.DDS Fileformat

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// DirectDraw's structures//////struct DDCOLORKEY{    DWORD       dwColorSpaceLowValue;   // low boundary of color space that is to                                        // be treated as Color Key, inclusive    DWORD       dwColorSpaceHighValue;  // high boundary of color space that is                                        // to be treated as Color Key, inclusive};		////DDPIXELFORMAT//struct DDPIXELFORMAT{    DWORD       dwSize;                 // size of structure    DWORD       dwFlags;                // pixel format flags    DWORD       dwFourCC;               // (FOURCC code)    union    {        DWORD   dwRGBBitCount;          // how many bits per pixel        DWORD   dwYUVBitCount;          // how many bits per pixel        DWORD   dwZBufferBitDepth;      // how many total bits/pixel in z buffer (including any stencil bits)        DWORD   dwAlphaBitDepth;        // how many bits for alpha channels        DWORD   dwLuminanceBitCount;    // how many bits per pixel        DWORD   dwBumpBitCount;         // how many bits per "buxel", total        DWORD   dwPrivateFormatBitCount;// Bits per pixel of private driver formats. Only valid in texture                                        // format list and if DDPF_D3DFORMAT is set    };    union    {        DWORD   dwRBitMask;             // mask for red bit        DWORD   dwYBitMask;             // mask for Y bits        DWORD   dwStencilBitDepth;      // how many stencil bits (note: dwZBufferBitDepth-dwStencilBitDepth is total Z-only bits)        DWORD   dwLuminanceBitMask;     // mask for luminance bits        DWORD   dwBumpDuBitMask;        // mask for bump map U delta bits        DWORD   dwOperations;           // DDPF_D3DFORMAT Operations    };    union    {        DWORD   dwGBitMask;             // mask for green bits        DWORD   dwUBitMask;             // mask for U bits        DWORD   dwZBitMask;             // mask for Z bits        DWORD   dwBumpDvBitMask;        // mask for bump map V delta bits        struct        {            WORD    wFlipMSTypes;       // Multisample methods supported via flip for this D3DFORMAT            WORD    wBltMSTypes;        // Multisample methods supported via blt for this D3DFORMAT        } MultiSampleCaps;    };    union    {        DWORD   dwBBitMask;             // mask for blue bits        DWORD   dwVBitMask;             // mask for V bits        DWORD   dwStencilBitMask;       // mask for stencil bits        DWORD   dwBumpLuminanceBitMask; // mask for luminance in bump map    };    union    {        DWORD   dwRGBAlphaBitMask;      // mask for alpha channel        DWORD   dwYUVAlphaBitMask;      // mask for alpha channel        DWORD   dwLuminanceAlphaBitMask;// mask for alpha channel        DWORD   dwRGBZBitMask;          // mask for Z channel        DWORD   dwYUVZBitMask;          // mask for Z channel    };};	//// DDSCAPS2// struct DDSCAPS2{    DWORD       dwCaps;         // capabilities of surface wanted    DWORD       dwCaps2;    DWORD       dwCaps3;    union    {        DWORD       dwCaps4;        DWORD       dwVolumeDepth;    };};	//// DDSURFACEDESC2//struct DDSURFACEDESC2{    DWORD               dwSize;                 // size of the DDSURFACEDESC structure    DWORD               dwFlags;                // determines what fields are valid    DWORD               dwHeight;               // height of surface to be created    DWORD               dwWidth;                // width of input surface    union    {        LONG            lPitch;                 // distance to start of next line (return value only)        DWORD           dwLinearSize;           // Formless late-allocated optimized surface size    };    union    {        DWORD           dwBackBufferCount;      // number of back buffers requested        DWORD           dwDepth;                // the depth if this is a volume texture     };    union    {        DWORD           dwMipMapCount;          // number of mip-map levels requestde                                                // dwZBufferBitDepth removed, use ddpfPixelFormat one instead        DWORD           dwRefreshRate;          // refresh rate (used when display mode is described)        DWORD           dwSrcVBHandle;          // The source used in VB::Optimize    };    DWORD               dwAlphaBitDepth;        // depth of alpha buffer requested    DWORD               dwReserved;             // reserved    LPVOID              lpSurface;              // pointer to the associated surface memory    union    {        DDCOLORKEY      ddckCKDestOverlay;      // color key for destination overlay use        DWORD           dwEmptyFaceColor;       // Physical color for empty cubemap faces    };    DDCOLORKEY          ddckCKDestBlt;          // color key for destination blt use    DDCOLORKEY          ddckCKSrcOverlay;       // color key for source overlay use    DDCOLORKEY          ddckCKSrcBlt;           // color key for source blt use    union    {        DDPIXELFORMAT   ddpfPixelFormat;        // pixel format description of the surface        DWORD           dwFVF;                  // vertex format description of vertex buffers    };    DDSCAPS2            ddsCaps;                // direct draw surface capabilities    DWORD               dwTextureStage;         // stage in multitexture cascade};	#define FOURCC_DXT1	MAKEFOURCC('D', 'X', 'T', '1')#define FOURCC_DXT3	MAKEFOURCC('D', 'X', 'T', '3')#define FOURCC_DXT5	MAKEFOURCC('D', 'X', 'T', '5')

//// Charge une texture depuis un fichier//// filename : nom du fichier .dds//bool	cTexture::LoadDDS(const char *filename){	DDSURFACEDESC2	ddsd;	char				filecode[4];	int				factor;	int				bufferSize;	int				format;	FILE				*file=NULL;	file = fopen(filename, "rb");	// Verify the file is a true .dds file	fread(&filecode, 1, 4, file);	if( strncmp( filecode, "DDS ", 4 ) != 0 )	{		DebugManager->Print(Error, __FUNCTION__, "\"%s\" is not a valid .dds file !", filename);		return false;	}	// Get the surface descriptor	fread(&ddsd, 1, sizeof(ddsd), file);	//	// Type de compression	switch(ddsd.ddpfPixelFormat.dwFourCC)	{	case FOURCC_DXT1:		// DXT1's compression ratio is 8:1		format = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;		factor = 2;		break;	case FOURCC_DXT3:		// DXT3's compression ratio is 4:1		format = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;		factor = 4;		break;	case FOURCC_DXT5:		// DXT5's compression ratio is 4:1		format = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;		factor = 4;		break;	default:		DebugManager->Print(Todo, __FUNCTION__, "The file \"%s\" doesn't appear to be compressed using DXT1, DXT3, or DXT5!", filename);		fclose(file);		return false;		break;	}	//	// Taille du buffer	//	if(!ddsd.dwLinearSize)	{		DebugManager->Print(Error, __FUNCTION__, "ddsd.dwLinearSize is 0 !");		fclose(file);		return false;	}	if (ddsd.dwMipMapCount > 1)	bufferSize = ddsd.dwLinearSize * factor;	else									bufferSize = ddsd.dwLinearSize;	ImageData = new unsigned char[bufferSize];	memset(ImageData, 0, bufferSize);	int ret = 0;	ret = fread(ImageData, 1, bufferSize, file);	fclose(file);	// Sauvegarde les infos	Width			= ddsd.dwWidth;	Height		= ddsd.dwHeight;	if(ddsd.ddpfPixelFormat.dwFourCC == FOURCC_DXT1 )	PixelFormat = PF_RGB;	else																PixelFormat = PF_RGBA;	//	// Generation de la texture	glGenTextures(1, (GLuint *)&GLid);	glBindTexture(GL_TEXTURE_2D, GLid);	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );	// Chargement des mipmaps	int nSize			= 0;	int nOffset			= 0;	int nHeight			= Height;	int nWidth			= Width;	int nNumMipMaps	= ddsd.dwMipMapCount;	int nBlockSize		= format == GL_COMPRESSED_RGBA_S3TC_DXT1_EXT ? 8 : 16;	for( unsigned long i = 0; i < ddsd.dwMipMapCount; ++i )	{		if( nWidth  == 0 ) nWidth  = 1;		if( nHeight == 0 ) nHeight = 1;		nSize = ((nWidth+3)/4) * ((nHeight+3)/4) * nBlockSize;		glCompressedTexImage2DARB( GL_TEXTURE_2D,			i,			format,			nWidth,			nHeight,			0,			nSize,			ImageData + nOffset );		nOffset += nSize;		// Moitie de la taille pour le prochain mipmap...		nWidth  /= 2;		nHeight /= 2;	}	 	 return true;}