From 03c3fa42a8872ddd28db65fb56913fc007530463 Mon Sep 17 00:00:00 2001
From: castano <castano@95f4ed2b-212e-0410-8b90-d31948207fce>
Date: Wed, 28 Sep 2011 16:40:59 +0000
Subject: [PATCH] Cosine power filter. A bit of renaming.

---
 src/nvtt/Context.cpp                 |  22 +--
 src/nvtt/Context.h                   |   4 +-
 src/nvtt/CubeImage.cpp               | 279 ++++++++++++++++++++++++---
 src/nvtt/CubeImage.h                 |  17 +-
 src/nvtt/TexImage.cpp                | 172 ++++++++---------
 src/nvtt/TexImage.h                  |   2 +-
 src/nvtt/nvtt.h                      |  84 ++++----
 src/nvtt/tests/imperativeapi.cpp     |   4 +-
 src/nvtt/tests/process_alpha_map.cpp |   6 +-
 src/nvtt/tests/testsuite.cpp         |  18 +-
 10 files changed, 424 insertions(+), 184 deletions(-)

diff --git a/src/nvtt/Context.cpp b/src/nvtt/Context.cpp
index fef0120..b426d40 100644
--- a/src/nvtt/Context.cpp
+++ b/src/nvtt/Context.cpp
@@ -132,18 +132,18 @@ int Compressor::estimateSize(const InputOptions & inputOptions, const Compressio
 }
 
 
-// TexImage API.
-bool Compressor::outputHeader(const TexImage & tex, int mipmapCount, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const
+// Surface API.
+bool Compressor::outputHeader(const Surface & tex, int mipmapCount, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const
 {
     return m.outputHeader(tex.type(), tex.width(), tex.height(), tex.depth(), mipmapCount, tex.isNormalMap(), compressionOptions.m, outputOptions.m);
 }
 
-bool Compressor::compress(const TexImage & tex, int face, int mipmap, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const
+bool Compressor::compress(const Surface & tex, int face, int mipmap, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const
 {
     return m.compress(tex, face, mipmap, compressionOptions.m, outputOptions.m);
 }
 
-int Compressor::estimateSize(const TexImage & tex, int mipmapCount, const CompressionOptions & compressionOptions) const
+int Compressor::estimateSize(const Surface & tex, int mipmapCount, const CompressionOptions & compressionOptions) const
 {
     const int w = tex.width();
     const int h = tex.height();
@@ -152,12 +152,12 @@ int Compressor::estimateSize(const TexImage & tex, int mipmapCount, const Compre
     return estimateSize(w, h, d, mipmapCount, compressionOptions);
 }
 
-bool Compressor::outputHeader(const CubeImage & cube, int mipmapCount, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const
+bool Compressor::outputHeader(const CubeSurface & cube, int mipmapCount, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const
 {
     return m.outputHeader(TextureType_Cube, cube.size(), cube.size(), 1, mipmapCount, false, compressionOptions.m, outputOptions.m);
 }
 
-bool Compressor::compress(const CubeImage & cube, int mipmap, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const
+bool Compressor::compress(const CubeSurface & cube, int mipmap, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const
 {
     for (int i = 0; i < 6; i++) {
         if(!m.compress(cube.face(i), i, mipmap, compressionOptions.m, outputOptions.m)) {
@@ -167,7 +167,7 @@ bool Compressor::compress(const CubeImage & cube, int mipmap, const CompressionO
     return true;
 }
 
-int Compressor::estimateSize(const CubeImage & cube, int mipmapCount, const CompressionOptions & compressionOptions) const
+int Compressor::estimateSize(const CubeSurface & cube, int mipmapCount, const CompressionOptions & compressionOptions) const
 {
     return 6 * estimateSize(cube.size(), cube.size(), 1, mipmapCount, compressionOptions);
 }
@@ -223,7 +223,7 @@ bool Compressor::Private::compress(const InputOptions::Private & inputOptions, c
         return false;
     }
 
-    nvtt::TexImage img;
+    nvtt::Surface img;
     img.setWrapMode(inputOptions.wrapMode);
     img.setAlphaMode(inputOptions.alphaMode);
     img.setNormalMap(inputOptions.isNormalMap);
@@ -269,7 +269,7 @@ bool Compressor::Private::compress(const InputOptions::Private & inputOptions, c
         // Resize input.
         img.resize(w, h, d, ResizeFilter_Box);
 
-        nvtt::TexImage tmp = img;
+        nvtt::Surface tmp = img;
         if (!img.isNormalMap()) {
             tmp.toGamma(inputOptions.outputGamma);
         }
@@ -333,7 +333,7 @@ bool Compressor::Private::compress(const InputOptions::Private & inputOptions, c
     return true;
 }
 
-bool Compressor::Private::compress(const TexImage & tex, int face, int mipmap, const CompressionOptions::Private & compressionOptions, const OutputOptions::Private & outputOptions) const
+bool Compressor::Private::compress(const Surface & tex, int face, int mipmap, const CompressionOptions::Private & compressionOptions, const OutputOptions::Private & outputOptions) const
 {
     if (!compress(tex.alphaMode(), tex.width(), tex.height(), tex.depth(), face, mipmap, tex.data(), compressionOptions, outputOptions)) {
         return false;
@@ -375,7 +375,7 @@ bool Compressor::Private::compress(AlphaMode alphaMode, int w, int h, int d, int
 }
 
 
-void Compressor::Private::quantize(TexImage & img, const CompressionOptions::Private & compressionOptions) const
+void Compressor::Private::quantize(Surface & img, const CompressionOptions::Private & compressionOptions) const
 {
     if (compressionOptions.enableColorDithering) {
         if (compressionOptions.format >= Format_BC1 && compressionOptions.format <= Format_BC3) {
diff --git a/src/nvtt/Context.h b/src/nvtt/Context.h
index 1ee7352..7faa447 100644
--- a/src/nvtt/Context.h
+++ b/src/nvtt/Context.h
@@ -46,10 +46,10 @@ namespace nvtt
         Private() {}
 
         bool compress(const InputOptions::Private & inputOptions, const CompressionOptions::Private & compressionOptions, const OutputOptions::Private & outputOptions) const;
-        bool compress(const TexImage & tex, int face, int mipmap, const CompressionOptions::Private & compressionOptions, const OutputOptions::Private & outputOptions) const;
+        bool compress(const Surface & tex, int face, int mipmap, const CompressionOptions::Private & compressionOptions, const OutputOptions::Private & outputOptions) const;
         bool compress(AlphaMode alphaMode, int w, int h, int d, int face, int mipmap, const float * data, const CompressionOptions::Private & compressionOptions, const OutputOptions::Private & outputOptions) const;
 
-        void quantize(TexImage & tex, const CompressionOptions::Private & compressionOptions) const;
+        void quantize(Surface & tex, const CompressionOptions::Private & compressionOptions) const;
 
         bool outputHeader(nvtt::TextureType textureType, int w, int h, int d, int mipmapCount, bool isNormalMap, const CompressionOptions::Private & compressionOptions, const OutputOptions::Private & outputOptions) const;
 
diff --git a/src/nvtt/CubeImage.cpp b/src/nvtt/CubeImage.cpp
index e71e0fe..dc53e37 100644
--- a/src/nvtt/CubeImage.cpp
+++ b/src/nvtt/CubeImage.cpp
@@ -24,41 +24,46 @@
 #include "CubeImage.h"
 #include "TexImage.h"
 
