencodingbitsRG11->data.selectorsG5;
+
+			
+			for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+			{
+				unsigned int uiShift = 45 - (3 * uiPixel);
+				m_auiRedSelectors[uiPixel] = (ulliSelectorBitsR >> uiShift) & (SELECTORS - 1);
+				m_auiGrnSelectors[uiPixel] = (ulliSelectorBitsG >> uiShift) & (SELECTORS - 1);
+			}
+
+			
+			for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+			{
+				float fRedDecodedData = 0.0f;
+				float fGrnDecodedData = 0.0f;
+				if (a_pblockParent->GetImageSource()->GetFormat() == Image::Format::RG11)
+				{
+					fRedDecodedData = DecodePixelRed(m_fRedBase, m_fRedMultiplier, m_uiRedModifierTableIndex, m_auiRedSelectors[uiPixel]);
+					fGrnDecodedData = DecodePixelRed(m_fGrnBase, m_fGrnMultiplier, m_uiGrnModifierTableIndex, m_auiGrnSelectors[uiPixel]);
+				}
+				else if (a_pblockParent->GetImageSource()->GetFormat() == Image::Format::SIGNED_RG11)
+				{
+					fRedDecodedData = DecodePixelRed(m_fRedBase + 128, m_fRedMultiplier, m_uiRedModifierTableIndex, m_auiRedSelectors[uiPixel]);
+					fGrnDecodedData = DecodePixelRed(m_fGrnBase + 128, m_fGrnMultiplier, m_uiGrnModifierTableIndex, m_auiGrnSelectors[uiPixel]);
+				}
+				else
+				{
+					assert(0);
+				}
+				m_afrgbaDecodedColors[uiPixel] = ColorFloatRGBA(fRedDecodedData, fGrnDecodedData, 0.0f, 1.0f);
+			}
+
+		}
+
+		CalcBlockError();
+ 	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// perform a single encoding iteration
+	// replace the encoding if a better encoding was found
+	// subsequent iterations generally take longer for each iteration
+	// set m_boolDone if encoding is perfect or encoding is finished based on a_fEffort
+	//
+	void Block4x4Encoding_RG11::PerformIteration(float a_fEffort)
+	{
+		assert(!m_boolDone);
+
+		switch (m_uiEncodingIterations)
+		{
+		case 0:
+			m_fError = FLT_MAX;
+			m_fGrnBlockError = FLT_MAX;		// artificially high value
+			m_fRedBlockError = FLT_MAX;
+			CalculateR11(8, 0.0f, 0.0f);
+			CalculateG11(8, 0.0f, 0.0f);
+			m_fError = (m_fGrnBlockError + m_fRedBlockError);
+			break;
+
+		case 1:
+			CalculateR11(8, 2.0f, 1.0f);
+			CalculateG11(8, 2.0f, 1.0f);
+			m_fError = (m_fGrnBlockError + m_fRedBlockError);
+			if (a_fEffort <= 24.5f)
+			{
+				m_boolDone = true;
+			}
+			break;
+
+		case 2:
+			CalculateR11(8, 12.0f, 1.0f);
+			CalculateG11(8, 12.0f, 1.0f);
+			m_fError = (m_fGrnBlockError + m_fRedBlockError);
+			if (a_fEffort <= 49.5f)
+			{
+				m_boolDone = true;
+			}
+			break;
+
+		case 3:
+			CalculateR11(7, 6.0f, 1.0f);
+			CalculateG11(7, 6.0f, 1.0f);
+			m_fError = (m_fGrnBlockError + m_fRedBlockError);
+			break;
+
+		case 4:
+			CalculateR11(6, 3.0f, 1.0f);
+			CalculateG11(6, 3.0f, 1.0f);
+			m_fError = (m_fGrnBlockError + m_fRedBlockError);
+			break;
+
+		case 5:
+			CalculateR11(5, 1.0f, 0.0f);
+			CalculateG11(5, 1.0f, 0.0f);
+			m_fError = (m_fGrnBlockError + m_fRedBlockError);
+			m_boolDone = true;
+			break;
+
+		default:
+			assert(0);
+			break;
+		}
+
+		m_uiEncodingIterations++;
+		SetDoneIfPerfect();
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// find the best combination of base color, multiplier and selectors
+	//
+	// a_uiSelectorsUsed limits the number of selector combinations to try
+	// a_fBaseRadius limits the range of base colors to try
+	// a_fMultiplierRadius limits the range of multipliers to try
+	//
+	void Block4x4Encoding_RG11::CalculateG11(unsigned int a_uiSelectorsUsed,
+		float a_fBaseRadius, float a_fMultiplierRadius)
+	{
+		// maps from virtual (monotonic) selector to etc selector
+		static const unsigned int auiVirtualSelectorMap[8] = { 3, 2, 1, 0, 4, 5, 6, 7 };
+
+		// find min/max Grn
+		float fMinGrn = 1.0f;
+		float fMaxGrn = 0.0f;
+		for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+		{
+			// ignore border pixels
+			float fAlpha = m_pafrgbaSource[uiPixel].fA;
+			if (isnan(fAlpha))
+			{
+				continue;
+			}
+
+			float fGrn = m_pafrgbaSource[uiPixel].fG;
+
+			if (fGrn < fMinGrn)
+			{
+				fMinGrn = fGrn;
+			}
+			if (fGrn > fMaxGrn)
+			{
+				fMaxGrn = fGrn;
+			}
+		}
+		assert(fMinGrn <= fMaxGrn);
+
+		float fGrnRange = (fMaxGrn - fMinGrn);
+
+		// try each modifier table entry							  
+		for (unsigned int uiTableEntry = 0; uiTableEntry < MODIFIER_TABLE_ENTRYS; uiTableEntry++)
+		{
+			for (unsigned int uiMinVirtualSelector = 0;
+			uiMinVirtualSelector <= (8 - a_uiSelectorsUsed);
+				uiMinVirtualSelector++)
+			{
+				unsigned int uiMaxVirtualSelector = uiMinVirtualSelector + a_uiSelectorsUsed - 1;
+
+				unsigned int uiMinSelector = auiVirtualSelectorMap[uiMinVirtualSelector];
+				unsigned int uiMaxSelector = auiVirtualSelectorMap[uiMaxVirtualSelector];
+
+				float fTableEntryCenter = -s_aafModifierTable[uiTableEntry][uiMinSelector];
+
+				float fTableEntryRange = s_aafModifierTable[uiTableEntry][uiMaxSelector] -
+					s_aafModifierTable[uiTableEntry][uiMinSelector];
+
+				float fCenterRatio = fTableEntryCenter / fTableEntryRange;
+
+				float fCenter = fMinGrn + fCenterRatio*fGrnRange;
+				fCenter = roundf(255.0f * fCenter) / 255.0f;
+
+				float fMinBase = fCenter - (a_fBaseRadius / 255.0f);
+				if (fMinBase < 0.0f)
+				{
+					fMinBase = 0.0f;
+				}
+
+				float fMaxBase = fCenter + (a_fBaseRadius / 255.0f);
+				if (fMaxBase > 1.0f)
+				{
+					fMaxBase = 1.0f;
+				}
+
+				for (float fBase = fMinBase; fBase <= fMaxBase; fBase += (0.999999f / 255.0f))
+				{
+					float fRangeMultiplier = roundf(fGrnRange / fTableEntryRange);
+
+					float fMinMultiplier = fRangeMultiplier - a_fMultiplierRadius;
+					if (fMinMultiplier < 1.0f)
+					{
+						fMinMultiplier = 0.0f;
+					}
+					else if (fMinMultiplier > 15.0f)
+					{
+						fMinMultiplier = 15.0f;
+					}
+
+					float fMaxMultiplier = fRangeMultiplier + a_fMultiplierRadius;
+					if (fMaxMultiplier < 1.0f)
+					{
+						fMaxMultiplier = 1.0f;
+					}
+					else if (fMaxMultiplier > 15.0f)
+					{
+						fMaxMultiplier = 15.0f;
+					}
+
+					for (float fMultiplier = fMinMultiplier; fMultiplier <= fMaxMultiplier; fMultiplier += 1.0f)
+					{
+						// find best selector for each pixel
+						unsigned int auiBestSelectors[PIXELS];
+						float afBestGrnError[PIXELS];
+						float afBestPixelGrn[PIXELS];
+
+						for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+						{
+							float fBestPixelGrnError = FLT_MAX;
+
+							for (unsigned int uiSelector = 0; uiSelector < SELECTORS; uiSelector++)
+							{
+								//DecodePixelRed is not red channel specific
+								float fPixelGrn = DecodePixelRed(fBase * 255.0f, fMultiplier, uiTableEntry, uiSelector);
+								
+								ColorFloatRGBA frgba(m_pafrgbaSource[uiPixel].fR, fPixelGrn, 0.0f, 1.0f);
+									
+								float fPixelGrnError = CalcPixelError(frgba, 1.0f, m_pafrgbaSource[uiPixel]);
+
+								if (fPixelGrnError < fBestPixelGrnError)
+								{
+									fBestPixelGrnError = fPixelGrnError;
+									auiBestSelectors[uiPixel] = uiSelector;
+									afBestGrnError[uiPixel] = fBestPixelGrnError;
+									afBestPixelGrn[uiPixel] = fPixelGrn;
+								}
+							}
+						}
+						float fBlockError = 0.0f;
+						for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+						{
+							fBlockError += afBestGrnError[uiPixel];
+						}
+
+						if (fBlockError < m_fGrnBlockError)
+						{
+							m_fGrnBlockError = fBlockError;
+
+							if (m_pblockParent->GetImageSource()->GetFormat() == Image::Format::RG11)
+							{
+								m_fGrnBase = 255.0f * fBase;
+							}
+							else if (m_pblockParent->GetImageSource()->GetFormat() == Image::Format::SIGNED_RG11)
+							{
+								m_fGrnBase = (fBase * 255) - 128;
+							}
+							else
+							{
+								assert(0);
+							}
+							m_fGrnMultiplier = fMultiplier;
+							m_uiGrnModifierTableIndex = uiTableEntry;
+							for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+							{
+								m_auiGrnSelectors[uiPixel] = auiBestSelectors[uiPixel];
+								m_afrgbaDecodedColors[uiPixel].fG = afBestPixelGrn[uiPixel];
+								m_afDecodedAlphas[uiPixel] = 1.0f;
+							}
+						}
+					}
+				}
+
+			}
+		}
+	}
+	
+	// ----------------------------------------------------------------------------------------------------
+	// set the encoding bits based on encoding state
+	//
+	void Block4x4Encoding_RG11::SetEncodingBits(void)
+	{
+		unsigned long long int ulliSelectorBitsR = 0;
+		unsigned long long int ulliSelectorBitsG = 0;
+		for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+		{
+			unsigned int uiShift = 45 - (3 * uiPixel);
+			ulliSelectorBitsR |= ((unsigned long long int)m_auiRedSelectors[uiPixel]) << uiShift;
+			ulliSelectorBitsG |= ((unsigned long long int)m_auiGrnSelectors[uiPixel]) << uiShift;
+		}
+		if (m_pblockParent->GetImageSource()->GetFormat() == Image::Format::RG11)
+		{
+			m_pencodingbitsRG11->data.baseR = (unsigned char)roundf(m_fRedBase);
+		}
+		else if (m_pblockParent->GetImageSource()->GetFormat() == Image::Format::SIGNED_RG11)
+		{
+			m_pencodingbitsRG11->data.baseR = (signed char)roundf(m_fRedBase);
+		}
+		else
+		{
+			assert(0);
+		}
+		m_pencodingbitsRG11->data.tableIndexR = m_uiRedModifierTableIndex;
+		m_pencodingbitsRG11->data.multiplierR = (unsigned char)roundf(m_fRedMultiplier);
+
+		m_pencodingbitsRG11->data.selectorsR0 = ulliSelectorBitsR >> 40;
+		m_pencodingbitsRG11->data.selectorsR1 = ulliSelectorBitsR >> 32;
+		m_pencodingbitsRG11->data.selectorsR2 = ulliSelectorBitsR >> 24;
+		m_pencodingbitsRG11->data.selectorsR3 = ulliSelectorBitsR >> 16;
+		m_pencodingbitsRG11->data.selectorsR4 = ulliSelectorBitsR >> 8;
+		m_pencodingbitsRG11->data.selectorsR5 = ulliSelectorBitsR;
+
+		if (m_pblockParent->GetImageSource()->GetFormat() == Image::Format::RG11)
+		{
+			m_pencodingbitsRG11->data.baseG = (unsigned char)roundf(m_fGrnBase);
+		}
+		else if (m_pblockParent->GetImageSource()->GetFormat() == Image::Format::SIGNED_RG11)
+		{
+			m_pencodingbitsRG11->data.baseG = (signed char)roundf(m_fGrnBase);
+		}
+		else
+		{
+			assert(0);
+		}
+		m_pencodingbitsRG11->data.tableIndexG = m_uiGrnModifierTableIndex;
+		m_pencodingbitsRG11->data.multiplierG = (unsigned char)roundf(m_fGrnMultiplier);
+
+		m_pencodingbitsRG11->data.selectorsG0 = ulliSelectorBitsG >> 40;
+		m_pencodingbitsRG11->data.selectorsG1 = ulliSelectorBitsG >> 32;
+		m_pencodingbitsRG11->data.selectorsG2 = ulliSelectorBitsG >> 24;
+		m_pencodingbitsRG11->data.selectorsG3 = ulliSelectorBitsG >> 16;
+		m_pencodingbitsRG11->data.selectorsG4 = ulliSelectorBitsG >> 8;
+		m_pencodingbitsRG11->data.selectorsG5 = ulliSelectorBitsG;
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+}

