/**

* MojoDDS; tools for dealing with DDS files.

*

* Please see the file LICENSE.txt in the source's root directory.

*

* This file written by Ryan C. Gordon.

*/

// Specs on DDS format: http://msdn.microsoft.com/en-us/library/bb943991.aspx/

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#include <assert.h>

#ifdef _MSC_VER

typedef unsigned __int8 uint8;

typedef unsigned __int32 uint32;

#else

#include <stdint.h>

typedef uint8_t uint8;

typedef uint32_t uint32;

#endif

#define STATICARRAYLEN(x) ( (sizeof ((x))) / (sizeof ((x)[0])) )

#define DDS_MAGIC 0x20534444 // 'DDS ' in littleendian.

#define DDS_HEADERSIZE 124

#define DDS_PIXFMTSIZE 32

#define DDSD_CAPS 0x1

#define DDSD_HEIGHT 0x2

#define DDSD_WIDTH 0x4

#define DDSD_PITCH 0x8

#define DDSD_FMT 0x1000

#define DDSD_MIPMAPCOUNT 0x20000

#define DDSD_LINEARSIZE 0x80000

#define DDSD_DEPTH 0x800000

#define DDSD_REQ (DDSD_CAPS | DDSD_HEIGHT | DDSD_WIDTH | DDSD_FMT)

#define DDSCAPS_ALPHA 0x2

#define DDSCAPS_COMPLEX 0x8

#define DDSCAPS_MIPMAP 0x400000

#define DDSCAPS_TEXTURE 0x1000

#define DDPF_ALPHAPIXELS 0x1

#define DDPF_ALPHA 0x2

#define DDPF_FOURCC 0x4

#define DDPF_RGB 0x40

#define DDPF_YUV 0x200

#define DDPF_LUMINANCE 0x20000

#define FOURCC_DXT1 0x31545844

#define FOURCC_DXT2 0x32545844

#define FOURCC_DXT3 0x33545844

#define FOURCC_DXT4 0x34545844

#define FOURCC_DXT5 0x35545844

#define FOURCC_DX10 0x30315844

#define GL_COMPRESSED_RGBA_S3TC_DXT1_EXT 0x83F1

#define GL_COMPRESSED_RGBA_S3TC_DXT3_EXT 0x83F2

#define GL_COMPRESSED_RGBA_S3TC_DXT5_EXT 0x83F3

#define GL_BGR 0x80E0

#define GL_BGRA 0x80E1

typedef struct

{

uint32 dwSize;

uint32 dwFlags;

uint32 dwFourCC;

uint32 dwRGBBitCount;

uint32 dwRBitMask;

uint32 dwGBitMask;

uint32 dwBBitMask;

uint32 dwABitMask;

} MOJODDS_PixelFormat;

typedef struct

{

uint32 dwSize;

uint32 dwFlags;

uint32 dwHeight;

uint32 dwWidth;

uint32 dwPitchOrLinearSize;

uint32 dwDepth;

uint32 dwMipMapCount;

uint32 dwReserved1[11];

MOJODDS_PixelFormat ddspf;

uint32 dwCaps;

uint32 dwCaps2;

uint32 dwCaps3;

uint32 dwCaps4;

uint32 dwReserved2;

} MOJODDS_Header;

static uint32 readui32(const uint8 **_ptr, size_t *_len)

{

uint32 retval = 0;

if (*_len < sizeof (retval))

*_len = 0;

else

{

const uint8 *ptr = *_ptr;

retval = (((uint32) ptr[0]) << 0) | (((uint32) ptr[1]) << 8) |

(((uint32) ptr[2]) << 16) | (((uint32) ptr[3]) << 24) ;

*_ptr += sizeof (retval);

*_len -= sizeof (retval);

} // else

return retval;

} // readui32

static int parse_dds(MOJODDS_Header *header, const uint8 **ptr, size_t *len,

unsigned int *_glfmt, unsigned int *_miplevels)

{

const uint32 pitchAndLinear = (DDSD_PITCH | DDSD_LINEARSIZE);

uint32 width = 0;

uint32 height = 0;

uint32 calcSize = 0;

uint32 calcSizeFlag = DDSD_LINEARSIZE;

int i;

// Files start with magic value...

if (readui32(ptr, len) != DDS_MAGIC)

return 0; // not a DDS file.

// Then comes the DDS header...

if (*len < DDS_HEADERSIZE)

return 0;

header->dwSize = readui32(ptr, len);

header->dwFlags = readui32(ptr, len);

header->dwHeight = readui32(ptr, len);

header->dwWidth = readui32(ptr, len);

header->dwPitchOrLinearSize = readui32(ptr, len);

header->dwDepth = readui32(ptr, len);

header->dwMipMapCount = readui32(ptr, len);

for (i = 0; i < STATICARRAYLEN(header->dwReserved1); i++)

header->dwReserved1[i] = readui32(ptr, len);

header->ddspf.dwSize = readui32(ptr, len);

header->ddspf.dwFlags = readui32(ptr, len);

header->ddspf.dwFourCC = readui32(ptr, len);

header->ddspf.dwRGBBitCount = readui32(ptr, len);

header->ddspf.dwRBitMask = readui32(ptr, len);

header->ddspf.dwGBitMask = readui32(ptr, len);

header->ddspf.dwBBitMask = readui32(ptr, len);

header->ddspf.dwABitMask = readui32(ptr, len);

header->dwCaps = readui32(ptr, len);

header->dwCaps2 = readui32(ptr, len);

header->dwCaps3 = readui32(ptr, len);

header->dwCaps4 = readui32(ptr, len);

header->dwReserved2 = readui32(ptr, len);

width = header->dwWidth;

height = header->dwHeight;

header->dwCaps &= ~DDSCAPS_ALPHA; // we'll get this from the pixel format.