+#include "nvmath/Vector.h"
+
+#include "nvcore/Array.h"
+
+
 using namespace nv;
 using namespace nvtt;
 
 
 
 
-CubeImage::CubeImage() : m(new CubeImage::Private())
+CubeSurface::CubeSurface() : m(new CubeSurface::Private())
 {
     m->addRef();
 }
 
-CubeImage::CubeImage(const CubeImage & cube) : m(cube.m)
+CubeSurface::CubeSurface(const CubeSurface & cube) : m(cube.m)
 {
     if (m != NULL) m->addRef();
 }
 
-CubeImage::~CubeImage()
+CubeSurface::~CubeSurface()
 {
     if (m != NULL) m->release();
     m = NULL;
 }
 
-void CubeImage::operator=(const CubeImage & cube)
+void CubeSurface::operator=(const CubeSurface & cube)
 {
     if (cube.m != NULL) cube.m->addRef();
     if (m != NULL) m->release();
     m = cube.m;
 }
 
-void CubeImage::detach()
+void CubeSurface::detach()
 {
     if (m->refCount() > 1)
     {
         m->release();
-        m = new CubeImage::Private(*m);
+        m = new CubeSurface::Private(*m);
         m->addRef();
         nvDebugCheck(m->refCount() == 1);
     }
@@ -66,73 +71,301 @@ void CubeImage::detach()
 
 
 
-bool CubeImage::isNull() const
+bool CubeSurface::isNull() const
 {
     return m->size == 0;
 }
 
-int CubeImage::size() const
+int CubeSurface::size() const
 {
     return m->size;
 }
 
-int CubeImage::countMipmaps() const
+int CubeSurface::countMipmaps() const
 {
     return nv::countMipmaps(m->size);
 }
 
-TexImage & CubeImage::face(int f)
+Surface & CubeSurface::face(int f)
 {
     nvDebugCheck(f >= 0 && f < 6);
     return m->face[f];
 }
 
-const TexImage & CubeImage::face(int f) const
+const Surface & CubeSurface::face(int f) const
 {
     nvDebugCheck(f >= 0 && f < 6);
     return m->face[f];
 }
 
 
-bool CubeImage::load(const char * fileName)
+bool CubeSurface::load(const char * fileName)
 {
     // @@ TODO
     return false;
 }
 
-bool CubeImage::save(const char * fileName) const
+bool CubeSurface::save(const char * fileName) const
 {
     // @@ TODO
     return false;
 }
 
 
-void CubeImage::fold(const TexImage & tex, CubeLayout layout)
+void CubeSurface::fold(const Surface & tex, CubeLayout layout)
 {
     // @@ TODO
 }
 
-TexImage CubeImage::unfold(CubeLayout layout) const
+Surface CubeSurface::unfold(CubeLayout layout) const
 {
     // @@ TODO
-    return TexImage();
+    return Surface();
 }
 
 
-CubeImage CubeImage::irradianceFilter(int size) const
+CubeSurface CubeSurface::irradianceFilter(int size) const
 {
     // @@ TODO
-    return CubeImage();
+    return CubeSurface();
 }
 
-CubeImage CubeImage::cosinePowerFilter(int size, float cosinePower) const
+
+// Small solid angle table that takes into account cube map symmetry.
+struct SolidAngleTable {
+
+    SolidAngleTable(int edgeLength) : size(edgeLength/2) {
+        // Allocate table.
+        data.resize(size * size);
+
+        // @@ Init table.
+
+    }
+
+
+    //
+    float lookup(int x, int y) const {
+        if (x >= size) x -= size;
+        else if (x < size) x = size - x - 1;
+        if (y >= size) y -= size;
+        else if (y < size) y = size - y - 1;
+
+        return data[y * size + x];
+    }
+
+    int size;
+    nv::Array<float> data;
+};
+
+
+// ilen = inverse edge length.
+Vector3 texelDirection(uint face, uint x, uint y, float ilen)
 {
-    // @@ TODO
-    return CubeImage();
+    float u = (float(x) + 0.5f) * (2 * ilen) - 1.0f;
+    float v = (float(y) + 0.5f) * (2 * ilen) - 1.0f;
+    nvDebugCheck(u >= 0.0f && u <= 1.0f);
+    nvDebugCheck(v >= 0.0f && v <= 1.0f);
+
+    Vector3 n;
+
+    if (face == 0) {
+        n.x = 1;
+        n.y = -v;
+        n.z = -u;
+    }
+    if (face == 1) {
+        n.x = -1;
+        n.y = -v;
+        n.z = u;
+    }
+
+    if (face == 2) {
+        n.x = u;
+        n.y = 1;
+        n.z = v;
+    }
+    if (face == 3) {
+        n.x = u;
+        n.y = -1;
+        n.z = -v;
+    }
+
+    if (face == 4) {
+        n.x = u;
+        n.y = -v;
+        n.z = 1;
+    }
+    if (face == 5) {
+        n.x = -u;
+        n.y = -v;
+        n.z = -1;
+    }
+
+    return normalizeFast(n);
+}
+
+struct VectorTable {
+    VectorTable(int edgeLength) : size(edgeLength) {
+        float invEdgeLength = 1.0f / edgeLength;
+
+        for (uint f = 0; f < 6; f++) {
+            for (uint y = 0; y < size; y++) {
+                for (uint x = 0; x < size; x++) {
+                    data[(f * size + y) * size + x] = texelDirection(f, x, y, invEdgeLength);
+                }
+            }
+        }
+    }
+
+    const Vector3 & lookup(uint f, uint x, uint y) {
+        nvDebugCheck(f < 6 && x < size && y < size);
+        return data[(f * size + y) * size + x];
+    }
+
+    int size;
+    nv::Array<Vector3> data;
+};
+
+
+CubeSurface CubeSurface::cosinePowerFilter(int size, float cosinePower) const
+{
+    const uint edgeLength = m->size;
+
+    // Allocate output cube.
+    CubeSurface filteredCube;
+    filteredCube.m->allocate(size);
+
+    SolidAngleTable solidAngleTable(edgeLength);
+    VectorTable vectorTable(edgeLength);
+
+#if 1
+    // Scatter approach.
+
+    // For each texel of the input cube.
+    // - Lookup our solid angle.
+    // - Determine to what texels of the output cube we contribute.
+    // - Add our contribution to the texels whose power is above threshold.
+
+    for (uint f = 0; f < 6; f++) {
+        const Surface & face = m->face[f];
+
+        for (uint y = 0; y < edgeLength; y++) {
+            for (uint x = 0; x < edgeLength; x++) {
+                float solidAngle = solidAngleTable.lookup(x, y);
+                float r = face.m->image->pixel(0, x, y, 0) * solidAngle;;
+                float g = face.m->image->pixel(1, x, y, 0) * solidAngle;;
+                float b = face.m->image->pixel(2, x, y, 0) * solidAngle;;
+
+                Vector3 texelDir = texelDirection(f, x, y, edgeLength);
+
+                for (uint ff = 0; ff < 6; ff++) {
+                    FloatImage * filteredFace = filteredCube.m->face[ff].m->image;
+
+                    for (uint yy = 0; yy < size; yy++) {
+                        for (uint xx = 0; xx < size; xx++) {
+
+                            Vector3 filterDir = texelDirection(ff, xx, yy, size);
+
+                            float power = powf(saturate(dot(texelDir, filterDir)), cosinePower);
+
+                            if (power > 0.01) {
+                                filteredFace->pixel(0, xx, yy, 0) += r * power;
+                                filteredFace->pixel(1, xx, yy, 0) += g * power;
+                                filteredFace->pixel(2, xx, yy, 0) += b * power;
+                                filteredFace->pixel(3, xx, yy, 0) += solidAngle * power;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    // Normalize contributions.
+    for (uint f = 0; f < 6; f++) {
+        FloatImage * filteredFace = filteredCube.m->face[f].m->image;
+
+        for (int i = 0; i < size*size; i++) {
+            float & r = filteredFace->pixel(0, i);
+            float & g = filteredFace->pixel(1, i);
+            float & b = filteredFace->pixel(2, i);
+            float & sum = filteredFace->pixel(3, i);
+            float isum = 1.0f / sum;
+            r *= isum;
+            g *= isum;
+            b *= isum;
+            sum = 1;
+        }
+    }
+
+#else
+
+    // Gather approach. This should be easier to parallelize, because there's no contention in the filtered output.
+
+    // For each texel of the output cube.
+    // - Determine what texels of the input cube contribute to it.
+    // - Add weighted contributions. Normalize.
+
+    // For each texel of the output cube. @@ Parallelize this loop.
+    for (uint f = 0; f < 6; f++) {
+        nvtt::Surface filteredFace = filteredCube.m->face[f];
+        FloatImage * filteredImage = filteredFace.m->image;
+
+        for (uint y = 0; y < size; y++) {
+            for (uint x = 0; x < size; x++) {
+
+                const Vector3 filterDir = texelDirection(f, x, y, size);
+
+                Vector3 color(0);
+                float sum = 0;
+
+                // For each texel of the input cube.
+                for (uint ff = 0; ff < 6; ff++) {
+                    const Surface & inputFace = m->face[ff];
+                    const FloatImage * inputImage = inputFace.m->image;
+
+                    for (uint yy = 0; yy < edgeLength; yy++) {
+                        for (uint xx = 0; xx < edgeLength; xx++) {
+
+                            // @@ We should probably store solid angle and direction together.
+                            Vector3 inputDir = vectorTable.lookup(ff, xx, yy);
+
+                            float power = powf(saturate(dot(inputDir, filterDir)), cosinePower);
+
+                            if (power > 0.01f) {    // @@ Adjustable threshold.
+                                float solidAngle = solidAngleTable.lookup(xx, yy);
+                                float contribution = solidAngle * power;
+
+                                sum += contribution;
+
+                                float r = inputImage->pixel(0, xx, yy, 0);
+                                float g = inputImage->pixel(1, xx, yy, 0);
+                                float b = inputImage->pixel(2, xx, yy, 0);
+
+                                color.r += r * contribution;
+                                color.g += g * contribution;
+                                color.b += b * contribution;
+                            }
+                        }
+                    }
+                }
+
+                color *= (1.0f / sum);
+
+                filteredImage->pixel(0, x, y, 0) = color.x;
+                filteredImage->pixel(1, x, y, 0) = color.y;
+                filteredImage->pixel(2, x, y, 0) = color.z;
+            }
+        }
+    }
+
+#endif
+
+    return filteredCube;
 }
 