extern/EtcLib/EtcCodec/EtcBlock4x4Encoding_RG11.h

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "EtcBlock4x4Encoding_RGB8.h"
+#include "EtcBlock4x4Encoding_R11.h"
+
+namespace Etc
+{
+	class Block4x4EncodingBits_RG11;
+
+	// ################################################################################
+	// Block4x4Encoding_RG11
+	// ################################################################################
+
+	class Block4x4Encoding_RG11 : public Block4x4Encoding_R11
+	{
+		float m_fGrnBase;
+		float m_fGrnMultiplier;
+		float m_fGrnBlockError;
+		unsigned int m_auiGrnSelectors[PIXELS];
+		unsigned int m_uiGrnModifierTableIndex;
+	public:
+
+		Block4x4Encoding_RG11(void);
+		virtual ~Block4x4Encoding_RG11(void);
+
+		virtual void InitFromSource(Block4x4 *a_pblockParent,
+			ColorFloatRGBA *a_pafrgbaSource,
+
+			unsigned char *a_paucEncodingBits, ErrorMetric a_errormetric);
+
+		virtual void InitFromEncodingBits(Block4x4 *a_pblockParent,
+			unsigned char *a_paucEncodingBits,
+			ColorFloatRGBA *a_pafrgbaSource,
+
+			ErrorMetric a_errormetric);
+
+		virtual void PerformIteration(float a_fEffort);
+
+		virtual void SetEncodingBits(void);
+
+		Block4x4EncodingBits_RG11 *m_pencodingbitsRG11;
+
+		void CalculateG11(unsigned int a_uiSelectorsUsed, float a_fBaseRadius, float a_fMultiplierRadius);
+
+		inline float GetGrnBase(void) const
+		{
+			return m_fGrnBase;
+		}
+
+		inline float GetGrnMultiplier(void) const
+		{
+			return m_fGrnMultiplier;
+		}
+
+		inline int GetGrnTableIndex(void) const
+		{
+			return m_uiGrnModifierTableIndex;
+		}
+
+		inline const unsigned int * GetGrnSelectors(void) const
+		{
+			return m_auiGrnSelectors;
+		}
+
+	};
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+
+} // namespace Etc

extern/EtcLib/EtcCodec/EtcBlock4x4Encoding_RGB8.h

@@ -0,0 +1,96 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "EtcBlock4x4Encoding_ETC1.h"
+
+namespace Etc
+{
+
+	class Block4x4Encoding_RGB8 : public Block4x4Encoding_ETC1
+	{
+	public:
+
+		Block4x4Encoding_RGB8(void);
+		virtual ~Block4x4Encoding_RGB8(void);
+
+		virtual void InitFromEncodingBits(Block4x4 *a_pblockParent,
+											unsigned char *a_paucEncodingBits,
+											ColorFloatRGBA *a_pafrgbaSource,
+
+											ErrorMetric a_errormetric);
+
+		virtual void PerformIteration(float a_fEffort);
+		
+		virtual void SetEncodingBits(void);
+
+		inline ColorFloatRGBA GetColor3(void) const
+		{
+			return m_frgbaColor3;
+		}
+
+	protected:
+
+		static const unsigned int PLANAR_CORNER_COLORS = 3;
+		static const unsigned int MAX_PLANAR_REGRESSION_SIZE = 4;
+		static const unsigned int TH_DISTANCES = 8;
+
+		static float s_afTHDistanceTable[TH_DISTANCES];
+
+		void TryPlanar(unsigned int a_uiRadius);
+		void TryTAndH(unsigned int a_uiRadius);
+
+		void InitFromEncodingBits_Planar(void);
+
+		ColorFloatRGBA	m_frgbaColor3;		// used for planar
+
+		void SetEncodingBits_T(void);
+		void SetEncodingBits_H(void);
+		void SetEncodingBits_Planar(void);
+
+		// state shared between iterations
+		ColorFloatRGBA	m_frgbaOriginalColor1_TAndH;
+		ColorFloatRGBA	m_frgbaOriginalColor2_TAndH;
+
+		void CalculateBaseColorsForTAndH(void);
+		void TryT(unsigned int a_uiRadius);
+		void TryT_BestSelectorCombination(void);
+		void TryH(unsigned int a_uiRadius);
+		void TryH_BestSelectorCombination(void);
+
+	private:
+
+		void InitFromEncodingBits_T(void);
+		void InitFromEncodingBits_H(void);
+
+		void CalculatePlanarCornerColors(void);
+
+		void ColorRegression(ColorFloatRGBA *a_pafrgbaPixels, unsigned int a_uiPixels,
+			ColorFloatRGBA *a_pfrgbaSlope, ColorFloatRGBA *a_pfrgbaOffset);
+
+		bool TwiddlePlanar(void);
+		bool TwiddlePlanarR();
+		bool TwiddlePlanarG();
+		bool TwiddlePlanarB();
+
+		void DecodePixels_T(void);
+		void DecodePixels_H(void);
+		void DecodePixels_Planar(void);
+
+	};
+
+} // namespace Etc

