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/**
 * @file image_DXT.h
 * @brief simple DXT compression / decompression code
 */
/*
        Jonathan Dummer
        2007-07-31-10.32

        simple DXT compression / decompression code

        public domain
*/

#ifndef HEADER_IMAGE_DXT
#define HEADER_IMAGE_DXT

/**
        Converts an image from an array of unsigned chars (RGB or RGBA) to
        DXT1 or DXT5, then saves the converted image to disk.
        \return 0 if failed, otherwise returns 1
**/
int
save_image_as_DDS
(
    const char *filename,
    int width, int height, int channels,
    const unsigned char *const data
);

/**
        take an image and convert it to DXT1 (no alpha)
**/
unsigned char*
convert_image_to_DXT1
(
    const unsigned char *const uncompressed,
    int width, int height, int channels,
    int *out_size
);

/**
        take an image and convert it to DXT5 (with alpha)
**/
unsigned char*
convert_image_to_DXT5
(
    const unsigned char *const uncompressed,
    int width, int height, int channels,
    int *out_size
);

/**     A bunch of DirectDraw Surface structures and flags **/
typedef struct
{
    unsigned int    dwMagic;
    unsigned int    dwSize;
    unsigned int    dwFlags;
    unsigned int    dwHeight;
    unsigned int    dwWidth;
    unsigned int    dwPitchOrLinearSize;
    unsigned int    dwDepth;
    unsigned int    dwMipMapCount;
    unsigned int    dwReserved1[ 11 ];

    /*  DDPIXELFORMAT   */
    struct
    {
        unsigned int    dwSize;
        unsigned int    dwFlags;
        unsigned int    dwFourCC;
        unsigned int    dwRGBBitCount;
        unsigned int    dwRBitMask;
        unsigned int    dwGBitMask;
        unsigned int    dwBBitMask;
        unsigned int    dwAlphaBitMask;
    }
    sPixelFormat;

    /*  DDCAPS2 */
    struct
    {
        unsigned int    dwCaps1;
        unsigned int    dwCaps2;
        unsigned int    dwDDSX;
        unsigned int    dwReserved;
    }
    sCaps;
    unsigned int    dwReserved2;
}
DDS_header ;

/*      the following constants were copied directly off the MSDN website       */

/*      The dwFlags member of the original DDSURFACEDESC2 structure
        can be set to one or more of the following values.      */
#define DDSD_CAPS       0x00000001
#define DDSD_HEIGHT     0x00000002
#define DDSD_WIDTH      0x00000004
#define DDSD_PITCH      0x00000008
#define DDSD_PIXELFORMAT        0x00001000
#define DDSD_MIPMAPCOUNT        0x00020000
#define DDSD_LINEARSIZE 0x00080000
#define DDSD_DEPTH      0x00800000

/*      DirectDraw Pixel Format */
#define DDPF_ALPHAPIXELS        0x00000001
#define DDPF_FOURCC     0x00000004
#define DDPF_RGB        0x00000040

/*      The dwCaps1 member of the DDSCAPS2 structure can be
        set to one or more of the following values.     */
#define DDSCAPS_COMPLEX 0x00000008
#define DDSCAPS_TEXTURE 0x00001000
#define DDSCAPS_MIPMAP  0x00400000

/*      The dwCaps2 member of the DDSCAPS2 structure can be
        set to one or more of the following values.             */
#define DDSCAPS2_CUBEMAP        0x00000200
#define DDSCAPS2_CUBEMAP_POSITIVEX      0x00000400
#define DDSCAPS2_CUBEMAP_NEGATIVEX      0x00000800
#define DDSCAPS2_CUBEMAP_POSITIVEY      0x00001000
#define DDSCAPS2_CUBEMAP_NEGATIVEY      0x00002000
#define DDSCAPS2_CUBEMAP_POSITIVEZ      0x00004000
#define DDSCAPS2_CUBEMAP_NEGATIVEZ      0x00008000
#define DDSCAPS2_VOLUME 0x00200000

#endif /* HEADER_IMAGE_DXT      */