 
-void CubeImage::toLinear(float gamma)
+void CubeSurface::toLinear(float gamma)
 {
     if (isNull()) return;
 
@@ -143,7 +376,7 @@ void CubeImage::toLinear(float gamma)
     }
 }
 
-void CubeImage::toGamma(float gamma)
+void CubeSurface::toGamma(float gamma)
 {
     if (isNull()) return;
 
diff --git a/src/nvtt/CubeImage.h b/src/nvtt/CubeImage.h
index 659675b..7836d6e 100644
--- a/src/nvtt/CubeImage.h
+++ b/src/nvtt/CubeImage.h
@@ -25,6 +25,9 @@
 #define NVTT_CUBEIMAGE_H
 
 #include "nvtt.h"
+#include "TexImage.h"
+
+#include "nvimage/FloatImage.h"
 
 #include "nvcore/RefCounted.h"
 #include "nvcore/Ptr.h"
@@ -33,7 +36,7 @@
 namespace nvtt
 {
 
-    struct CubeImage::Private : public nv::RefCounted
+    struct CubeSurface::Private : public nv::RefCounted
     {
         void operator=(const Private &);
     public:
@@ -56,8 +59,18 @@ namespace nvtt
         {
         }
 
+        void allocate(int size)
+        {
+            this->size = size;
+            for (uint i = 0; i < 6; i++) {
+                face[i].detach();
+                face[i].m->image = new nv::FloatImage;
+                face[i].m->image->allocate(size, size, 1);
+            }
+        }
+
         int size;
-        TexImage face[6];
+        Surface face[6];
     };
 
 } // nvtt namespace
diff --git a/src/nvtt/TexImage.cpp b/src/nvtt/TexImage.cpp
index 356e81f..c4435bf 100644
--- a/src/nvtt/TexImage.cpp
+++ b/src/nvtt/TexImage.cpp
@@ -184,41 +184,41 @@ void nv::getTargetExtent(int & w, int & h, int & d, int maxExtent, RoundMode rou
 
 
 
-TexImage::TexImage() : m(new TexImage::Private())
+Surface::Surface() : m(new Surface::Private())
 {
     m->addRef();
 }
 
-TexImage::TexImage(const TexImage & tex) : m(tex.m)
+Surface::Surface(const Surface & tex) : m(tex.m)
 {
     if (m != NULL) m->addRef();
 }
 
-TexImage::~TexImage()
+Surface::~Surface()
 {
     if (m != NULL) m->release();
     m = NULL;
 }
 
-void TexImage::operator=(const TexImage & tex)
+void Surface::operator=(const Surface & tex)
 {
     if (tex.m != NULL) tex.m->addRef();
     if (m != NULL) m->release();
     m = tex.m;
 }
 
-void TexImage::detach()
+void Surface::detach()
 {
     if (m->refCount() > 1)
     {
         m->release();
-        m = new TexImage::Private(*m);
+        m = new Surface::Private(*m);
         m->addRef();
         nvDebugCheck(m->refCount() == 1);
     }
 }
 
-void TexImage::setWrapMode(WrapMode wrapMode)
+void Surface::setWrapMode(WrapMode wrapMode)
 {
     if (m->wrapMode != wrapMode)
     {
@@ -227,7 +227,7 @@ void TexImage::setWrapMode(WrapMode wrapMode)
     }
 }
 
-void TexImage::setAlphaMode(AlphaMode alphaMode)
+void Surface::setAlphaMode(AlphaMode alphaMode)
 {
     if (m->alphaMode != alphaMode)
     {
@@ -236,7 +236,7 @@ void TexImage::setAlphaMode(AlphaMode alphaMode)
     }
 }
 
-void TexImage::setNormalMap(bool isNormalMap)
+void Surface::setNormalMap(bool isNormalMap)
 {
     if (m->isNormalMap != isNormalMap)
     {
@@ -245,63 +245,63 @@ void TexImage::setNormalMap(bool isNormalMap)
     }
 }
 
-bool TexImage::isNull() const
+bool Surface::isNull() const
 {
     return m->image == NULL;
 }
 
-int TexImage::width() const
+int Surface::width() const
 {
     if (m->image != NULL) return m->image->width();
     return 0;
 }
 
-int TexImage::height() const
+int Surface::height() const
 {
     if (m->image != NULL) return m->image->height();
     return 0;
 }
 