if (header->dwSize != DDS_HEADERSIZE) // header size must be 124.

return 0;

else if (header->ddspf.dwSize != DDS_PIXFMTSIZE) // size must be 32.

return 0;

else if ((header->dwFlags & DDSD_REQ) != DDSD_REQ) // must have these bits.

return 0;

else if ((header->dwCaps & DDSCAPS_TEXTURE) == 0)

return 0;

else if (header->dwCaps2 != 0) // !!! FIXME (non-zero with other bits in dwCaps set)

return 0;

else if ((header->dwFlags & pitchAndLinear) == pitchAndLinear)

return 0; // can't specify both.

*_miplevels = (header->dwCaps & DDSCAPS_MIPMAP) ? header->dwMipMapCount : 1;

if (header->ddspf.dwFlags & DDPF_FOURCC)

{

switch (header->ddspf.dwFourCC)

{

case FOURCC_DXT1:

*_glfmt = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;

calcSize = ((width ? ((width + 3) / 4) : 1) * 8) *

(height ? ((height + 3) / 4) : 1);

break;

case FOURCC_DXT3:

*_glfmt = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;

calcSize = ((width ? ((width + 3) / 4) : 1) * 16) *

(height ? ((height + 3) / 4) : 1);

break;

case FOURCC_DXT5:

*_glfmt = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;

calcSize = ((width ? ((width + 3) / 4) : 1) * 16) *

(height ? ((height + 3) / 4) : 1);

break;

// !!! FIXME: DX10 is an extended header, introduced by DirectX 10.

//case FOURCC_DX10: do_something(); break;

//case FOURCC_DXT2: // premultiplied alpha unsupported.

//case FOURCC_DXT4: // premultiplied alpha unsupported.

default:

return 0; // unsupported data format.

} // switch

} // if

// no FourCC...uncompressed data.

else if (header->ddspf.dwFlags & DDPF_RGB)

{

if ( (header->ddspf.dwRBitMask != 0x00FF0000) ||

(header->ddspf.dwGBitMask != 0x0000FF00) ||

(header->ddspf.dwBBitMask != 0x000000FF) )

return 0; // !!! FIXME: deal with this.

if (header->ddspf.dwFlags & DDPF_ALPHAPIXELS)

{

if ( (header->ddspf.dwRGBBitCount != 32) ||

(header->ddspf.dwABitMask != 0xFF000000) )

return 0; // unsupported.

*_glfmt = GL_BGRA;

} // if

else

{

if (header->ddspf.dwRGBBitCount != 24)

return 0; // unsupported.

*_glfmt = GL_BGR;

} // else

calcSizeFlag = DDSD_PITCH;

calcSize = ((width * header->ddspf.dwRGBBitCount) + 7) / 8;

} // else if

//else if (header->ddspf.dwFlags & DDPF_LUMINANCE) // !!! FIXME

//else if (header->ddspf.dwFlags & DDPF_YUV) // !!! FIXME

//else if (header->ddspf.dwFlags & DDPF_ALPHA) // !!! FIXME

else

{

return 0; // unsupported data format.

} // else if

// no pitch or linear size? Calculate it.

if ((header->dwFlags & pitchAndLinear) == 0)

{

if (!calcSizeFlag)

{

assert(0 && "should have caught this up above");

return 0; // uh oh.

} // if

header->dwPitchOrLinearSize = calcSize;

header->dwFlags |= calcSizeFlag;

} // if

return 1;

} // parse_dds

// !!! FIXME: improve the crap out of this API later.

int MOJODDS_isDDS(const void *_ptr, const unsigned long _len)

{

size_t len = (size_t) _len;

const uint8 *ptr = (const uint8 *) _ptr;

return (readui32(&ptr, &len) == DDS_MAGIC);

} // MOJODDS_isDDS

int MOJODDS_getTexture(const void *_ptr, const unsigned long _len,

const void **_tex, unsigned long *_texlen,

unsigned int *_glfmt, unsigned int *_w,

unsigned int *_h, unsigned int *_miplevels)

{

size_t len = (size_t) _len;

const uint8 *ptr = (const uint8 *) _ptr;

MOJODDS_Header header;

if (!parse_dds(&header, &ptr, &len, _glfmt, _miplevels))

return 0;

*_tex = (const void *) ptr;

*_w = (unsigned int) header.dwWidth;

*_h = (unsigned int) header.dwHeight;

*_texlen = (unsigned long) header.dwPitchOrLinearSize;

if (header.dwFlags & DDSD_PITCH)

*_texlen *= header.dwHeight;

return 1;

} // MOJODDS_getTexture

// end of mojodds.c ...