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IABSD.fr/xenocara/lib/libtxc_dxtn/txc_fetch_dxtn.c
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- lib/libtxc_dxtn/txc_fetch_dxtn.c
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/* * libtxc_dxtn * Version: 1.0 * * 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 ((dxt_type > 1) || (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 }