nvtt.h

// Copyright (c) 2009-2011 Ignacio Castano <castano@gmail.com>
// Copyright (c) 2007-2009 NVIDIA Corporation -- Ignacio Castano <icastano@nvidia.com>
// 
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without
// restriction, including without limitation the rights to use,
// copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following
// conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.

#pragma once
#ifndef NVTT_H
#define NVTT_H

// Function linkage
#if NVTT_SHARED

#if defined _WIN32 || defined WIN32 || defined __NT__ || defined __WIN32__ || defined __MINGW32__
#  ifdef NVTT_EXPORTS
#    define NVTT_API __declspec(dllexport)
#  else
#    define NVTT_API __declspec(dllimport)
#  endif
#endif

#if defined __GNUC__ >= 4
#  ifdef NVTT_EXPORTS
#    define NVTT_API __attribute__((visibility("default")))
#  endif
#endif

#endif // NVTT_SHARED

#if !defined NVTT_API
#  define NVTT_API
#endif

#define NVTT_VERSION 20102

#define NVTT_FORBID_COPY(Class) \
    private: \
        Class(const Class &); \
        void operator=(const Class &); \
    public:

#define NVTT_DECLARE_PIMPL(Class) \
    public: \
        struct Private; \
        Private & m


// Public interface.
namespace nvtt
{
    // Forward declarations.
    struct Surface;
    struct CubeSurface;


    // Supported block-compression formats.
    // @@ I wish I had distinguished between "formats" and compressors.
    // That is:
    // - 'DXT1' is a format 'DXT1a' and 'DXT1n' are DXT1 compressors.
    // - 'DXT3' is a format 'DXT3n' is a DXT3 compressor.
    // Having multiple enums for the same ids only creates confusion. Clean this up.
    enum Format
    {
        // No block-compression (linear).
        Format_RGB,
        Format_RGBA = Format_RGB,

        // DX9 formats.
        Format_DXT1,
        Format_DXT1a,   // DXT1 with binary alpha.
        Format_DXT3,
        Format_DXT5,
        Format_DXT5n,   // Compressed HILO: R=1, G=y, B=0, A=x

        // DX10 formats.
        Format_BC1 = Format_DXT1,
        Format_BC1a = Format_DXT1a,
        Format_BC2 = Format_DXT3,
        Format_BC3 = Format_DXT5,
        Format_BC3n = Format_DXT5n,
        Format_BC4,     // ATI1
        Format_BC5,     // 3DC, ATI2

        Format_DXT1n,   // Not supported.
        Format_CTX1,    // Not supported.

        Format_BC6,
        Format_BC7,

        Format_BC3_RGBM,

        Format_ETC1,
        Format_ETC2_R,
        Format_ETC2_RG,
        Format_ETC2_RGB,
        Format_ETC2_RGBA,
        Format_ETC2_RGB_A1,

        Format_ETC2_RGBM,

        Format_PVR_2BPP_RGB,     // Using PVR textools.
        Format_PVR_4BPP_RGB,
        Format_PVR_2BPP_RGBA,
        Format_PVR_4BPP_RGBA,

        Format_Count
    };

    // Pixel types. These basically indicate how the output should be interpreted, but do not have any influence over the input. They are only relevant in RGBA mode.
    enum PixelType
    {
        PixelType_UnsignedNorm = 0,
        PixelType_SignedNorm = 1,   // Not supported yet.
        PixelType_UnsignedInt = 2,  // Not supported yet.
        PixelType_SignedInt = 3,    // Not supported yet.
        PixelType_Float = 4,
        PixelType_UnsignedFloat = 5,
        PixelType_SharedExp = 6,    // Shared exponent.
    };

    // Quality modes.
    enum Quality
    {
        Quality_Fastest,
        Quality_Normal,
        Quality_Production,
        Quality_Highest,
    };

    // DXT decoder.
    enum Decoder
    {
        Decoder_D3D10,
        Decoder_D3D9,
        Decoder_NV5x,
        //Decoder_RSX, // To take advantage of DXT5 bug.
    };


    // Compression options. This class describes the desired compression format and other compression settings.
    struct CompressionOptions
    {
        NVTT_FORBID_COPY(CompressionOptions);
        NVTT_DECLARE_PIMPL(CompressionOptions);