extern/EtcLib/EtcCodec/EtcBlock4x4Encoding_RGB8A1.h

@@ -0,0 +1,129 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "EtcBlock4x4Encoding_RGB8.h"
+#include "EtcErrorMetric.h"
+#include "EtcBlock4x4EncodingBits.h"
+
+namespace Etc
+{
+
+	// ################################################################################
+	// Block4x4Encoding_RGB8A1
+	// RGB8A1 if not completely opaque or transparent
+	// ################################################################################
+
+	class Block4x4Encoding_RGB8A1 : public Block4x4Encoding_RGB8
+	{
+	public:
+
+		static const unsigned int TRANSPARENT_SELECTOR = 2;
+
+		Block4x4Encoding_RGB8A1(void);
+		virtual ~Block4x4Encoding_RGB8A1(void);
+
+		virtual void InitFromSource(Block4x4 *a_pblockParent,
+									ColorFloatRGBA *a_pafrgbaSource,
+									unsigned char *a_paucEncodingBits,
+									ErrorMetric a_errormetric);
+
+		virtual void InitFromEncodingBits(Block4x4 *a_pblockParent,
+											unsigned char *a_paucEncodingBits,
+											ColorFloatRGBA *a_pafrgbaSource,
+											ErrorMetric a_errormetric);
+
+		virtual void PerformIteration(float a_fEffort);
+
+		virtual void SetEncodingBits(void);
+
+		void InitFromEncodingBits_ETC1(Block4x4 *a_pblockParent,
+										unsigned char *a_paucEncodingBits,
+										ColorFloatRGBA *a_pafrgbaSource,
+										ErrorMetric a_errormetric);
+
+		void InitFromEncodingBits_T(void);
+		void InitFromEncodingBits_H(void);
+
+		void PerformFirstIteration(void);
+
+		void Decode_ETC1(void);
+		void DecodePixels_T(void);
+		void DecodePixels_H(void);
+		void SetEncodingBits_ETC1(void);
+		void SetEncodingBits_T(void);
+		void SetEncodingBits_H(void);
+
+	protected:
+
+		bool m_boolOpaque;				// all source pixels have alpha >= 0.5
+		bool m_boolTransparent;			// all source pixels have alpha < 0.5
+		bool m_boolPunchThroughPixels;	// some source pixels have alpha < 0.5
+
+		static float s_aafCwOpaqueUnsetTable[CW_RANGES][SELECTORS];
+
+	private:
+
+		void TryDifferential(bool a_boolFlip, unsigned int a_uiRadius,
+								int a_iGrayOffset1, int a_iGrayOffset2);
+		void TryDifferentialHalf(DifferentialTrys::Half *a_phalf);
+
+		void TryT(unsigned int a_uiRadius);
+		void TryT_BestSelectorCombination(void);
+		void TryH(unsigned int a_uiRadius);
+		void TryH_BestSelectorCombination(void);
+
+		void TryDegenerates1(void);
+		void TryDegenerates2(void);
+		void TryDegenerates3(void);
+		void TryDegenerates4(void);
+
+	};
+
+	// ################################################################################
+	// Block4x4Encoding_RGB8A1_Opaque
+	// RGB8A1 if all pixels have alpha==1
+	// ################################################################################
+
+	class Block4x4Encoding_RGB8A1_Opaque : public Block4x4Encoding_RGB8A1
+	{
+	public:
+
+		virtual void PerformIteration(float a_fEffort);
+
+		void PerformFirstIteration(void);
+
+	private:
+
+	};
+
+	// ################################################################################
+	// Block4x4Encoding_RGB8A1_Transparent
+	// RGB8A1 if all pixels have alpha==0
+	// ################################################################################
+
+	class Block4x4Encoding_RGB8A1_Transparent : public Block4x4Encoding_RGB8A1
+	{
+	public:
+
+		virtual void PerformIteration(float a_fEffort);
+
+	private:
+
+	};
+
+} // namespace Etc