-int TexImage::depth() const
+int Surface::depth() const
 {
     if (m->image != NULL) return m->image->depth();
     return 0;
 }
 
-WrapMode TexImage::wrapMode() const
+WrapMode Surface::wrapMode() const
 {
     return m->wrapMode;
 }
 
-AlphaMode TexImage::alphaMode() const
+AlphaMode Surface::alphaMode() const
 {
     return m->alphaMode;
 }
 
-bool TexImage::isNormalMap() const
+bool Surface::isNormalMap() const
 {
     return m->isNormalMap;
 }
 
-TextureType TexImage::type() const
+TextureType Surface::type() const
 {
     return m->type;
 }
 
-int TexImage::countMipmaps() const
+int Surface::countMipmaps() const
 {
     if (m->image == NULL) return 0;
     return ::countMipmaps(m->image->width(), m->image->height(), 1);
 }
 
-float TexImage::alphaTestCoverage(float alphaRef/*= 0.5*/) const
+float Surface::alphaTestCoverage(float alphaRef/*= 0.5*/) const
 {
     if (m->image == NULL) return 0.0f;
 
     return m->image->alphaTestCoverage(alphaRef, 3);
 }
 
-float TexImage::average(int channel, int alpha_channel/*= -1*/, float gamma /*= 2.2f*/) const
+float Surface::average(int channel, int alpha_channel/*= -1*/, float gamma /*= 2.2f*/) const
 {
     if (m->image == NULL) return 0.0f;
 
@@ -337,12 +337,12 @@ float TexImage::average(int channel, int alpha_channel/*= -1*/, float gamma /*=
     return sum / denom;
 }
 
-const float * TexImage::data() const
+const float * Surface::data() const
 {
     return m->image->channel(0);
 }
 
-void TexImage::histogram(int channel, float rangeMin, float rangeMax, int binCount, int * binPtr) const
+void Surface::histogram(int channel, float rangeMin, float rangeMax, int binCount, int * binPtr) const
 {
     // We assume it's clear in case we want to accumulate multiple histograms.
     //memset(bins, 0, sizeof(int)*count);
@@ -364,7 +364,7 @@ void TexImage::histogram(int channel, float rangeMin, float rangeMax, int binCou
     }
 }
 
-void TexImage::range(int channel, float * rangeMin, float * rangeMax)
+void Surface::range(int channel, float * rangeMin, float * rangeMax)
 {
     Vector2 range(FLT_MAX, -FLT_MAX);
 
@@ -384,7 +384,7 @@ void TexImage::range(int channel, float * rangeMin, float * rangeMax)
 }
 
 
-bool TexImage::load(const char * fileName, bool * hasAlpha/*= NULL*/)
+bool Surface::load(const char * fileName, bool * hasAlpha/*= NULL*/)
 {
     AutoPtr<FloatImage> img(ImageIO::loadFloat(fileName));
     if (img == NULL) {
@@ -406,7 +406,7 @@ bool TexImage::load(const char * fileName, bool * hasAlpha/*= NULL*/)
     return true;
 }
 
-bool TexImage::save(const char * fileName) const
+bool Surface::save(const char * fileName) const
 {
     if (m->image != NULL)
     {
@@ -416,7 +416,7 @@ bool TexImage::save(const char * fileName) const
     return false;
 }
 
-bool TexImage::setImage(nvtt::InputFormat format, int w, int h, int d, const void * data)
+bool Surface::setImage(nvtt::InputFormat format, int w, int h, int d, const void * data)
 {
     detach();
 
@@ -488,7 +488,7 @@ bool TexImage::setImage(nvtt::InputFormat format, int w, int h, int d, const voi
     return true;
 }
 
-bool TexImage::setImage(InputFormat format, int w, int h, int d, const void * r, const void * g, const void * b, const void * a)
+bool Surface::setImage(InputFormat format, int w, int h, int d, const void * r, const void * g, const void * b, const void * a)
 {
     detach();
 
@@ -561,7 +561,7 @@ bool TexImage::setImage(InputFormat format, int w, int h, int d, const void * r,
 }
 
 // @@ Add support for compressed 3D textures.
-bool TexImage::setImage2D(Format format, Decoder decoder, int w, int h, const void * data)
+bool Surface::setImage2D(Format format, Decoder decoder, int w, int h, const void * data)
 {
     if (format != nvtt::Format_BC1 && format != nvtt::Format_BC2 && format != nvtt::Format_BC3 && format != nvtt::Format_BC4 && format != nvtt::Format_BC5)
     {
@@ -693,7 +693,7 @@ static void getDefaultFilterWidthAndParams(int filter, float * filterWidth, floa
     }
 }
 
-void TexImage::resize(int w, int h, int d, ResizeFilter filter)
+void Surface::resize(int w, int h, int d, ResizeFilter filter)
 {
     float filterWidth;
     float params[2];
@@ -702,7 +702,7 @@ void TexImage::resize(int w, int h, int d, ResizeFilter filter)
     resize(w, h, d, filter, filterWidth, params);
 }
 
-void TexImage::resize(int w, int h, int d, ResizeFilter filter, float filterWidth, const float * params)
+void Surface::resize(int w, int h, int d, ResizeFilter filter, float filterWidth, const float * params)
 {
     FloatImage * img = m->image;
     if (img == NULL || (w == img->width() && h == img->height() && d == img->depth())) {
@@ -770,7 +770,7 @@ void TexImage::resize(int w, int h, int d, ResizeFilter filter, float filterWidt
     m->image = img;
 }
 
-void TexImage::resize(int maxExtent, RoundMode roundMode, ResizeFilter filter)
+void Surface::resize(int maxExtent, RoundMode roundMode, ResizeFilter filter)
 {
     float filterWidth;
     float params[2];
@@ -779,7 +779,7 @@ void TexImage::resize(int maxExtent, RoundMode roundMode, ResizeFilter filter)
     resize(maxExtent, roundMode, filter, filterWidth, params);
 }
 
-void TexImage::resize(int maxExtent, RoundMode roundMode, ResizeFilter filter, float filterWidth, const float * params)
+void Surface::resize(int maxExtent, RoundMode roundMode, ResizeFilter filter, float filterWidth, const float * params)
 {
     if (m->image == NULL) return;
 
@@ -792,7 +792,7 @@ void TexImage::resize(int maxExtent, RoundMode roundMode, ResizeFilter filter, f
     resize(w, h, d, filter, filterWidth, params);
 }
 
-bool TexImage::buildNextMipmap(MipmapFilter filter)
+bool Surface::buildNextMipmap(MipmapFilter filter)
 {
     float filterWidth;
     float params[2];
@@ -801,7 +801,7 @@ bool TexImage::buildNextMipmap(MipmapFilter filter)
     return buildNextMipmap(filter, filterWidth, params);
 }
 
-bool TexImage::buildNextMipmap(MipmapFilter filter, float filterWidth, const float * params)
+bool Surface::buildNextMipmap(MipmapFilter filter, float filterWidth, const float * params)
 {
     FloatImage * img = m->image;
     if (img == NULL || (img->width() == 1 && img->height() == 1 && img->depth() == 1)) {
@@ -864,7 +864,7 @@ bool TexImage::buildNextMipmap(MipmapFilter filter, float filterWidth, const flo
     return true;
 }
 
-void TexImage::canvasSize(int w, int h, int d)
+void Surface::canvasSize(int w, int h, int d)
 {
     nvDebugCheck(w > 0 && h > 0 && d > 0);
 