        NVTT_API CompressionOptions();
        NVTT_API ~CompressionOptions();

        NVTT_API void reset();

        NVTT_API void setFormat(Format format);
        NVTT_API void setQuality(Quality quality);
        NVTT_API void setColorWeights(float red, float green, float blue, float alpha = 1.0f);
        NVTT_API void setRGBMThreshold(float min_m);

        NVTT_API void setExternalCompressor(const char * name);

        // Set color mask to describe the RGB/RGBA format.
        NVTT_API void setPixelFormat(unsigned int bitcount, unsigned int rmask, unsigned int gmask, unsigned int bmask, unsigned int amask);
        NVTT_API void setPixelFormat(unsigned char rsize, unsigned char gsize, unsigned char bsize, unsigned char asize);

        NVTT_API void setPixelType(PixelType pixelType);

        NVTT_API void setPitchAlignment(int pitchAlignment);

        // @@ I wish this wasn't part of the compression options. Quantization is applied before compression. We don't have compressors with error diffusion. 
        // @@ These options are only taken into account when using the InputOptions API.
        NVTT_API void setQuantization(bool colorDithering, bool alphaDithering, bool binaryAlpha, int alphaThreshold = 127);

        NVTT_API void setTargetDecoder(Decoder decoder);

        // Translate to and from D3D formats.
        NVTT_API Format format() const;
        NVTT_API unsigned int d3d9Format() const;
        NVTT_API unsigned int dxgiFormat() const;
        //NVTT_API bool setD3D9Format(unsigned int format);
        //NVTT_API bool setDxgiFormat(unsigned int format);
    };

    /*
    // DXGI_FORMAT_R16G16_FLOAT
    compressionOptions.setPixelType(PixelType_Float);
    compressionOptions.setPixelFormat2(16, 16, 0, 0);

    // DXGI_FORMAT_R32G32B32A32_FLOAT
    compressionOptions.setPixelType(PixelType_Float);
    compressionOptions.setPixelFormat2(32, 32, 32, 32);
    */


    // Wrap modes.
    enum WrapMode
    {
        WrapMode_Clamp,
        WrapMode_Repeat,
        WrapMode_Mirror,
    };

    // Texture types.
    enum TextureType
    {
        TextureType_2D,
        TextureType_Cube,
        TextureType_3D,
        TextureType_Array,
    };

    // Input formats.
    enum InputFormat
    {
        InputFormat_BGRA_8UB,   // Normalized [0, 1] 8 bit fixed point.
        InputFormat_RGBA_16F,   // 16 bit floating point.
        InputFormat_RGBA_32F,   // 32 bit floating point.
        InputFormat_R_32F,      // Single channel 32 bit floating point.
    };

    // Mipmap downsampling filters.
    enum MipmapFilter
    {
        MipmapFilter_Box,       // Box filter is quite good and very fast.
        MipmapFilter_Triangle,  // Triangle filter blurs the results too much, but that might be what you want.
        MipmapFilter_Kaiser,    // Kaiser-windowed Sinc filter is the best downsampling filter.
    };

    // Texture resize filters.
    enum ResizeFilter
    {
        ResizeFilter_Box,
        ResizeFilter_Triangle,
        ResizeFilter_Kaiser,
        ResizeFilter_Mitchell,
    };

    // Extents rounding mode.
    enum RoundMode
    {
        RoundMode_None,
        RoundMode_ToNextPowerOfTwo,
        RoundMode_ToNearestPowerOfTwo,
        RoundMode_ToPreviousPowerOfTwo,
        RoundMode_ToNextMultipleOfFour,                     // (New in NVTT 2.1)
        RoundMode_ToNearestMultipleOfFour,                  // (New in NVTT 2.1)
        RoundMode_ToPreviousMultipleOfFour,                 // (New in NVTT 2.1)
    };

    // Alpha mode.
    enum AlphaMode
    {
        AlphaMode_None,
        AlphaMode_Transparency,
        AlphaMode_Premultiplied,
    };

    // Extents shape restrictions
    enum ShapeRestriction
    {
        ShapeRestriction_None,
        ShapeRestriction_Square,    
    };


    // Input options. Specify format and layout of the input texture. (Deprecated in NVTT 2.1)
    struct InputOptions
    {
        NVTT_FORBID_COPY(InputOptions);
        NVTT_DECLARE_PIMPL(InputOptions);

