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Diffstat (limited to 'dxtn/txc_fetch_dxtn.cc')
-rw-r--r-- | dxtn/txc_fetch_dxtn.cc | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/dxtn/txc_fetch_dxtn.cc b/dxtn/txc_fetch_dxtn.cc new file mode 100644 index 000000000..1004b7cec --- /dev/null +++ b/dxtn/txc_fetch_dxtn.cc @@ -0,0 +1,243 @@ +/* + * libtxc_dxtn + * Version: 0.1 + * + * Copyright (C) 2004 Roland Scheidegger All Rights Reserved. + * + * 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 + * BRIAN PAUL 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. + */ + +#include <stdio.h> +#include "txc_dxtn.h" + +#define EXP5TO8R(packedcol) \ + ((((packedcol) >> 8) & 0xf8) | (((packedcol) >> 13) & 0x7)) + +#define EXP6TO8G(packedcol) \ + ((((packedcol) >> 3) & 0xfc) | (((packedcol) >> 9) & 0x3)) + +#define EXP5TO8B(packedcol) \ + ((((packedcol) << 3) & 0xf8) | (((packedcol) >> 2) & 0x7)) + +#define EXP4TO8(col) \ + ((col) | ((col) << 4)) + +/* inefficient. To be efficient, it would be necessary to decode 16 pixels at once */ + +static void dxt135_decode_imageblock ( const GLubyte *img_block_src, + GLint i, GLint j, GLuint dxt_type, GLvoid *texel ) { + GLchan *rgba = (GLchan *) texel; + const GLushort color0 = img_block_src[0] | (img_block_src[1] << 8); + const GLushort color1 = img_block_src[2] | (img_block_src[3] << 8); + const GLuint bits = img_block_src[4] | (img_block_src[5] << 8) | + (img_block_src[6] << 16) | (img_block_src[7] << 24); + /* What about big/little endian? */ + GLubyte bit_pos = 2 * (j * 4 + i) ; + GLubyte code = (GLubyte) ((bits >> bit_pos) & 3); + + rgba[ACOMP] = CHAN_MAX; + switch (code) { + case 0: + rgba[RCOMP] = UBYTE_TO_CHAN( EXP5TO8R(color0) ); + rgba[GCOMP] = UBYTE_TO_CHAN( EXP6TO8G(color0) ); + rgba[BCOMP] = UBYTE_TO_CHAN( EXP5TO8B(color0) ); + break; + case 1: + rgba[RCOMP] = UBYTE_TO_CHAN( EXP5TO8R(color1) ); + rgba[GCOMP] = UBYTE_TO_CHAN( EXP6TO8G(color1) ); + rgba[BCOMP] = UBYTE_TO_CHAN( EXP5TO8B(color1) ); + break; + case 2: + if (color0 > color1) { + rgba[RCOMP] = UBYTE_TO_CHAN( ((EXP5TO8R(color0) * 2 + EXP5TO8R(color1)) / 3) ); + rgba[GCOMP] = UBYTE_TO_CHAN( ((EXP6TO8G(color0) * 2 + EXP6TO8G(color1)) / 3) ); + rgba[BCOMP] = UBYTE_TO_CHAN( ((EXP5TO8B(color0) * 2 + EXP5TO8B(color1)) / 3) ); + } + else { + rgba[RCOMP] = UBYTE_TO_CHAN( ((EXP5TO8R(color0) + EXP5TO8R(color1)) / 2) ); + rgba[GCOMP] = UBYTE_TO_CHAN( ((EXP6TO8G(color0) + EXP6TO8G(color1)) / 2) ); + rgba[BCOMP] = UBYTE_TO_CHAN( ((EXP5TO8B(color0) + EXP5TO8B(color1)) / 2) ); + } + break; + case 3: + if ((dxt_type > 1) || (color0 > color1)) { + rgba[RCOMP] = UBYTE_TO_CHAN( ((EXP5TO8R(color0) + EXP5TO8R(color1) * 2) / 3) ); + rgba[GCOMP] = UBYTE_TO_CHAN( ((EXP6TO8G(color0) + EXP6TO8G(color1) * 2) / 3) ); + rgba[BCOMP] = UBYTE_TO_CHAN( ((EXP5TO8B(color0) + EXP5TO8B(color1) * 2) / 3) ); + } + else { + rgba[RCOMP] = 0; + rgba[GCOMP] = 0; + rgba[BCOMP] = 0; + if (dxt_type == 1) rgba[ACOMP] = UBYTE_TO_CHAN(0); + } + break; + default: + /* CANNOT happen (I hope) */ + break; + } +} + + +void fetch_2d_texel_rgb_dxt1(GLint srcRowStride, const GLubyte *pixdata, + GLint i, GLint j, GLvoid *texel) +{ + /* 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); +} + + +void fetch_2d_texel_rgba_dxt1(GLint srcRowStride, const GLubyte *pixdata, + GLint i, GLint j, GLvoid *texel) +{ + /* 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); +} + +void fetch_2d_texel_rgba_dxt3(GLint srcRowStride, const GLubyte *pixdata, + GLint i, GLint j, GLvoid *texel) { + + /* 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 + +} + +void fetch_2d_texel_rgba_dxt5(GLint srcRowStride, const GLubyte *pixdata, + GLint i, GLint j, GLvoid *texel) { + + /* 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 +} |