@@ -901,7 +901,7 @@ void TexImage::canvasSize(int w, int h, int d)
 
 
 // Color transforms.
-void TexImage::toLinear(float gamma)
+void Surface::toLinear(float gamma)
 {
     if (m->image == NULL) return;
     if (equal(gamma, 1.0f)) return;
@@ -911,7 +911,7 @@ void TexImage::toLinear(float gamma)
     m->image->toLinear(0, 3, gamma);
 }
 
-void TexImage::toGamma(float gamma)
+void Surface::toGamma(float gamma)
 {
     if (m->image == NULL) return;
     if (equal(gamma, 1.0f)) return;
@@ -930,7 +930,7 @@ static float toSrgb(float f) {
     return f;
 }
 
-void TexImage::toSrgb()
+void Surface::toSrgb()
 {
     FloatImage * img = m->image;
     if (img == NULL) return;
@@ -960,7 +960,7 @@ static float toXenonSrgb(float f) {
     return f;
 }
 
-void TexImage::toXenonSrgb()
+void Surface::toXenonSrgb()
 {
     FloatImage * img = m->image;
     if (img == NULL) return;
@@ -981,7 +981,7 @@ void TexImage::toXenonSrgb()
 }
 
 
-void TexImage::transform(const float w0[4], const float w1[4], const float w2[4], const float w3[4], const float offset[4])
+void Surface::transform(const float w0[4], const float w1[4], const float w2[4], const float w3[4], const float offset[4])
 {
     if (m->image == NULL) return;
 
@@ -998,7 +998,7 @@ void TexImage::transform(const float w0[4], const float w1[4], const float w2[4]
     m->image->transform(0, xform, voffset);
 }
 
-void TexImage::swizzle(int r, int g, int b, int a)
+void Surface::swizzle(int r, int g, int b, int a)
 {
     if (m->image == NULL) return;
     if (r == 0 && g == 1 && b == 2 && a == 3) return;
@@ -1009,7 +1009,7 @@ void TexImage::swizzle(int r, int g, int b, int a)
 }
 
 // color * scale + bias
-void TexImage::scaleBias(int channel, float scale, float bias)
+void Surface::scaleBias(int channel, float scale, float bias)
 {
     if (m->image == NULL) return;
     if (equal(scale, 1.0f) && equal(bias, 0.0f)) return;
@@ -1019,7 +1019,7 @@ void TexImage::scaleBias(int channel, float scale, float bias)
     m->image->scaleBias(channel, 1, scale, bias);
 }
 
-void TexImage::clamp(int channel, float low, float high)
+void Surface::clamp(int channel, float low, float high)
 {
     if (m->image == NULL) return;
 
@@ -1028,14 +1028,14 @@ void TexImage::clamp(int channel, float low, float high)
     m->image->clamp(channel, 1, low, high);
 }
 
-void TexImage::packNormal()
+void Surface::packNormal()
 {
     scaleBias(0, 0.5f, 0.5f);
     scaleBias(1, 0.5f, 0.5f);
     scaleBias(2, 0.5f, 0.5f);
 }
 
-void TexImage::expandNormal()
+void Surface::expandNormal()
 {
     scaleBias(0, 2.0f, -1.0f);
     scaleBias(1, 2.0f, -1.0f);
@@ -1043,7 +1043,7 @@ void TexImage::expandNormal()
 }
 
 
-void TexImage::blend(float red, float green, float blue, float alpha, float t)
+void Surface::blend(float red, float green, float blue, float alpha, float t)
 {
     if (m->image == NULL) return;
 
@@ -1065,7 +1065,7 @@ void TexImage::blend(float red, float green, float blue, float alpha, float t)
     }
 }
 
-void TexImage::premultiplyAlpha()
+void Surface::premultiplyAlpha()
 {
     if (m->image == NULL) return;
 
@@ -1087,7 +1087,7 @@ void TexImage::premultiplyAlpha()
 }
 
 
-void TexImage::toGreyScale(float redScale, float greenScale, float blueScale, float alphaScale)
+void Surface::toGreyScale(float redScale, float greenScale, float blueScale, float alphaScale)
 {
     if (m->image == NULL) return;
 
@@ -1114,7 +1114,7 @@ void TexImage::toGreyScale(float redScale, float greenScale, float blueScale, fl
 }
 
 // Draw colored border.
-void TexImage::setBorder(float r, float g, float b, float a)
+void Surface::setBorder(float r, float g, float b, float a)
 {
     if (m->image == NULL) return;
 
@@ -1156,7 +1156,7 @@ void TexImage::setBorder(float r, float g, float b, float a)
 }
 
 // Fill image with the given color.
-void TexImage::fill(float red, float green, float blue, float alpha)
+void Surface::fill(float red, float green, float blue, float alpha)
 {
     if (m->image == NULL) return;
 
@@ -1179,7 +1179,7 @@ void TexImage::fill(float red, float green, float blue, float alpha)
 }
 
 
-void TexImage::scaleAlphaToCoverage(float coverage, float alphaRef/*= 0.5f*/)
+void Surface::scaleAlphaToCoverage(float coverage, float alphaRef/*= 0.5f*/)
 {
     if (m->image == NULL) return;
 
@@ -1188,7 +1188,7 @@ void TexImage::scaleAlphaToCoverage(float coverage, float alphaRef/*= 0.5f*/)
     m->image->scaleAlphaToCoverage(coverage, alphaRef, 3);
 }
 
-/*bool TexImage::normalizeRange(float * rangeMin, float * rangeMax)
+/*bool Surface::normalizeRange(float * rangeMin, float * rangeMax)
 {
     if (m->image == NULL) return false;
 
@@ -1218,7 +1218,7 @@ void TexImage::scaleAlphaToCoverage(float coverage, float alphaRef/*= 0.5f*/)
 
 // Ideally you should compress/quantize the RGB and M portions independently.
 // Once you have M quantized, you would compute the corresponding RGB and quantize that.
-void TexImage::toRGBM(float range/*= 1*/, float threshold/*= 0.25*/)
+void Surface::toRGBM(float range/*= 1*/, float threshold/*= 0.25*/)
 {
     if (m->image == NULL) return;
 
@@ -1286,7 +1286,7 @@ void TexImage::toRGBM(float range/*= 1*/, float threshold/*= 0.25*/)
     }
 }
 
-void TexImage::fromRGBM(float range/*= 1*/)
+void Surface::fromRGBM(float range/*= 1*/)
 {
     if (m->image == NULL) return;
 
@@ -1311,7 +1311,7 @@ void TexImage::fromRGBM(float range/*= 1*/)
 
 
 // Y is in the [0, 1] range, while CoCg are in the [-1, 1] range.
-void TexImage::toYCoCg()
+void Surface::toYCoCg()
 {
     if (m->image == NULL) return;
 
@@ -1348,7 +1348,7 @@ void TexImage::toYCoCg()
 // @@ Add support for threshold.
 // We could do something to prevent scale values from adjacent blocks from being too different to each other
 // and minimize bilinear interpolation artifacts.
-void TexImage::blockScaleCoCg(int bits/*= 5*/, float threshold/*= 0.0*/)
+void Surface::blockScaleCoCg(int bits/*= 5*/, float threshold/*= 0.0*/)
 {
     if (m->image == NULL || m->image->depth() != 1) return;
 
@@ -1406,7 +1406,7 @@ void TexImage::blockScaleCoCg(int bits/*= 5*/, float threshold/*= 0.0*/)
     }
 }
 