extern/EtcLib/EtcCodec/EtcBlock4x4Encoding_RGBA8.cpp

@@ -0,0 +1,474 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+EtcBlock4x4Encoding_RGBA8.cpp contains:
+	Block4x4Encoding_RGBA8
+	Block4x4Encoding_RGBA8_Opaque
+	Block4x4Encoding_RGBA8_Transparent
+
+These encoders are used when targetting file format RGBA8.
+
+Block4x4Encoding_RGBA8_Opaque is used when all pixels in the 4x4 block are opaque
+Block4x4Encoding_RGBA8_Transparent is used when all pixels in the 4x4 block are transparent
+Block4x4Encoding_RGBA8 is used when there is a mixture of alphas in the 4x4 block
+
+*/
+
+#include "EtcConfig.h"
+#include "EtcBlock4x4Encoding_RGBA8.h"
+
+#include "EtcBlock4x4EncodingBits.h"
+#include "EtcBlock4x4.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <float.h>
+#include <limits>
+
+namespace Etc
+{
+
+	// ####################################################################################################
+	// Block4x4Encoding_RGBA8
+	// ####################################################################################################
+
+	float Block4x4Encoding_RGBA8::s_aafModifierTable[MODIFIER_TABLE_ENTRYS][ALPHA_SELECTORS]
+	{
+		{ -3.0f / 255.0f, -6.0f / 255.0f,  -9.0f / 255.0f, -15.0f / 255.0f, 2.0f / 255.0f, 5.0f / 255.0f, 8.0f / 255.0f, 14.0f / 255.0f },
+		{ -3.0f / 255.0f, -7.0f / 255.0f, -10.0f / 255.0f, -13.0f / 255.0f, 2.0f / 255.0f, 6.0f / 255.0f, 9.0f / 255.0f, 12.0f / 255.0f },
+		{ -2.0f / 255.0f, -5.0f / 255.0f,  -8.0f / 255.0f, -13.0f / 255.0f, 1.0f / 255.0f, 4.0f / 255.0f, 7.0f / 255.0f, 12.0f / 255.0f },
+		{ -2.0f / 255.0f, -4.0f / 255.0f,  -6.0f / 255.0f, -13.0f / 255.0f, 1.0f / 255.0f, 3.0f / 255.0f, 5.0f / 255.0f, 12.0f / 255.0f },
+
+		{ -3.0f / 255.0f, -6.0f / 255.0f,  -8.0f / 255.0f, -12.0f / 255.0f, 2.0f / 255.0f, 5.0f / 255.0f, 7.0f / 255.0f, 11.0f / 255.0f },
+		{ -3.0f / 255.0f, -7.0f / 255.0f,  -9.0f / 255.0f, -11.0f / 255.0f, 2.0f / 255.0f, 6.0f / 255.0f, 8.0f / 255.0f, 10.0f / 255.0f },
+		{ -4.0f / 255.0f, -7.0f / 255.0f,  -8.0f / 255.0f, -11.0f / 255.0f, 3.0f / 255.0f, 6.0f / 255.0f, 7.0f / 255.0f, 10.0f / 255.0f },
+		{ -3.0f / 255.0f, -5.0f / 255.0f,  -8.0f / 255.0f, -11.0f / 255.0f, 2.0f / 255.0f, 4.0f / 255.0f, 7.0f / 255.0f, 10.0f / 255.0f },
+
+		{ -2.0f / 255.0f, -6.0f / 255.0f,  -8.0f / 255.0f, -10.0f / 255.0f, 1.0f / 255.0f, 5.0f / 255.0f, 7.0f / 255.0f,  9.0f / 255.0f },
+		{ -2.0f / 255.0f, -5.0f / 255.0f,  -8.0f / 255.0f, -10.0f / 255.0f, 1.0f / 255.0f, 4.0f / 255.0f, 7.0f / 255.0f,  9.0f / 255.0f },
+		{ -2.0f / 255.0f, -4.0f / 255.0f,  -8.0f / 255.0f, -10.0f / 255.0f, 1.0f / 255.0f, 3.0f / 255.0f, 7.0f / 255.0f,  9.0f / 255.0f },
+		{ -2.0f / 255.0f, -5.0f / 255.0f,  -7.0f / 255.0f, -10.0f / 255.0f, 1.0f / 255.0f, 4.0f / 255.0f, 6.0f / 255.0f,  9.0f / 255.0f },
+
+		{ -3.0f / 255.0f, -4.0f / 255.0f,  -7.0f / 255.0f, -10.0f / 255.0f, 2.0f / 255.0f, 3.0f / 255.0f, 6.0f / 255.0f,  9.0f / 255.0f },
+		{ -1.0f / 255.0f, -2.0f / 255.0f,  -3.0f / 255.0f, -10.0f / 255.0f, 0.0f / 255.0f, 1.0f / 255.0f, 2.0f / 255.0f,  9.0f / 255.0f },
+		{ -4.0f / 255.0f, -6.0f / 255.0f,  -8.0f / 255.0f,  -9.0f / 255.0f, 3.0f / 255.0f, 5.0f / 255.0f, 7.0f / 255.0f,  8.0f / 255.0f },
+		{ -3.0f / 255.0f, -5.0f / 255.0f,  -7.0f / 255.0f,  -9.0f / 255.0f, 2.0f / 255.0f, 4.0f / 255.0f, 6.0f / 255.0f,  8.0f / 255.0f }
+	};
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+	Block4x4Encoding_RGBA8::Block4x4Encoding_RGBA8(void)
+	{
+
+		m_pencodingbitsA8 = nullptr;
+
+	}
+	Block4x4Encoding_RGBA8::~Block4x4Encoding_RGBA8(void) {}
+	// ----------------------------------------------------------------------------------------------------
+	// initialization prior to encoding
+	// a_pblockParent points to the block associated with this encoding
+	// a_errormetric is used to choose the best encoding
+	// a_pafrgbaSource points to a 4x4 block subset of the source image
+	// a_paucEncodingBits points to the final encoding bits
+	//
+	void Block4x4Encoding_RGBA8::InitFromSource(Block4x4 *a_pblockParent,
+												ColorFloatRGBA *a_pafrgbaSource,
+												unsigned char *a_paucEncodingBits, ErrorMetric a_errormetric)
+	{
+		Block4x4Encoding::Init(a_pblockParent, a_pafrgbaSource,a_errormetric);
+
+		m_pencodingbitsA8 = (Block4x4EncodingBits_A8 *)a_paucEncodingBits;
+		m_pencodingbitsRGB8 = (Block4x4EncodingBits_RGB8 *)(a_paucEncodingBits + sizeof(Block4x4EncodingBits_A8));
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// initialization from the encoding bits of a previous encoding
+	// a_pblockParent points to the block associated with this encoding
+	// a_errormetric is used to choose the best encoding
+	// a_pafrgbaSource points to a 4x4 block subset of the source image
+	// a_paucEncodingBits points to the final encoding bits of a previous encoding
+	//
+	void Block4x4Encoding_RGBA8::InitFromEncodingBits(Block4x4 *a_pblockParent,
+														unsigned char *a_paucEncodingBits,
+														ColorFloatRGBA *a_pafrgbaSource,
+														ErrorMetric a_errormetric)
+	{
+
+		m_pencodingbitsA8 = (Block4x4EncodingBits_A8 *)a_paucEncodingBits;
+		m_pencodingbitsRGB8 = (Block4x4EncodingBits_RGB8 *)(a_paucEncodingBits + sizeof(Block4x4EncodingBits_A8));
+
+		// init RGB portion
+		Block4x4Encoding_RGB8::InitFromEncodingBits(a_pblockParent,
+													(unsigned char *) m_pencodingbitsRGB8,
+													a_pafrgbaSource,
+													a_errormetric);
+
+		// init A8 portion
+		// has to be done after InitFromEncodingBits()
+		{
+			m_fBase = m_pencodingbitsA8->data.base / 255.0f;
+			m_fMultiplier = (float)m_pencodingbitsA8->data.multiplier;
+			m_uiModifierTableIndex = m_pencodingbitsA8->data.table;
+
+			unsigned long long int ulliSelectorBits = 0;
+			ulliSelectorBits |= (unsigned long long int)m_pencodingbitsA8->data.selectors0 << 40;
+			ulliSelectorBits |= (unsigned long long int)m_pencodingbitsA8->data.selectors1 << 32;
+			ulliSelectorBits |= (unsigned long long int)m_pencodingbitsA8->data.selectors2 << 24;
+			ulliSelectorBits |= (unsigned long long int)m_pencodingbitsA8->data.selectors3 << 16;
+			ulliSelectorBits |= (unsigned long long int)m_pencodingbitsA8->data.selectors4 << 8;
+			ulliSelectorBits |= (unsigned long long int)m_pencodingbitsA8->data.selectors5;
+			for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+			{
+				unsigned int uiShift = 45 - (3 * uiPixel);
+				m_auiAlphaSelectors[uiPixel] = (ulliSelectorBits >> uiShift) & (ALPHA_SELECTORS - 1);
+			}
+
+			// decode the alphas
+			// calc alpha error
+			m_fError = 0.0f;
+			for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+			{
+				m_afDecodedAlphas[uiPixel] = DecodePixelAlpha(m_fBase, m_fMultiplier,
+					m_uiModifierTableIndex,
+					m_auiAlphaSelectors[uiPixel]);
+
+				float fDeltaAlpha = m_afDecodedAlphas[uiPixel] - m_pafrgbaSource[uiPixel].fA;
+				m_fError += fDeltaAlpha * fDeltaAlpha;
+			}
+		}
+
+		// redo error calc to include alpha
+		CalcBlockError();
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// perform a single encoding iteration
+	// replace the encoding if a better encoding was found
+	// subsequent iterations generally take longer for each iteration
+	// set m_boolDone if encoding is perfect or encoding is finished based on a_fEffort
+	//
+	// similar to Block4x4Encoding_RGB8_Base::Encode_RGB8(), but with alpha added
+	//
+	void Block4x4Encoding_RGBA8::PerformIteration(float a_fEffort)
+	{
+		assert(!m_boolDone);
+
+		if (m_uiEncodingIterations == 0)
+		{
+			if (a_fEffort < 24.9f)
+			{
+				CalculateA8(0.0f);
+			}
+			else if (a_fEffort < 49.9f)
+			{
+				CalculateA8(1.0f);
+			}
+			else
+			{
+				CalculateA8(2.0f);
+			}
+		}
+
+		Block4x4Encoding_RGB8::PerformIteration(a_fEffort);
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// find the best combination of base alpga, multiplier and selectors
+	//
+	// a_fRadius limits the range of base alpha to try
+	//
+	void Block4x4Encoding_RGBA8::CalculateA8(float a_fRadius)
+	{
+
+		// find min/max alpha
+		float fMinAlpha = 1.0f;
+		float fMaxAlpha = 0.0f;
+		for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+		{
+			float fAlpha = m_pafrgbaSource[uiPixel].fA;