        NVTT_API InputOptions();
        NVTT_API ~InputOptions();

        // Set default options.
        NVTT_API void reset();

        // Setup input layout.
        NVTT_API void setTextureLayout(TextureType type, int w, int h, int d = 1, int arraySize = 1);
        NVTT_API void resetTextureLayout();

        // Set mipmap data. Copies the data.
        NVTT_API bool setMipmapData(const void * data, int w, int h, int d = 1, int face = 0, int mipmap = 0);

        // Describe the format of the input.
        NVTT_API void setFormat(InputFormat format);

        // Set the way the input alpha channel is interpreted. @@ Not implemented!
        NVTT_API void setAlphaMode(AlphaMode alphaMode);

        // Set gamma settings.
        NVTT_API void setGamma(float inputGamma, float outputGamma);

        // Set texture wrapping mode.
        NVTT_API void setWrapMode(WrapMode mode);

        // Set mipmapping options.
        NVTT_API void setMipmapFilter(MipmapFilter filter);
        NVTT_API void setMipmapGeneration(bool enabled, int maxLevel = -1);
        NVTT_API void setKaiserParameters(float width, float alpha, float stretch);

        // Set normal map options.
        NVTT_API void setNormalMap(bool b);
        NVTT_API void setConvertToNormalMap(bool convert);
        NVTT_API void setHeightEvaluation(float redScale, float greenScale, float blueScale, float alphaScale);
        NVTT_API void setNormalFilter(float sm, float medium, float big, float large);
        NVTT_API void setNormalizeMipmaps(bool b);

        // Set resizing options.
        NVTT_API void setMaxExtents(int d);
        NVTT_API void setRoundMode(RoundMode mode);
    };


    // Output handler.
    struct OutputHandler
    {
        virtual ~OutputHandler() {}

        // Indicate the start of a new compressed image that's part of the final texture.
        virtual void beginImage(int size, int width, int height, int depth, int face, int miplevel) = 0;

        // Output data. Compressed data is output as soon as it's generated to minimize memory allocations.
        virtual bool writeData(const void * data, int size) = 0;

        // Indicate the end of the compressed image. (New in NVTT 2.1)
        virtual void endImage() = 0;
    };

    // Error codes.
    enum Error
    {
        Error_Unknown,
        Error_InvalidInput,
        Error_UnsupportedFeature,
        Error_CudaError,
        Error_FileOpen,
        Error_FileWrite,
        Error_UnsupportedOutputFormat,
        Error_Count
    };

    // Error handler.
    struct ErrorHandler
    {
        virtual ~ErrorHandler() {}

        // Signal error.
        virtual void error(Error e) = 0;
    };

    // Container.
    enum Container
    {
        Container_DDS,
        Container_DDS10,
        Container_KTX,   // Khronos Texture: http://www.khronos.org/opengles/sdk/tools/KTX/
        // Container_VTF,   // Valve Texture Format: http://developer.valvesoftware.com/wiki/Valve_Texture_Format
    };


    // Output Options. This class holds pointers to the interfaces that are used to report the output of
    // the compressor to the user.
    struct OutputOptions
    {
        NVTT_FORBID_COPY(OutputOptions);
        NVTT_DECLARE_PIMPL(OutputOptions);

        NVTT_API OutputOptions();
        NVTT_API ~OutputOptions();

        // Set default options.
        NVTT_API void reset();

        NVTT_API void setFileName(const char * fileName);
        NVTT_API void setFileHandle(void * fp);

        NVTT_API void setOutputHandler(OutputHandler * outputHandler);
        NVTT_API void setErrorHandler(ErrorHandler * errorHandler);

        NVTT_API void setOutputHeader(bool outputHeader);
        NVTT_API void setContainer(Container container);
        NVTT_API void setUserVersion(int version);
        NVTT_API void setSrgbFlag(bool b);
    };

    // (New in NVTT 2.1)
    typedef void Task(void * context, int id);

    // (New in NVTT 2.1)
    struct TaskDispatcher
    {
        virtual ~TaskDispatcher() {}

        virtual void dispatch(Task * task, void * context, int count) = 0;
    };

    // Context.
    struct Compressor
    {
        NVTT_FORBID_COPY(Compressor);
        NVTT_DECLARE_PIMPL(Compressor);