-void TexImage::fromYCoCg()
+void Surface::fromYCoCg()
 {
     if (m->image == NULL) return;
 
@@ -1439,7 +1439,7 @@ void TexImage::fromYCoCg()
     }
 }
 
-void TexImage::toLUVW(float range/*= 1.0f*/)
+void Surface::toLUVW(float range/*= 1.0f*/)
 {
     if (m->image == NULL) return;
 
@@ -1468,13 +1468,13 @@ void TexImage::toLUVW(float range/*= 1.0f*/)
     }
 }
 
-void TexImage::fromLUVW(float range/*= 1.0f*/)
+void Surface::fromLUVW(float range/*= 1.0f*/)
 {
     // Decompression is the same as in RGBM.
     fromRGBM(range * sqrtf(3));
 }
 
-void TexImage::abs(int channel)
+void Surface::abs(int channel)
 {
     if (m->image == NULL) return;
 
@@ -1489,7 +1489,7 @@ void TexImage::abs(int channel)
     }
 }
 
-void TexImage::convolve(int channel, int kernelSize, float * kernelData)
+void Surface::convolve(int channel, int kernelSize, float * kernelData)
 {
     if (m->image == NULL) return;
 
@@ -1500,7 +1500,7 @@ void TexImage::convolve(int channel, int kernelSize, float * kernelData)
 }
 
 /*
-void TexImage::blockLuminanceScale(float scale)
+void Surface::blockLuminanceScale(float scale)
 {
     if (m->image == NULL) return;
 
@@ -1575,7 +1575,7 @@ void TexImage::blockLuminanceScale(float scale)
 */
 
 /*
-void TexImage::toJPEGLS()
+void Surface::toJPEGLS()
 {
     if (m->image == NULL) return;
 
@@ -1598,7 +1598,7 @@ void TexImage::toJPEGLS()
     }
 }
 
-void TexImage::fromJPEGLS()
+void Surface::fromJPEGLS()
 {
     if (m->image == NULL) return;
 
@@ -1624,7 +1624,7 @@ void TexImage::fromJPEGLS()
 
 
 // If dither is true, this uses Floyd-Steinberg dithering method.
-void TexImage::binarize(int channel, float threshold, bool dither)
+void Surface::binarize(int channel, float threshold, bool dither)
 {
     if (m->image == NULL) return;
 
@@ -1687,7 +1687,7 @@ void TexImage::binarize(int channel, float threshold, bool dither)
 // Assumes input is in [0, 1] range. Output is in the [0, 1] range, but rounded to the middle of each bin.
 // If exactEndPoints is true, [0, 1] are represented exactly, and the correponding bins are half the size, so quantization is not truly uniform.
 // When dither is true, this uses Floyd-Steinberg dithering.
-void TexImage::quantize(int channel, int bits, bool exactEndPoints, bool dither)
+void Surface::quantize(int channel, int bits, bool exactEndPoints, bool dither)
 {
     if (m->image == NULL) return;
 
@@ -1758,7 +1758,7 @@ void TexImage::quantize(int channel, int bits, bool exactEndPoints, bool dither)
 
 
 // Set normal map options.
-void TexImage::toNormalMap(float sm, float medium, float big, float large)
+void Surface::toNormalMap(float sm, float medium, float big, float large)
 {
     if (m->image == NULL) return;
 
@@ -1777,7 +1777,7 @@ void TexImage::toNormalMap(float sm, float medium, float big, float large)
     m->isNormalMap = true;
 }
 
-void TexImage::normalizeNormalMap()
+void Surface::normalizeNormalMap()
 {
     if (m->image == NULL) return;
     if (!m->isNormalMap) return;
@@ -1787,7 +1787,7 @@ void TexImage::normalizeNormalMap()
     nv::normalizeNormalMap(m->image);
 }
 
-void TexImage::transformNormals(NormalTransform xform)
+void Surface::transformNormals(NormalTransform xform)
 {
     if (m->image == NULL) return;
 
@@ -1860,7 +1860,7 @@ void TexImage::transformNormals(NormalTransform xform)
     img->packNormals(0);
 }
 
-void TexImage::reconstructNormals(NormalTransform xform)
+void Surface::reconstructNormals(NormalTransform xform)
 {
     if (m->image == NULL) return;
 
@@ -1909,7 +1909,7 @@ void TexImage::reconstructNormals(NormalTransform xform)
     img->packNormals(0);
 }
 
-void TexImage::toCleanNormalMap()
+void Surface::toCleanNormalMap()
 {
     if (m->image == NULL) return;
 
@@ -1929,21 +1929,21 @@ void TexImage::toCleanNormalMap()
 }
 
 // [-1,1] -> [ 0,1]
-void TexImage::packNormals() {
+void Surface::packNormals() {
     if (m->image == NULL) return;
     detach();
     m->image->packNormals(0);
 }
 
 // [ 0,1] -> [-1,1]
-void TexImage::expandNormals() {
+void Surface::expandNormals() {
     if (m->image == NULL) return;
     detach();
     m->image->expandNormals(0);
 }
 
 
-void TexImage::flipX()
+void Surface::flipX()
 {
     if (m->image == NULL) return;
 
@@ -1952,7 +1952,7 @@ void TexImage::flipX()
     m->image->flipX();
 }
 
-void TexImage::flipY()
+void Surface::flipY()
 {
     if (m->image == NULL) return;
 
@@ -1961,7 +1961,7 @@ void TexImage::flipY()
     m->image->flipY();
 }
 
-void TexImage::flipZ()
+void Surface::flipZ()
 {
     if (m->image == NULL) return;
 
@@ -1970,12 +1970,12 @@ void TexImage::flipZ()
     m->image->flipZ();
 }
 
-bool TexImage::copyChannel(const TexImage & srcImage, int srcChannel)
+bool Surface::copyChannel(const Surface & srcImage, int srcChannel)
 {
     return copyChannel(srcImage, srcChannel, srcChannel);
 }
 
-bool TexImage::copyChannel(const TexImage & srcImage, int srcChannel, int dstChannel)
+bool Surface::copyChannel(const Surface & srcImage, int srcChannel, int dstChannel)
 {
     if (srcChannel < 0 || srcChannel > 3 || dstChannel < 0 || dstChannel > 3) return false;
 
@@ -1994,7 +1994,7 @@ bool TexImage::copyChannel(const TexImage & srcImage, int srcChannel, int dstCha
     return true;
 }
 
-bool TexImage::addChannel(const TexImage & srcImage, int srcChannel, int dstChannel, float scale)
+bool Surface::addChannel(const Surface & srcImage, int srcChannel, int dstChannel, float scale)
 {
     if (srcChannel < 0 || srcChannel > 3 || dstChannel < 0 || dstChannel > 3) return false;
 
@@ -2024,43 +2024,43 @@ bool TexImage::addChannel(const TexImage & srcImage, int srcChannel, int dstChan
 
 
 
-float nvtt::rmsError(const TexImage & reference, const TexImage & image)
+float nvtt::rmsError(const Surface & reference, const Surface & image)
 {
     return nv::rmsColorError(reference.m->image, image.m->image, reference.alphaMode() == nvtt::AlphaMode_Transparency);
 }
 
 
-float nvtt::rmsAlphaError(const TexImage & reference, const TexImage & image)
+float nvtt::rmsAlphaError(const Surface & reference, const Surface & image)
 {
     return nv::rmsAlphaError(reference.m->image, image.m->image);
 }
 