+
+			// ignore border pixels
+			if (isnan(fAlpha))
+			{
+				continue;
+			}
+
+			if (fAlpha < fMinAlpha)
+			{
+				fMinAlpha = fAlpha;
+			}
+			if (fAlpha > fMaxAlpha)
+			{
+				fMaxAlpha = fAlpha;
+			}
+		}
+		assert(fMinAlpha <= fMaxAlpha);
+
+		float fAlphaRange = fMaxAlpha - fMinAlpha;
+
+		// try each modifier table entry
+		m_fError = FLT_MAX;		// artificially high value
+		for (unsigned int uiTableEntry = 0; uiTableEntry < MODIFIER_TABLE_ENTRYS; uiTableEntry++)
+		{
+			static const unsigned int MIN_VALUE_SELECTOR = 3;
+			static const unsigned int MAX_VALUE_SELECTOR = 7;
+
+			float fTableEntryCenter = -s_aafModifierTable[uiTableEntry][MIN_VALUE_SELECTOR];
+
+			float fTableEntryRange = s_aafModifierTable[uiTableEntry][MAX_VALUE_SELECTOR] -
+				s_aafModifierTable[uiTableEntry][MIN_VALUE_SELECTOR];
+
+			float fCenterRatio = fTableEntryCenter / fTableEntryRange;
+
+			float fCenter = fMinAlpha + fCenterRatio*fAlphaRange;
+			fCenter = roundf(255.0f * fCenter) / 255.0f;
+
+			float fMinBase = fCenter - (a_fRadius / 255.0f);
+			if (fMinBase < 0.0f)
+			{
+				fMinBase = 0.0f;
+			}
+
+			float fMaxBase = fCenter + (a_fRadius / 255.0f);
+			if (fMaxBase > 1.0f)
+			{
+				fMaxBase = 1.0f;
+			}
+
+			for (float fBase = fMinBase; fBase <= fMaxBase; fBase += (0.999999f / 255.0f))
+			{
+
+				float fRangeMultiplier = roundf(fAlphaRange / fTableEntryRange);
+
+				float fMinMultiplier = fRangeMultiplier - a_fRadius;
+				if (fMinMultiplier < 1.0f)
+				{
+					fMinMultiplier = 1.0f;
+				}
+				else if (fMinMultiplier > 15.0f)
+				{
+					fMinMultiplier = 15.0f;
+				}
+
+				float fMaxMultiplier = fRangeMultiplier + a_fRadius;
+				if (fMaxMultiplier < 1.0f)
+				{
+					fMaxMultiplier = 1.0f;
+				}
+				else if (fMaxMultiplier > 15.0f)
+				{
+					fMaxMultiplier = 15.0f;
+				}
+
+				for (float fMultiplier = fMinMultiplier; fMultiplier <= fMaxMultiplier; fMultiplier += 1.0f)
+				{
+					// find best selector for each pixel
+					unsigned int auiBestSelectors[PIXELS];
+					float afBestAlphaError[PIXELS];
+					float afBestDecodedAlphas[PIXELS];
+					for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+					{
+						float fBestPixelAlphaError = FLT_MAX;
+						for (unsigned int uiSelector = 0; uiSelector < ALPHA_SELECTORS; uiSelector++)
+						{
+							float fDecodedAlpha = DecodePixelAlpha(fBase, fMultiplier, uiTableEntry, uiSelector);
+
+							// border pixels (NAN) should have zero error
+							float fPixelDeltaAlpha = isnan(m_pafrgbaSource[uiPixel].fA) ?
+															0.0f :
+															fDecodedAlpha - m_pafrgbaSource[uiPixel].fA;
+
+							float fPixelAlphaError = fPixelDeltaAlpha * fPixelDeltaAlpha;
+
+							if (fPixelAlphaError < fBestPixelAlphaError)
+							{
+								fBestPixelAlphaError = fPixelAlphaError;
+								auiBestSelectors[uiPixel] = uiSelector;
+								afBestAlphaError[uiPixel] = fBestPixelAlphaError;
+								afBestDecodedAlphas[uiPixel] = fDecodedAlpha;
+							}
+						}
+					}
+
+					float fBlockError = 0.0f;
+					for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+					{
+						fBlockError += afBestAlphaError[uiPixel];
+					}
+
+					if (fBlockError < m_fError)
+					{
+						m_fError = fBlockError;
+
+						m_fBase = fBase;
+						m_fMultiplier = fMultiplier;
+						m_uiModifierTableIndex = uiTableEntry;
+						for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+						{
+							m_auiAlphaSelectors[uiPixel] = auiBestSelectors[uiPixel];
+							m_afDecodedAlphas[uiPixel] = afBestDecodedAlphas[uiPixel];
+						}
+					}
+				}
+			}
+
+		}
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// set the encoding bits based on encoding state
+	//
+	void Block4x4Encoding_RGBA8::SetEncodingBits(void)
+	{
+
+		// set the RGB8 portion
+		Block4x4Encoding_RGB8::SetEncodingBits();
+
+		// set the A8 portion
+		{
+			m_pencodingbitsA8->data.base = (unsigned char)roundf(255.0f * m_fBase);
+			m_pencodingbitsA8->data.table = m_uiModifierTableIndex;
+			m_pencodingbitsA8->data.multiplier = (unsigned char)roundf(m_fMultiplier);
+
+			unsigned long long int ulliSelectorBits = 0;
+			for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+			{
+				unsigned int uiShift = 45 - (3 * uiPixel);
+				ulliSelectorBits |= ((unsigned long long int)m_auiAlphaSelectors[uiPixel]) << uiShift;
+			}
+
+			m_pencodingbitsA8->data.selectors0 = ulliSelectorBits >> 40;
+			m_pencodingbitsA8->data.selectors1 = ulliSelectorBits >> 32;
+			m_pencodingbitsA8->data.selectors2 = ulliSelectorBits >> 24;
+			m_pencodingbitsA8->data.selectors3 = ulliSelectorBits >> 16;
+			m_pencodingbitsA8->data.selectors4 = ulliSelectorBits >> 8;
+			m_pencodingbitsA8->data.selectors5 = ulliSelectorBits;
+		}
+
+	}
+
+	// ####################################################################################################
+	// Block4x4Encoding_RGBA8_Opaque
+	// ####################################################################################################
+
+	// ----------------------------------------------------------------------------------------------------
+	// perform a single encoding iteration
+	// replace the encoding if a better encoding was found
+	// subsequent iterations generally take longer for each iteration
+	// set m_boolDone if encoding is perfect or encoding is finished based on a_fEffort
+	//
+	void Block4x4Encoding_RGBA8_Opaque::PerformIteration(float a_fEffort)
+	{
+		assert(!m_boolDone);
+
+		if (m_uiEncodingIterations == 0)
+		{
+			m_fError = 0.0f;
+
+			for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+			{
+				m_afDecodedAlphas[uiPixel] = 1.0f;
+			}
+		}
+
+		Block4x4Encoding_RGB8::PerformIteration(a_fEffort);
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// set the encoding bits based on encoding state
+	//
+	void Block4x4Encoding_RGBA8_Opaque::SetEncodingBits(void)
+	{
+
+		// set the RGB8 portion
+		Block4x4Encoding_RGB8::SetEncodingBits();
+
+		// set the A8 portion
+		m_pencodingbitsA8->data.base = 255;
+		m_pencodingbitsA8->data.table = 15;
+		m_pencodingbitsA8->data.multiplier = 15;
+		m_pencodingbitsA8->data.selectors0 = 0xFF;
+		m_pencodingbitsA8->data.selectors1 = 0xFF;
+		m_pencodingbitsA8->data.selectors2 = 0xFF;
+		m_pencodingbitsA8->data.selectors3 = 0xFF;
+		m_pencodingbitsA8->data.selectors4 = 0xFF;
+		m_pencodingbitsA8->data.selectors5 = 0xFF;
+
+	}
+
+	// ####################################################################################################
+	// Block4x4Encoding_RGBA8_Transparent
+	// ####################################################################################################
+
+	// ----------------------------------------------------------------------------------------------------
+	// perform a single encoding iteration
+	// replace the encoding if a better encoding was found
+	// subsequent iterations generally take longer for each iteration
+	// set m_boolDone if encoding is perfect or encoding is finished based on a_fEffort
+	//
+	void Block4x4Encoding_RGBA8_Transparent::PerformIteration(float )
+	{
+		assert(!m_boolDone);
+		assert(m_uiEncodingIterations == 0);
+
+		m_mode = MODE_ETC1;
+		m_boolDiff = true;
+		m_boolFlip = false;
+
+		for (unsigned int uiPixel = 0; uiPixel < PIXELS; uiPixel++)
+		{
+			m_afrgbaDecodedColors[uiPixel] = ColorFloatRGBA();
+			m_afDecodedAlphas[uiPixel] = 0.0f;
+		}
+
+		m_fError = 0.0f;
+
+		m_boolDone = true;
+		m_uiEncodingIterations++;
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// set the encoding bits based on encoding state
+	//
+	void Block4x4Encoding_RGBA8_Transparent::SetEncodingBits(void)
+	{
+
+		Block4x4Encoding_RGB8::SetEncodingBits();
+
+		// set the A8 portion
+		m_pencodingbitsA8->data.base = 0;
+		m_pencodingbitsA8->data.table = 0;
+		m_pencodingbitsA8->data.multiplier = 1;
+		m_pencodingbitsA8->data.selectors0 = 0;
+		m_pencodingbitsA8->data.selectors1 = 0;
+		m_pencodingbitsA8->data.selectors2 = 0;
+		m_pencodingbitsA8->data.selectors3 = 0;
+		m_pencodingbitsA8->data.selectors4 = 0;
+		m_pencodingbitsA8->data.selectors5 = 0;
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+}