        NVTT_API Compressor();
        NVTT_API ~Compressor();

        // Context settings.
        NVTT_API void enableCudaAcceleration(bool enable);
        NVTT_API bool isCudaAccelerationEnabled() const;
        NVTT_API void setTaskDispatcher(TaskDispatcher * disp); // (New in NVTT 2.1)

        // InputOptions API.
        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;

        // Surface API. (New in NVTT 2.1)
        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;

        // CubeSurface API. (New in NVTT 2.1)
        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. (New in NVTT 2.1)
        NVTT_API bool outputHeader(TextureType type, int w, int h, int d, int arraySize, int mipmapCount, bool isNormalMap, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const;
        NVTT_API bool compress(int w, int h, int d, int face, int mipmap, const float * rgba, const CompressionOptions & compressionOptions, const OutputOptions & outputOptions) const;
        NVTT_API int estimateSize(int w, int h, int d, int mipmapCount, const CompressionOptions & compressionOptions) const;
    };

    // "Compressor" is deprecated. This should have been called "Context"
    typedef Compressor Context;

    // (New in NVTT 2.1)
    enum NormalTransform {
        NormalTransform_Orthographic,
        NormalTransform_Stereographic,
        NormalTransform_Paraboloid,
        NormalTransform_Quartic
        //NormalTransform_DualParaboloid,
    };

    // (New in NVTT 2.1)
    enum ToneMapper {
        ToneMapper_Linear,
        ToneMapper_Reindhart,
        ToneMapper_Halo,
        ToneMapper_Lightmap,
    };

    // Transform the given x,y,z coordinates.
    typedef void WarpFunction(float & x, float & y, float & z);


    // A surface is one level of a 2D or 3D texture. (New in NVTT 2.1)
    // @@ It would be nice to add support for texture borders for correct resizing of tiled textures and constrained DXT compression.
    struct Surface
    {
        NVTT_API Surface();
        NVTT_API Surface(const Surface & img);
        NVTT_API ~Surface();

        NVTT_API void operator=(const Surface & img);

        // Texture parameters.
        NVTT_API void setWrapMode(WrapMode mode);
        NVTT_API void setAlphaMode(AlphaMode alphaMode);
        NVTT_API void setNormalMap(bool isNormalMap);

        // Queries.
        NVTT_API bool isNull() const;
        NVTT_API int width() const;
        NVTT_API int height() const;
        NVTT_API int depth() const;
        NVTT_API TextureType type() const;
        NVTT_API WrapMode wrapMode() const;
        NVTT_API AlphaMode alphaMode() const;
        NVTT_API bool isNormalMap() const;
        NVTT_API int countMipmaps() const;
        NVTT_API int countMipmaps(int min_size) const;
        NVTT_API float alphaTestCoverage(float alphaRef = 0.5, int alpha_channel = 3) const;
        NVTT_API float average(int channel, int alpha_channel = -1, float gamma = 2.2f) const;
        NVTT_API const float * data() const;
        NVTT_API const float * channel(int i) const;
        NVTT_API void histogram(int channel, float rangeMin, float rangeMax, int binCount, int * binPtr) const;
        NVTT_API void range(int channel, float * rangeMin, float * rangeMax, int alpha_channel = -1, float alpha_ref = 0.f) const;

        // Texture data.
        NVTT_API bool load(const char * fileName, bool * hasAlpha = 0);
        NVTT_API bool save(const char * fileName, bool hasAlpha = 0, bool hdr = 0) const;
        NVTT_API bool setImage(int w, int h, int d);
        NVTT_API bool setImage(InputFormat format, int w, int h, int d, const void * data);
        NVTT_API bool setImage(InputFormat format, int w, int h, int d, const void * r, const void * g, const void * b, const void * a);
        NVTT_API bool setImage2D(Format format, Decoder decoder, int w, int h, const void * data);

        // Resizing methods.
        NVTT_API void resize(int w, int h, int d, ResizeFilter filter);
        NVTT_API void resize(int w, int h, int d, ResizeFilter filter, float filterWidth, const float * params = 0);
        NVTT_API void resize(int maxExtent, RoundMode mode, ResizeFilter filter);
        NVTT_API void resize(int maxExtent, RoundMode mode, ResizeFilter filter, float filterWidth, const float * params = 0);
        NVTT_API void resizeMakeSquare(int maxExtent, RoundMode roundMode, ResizeFilter filter);
        NVTT_API void autoResize(float errorTolerance, RoundMode mode, ResizeFilter filter);