 
-float nvtt::cieLabError(const TexImage & reference, const TexImage & image)
+float nvtt::cieLabError(const Surface & reference, const Surface & image)
 {
     return nv::cieLabError(reference.m->image, image.m->image);
 }
 
-float nvtt::angularError(const TexImage & reference, const TexImage & image)
+float nvtt::angularError(const Surface & reference, const Surface & image)
 {
     //return nv::averageAngularError(reference.m->image, image.m->image);
     return nv::rmsAngularError(reference.m->image, image.m->image);
 }
 
 
-TexImage nvtt::diff(const TexImage & reference, const TexImage & image, float scale)
+Surface nvtt::diff(const Surface & reference, const Surface & image, float scale)
 {
     const FloatImage * ref = reference.m->image;
     const FloatImage * img = image.m->image;
 
     if (!sameLayout(img, ref)) {
-        return TexImage();
+        return Surface();
     }
 
     nvDebugCheck(img->componentCount() == 4);
     nvDebugCheck(ref->componentCount() == 4);
 
-    nvtt::TexImage diffImage;
+    nvtt::Surface diffImage;
     FloatImage * diff = diffImage.m->image = new FloatImage;
     diff->allocate(4, img->width(), img->height(), img->depth());
 
diff --git a/src/nvtt/TexImage.h b/src/nvtt/TexImage.h
index e8ef412..db23acd 100644
--- a/src/nvtt/TexImage.h
+++ b/src/nvtt/TexImage.h
@@ -36,7 +36,7 @@
 namespace nvtt
 {
 
-    struct TexImage::Private : public nv::RefCounted
+    struct Surface::Private : public nv::RefCounted
     {
         void operator=(const Private &);
     public:
diff --git a/src/nvtt/nvtt.h b/src/nvtt/nvtt.h
index 295e71e..22eacdb 100644
--- a/src/nvtt/nvtt.h
+++ b/src/nvtt/nvtt.h
@@ -67,8 +67,8 @@
 namespace nvtt
 {
     // Forward declarations.
-    struct TexImage;
-    struct CubeImage;
+    struct Surface;
+    struct CubeSurface;
 
     /// Supported compression formats.
     enum Format
@@ -378,15 +378,15 @@ namespace nvtt
         NVTT_API bool process(const InputOptions & inputOptions, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const;
         NVTT_API int estimateSize(const InputOptions & inputOptions, const CompressionOptions & compressionOptions) const;
 
-        // TexImage API.
-        NVTT_API bool outputHeader(const TexImage & tex, int mipmapCount, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const;
-        NVTT_API bool compress(const TexImage & tex, int face, int mipmap, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const;
-        NVTT_API int estimateSize(const TexImage & tex, int mipmapCount, const CompressionOptions & compressionOptions) const;
+        // Surface API.
+        NVTT_API bool outputHeader(const Surface & img, int mipmapCount, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const;
+        NVTT_API bool compress(const Surface & img, int face, int mipmap, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const;
+        NVTT_API int estimateSize(const Surface & img, int mipmapCount, const CompressionOptions & compressionOptions) const;
 
-        // CubeImage API.
-        NVTT_API bool outputHeader(const CubeImage & cube, int mipmapCount, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const;
-        NVTT_API bool compress(const CubeImage & cube, int mipmap, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const;
-        NVTT_API int estimateSize(const CubeImage & cube, int mipmapCount, const CompressionOptions & compressionOptions) const;
+        // CubeSurface API.
+        NVTT_API bool outputHeader(const CubeSurface & cube, int mipmapCount, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const;
+        NVTT_API bool compress(const CubeSurface & cube, int mipmap, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const;
+        NVTT_API int estimateSize(const CubeSurface & cube, int mipmapCount, const CompressionOptions & compressionOptions) const;
 
         // Raw API.
         NVTT_API bool outputHeader(TextureType type, int w, int h, int d, int mipmapCount, bool isNormalMap, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const;
@@ -405,14 +405,15 @@ namespace nvtt
         //NormalTransform_DualParaboloid,
     };
 
-    /// A texture mipmap.
-    struct TexImage
+
+    /// A surface is a texture mipmap. Can be 2D or 3D.
+    struct Surface
     {
-        NVTT_API TexImage();
-        NVTT_API TexImage(const TexImage & tex);
-        NVTT_API ~TexImage();
+        NVTT_API Surface();
+        NVTT_API Surface(const Surface & img);
+        NVTT_API ~Surface();
 
-        NVTT_API void operator=(const TexImage & tex);
+        NVTT_API void operator=(const Surface & img);
 
         // Texture parameters.
         NVTT_API void setWrapMode(WrapMode mode);
@@ -500,19 +501,12 @@ namespace nvtt
         NVTT_API void flipZ();
 
         // Copy image data.
-        NVTT_API bool copyChannel(const TexImage & srcImage, int srcChannel);
-        NVTT_API bool copyChannel(const TexImage & srcImage, int srcChannel, int dstChannel);
-
-        NVTT_API bool addChannel(const TexImage & img, int srcChannel, int dstChannel, float scale);
+        NVTT_API bool copyChannel(const Surface & srcImage, int srcChannel);
+        NVTT_API bool copyChannel(const Surface & srcImage, int srcChannel, int dstChannel);
 
-        // Error compare.
-        NVTT_API friend float rmsError(const TexImage & reference, const TexImage & img);
-        NVTT_API friend float rmsAlphaError(const TexImage & reference, const TexImage & img);
-        NVTT_API friend float cieLabError(const TexImage & reference, const TexImage & img);
-        NVTT_API friend float angularError(const TexImage & reference, const TexImage & img);
-        NVTT_API friend TexImage diff(const TexImage & reference, const TexImage & img, float scale);
+        NVTT_API bool addChannel(const Surface & img, int srcChannel, int dstChannel, float scale);
 
-    private:
+    //private:
         void detach();
 
         struct Private;
@@ -528,14 +522,14 @@ namespace nvtt
         CubeLayout_LatitudeLongitude,
     };
 
-    /// A cubemap mipmap.
-    struct CubeImage
+    /// A cubemap mipmap. CubeSurface?
+    struct CubeSurface
     {
-        NVTT_API CubeImage();
-        NVTT_API CubeImage(const CubeImage & tex);
-        NVTT_API ~CubeImage();
+        NVTT_API CubeSurface();
+        NVTT_API CubeSurface(const CubeSurface & img);
+        NVTT_API ~CubeSurface();
 
-        NVTT_API void operator=(const CubeImage & tex);
+        NVTT_API void operator=(const CubeSurface & img);
 
         // Queries.
         NVTT_API bool isNull() const;
@@ -546,20 +540,20 @@ namespace nvtt
         NVTT_API bool load(const char * fileName);
         NVTT_API bool save(const char * fileName) const;
 
-        TexImage & face(int face);
-        const TexImage & face(int face) const;
+        Surface & face(int face);
+        const Surface & face(int face) const;
 
         // Layout conversion.
-        void fold(const TexImage & img, CubeLayout layout);
-        TexImage unfold(CubeLayout layout) const;
+        void fold(const Surface & img, CubeLayout layout);
+        Surface unfold(CubeLayout layout) const;
 
         // @@ Angular extent filtering.
 
         // @@ Add resizing methods.
 