extern/EtcLib/EtcCodec/EtcBlock4x4Encoding_RGBA8.h

@@ -0,0 +1,121 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "EtcBlock4x4Encoding_RGB8.h"
+
+namespace Etc
+{
+	class Block4x4EncodingBits_A8;
+
+	// ################################################################################
+	// Block4x4Encoding_RGBA8
+	// RGBA8 if not completely opaque or transparent
+	// ################################################################################
+
+	class Block4x4Encoding_RGBA8 : public Block4x4Encoding_RGB8
+	{
+	public:
+
+		Block4x4Encoding_RGBA8(void);
+		virtual ~Block4x4Encoding_RGBA8(void);
+
+		virtual void InitFromSource(Block4x4 *a_pblockParent,
+									ColorFloatRGBA *a_pafrgbaSource,
+									unsigned char *a_paucEncodingBits, ErrorMetric a_errormetric);
+
+		virtual void InitFromEncodingBits(Block4x4 *a_pblockParent,
+											unsigned char *a_paucEncodingBits,
+											ColorFloatRGBA *a_pafrgbaSource,
+											ErrorMetric a_errormetric);
+
+		virtual void PerformIteration(float a_fEffort);
+
+		virtual void SetEncodingBits(void);
+
+	protected:
+
+		static const unsigned int MODIFIER_TABLE_ENTRYS = 16;
+		static const unsigned int ALPHA_SELECTOR_BITS = 3;
+		static const unsigned int ALPHA_SELECTORS = 1 << ALPHA_SELECTOR_BITS;
+
+		static float s_aafModifierTable[MODIFIER_TABLE_ENTRYS][ALPHA_SELECTORS];
+
+		void CalculateA8(float a_fRadius);
+
+		Block4x4EncodingBits_A8 *m_pencodingbitsA8;	// A8 portion of Block4x4EncodingBits_RGBA8
+
+		float m_fBase;
+		float m_fMultiplier;
+		unsigned int m_uiModifierTableIndex;
+		unsigned int m_auiAlphaSelectors[PIXELS];
+
+	private:
+
+		inline float DecodePixelAlpha(float a_fBase, float a_fMultiplier,
+										unsigned int a_uiTableIndex, unsigned int a_uiSelector)
+		{
+			float fPixelAlpha = a_fBase + 
+								a_fMultiplier*s_aafModifierTable[a_uiTableIndex][a_uiSelector];
+			if (fPixelAlpha < 0.0f)
+			{
+				fPixelAlpha = 0.0f;
+			}
+			else if (fPixelAlpha > 1.0f)
+			{
+				fPixelAlpha = 1.0f;
+			}
+
+			return fPixelAlpha;
+		}
+
+	};
+
+	// ################################################################################
+	// Block4x4Encoding_RGBA8_Opaque
+	// RGBA8 if all pixels have alpha==1
+	// ################################################################################
+
+	class Block4x4Encoding_RGBA8_Opaque : public Block4x4Encoding_RGBA8
+	{
+	public:
+
+		virtual void PerformIteration(float a_fEffort);
+
+		virtual void SetEncodingBits(void);
+
+	};
+
+	// ################################################################################
+	// Block4x4Encoding_RGBA8_Transparent
+	// RGBA8 if all pixels have alpha==0
+	// ################################################################################
+
+	class Block4x4Encoding_RGBA8_Transparent : public Block4x4Encoding_RGBA8
+	{
+	public:
+
+		virtual void PerformIteration(float a_fEffort);
+
+		virtual void SetEncodingBits(void);
+
+	};
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+
+} // namespace Etc

extern/EtcLib/EtcCodec/EtcDifferentialTrys.cpp

@@ -0,0 +1,173 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+EtcDifferentialTrys.cpp
+
+Gathers the results of the various encoding trys for both halves of a 4x4 block for Differential mode
+
+*/
+
+#include "EtcConfig.h"
+#include "EtcDifferentialTrys.h"
+
+#include <assert.h>
+
+namespace Etc
+{
+
+	// ----------------------------------------------------------------------------------------------------
+	// construct a list of trys (encoding attempts)
+	//
+	// a_frgbaColor1 is the basecolor for the first half
+	// a_frgbaColor2 is the basecolor for the second half
+	// a_pauiPixelMapping1 is the pixel order for the first half
+	// a_pauiPixelMapping2 is the pixel order for the second half
+	// a_uiRadius is the amount to vary the base colors
+	//
+	DifferentialTrys::DifferentialTrys(ColorFloatRGBA a_frgbaColor1, ColorFloatRGBA a_frgbaColor2,
+										const unsigned int *a_pauiPixelMapping1,
+										const unsigned int *a_pauiPixelMapping2,
+										unsigned int a_uiRadius,
+										int a_iGrayOffset1, int a_iGrayOffset2)
+	{
+		assert(a_uiRadius <= MAX_RADIUS);
+
+		m_boolSeverelyBentColors = false;
+
+		ColorFloatRGBA frgbaQuantizedColor1 = a_frgbaColor1.QuantizeR5G5B5();
+		ColorFloatRGBA frgbaQuantizedColor2 = a_frgbaColor2.QuantizeR5G5B5();
+
+		// quantize base colors
+		// ensure that trys with a_uiRadius don't overflow
+		int iRed1 = MoveAwayFromEdge(frgbaQuantizedColor1.IntRed(31.0f)+a_iGrayOffset1, a_uiRadius);
+		int iGreen1 = MoveAwayFromEdge(frgbaQuantizedColor1.IntGreen(31.0f) + a_iGrayOffset1, a_uiRadius);
+		int iBlue1 = MoveAwayFromEdge(frgbaQuantizedColor1.IntBlue(31.0f) + a_iGrayOffset1, a_uiRadius);
+		int iRed2 = MoveAwayFromEdge(frgbaQuantizedColor2.IntRed(31.0f) + a_iGrayOffset2, a_uiRadius);
+		int iGreen2 = MoveAwayFromEdge(frgbaQuantizedColor2.IntGreen(31.0f) + a_iGrayOffset2, a_uiRadius);
+		int iBlue2 = MoveAwayFromEdge(frgbaQuantizedColor2.IntBlue(31.0f) + a_iGrayOffset2, a_uiRadius);
+
+		int iDeltaRed = iRed2 - iRed1;
+		int iDeltaGreen = iGreen2 - iGreen1;
+		int iDeltaBlue = iBlue2 - iBlue1;
+
+		// make sure components are within range
+		{
+			if (iDeltaRed > 3)
+			{
+				if (iDeltaRed > 7)
+				{
+					m_boolSeverelyBentColors = true;
+				}
+
+				iRed1 += (iDeltaRed - 3) / 2;
+				iRed2 = iRed1 + 3;
+				iDeltaRed = 3;
+			}
+			else if (iDeltaRed < -4)
+			{
+				if (iDeltaRed < -8)
+				{
+					m_boolSeverelyBentColors = true;
+				}
+
+				iRed1 += (iDeltaRed + 4) / 2;
+				iRed2 = iRed1 - 4;
+				iDeltaRed = -4;
+			}
+			assert(iRed1 >= (signed)(0 + a_uiRadius) && iRed1 <= (signed)(31 - a_uiRadius));
+			assert(iRed2 >= (signed)(0 + a_uiRadius) && iRed2 <= (signed)(31 - a_uiRadius));
+			assert(iDeltaRed >= -4 && iDeltaRed <= 3);
+
+			if (iDeltaGreen > 3)
+			{
+				if (iDeltaGreen > 7)
+				{
+					m_boolSeverelyBentColors = true;
+				}
+
+				iGreen1 += (iDeltaGreen - 3) / 2;
+				iGreen2 = iGreen1 + 3;
+				iDeltaGreen = 3;
+			}
+			else if (iDeltaGreen < -4)
+			{
+				if (iDeltaGreen < -8)
+				{
+					m_boolSeverelyBentColors = true;
+				}
+
+				iGreen1 += (iDeltaGreen + 4) / 2;
+				iGreen2 = iGreen1 - 4;
+				iDeltaGreen = -4;
+			}
+			assert(iGreen1 >= (signed)(0 + a_uiRadius) && iGreen1 <= (signed)(31 - a_uiRadius));
+			assert(iGreen2 >= (signed)(0 + a_uiRadius) && iGreen2 <= (signed)(31 - a_uiRadius));
+			assert(iDeltaGreen >= -4 && iDeltaGreen <= 3);
+
+			if (iDeltaBlue > 3)
+			{
+				if (iDeltaBlue > 7)
+				{
+					m_boolSeverelyBentColors = true;
+				}
+
+				iBlue1 += (iDeltaBlue - 3) / 2;
+				iBlue2 = iBlue1 + 3;
+				iDeltaBlue = 3;
+			}
+			else if (iDeltaBlue < -4)
+			{
+				if (iDeltaBlue < -8)
+				{
+					m_boolSeverelyBentColors = true;
+				}
+
+				iBlue1 += (iDeltaBlue + 4) / 2;
+				iBlue2 = iBlue1 - 4;
+				iDeltaBlue = -4;
+			}
+			assert(iBlue1 >= (signed)(0+a_uiRadius) && iBlue1 <= (signed)(31 - a_uiRadius));
+			assert(iBlue2 >= (signed)(0 + a_uiRadius) && iBlue2 <= (signed)(31 - a_uiRadius));
+			assert(iDeltaBlue >= -4 && iDeltaBlue <= 3);
+		}
+
+		m_half1.Init(iRed1, iGreen1, iBlue1, a_pauiPixelMapping1, a_uiRadius);
+		m_half2.Init(iRed2, iGreen2, iBlue2, a_pauiPixelMapping2, a_uiRadius);
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+	void DifferentialTrys::Half::Init(int a_iRed, int a_iGreen, int a_iBlue, 
+										const unsigned int *a_pauiPixelMapping, unsigned int a_uiRadius)
+	{
+
+		m_iRed = a_iRed;
+		m_iGreen = a_iGreen;
+		m_iBlue = a_iBlue;
+
+		m_pauiPixelMapping = a_pauiPixelMapping;
+		m_uiRadius = a_uiRadius;
+
+		m_uiTrys = 0;
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+
+} // namespace Etc