        NVTT_API bool buildNextMipmap(MipmapFilter filter, int min_size = 1);
        NVTT_API bool buildNextMipmap(MipmapFilter filter, float filterWidth, const float * params = 0, int min_size = 1);
        NVTT_API bool buildNextMipmapSolidColor(const float * const color_components);
        NVTT_API void canvasSize(int w, int h, int d);
        // associated to resizing:
        NVTT_API bool canMakeNextMipmap(int min_size = 1);

        // Color transforms.
        NVTT_API void toLinear(float gamma);
        NVTT_API void toGamma(float gamma);
        NVTT_API void toLinear(int channel, float gamma);
        NVTT_API void toGamma(int channel, float gamma);
        NVTT_API void toSrgb();
        NVTT_API void toSrgbFast();
        NVTT_API void toLinearFromSrgb();
        NVTT_API void toLinearFromSrgbFast();
        NVTT_API void toXenonSrgb();
        NVTT_API void transform(const float w0[4], const float w1[4], const float w2[4], const float w3[4], const float offset[4]);
        NVTT_API void swizzle(int r, int g, int b, int a);
        NVTT_API void scaleBias(int channel, float scale, float bias);
        NVTT_API void clamp(int channel, float low = 0.0f, float high = 1.0f);
        NVTT_API void blend(float r, float g, float b, float a, float t);
        NVTT_API void premultiplyAlpha();
        NVTT_API void toGreyScale(float redScale, float greenScale, float blueScale, float alphaScale);
        NVTT_API void setBorder(float r, float g, float b, float a);
        NVTT_API void fill(float r, float g, float b, float a);
        NVTT_API void scaleAlphaToCoverage(float coverage, float alphaRef = 0.5f, int alpha_channel = 3);
        NVTT_API void toRGBM(float range = 1.0f, float threshold = 0.25f);
        NVTT_API void fromRGBM(float range = 1.0f, float threshold = 0.25f);
        NVTT_API void toLM(float range = 1.0f, float threshold = 0.0f);
        NVTT_API void toRGBE(int mantissaBits, int exponentBits);
        NVTT_API void fromRGBE(int mantissaBits, int exponentBits);
        NVTT_API void toYCoCg();
        NVTT_API void blockScaleCoCg(int bits = 5, float threshold = 0.0f);
        NVTT_API void fromYCoCg();
        NVTT_API void toLUVW(float range = 1.0f);
        NVTT_API void fromLUVW(float range = 1.0f);
        NVTT_API void abs(int channel);
        NVTT_API void convolve(int channel, int kernelSize, float * kernelData);
        NVTT_API void toLogScale(int channel, float base);
        NVTT_API void fromLogScale(int channel, float base);
        NVTT_API void setAtlasBorder(int w, int h, float r, float g, float b, float a);

        NVTT_API void toneMap(ToneMapper tm, float * parameters);

        //NVTT_API void blockLuminanceScale(float scale);

        // Color quantization.
        NVTT_API void binarize(int channel, float threshold, bool dither);
        NVTT_API void quantize(int channel, int bits, bool exactEndPoints, bool dither);

        // Normal map transforms.
        NVTT_API void toNormalMap(float sm, float medium, float big, float large);
        NVTT_API void normalizeNormalMap();
        NVTT_API void transformNormals(NormalTransform xform);
        NVTT_API void reconstructNormals(NormalTransform xform);
        NVTT_API void toCleanNormalMap();
        NVTT_API void packNormals(float scale = 0.5f, float bias = 0.5f);       // [-1,1] -> [ 0,1]
        NVTT_API void expandNormals(float scale = 2.0f, float bias = -1.0f);    // [ 0,1] -> [-1,1]
        NVTT_API Surface createToksvigMap(float power) const;
        NVTT_API Surface createCleanMap() const;

        // Geometric transforms.
        NVTT_API void flipX();
        NVTT_API void flipY();
        NVTT_API void flipZ();
        NVTT_API Surface createSubImage(int x0, int x1, int y0, int y1, int z0, int z1) const;

