txc_dxtn.h File Reference

#include <GL/gl.h>

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Macros
#define	UBYTE_TO_CHAN(b)   (b)
#define	CHAN_MAX   255
#define	RCOMP   0
#define	GCOMP   1
#define	BCOMP   2
#define	ACOMP   3

Typedefs
typedef GLubyte	GLchan

Functions
void	fetch_2d_texel_rgb_dxt1 (GLint srcRowStride, const GLubyte *pixdata, GLint i, GLint j, GLvoid *texel)
void	fetch_2d_texel_rgba_dxt1 (GLint srcRowStride, const GLubyte *pixdata, GLint i, GLint j, GLvoid *texel)
void	fetch_2d_texel_rgba_dxt3 (GLint srcRowStride, const GLubyte *pixdata, GLint i, GLint j, GLvoid *texel)
void	fetch_2d_texel_rgba_dxt5 (GLint srcRowStride, const GLubyte *pixdata, GLint i, GLint j, GLvoid *texel)
void	tx_compress_dxtn (GLint srccomps, GLint width, GLint height, const GLubyte *srcPixData, GLenum destformat, GLubyte *dest, GLint dstRowStride)

Macro Definition Documentation

ACOMP

#define ACOMP   3

Definition at line 36 of file txc_dxtn.h.

BCOMP

#define BCOMP   2

Definition at line 35 of file txc_dxtn.h.

CHAN_MAX

#define CHAN_MAX   255

Definition at line 32 of file txc_dxtn.h.

GCOMP

#define GCOMP   1

Definition at line 34 of file txc_dxtn.h.

RCOMP

#define RCOMP   0

Definition at line 33 of file txc_dxtn.h.

UBYTE_TO_CHAN

#define UBYTE_TO_CHAN

(

b

)

(b)

Definition at line 31 of file txc_dxtn.h.

Typedef Documentation

GLchan

typedef GLubyte GLchan

Definition at line 30 of file txc_dxtn.h.

Function Documentation

fetch_2d_texel_rgb_dxt1()

void fetch_2d_texel_rgb_dxt1	(	GLint	srcRowStride,
		const GLubyte *	pixdata,
		GLint	i,
		GLint	j,
		GLvoid *	texel
	)

Definition at line 97 of file txc_fetch_dxtn.c.

{
   /* Extract the (i,j) pixel from pixdata and return it
    * in texel[RCOMP], texel[GCOMP], texel[BCOMP], texel[ACOMP].
    */
 
   const GLubyte *blksrc = (pixdata + ((srcRowStride + 3) / 4 * (j / 4) + (i / 4)) * 8);
   dxt135_decode_imageblock(blksrc, (i&3), (j&3), 0, texel);
}

fetch_2d_texel_rgba_dxt1()

void fetch_2d_texel_rgba_dxt1	(	GLint	srcRowStride,
		const GLubyte *	pixdata,
		GLint	i,
		GLint	j,
		GLvoid *	texel
	)

Definition at line 109 of file txc_fetch_dxtn.c.

{
   /* Extract the (i,j) pixel from pixdata and return it
    * in texel[RCOMP], texel[GCOMP], texel[BCOMP], texel[ACOMP].
    */
 
   const GLubyte *blksrc = (pixdata + ((srcRowStride + 3) / 4 * (j / 4) + (i / 4)) * 8);
   dxt135_decode_imageblock(blksrc, (i&3), (j&3), 1, texel);
}

Referenced by D3DXLoadSurfaceFromMemory(), and wined3d_dxtn_init().

fetch_2d_texel_rgba_dxt3()

void fetch_2d_texel_rgba_dxt3	(	GLint	srcRowStride,
		const GLubyte *	pixdata,
		GLint	i,
		GLint	j,
		GLvoid *	texel
	)

Definition at line 120 of file txc_fetch_dxtn.c.

                                                          {
 
   /* Extract the (i,j) pixel from pixdata and return it
    * in texel[RCOMP], texel[GCOMP], texel[BCOMP], texel[ACOMP].
    */
 
   GLchan *rgba = (GLchan *) texel;
   const GLubyte *blksrc = (pixdata + ((srcRowStride + 3) / 4 * (j / 4) + (i / 4)) * 16);
#if 0
   /* Simple 32bit version. */
/* that's pretty brain-dead for a single pixel, isn't it? */
   const GLubyte bit_pos = 4 * ((j&3) * 4 + (i&3));
   const GLuint alpha_low = blksrc[0] | (blksrc[1] << 8) | (blksrc[2] << 16) | (blksrc[3] << 24);
   const GLuint alpha_high = blksrc[4] | (blksrc[5] << 8) | (blksrc[6] << 16) | (blksrc[7] << 24);
 
   dxt135_decode_imageblock(blksrc + 8, (i&3), (j&3), 2, texel);
   if (bit_pos < 32)
      rgba[ACOMP] = UBYTE_TO_CHAN( (GLubyte)(EXP4TO8((alpha_low >> bit_pos) & 15)) );
   else
      rgba[ACOMP] = UBYTE_TO_CHAN( (GLubyte)(EXP4TO8((alpha_high >> (bit_pos - 32)) & 15)) );
#endif
#if 1
/* TODO test this! */
   const GLubyte anibble = (blksrc[((j&3) * 4 + (i&3)) / 2] >> (4 * (i&1))) & 0xf;
   dxt135_decode_imageblock(blksrc + 8, (i&3), (j&3), 2, texel);
   rgba[ACOMP] = UBYTE_TO_CHAN( (GLubyte)(EXP4TO8(anibble)) );
#endif
 