extern/EtcLib/EtcCodec/EtcDifferentialTrys.h

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "EtcColorFloatRGBA.h"
+
+namespace Etc
+{
+
+	class DifferentialTrys
+	{
+	public:
+
+		static const unsigned int MAX_RADIUS = 2;
+
+		DifferentialTrys(ColorFloatRGBA a_frgbaColor1,
+							ColorFloatRGBA a_frgbaColor2,
+							const unsigned int *a_pauiPixelMapping1,
+							const unsigned int *a_pauiPixelMapping2,
+							unsigned int a_uiRadius,
+							int a_iGrayOffset1, int a_iGrayOffset2);
+
+		inline static int MoveAwayFromEdge(int a_i, int a_iDistance)
+		{
+			if (a_i < (0+ a_iDistance))
+			{
+				return (0 + a_iDistance);
+			}
+			else if (a_i > (31- a_iDistance))
+			{
+				return (31 - a_iDistance);
+			}
+
+			return a_i;
+		}
+
+		class Try
+		{
+        public :
+			static const unsigned int SELECTORS = 8;	// per half
+
+			int m_iRed;
+			int m_iGreen;
+			int m_iBlue;
+			unsigned int m_uiCW;
+			unsigned int m_auiSelectors[SELECTORS];
+			float m_fError;
+        };
+
+		class Half
+		{
+		public:
+
+			static const unsigned int MAX_TRYS = 125;
+
+			void Init(int a_iRed, int a_iGreen, int a_iBlue, 
+						const unsigned int *a_pauiPixelMapping,
+						unsigned int a_uiRadius);
+
+			// center of trys
+			int m_iRed;
+			int m_iGreen;
+			int m_iBlue;
+
+			const unsigned int *m_pauiPixelMapping;
+			unsigned int m_uiRadius;
+
+			unsigned int m_uiTrys;
+			Try m_atry[MAX_TRYS];
+
+			Try *m_ptryBest;
+		};
+
+		Half m_half1;
+		Half m_half2;
+
+		bool m_boolSeverelyBentColors;
+	};
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+
+} // namespace Etc

extern/EtcLib/EtcCodec/EtcErrorMetric.h

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+namespace Etc
+{
+
+	enum ErrorMetric
+	{
+		RGBA,
+		REC709,
+		NUMERIC,
+		NORMALXYZ,
+		//
+		ERROR_METRICS,
+		//
+		BT709 = REC709
+	};
+
+	inline const char *ErrorMetricToString(ErrorMetric errorMetric)
+	{
+		switch (errorMetric)
+		{
+		case RGBA:
+			return "RGBA";
+		case REC709:
+			return "REC709";
+		case NUMERIC:
+			return "NUMERIC";
+		case NORMALXYZ:
+			return "NORMALXYZ";
+		case ERROR_METRICS:
+		default:
+			return "UNKNOWN";
+		}
+	}
+} // namespace Etc

extern/EtcLib/EtcCodec/EtcIndividualTrys.cpp

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+EtcIndividualTrys.cpp
+
+Gathers the results of the various encoding trys for both halves of a 4x4 block for Individual mode
+
+*/
+
+#include "EtcConfig.h"
+#include "EtcIndividualTrys.h"
+
+#include <assert.h>
+
+namespace Etc
+{
+
+	// ----------------------------------------------------------------------------------------------------
+	// construct a list of trys (encoding attempts)
+	//
+	// a_frgbaColor1 is the basecolor for the first half
+	// a_frgbaColor2 is the basecolor for the second half
+	// a_pauiPixelMapping1 is the pixel order for the first half
+	// a_pauiPixelMapping2 is the pixel order for the second half
+	// a_uiRadius is the amount to vary the base colors
+	//
+	IndividualTrys::IndividualTrys(ColorFloatRGBA a_frgbaColor1, ColorFloatRGBA a_frgbaColor2,
+									const unsigned int *a_pauiPixelMapping1,
+									const unsigned int *a_pauiPixelMapping2,
+									unsigned int a_uiRadius)
+	{
+		assert(a_uiRadius <= MAX_RADIUS);
+
+		ColorFloatRGBA frgbaQuantizedColor1 = a_frgbaColor1.QuantizeR4G4B4();
+		ColorFloatRGBA frgbaQuantizedColor2 = a_frgbaColor2.QuantizeR4G4B4();
+
+		// quantize base colors
+		// ensure that trys with a_uiRadius don't overflow
+		int iRed1 = MoveAwayFromEdge(frgbaQuantizedColor1.IntRed(15.0f), a_uiRadius);
+		int iGreen1 = MoveAwayFromEdge(frgbaQuantizedColor1.IntGreen(15.0f), a_uiRadius);
+		int iBlue1 = MoveAwayFromEdge(frgbaQuantizedColor1.IntBlue(15.0f), a_uiRadius);
+		int iRed2 = MoveAwayFromEdge(frgbaQuantizedColor2.IntRed(15.0f), a_uiRadius);
+		int iGreen2 = MoveAwayFromEdge(frgbaQuantizedColor2.IntGreen(15.0f), a_uiRadius);
+		int iBlue2 = MoveAwayFromEdge(frgbaQuantizedColor2.IntBlue(15.0f), a_uiRadius);
+
+		m_half1.Init(iRed1, iGreen1, iBlue1, a_pauiPixelMapping1, a_uiRadius);
+		m_half2.Init(iRed2, iGreen2, iBlue2, a_pauiPixelMapping2, a_uiRadius);
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+	void IndividualTrys::Half::Init(int a_iRed, int a_iGreen, int a_iBlue,
+									const unsigned int *a_pauiPixelMapping, unsigned int a_uiRadius)
+	{
+
+		m_iRed = a_iRed;
+		m_iGreen = a_iGreen;
+		m_iBlue = a_iBlue;
+
+		m_pauiPixelMapping = a_pauiPixelMapping;
+		m_uiRadius = a_uiRadius;
+
+		m_uiTrys = 0;
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+
+} // namespace Etc

extern/EtcLib/EtcCodec/EtcIndividualTrys.h

@@ -0,0 +1,95 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "EtcColorFloatRGBA.h"
+
+namespace Etc
+{
+
+	class IndividualTrys
+	{
+	public:
+
+		static const unsigned int MAX_RADIUS = 1;
+
+		IndividualTrys(ColorFloatRGBA a_frgbaColor1,
+						ColorFloatRGBA a_frgbaColor2,
+						const unsigned int *a_pauiPixelMapping1,
+						const unsigned int *a_pauiPixelMapping2,
+						unsigned int a_uiRadius);
+
+		inline static int MoveAwayFromEdge(int a_i, int a_iDistance)
+		{
+			if (a_i < (0+ a_iDistance))
+			{
+				return (0 + a_iDistance);
+			}
+			else if (a_i > (15- a_iDistance))
+			{
+				return (15 - a_iDistance);
+			}
+
+			return a_i;
+		}
+
+		class Try
+		{
+        public :
+			static const unsigned int SELECTORS = 8;	// per half
+
+			int m_iRed;
+			int m_iGreen;
+			int m_iBlue;
+			unsigned int m_uiCW;
+			unsigned int m_auiSelectors[SELECTORS];
+			float m_fError;
+        };
+
+		class Half
+		{
+		public:
+
+			static const unsigned int MAX_TRYS = 27;
+
+			void Init(int a_iRed, int a_iGreen, int a_iBlue, 
+						const unsigned int *a_pauiPixelMapping,
+						unsigned int a_uiRadius);
+
+			// center of trys
+			int m_iRed;
+			int m_iGreen;
+			int m_iBlue;
+
+			const unsigned int *m_pauiPixelMapping;
+			unsigned int m_uiRadius;
+
+			unsigned int m_uiTrys;
+			Try m_atry[MAX_TRYS];
+
+			Try *m_ptryBest;
+		};
+
+		Half m_half1;
+		Half m_half2;
+
+	};
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+
+} // namespace Etc