        NVTT_API Surface warp(int w, int h, WarpFunction * f) const;
        NVTT_API Surface warp(int w, int h, int d, WarpFunction * f) const;


        // Copy image data.
        NVTT_API bool copyChannel(const Surface & srcImage, int srcChannel);
        NVTT_API bool copyChannel(const Surface & srcImage, int srcChannel, int dstChannel);

        NVTT_API bool addChannel(const Surface & img, int srcChannel, int dstChannel, float scale);

        NVTT_API bool copy(const Surface & src, int xsrc, int ysrc, int zsrc, int xsize, int ysize, int zsize, int xdst, int ydst, int zdst);


    //private:
        void detach();

        struct Private;
        Private * m;
    };


    // Cube layout formats. (New in NVTT 2.1)
    enum CubeLayout {
        CubeLayout_VerticalCross,
        CubeLayout_HorizontalCross,
        CubeLayout_Column,
        CubeLayout_Row,
        CubeLayout_LatitudeLongitude
    };

    // (New in NVTT 2.1)
    enum EdgeFixup {
        EdgeFixup_None,
        EdgeFixup_Stretch,
        EdgeFixup_Warp,
        EdgeFixup_Average,
    };

    // A CubeSurface is one level of a cube map texture. (New in NVTT 2.1)
    struct CubeSurface
    {
        NVTT_API CubeSurface();
        NVTT_API CubeSurface(const CubeSurface & img);
        NVTT_API ~CubeSurface();

        NVTT_API void operator=(const CubeSurface & img);

        // Queries.
        NVTT_API bool isNull() const;
        NVTT_API int edgeLength() const;
        NVTT_API int countMipmaps() const;

        // Texture data.
        NVTT_API bool load(const char * fileName, int mipmap);
        NVTT_API bool save(const char * fileName) const;

        NVTT_API Surface & face(int face);
        NVTT_API const Surface & face(int face) const;

        // Layout conversion. @@ Not implemented.
        NVTT_API void fold(const Surface & img, CubeLayout layout);
        NVTT_API Surface unfold(CubeLayout layout) const;

        // @@ Angular extent filtering.

        // @@ Add resizing methods.

        // @@ Add edge fixup methods.

        NVTT_API float average(int channel) const;
        NVTT_API void range(int channel, float * minimum_ptr, float * maximum_ptr) const;
        NVTT_API void clamp(int channel, float low = 0.0f, float high = 1.0f);


        // Filtering.
        NVTT_API CubeSurface irradianceFilter(int size, EdgeFixup fixupMethod) const;
        NVTT_API CubeSurface cosinePowerFilter(int size, float cosinePower, EdgeFixup fixupMethod) const;

        NVTT_API CubeSurface fastResample(int size, EdgeFixup fixupMethod) const;

        // Spherical Harmonics:
        NVTT_API void computeLuminanceIrradianceSH3(float sh[9]) const;
        NVTT_API void computeIrradianceSH3(int channel, float sh[9]) const;

        /*
        NVTT_API void resize(int w, int h, ResizeFilter filter);
        NVTT_API void resize(int w, int h, ResizeFilter filter, float filterWidth, const float * params = 0);
        NVTT_API void resize(int maxExtent, RoundMode mode, ResizeFilter filter);
        NVTT_API void resize(int maxExtent, RoundMode mode, ResizeFilter filter, float filterWidth, const float * params = 0);
        NVTT_API bool buildNextMipmap(MipmapFilter filter);
        NVTT_API bool buildNextMipmap(MipmapFilter filter, float filterWidth, const float * params = 0);
        */

        // Color transforms.
        NVTT_API void toLinear(float gamma);
        NVTT_API void toGamma(float gamma);

    //private:
        void detach();

        struct Private;
        Private * m;
    };


    // Return string for the given error code.
    NVTT_API const char * errorString(Error e);

    // Return NVTT version.
    NVTT_API unsigned int version();

    // Image comparison and error measurement functions. (New in NVTT 2.1)
    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_API float rmsToneMappedError(const Surface & reference, const Surface & img, float exposure);


    NVTT_API Surface histogram(const Surface & img, int width, int height);
    NVTT_API Surface histogram(const Surface & img, float minRange, float maxRange, int width, int height);

} // nvtt namespace

#endif // NVTT_H