}

Referenced by D3DXLoadSurfaceFromMemory(), and wined3d_dxtn_init().

fetch_2d_texel_rgba_dxt5()

void fetch_2d_texel_rgba_dxt5	(	GLint	srcRowStride,
		const GLubyte *	pixdata,
		GLint	i,
		GLint	j,
		GLvoid *	texel
	)

Definition at line 151 of file txc_fetch_dxtn.c.

                                                          {
 
   /* Extract the (i,j) pixel from pixdata and return it
    * in texel[RCOMP], texel[GCOMP], texel[BCOMP], texel[ACOMP].
    */
 
   GLchan *rgba = (GLchan *) texel;
   const GLubyte *blksrc = (pixdata + ((srcRowStride + 3) / 4 * (j / 4) + (i / 4)) * 16);
   const GLubyte alpha0 = blksrc[0];
   const GLubyte alpha1 = blksrc[1];
#if 0
   const GLubyte bit_pos = 3 * ((j&3) * 4 + (i&3));
   /* simple 32bit version */
   const GLuint bits_low = blksrc[2] | (blksrc[3] << 8) | (blksrc[4] << 16) | (blksrc[5] << 24);
   const GLuint bits_high = blksrc[6] | (blksrc[7] << 8);
   GLubyte code;
 
   if (bit_pos < 30)
      code = (GLubyte) ((bits_low >> bit_pos) & 7);
   else if (bit_pos == 30)
      code = (GLubyte) ((bits_low >> 30) & 3) | ((bits_high << 2) & 4);
   else
      code = (GLubyte) ((bits_high >> (bit_pos - 32)) & 7);
#endif
#if 1
/* TODO test this! */
   const GLubyte bit_pos = ((j&3) * 4 + (i&3)) * 3;
   const GLubyte acodelow = blksrc[2 + bit_pos / 8];
   const GLubyte acodehigh = blksrc[3 + bit_pos / 8];
   const GLubyte code = (acodelow >> (bit_pos & 0x7) |
      (acodehigh  << (8 - (bit_pos & 0x7)))) & 0x7;
#endif
   dxt135_decode_imageblock(blksrc + 8, (i&3), (j&3), 2, texel);
#if 0
   if (alpha0 > alpha1) {
      switch (code) {
      case 0:
         rgba[ACOMP] = UBYTE_TO_CHAN( alpha0 );
         break;
      case 1:
         rgba[ACOMP] = UBYTE_TO_CHAN( alpha1 );
         break;
      case 2:
      case 3:
      case 4:
      case 5:
      case 6:
      case 7:
         rgba[ACOMP] = UBYTE_TO_CHAN( ((alpha0 * (8 - code) + (alpha1 * (code - 1))) / 7) );
         break;
      }
   }
   else {
      switch (code) {
      case 0:
         rgba[ACOMP] = UBYTE_TO_CHAN( alpha0 );
         break;
      case 1:
         rgba[ACOMP] = UBYTE_TO_CHAN( alpha1 );
         break;
      case 2:
      case 3:
      case 4:
      case 5:
         rgba[ACOMP] = UBYTE_TO_CHAN( ((alpha0 * (6 - code) + (alpha1 * (code - 1))) / 5) );
         break;
      case 6:
         rgba[ACOMP] = 0;
         break;
      case 7:
         rgba[ACOMP] = CHAN_MAX;
         break;
      }
   }
#endif
/* not sure. Which version is faster? */
#if 1
/* TODO test this */
   if (code == 0)
      rgba[ACOMP] = UBYTE_TO_CHAN( alpha0 );
   else if (code == 1)
      rgba[ACOMP] = UBYTE_TO_CHAN( alpha1 );
   else if (alpha0 > alpha1)
      rgba[ACOMP] = UBYTE_TO_CHAN( ((alpha0 * (8 - code) + (alpha1 * (code - 1))) / 7) );
   else if (code < 6)
      rgba[ACOMP] = UBYTE_TO_CHAN( ((alpha0 * (6 - code) + (alpha1 * (code - 1))) / 5) );
   else if (code == 6)
      rgba[ACOMP] = 0;
   else
      rgba[ACOMP] = CHAN_MAX;
#endif
}

Referenced by D3DXLoadSurfaceFromMemory(), and wined3d_dxtn_init().

tx_compress_dxtn()

void tx_compress_dxtn	(	GLint	srccomps,
		GLint	width,
		GLint	height,
		const GLubyte *	srcPixData,
		GLenum	destformat,
		GLubyte *	dest,
		GLint	dstRowStride
	)

Definition at line 758 of file txc_compress_dxtn.c.