         // Filtering.
-        CubeImage irradianceFilter(int size) const;
-        CubeImage cosinePowerFilter(int size, float cosinePower) const;
+        CubeSurface irradianceFilter(int size) const;
+        CubeSurface cosinePowerFilter(int size, float cosinePower) const;
 
 
         /*
@@ -575,7 +569,7 @@ namespace nvtt
         NVTT_API void toLinear(float gamma);
         NVTT_API void toGamma(float gamma);
 
-    private:
+    //private:
         void detach();
 
         struct Private;
@@ -589,11 +583,11 @@ namespace nvtt
     // Return NVTT version.
     NVTT_API unsigned int version();
 
-    NVTT_API float rmsError(const TexImage & reference, const TexImage & img);
-    NVTT_API float rmsAlphaError(const TexImage & reference, const TexImage & img);
-    NVTT_API float cieLabError(const TexImage & reference, const TexImage & img);
-    NVTT_API float angularError(const TexImage & reference, const TexImage & img);
-    NVTT_API TexImage diff(const TexImage & reference, const TexImage & img, float scale);
+    NVTT_API float rmsError(const Surface & reference, const Surface & img);
+    NVTT_API float rmsAlphaError(const Surface & reference, const Surface & img);
+    NVTT_API float cieLabError(const Surface & reference, const Surface & img);
+    NVTT_API float angularError(const Surface & reference, const Surface & img);
+    NVTT_API Surface diff(const Surface & reference, const Surface & img, float scale);
 
 
 } // nvtt namespace
diff --git a/src/nvtt/tests/imperativeapi.cpp b/src/nvtt/tests/imperativeapi.cpp
index bd319aa..8b5593b 100644
--- a/src/nvtt/tests/imperativeapi.cpp
+++ b/src/nvtt/tests/imperativeapi.cpp
@@ -38,7 +38,7 @@ int main(int argc, char *argv[])
     context.enableCudaAcceleration(false);
 
     // Load input image.
-    nvtt::TexImage image;
+    nvtt::Surface image;
     if (!image.load(inputFileName)) {
         return EXIT_FAILURE;
     }
@@ -76,7 +76,7 @@ int main(int argc, char *argv[])
     int m = 1;
     while (image.buildNextMipmap(nvtt::MipmapFilter_Kaiser))
     {
-        nvtt::TexImage tmpImage = image;
+        nvtt::Surface tmpImage = image;
         tmpImage.toGamma(gamma);
 
         tmpImage.scaleAlphaToCoverage(coverage, alphaRef);
diff --git a/src/nvtt/tests/process_alpha_map.cpp b/src/nvtt/tests/process_alpha_map.cpp
index 6452d11..425122e 100644
--- a/src/nvtt/tests/process_alpha_map.cpp
+++ b/src/nvtt/tests/process_alpha_map.cpp
@@ -43,7 +43,7 @@ int main(int argc, char *argv[])
     context.enableCudaAcceleration(false);
 
     // Load color map.
-    nvtt::TexImage colorMap;
+    nvtt::Surface colorMap;
     if (!colorMap.load(inputFileNameColor)) {
         printf("Image '%s' could not be loaded.\n", inputFileNameColor);
         return EXIT_FAILURE;
@@ -63,7 +63,7 @@ int main(int argc, char *argv[])
     colorOutputOptions.setFileName(outputFileNameColor.str());
 
     // Load normal map.
-    nvtt::TexImage normalMap;
+    nvtt::Surface normalMap;
     if (inputFileNameNormal != NULL) {
         if (!normalMap.load(inputFileNameColor)) {
             printf("Image '%s' could not be loaded.\n", inputFileNameNormal);
@@ -123,7 +123,7 @@ int main(int argc, char *argv[])
     {
         colorMap.scaleAlphaToCoverage(coverage, alphaRef);
             
-        nvtt::TexImage tmpColorMap = colorMap;
+        nvtt::Surface tmpColorMap = colorMap;
         tmpColorMap.toGamma(gamma);
 
         context.compress(tmpColorMap, 0, m, colorCompressionOptions, colorOutputOptions);
diff --git a/src/nvtt/tests/testsuite.cpp b/src/nvtt/tests/testsuite.cpp
index fb31c47..db3a863 100644
--- a/src/nvtt/tests/testsuite.cpp
+++ b/src/nvtt/tests/testsuite.cpp
@@ -280,9 +280,9 @@ struct MyOutputHandler : public nvtt::OutputHandler
         return true;
     }
 
-    nvtt::TexImage decompress(Mode mode, nvtt::Format format, nvtt::Decoder decoder)
+    nvtt::Surface decompress(Mode mode, nvtt::Format format, nvtt::Decoder decoder)
     {
-        nvtt::TexImage img;
+        nvtt::Surface img;
         img.setImage2D(format, decoder, m_width, m_height, m_data);
         return img;
     }
@@ -576,7 +576,7 @@ int main(int argc, char *argv[])
     //int failedTests = 0;
     //float totalDiff = 0;
 
-    nvtt::TexImage img;
+    nvtt::Surface img;
 
     printf("Running Test: %s\n", set.name);
 
@@ -640,7 +640,7 @@ int main(int argc, char *argv[])
                 img.toGamma(2);
             }
 
-            nvtt::TexImage tmp = img;
+            nvtt::Surface tmp = img;
             if (mode == Mode_BC1) {
                 if (set.type == ImageType_HDR) {
                     /*for (int i = 0; i < 3; i++) {
@@ -727,7 +727,7 @@ int main(int argc, char *argv[])
             printf("  Time: \t%.3f sec\n", timer.elapsed());
             totalTime += timer.elapsed();
 
-            nvtt::TexImage img_out = outputHandler.decompress(mode, format, decoder);
+            nvtt::Surface img_out = outputHandler.decompress(mode, format, decoder);
             img_out.setAlphaMode(img.alphaMode());
             img_out.setNormalMap(img.isNormalMap());
 
@@ -796,14 +796,14 @@ int main(int argc, char *argv[])
                 tmp.transformNormals(nvtt::NormalTransform_DualParaboloid);
             }*/
 
-            nvtt::TexImage diff = nvtt::diff(img, img_out, 1.0f);
+            nvtt::Surface diff = nvtt::diff(img, img_out, 1.0f);
 
             //bool residualCompression = (set.type == ImageType_HDR);
             bool residualCompression = (mode == Mode_BC3_RGBS);
             if (residualCompression)
             {
                 float residualScale = 8.0f;
-                nvtt::TexImage residual = diff;
+                nvtt::Surface residual = diff;
                 for (int j = 0; j < 3; j++) {
                     residual.scaleBias(j, residualScale, 0.5); // @@ The residual scale is fairly arbitrary.
                     residual.clamp(j);
@@ -821,7 +821,7 @@ int main(int argc, char *argv[])
                 
                 context.compress(residual, 0, 0, compressionOptions, outputOptions);
 
-                nvtt::TexImage residual_out = outputHandler.decompress(mode, format, decoder);
+                nvtt::Surface residual_out = outputHandler.decompress(mode, format, decoder);
 
                 /*outputFileName.format("%s/%s", outputFilePath.str(), set.fileNames[i]);
                 outputFileName.stripExtension();
@@ -904,7 +904,7 @@ int main(int argc, char *argv[])
                 regressFileName.stripExtension();
                 regressFileName.append(".png");
 
-                nvtt::TexImage img_reg;
+                nvtt::Surface img_reg;
                 if (!img_reg.load(regressFileName.str()))
                 {
                     printf("Regression image '%s' not found.\n", regressFileName.str());