extern/EtcLib/EtcCodec/EtcSortedBlockList.cpp

@@ -0,0 +1,228 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+EtcSortedBlockList.cpp
+
+SortedBlockList is a list of 4x4 blocks that can be used by the "effort" system to prioritize
+the encoding of the 4x4 blocks.
+
+The sorting is done with buckets, where each bucket is an indication of how much error each 4x4 block has
+
+*/
+
+#include "EtcConfig.h"
+#include "EtcSortedBlockList.h"
+
+#include "EtcBlock4x4.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+namespace Etc
+{
+
+	// ----------------------------------------------------------------------------------------------------
+	// construct an empty list
+	//
+	// allocate enough memory to add all of the image's 4x4 blocks later
+	// allocate enough buckets to sort the blocks
+	//
+	SortedBlockList::SortedBlockList(unsigned int a_uiImageBlocks, unsigned int a_uiBuckets)
+	{
+		m_uiImageBlocks = a_uiImageBlocks;
+		m_iBuckets = (int)a_uiBuckets;
+
+		m_uiAddedBlocks = 0;
+		m_uiSortedBlocks = 0;
+		m_palinkPool = new Link[m_uiImageBlocks];
+		m_pabucket = new Bucket[m_iBuckets];
+		m_fMaxError = 0.0f;
+
+		InitBuckets();
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	//
+	SortedBlockList::~SortedBlockList(void)
+	{
+		delete[] m_palinkPool;
+		delete[] m_pabucket;
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+    // add a 4x4 block to the list
+	// the 4x4 block will be sorted later
+	//
+    void SortedBlockList::AddBlock(Block4x4 *a_pblock)
+    {
+        assert(m_uiAddedBlocks < m_uiImageBlocks);
+        Link *plink = &m_palinkPool[m_uiAddedBlocks++];
+		plink->Init(a_pblock);
+    }
+
+	// ----------------------------------------------------------------------------------------------------
+	// sort all of the 4x4 blocks that have been added to the list
+	//
+	// first, determine the maximum error, then assign an error range to each bucket
+	// next, determine which bucket each 4x4 block belongs to based on the 4x4 block's error
+	// add the 4x4 block to the appropriate bucket
+	// lastly, walk thru the buckets and add each bucket to a sorted linked list
+	//
+	// the resultant sorting is an approximate sorting from most to least error
+	//
+    void SortedBlockList::Sort(void)
+    {
+		assert(m_uiAddedBlocks == m_uiImageBlocks);
+        InitBuckets();
+
+        // find max block error
+        m_fMaxError = -1.0f;
+
+        for (unsigned int uiLink = 0; uiLink < m_uiAddedBlocks; uiLink++)
+        {
+            Link *plinkBlock = &m_palinkPool[uiLink];
+
+            float fBlockError = plinkBlock->GetBlock()->GetError();
+            if (fBlockError > m_fMaxError)
+            {
+                m_fMaxError = fBlockError;
+            }
+        }
+        // prevent divide by zero or divide by negative
+        if (m_fMaxError <= 0.0f)
+        {
+            m_fMaxError = 1.0f;
+        }
+		//used for debugging
+		//int numDone = 0;
+        // put all of the blocks with unfinished encodings into the appropriate bucket
+		m_uiSortedBlocks = 0;
+        for (unsigned int uiLink = 0; uiLink < m_uiAddedBlocks; uiLink++)
+        {
+            Link *plinkBlock = &m_palinkPool[uiLink];
+
+			// if the encoding is done, don't add it to the list
+			if (plinkBlock->GetBlock()->GetEncoding()->IsDone())
+			{
+				//numDone++;
+				continue;
+			}
+
+            // calculate the appropriate sort bucket
+            float fBlockError = plinkBlock->GetBlock()->GetError();
+            int iBucket = (int) floorf(m_iBuckets * fBlockError / m_fMaxError);
+            // clamp to bucket index
+            iBucket = iBucket < 0 ? 0 : iBucket >= m_iBuckets ? m_iBuckets - 1 : iBucket;
+
+            // add block to bucket
+			{
+				Bucket *pbucket = &m_pabucket[iBucket];
+				if (pbucket->plinkLast)
+				{
+					pbucket->plinkLast->SetNext(plinkBlock);
+					pbucket->plinkLast = plinkBlock;
+				}
+				else
+				{
+					pbucket->plinkFirst = pbucket->plinkLast = plinkBlock;
+				}
+				plinkBlock->SetNext(nullptr);
+			}
+
+			m_uiSortedBlocks++;
+
+            if (0)
+            {
+                printf("%u: e=%.3f\n", uiLink, fBlockError);
+                Print();
+                printf("\n\n\n");
+            }
+        }
+		//printf("num blocks already done: %d\n",numDone);
+		//link the blocks together across buckets
+		m_plinkFirst = nullptr;
+		m_plinkLast = nullptr;
+		for (int iBucket = m_iBuckets - 1; iBucket >= 0; iBucket--)
+		{
+			Bucket *pbucket = &m_pabucket[iBucket];
+
+			if (pbucket->plinkFirst)
+			{
+				if (m_plinkFirst == nullptr)
+				{
+					m_plinkFirst = pbucket->plinkFirst;
+				}
+				else
+				{
+					assert(pbucket->plinkLast->GetNext() == nullptr);
+					m_plinkLast->SetNext(pbucket->plinkFirst);
+				}
+
+				m_plinkLast = pbucket->plinkLast;
+			}
+		}
+
+
+	}
+
+	// ----------------------------------------------------------------------------------------------------
+	// clear all of the buckets.  normally done in preparation for a sort
+	//
+	void SortedBlockList::InitBuckets(void)
+    {
+        for (int iBucket = 0; iBucket < m_iBuckets; iBucket++)
+        {
+            Bucket *pbucket = &m_pabucket[iBucket];
+
+            pbucket->plinkFirst = 0;
+            pbucket->plinkLast = 0;
+        }
+    }
+
+    // ----------------------------------------------------------------------------------------------------
+    // print out the list of sorted 4x4 blocks
+	// normally used for debugging
+	//
+    void SortedBlockList::Print(void)
+    {
+        for (int iBucket = m_iBuckets-1; iBucket >= 0; iBucket--)
+        {
+            Bucket *pbucket = &m_pabucket[iBucket];
+
+            unsigned int uiBlocks = 0;
+            for (Link *plink = pbucket->plinkFirst; plink != nullptr; plink = plink->GetNext() )
+            {
+                uiBlocks++;
+
+				if (plink == pbucket->plinkLast)
+				{
+					break;
+				}
+            }
+
+            float fBucketError = m_fMaxError * iBucket / m_iBuckets;
+            float fBucketRMS = sqrtf(fBucketError / (4.0f*16.0f) );
+            printf("%3d: e=%.3f rms=%.6f %u\n", iBucket, fBucketError, fBucketRMS, uiBlocks);
+        }
+    }
+
+    // ----------------------------------------------------------------------------------------------------
+    //
+
+}   // namespace Etc

extern/EtcLib/EtcCodec/EtcSortedBlockList.h

@@ -0,0 +1,124 @@
+/*
+ * Copyright 2015 The Etc2Comp Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+namespace Etc
+{
+	class Block4x4;
+
+    class SortedBlockList
+    {
+    public:
+
+		class Link
+		{
+		public:
+
+			inline void Init(Block4x4 *a_pblock)
+			{
+				m_pblock = a_pblock;
+				m_plinkNext = nullptr;
+			}
+
+			inline Block4x4 * GetBlock(void)
+			{
+				return m_pblock;
+			}
+
+			inline void SetNext(Link *a_plinkNext)
+			{
+				m_plinkNext = a_plinkNext;
+			}
+
+			inline Link * GetNext(void)
+			{
+				return m_plinkNext;
+			}
+
+			inline Link * Advance(unsigned int a_uiSteps = 1)
+			{
+				Link *plink = this;
+
+				for (unsigned int uiStep = 0; uiStep < a_uiSteps; uiStep++)
+				{
+					if (plink == nullptr)
+					{
+						break;
+					}
+
+					plink = plink->m_plinkNext;
+				}
+
+				return plink;
+			}
+
+		private:
+
+			Block4x4 *m_pblock;
+			Link *m_plinkNext;
+		};
+
+		SortedBlockList(unsigned int a_uiImageBlocks, unsigned int a_uiBuckets);
+		~SortedBlockList(void);
+
+        void AddBlock(Block4x4 *a_pblock);
+
+        void Sort(void);
+
+		inline Link * GetLinkToFirstBlock(void)
+		{
+			return m_plinkFirst;
+		}
+
+		inline unsigned int GetNumberOfAddedBlocks(void)
+		{
+			return m_uiAddedBlocks;
+		}
+
+		inline unsigned int GetNumberOfSortedBlocks(void)
+		{
+			return m_uiSortedBlocks;
+		}
+
+		void Print(void);
+
+	private:
+
+        void InitBuckets(void);
+
+        class Bucket
+        {
+        public:
+            Link *plinkFirst;
+            Link *plinkLast;
+        };
+
+        unsigned int m_uiImageBlocks;
+        int m_iBuckets;
+
+		unsigned int m_uiAddedBlocks;
+		unsigned int m_uiSortedBlocks;
+		Link *m_palinkPool;
+        Bucket *m_pabucket;
+        float m_fMaxError;
+
+		Link *m_plinkFirst;
+		Link *m_plinkLast;
+
+    };
+
+} // namespace Etc