{
      GLubyte *blkaddr = dest;
      GLubyte srcpixels[4][4][4];
      const GLchan *srcaddr = srcPixData;
      GLint numxpixels, numypixels;
      GLint i, j;
      GLint dstRowDiff;
 
   switch (destFormat) {
   case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
   case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
      /* hmm we used to get called without dstRowStride... */
      dstRowDiff = dstRowStride >= (width * 2) ? dstRowStride - (((width + 3) & ~3) * 2) : 0;
/*      fprintf(stderr, "dxt1 tex width %d tex height %d dstRowStride %d\n",
              width, height, dstRowStride); */
      for (j = 0; j < height; j += 4) {
         if (height > j + 3) numypixels = 4;
         else numypixels = height - j;
         srcaddr = srcPixData + j * width * srccomps;
         for (i = 0; i < width; i += 4) {
            if (width > i + 3) numxpixels = 4;
            else numxpixels = width - i;
            extractsrccolors(srcpixels, srcaddr, width, numxpixels, numypixels, srccomps);
            encodedxtcolorblockfaster(blkaddr, srcpixels, numxpixels, numypixels, destFormat);
            srcaddr += srccomps * numxpixels;
            blkaddr += 8;
         }
         blkaddr += dstRowDiff;
      }
      break;
   case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
      dstRowDiff = dstRowStride >= (width * 4) ? dstRowStride - (((width + 3) & ~3) * 4) : 0;
/*      fprintf(stderr, "dxt3 tex width %d tex height %d dstRowStride %d\n",
              width, height, dstRowStride); */
      for (j = 0; j < height; j += 4) {
         if (height > j + 3) numypixels = 4;
         else numypixels = height - j;
         srcaddr = srcPixData + j * width * srccomps;
         for (i = 0; i < width; i += 4) {
            if (width > i + 3) numxpixels = 4;
            else numxpixels = width - i;
            extractsrccolors(srcpixels, srcaddr, width, numxpixels, numypixels, srccomps);
            *blkaddr++ = (srcpixels[0][0][3] >> 4) | (srcpixels[0][1][3] & 0xf0);
            *blkaddr++ = (srcpixels[0][2][3] >> 4) | (srcpixels[0][3][3] & 0xf0);
            *blkaddr++ = (srcpixels[1][0][3] >> 4) | (srcpixels[1][1][3] & 0xf0);
            *blkaddr++ = (srcpixels[1][2][3] >> 4) | (srcpixels[1][3][3] & 0xf0);
            *blkaddr++ = (srcpixels[2][0][3] >> 4) | (srcpixels[2][1][3] & 0xf0);
            *blkaddr++ = (srcpixels[2][2][3] >> 4) | (srcpixels[2][3][3] & 0xf0);
            *blkaddr++ = (srcpixels[3][0][3] >> 4) | (srcpixels[3][1][3] & 0xf0);
            *blkaddr++ = (srcpixels[3][2][3] >> 4) | (srcpixels[3][3][3] & 0xf0);
            encodedxtcolorblockfaster(blkaddr, srcpixels, numxpixels, numypixels, destFormat);
            srcaddr += srccomps * numxpixels;
            blkaddr += 8;
         }
         blkaddr += dstRowDiff;
      }
      break;
   case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
      dstRowDiff = dstRowStride >= (width * 4) ? dstRowStride - (((width + 3) & ~3) * 4) : 0;
/*      fprintf(stderr, "dxt5 tex width %d tex height %d dstRowStride %d\n",
              width, height, dstRowStride); */
      for (j = 0; j < height; j += 4) {
         if (height > j + 3) numypixels = 4;
         else numypixels = height - j;
         srcaddr = srcPixData + j * width * srccomps;
         for (i = 0; i < width; i += 4) {
            if (width > i + 3) numxpixels = 4;
            else numxpixels = width - i;
            extractsrccolors(srcpixels, srcaddr, width, numxpixels, numypixels, srccomps);
            encodedxt5alpha(blkaddr, srcpixels, numxpixels, numypixels);
            encodedxtcolorblockfaster(blkaddr + 8, srcpixels, numxpixels, numypixels, destFormat);
            srcaddr += srccomps * numxpixels;
            blkaddr += 16;
         }
         blkaddr += dstRowDiff;
      }
      break;
   default:
      fprintf(stderr, "libdxtn: Bad dstFormat %d in tx_compress_dxtn\n", destFormat);
      return;
   }
}