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