src/mesa/main/texcompress.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.1
   4  *
   5  * Copyright (C) 1999-2004  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 /**
  27  * \file texcompress.c
  28  * Helper functions for texture compression.
  29  */
  30
  31
  32 #include "glheader.h"
  33 #include "imports.h"
  34 #include "colormac.h"
  35 #include "context.h"
  36 #include "image.h"
  37 #include "texcompress.h"
  38 #include "texformat.h"
  39 #include "texstore.h"
  40
  41 /**
  42  * Get the list of supported internal compression formats.
  43  *
  44  * \param ctx GL context.
  45  * \param formats the resulting format list (may be NULL).
  46  *
  47  * \return number of formats.
  48  */
  49 GLuint
  50 _mesa_get_compressed_formats( GLcontext *ctx, GLint *formats )
  51 {
  52    GLuint n = 0;
  53    if (ctx->Extensions.ARB_texture_compression) {
  54       if (ctx->Extensions.TDFX_texture_compression_FXT1) {
  55          if (formats) {
  56             formats[n++] = GL_COMPRESSED_RGB_FXT1_3DFX;
  57             formats[n++] = GL_COMPRESSED_RGBA_FXT1_3DFX;
  58          }
  59          else {
  60             n += 2;
  61          }
  62       }
  63       if (ctx->Extensions.EXT_texture_compression_s3tc) {
  64          if (formats) {
  65             formats[n++] = GL_COMPRESSED_RGB_S3TC_DXT1_EXT;
  66             /* Skip this one because it has a restriction (all transparent
  67              * pixels become black).  See the texture compressions spec for
  68              * a detailed explanation.  This is what NVIDIA does.
  69             formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
  70             */
  71             formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
  72             formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
  73          }
  74          else {
  75             n += 3;
  76          }
  77       }
  78       if (ctx->Extensions.S3_s3tc) {
  79          if (formats) {
  80             formats[n++] = GL_RGB_S3TC;
  81             formats[n++] = GL_RGB4_S3TC;
  82             formats[n++] = GL_RGBA_S3TC;
  83             formats[n++] = GL_RGBA4_S3TC;
  84          }
  85          else {
  86             n += 4;
  87          }
  88       }
  89    }
  90    return n;
  91 }
  92
  93
  94
  95 /**
  96  * Return number of bytes needed to store a texture of the given size
  97  * using the specified compressed format.
  98  * This is called via the ctx->Driver.CompressedTextureSize function,
  99  * unless a device driver overrides it.
 100  *
 101  * \param width texture width in texels.
 102  * \param height texture height in texels.
 103  * \param depth texture depth in texels.
 104  * \param format - one of the specific compressed texture formats
 105  *
 106  * \return size in bytes, or zero if bad format
 107  */
 108 GLuint
 109 _mesa_compressed_texture_size( GLcontext *ctx,
 110                                GLsizei width, GLsizei height, GLsizei depth,
 111                                GLenum format )
 112 {
 113    GLuint size;
 114
 115    ASSERT(depth == 1);
 116
 117    switch (format) {
 118    case GL_COMPRESSED_RGB_FXT1_3DFX:
 119    case GL_COMPRESSED_RGBA_FXT1_3DFX:
 120       /* round up width to next multiple of 8, height to next multiple of 4 */
 121       width = (width + 7) & ~7;
 122       height = (height + 3) & ~3;
 123       /* 16 bytes per 8x4 tile of RGB[A] texels */
 124       size = width * height / 2;
 125       /* Textures smaller than 8x4 will effectively be made into 8x4 and
 126        * take 16 bytes.
 127        */
 128       if (size < 16)
 129          size = 16;
 130       return size;
 131    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
 132    case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 133    case GL_RGB_S3TC:
 134    case GL_RGB4_S3TC:
 135       /* round up width, height to next multiple of 4 */
 136       width = (width + 3) & ~3;
 137       height = (height + 3) & ~3;
 138       /* 8 bytes per 4x4 tile of RGB[A] texels */
 139       size = width * height / 2;
 140       /* Textures smaller than 4x4 will effectively be made into 4x4 and
 141        * take 8 bytes.
 142        */
 143       if (size < 8)
 144          size = 8;
 145       return size;
 146    case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
 147    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
 148    case GL_RGBA_S3TC:
 149    case GL_RGBA4_S3TC:
 150       /* round up width, height to next multiple of 4 */
 151       width = (width + 3) & ~3;
 152       height = (height + 3) & ~3;
 153       /* 16 bytes per 4x4 tile of RGBA texels */
 154       size = width * height; /* simple! */
 155       /* Textures smaller than 4x4 will effectively be made into 4x4 and
 156        * take 16 bytes.
 157        */
 158       if (size < 16)
 159          size = 16;
 160       return size;
 161    default:
 162       _mesa_problem(ctx, "bad texformat in compressed_texture_size");
 163       return 0;
 164    }
 165 }
 166
 167
 168 /*
 169  * Compute the bytes per row in a compressed texture image.
 170  * We use this for computing the destination address for sub-texture updates.
 171  * \param format  one of the specific texture compression formats
 172  * \param width  image width in pixels
 173  * \return stride, in bytes, between rows for compressed image
 174  */
 175 GLint
 176 _mesa_compressed_row_stride(GLenum format, GLsizei width)
 177 {
 178    GLint stride;
 179
 180    switch (format) {
 181    case GL_COMPRESSED_RGB_FXT1_3DFX:
 182    case GL_COMPRESSED_RGBA_FXT1_3DFX:
 183       stride = ((width + 7) / 8) * 16; /* 16 bytes per 8x4 tile */
 184       break;
 185    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
 186    case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 187    case GL_RGB_S3TC:
 188    case GL_RGB4_S3TC:
 189       stride = ((width + 3) / 4) * 8; /* 8 bytes per 4x4 tile */
 190       break;
 191    case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
 192    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
 193    case GL_RGBA_S3TC:
 194    case GL_RGBA4_S3TC:
 195       stride = ((width + 3) / 4) * 16; /* 16 bytes per 4x4 tile */
 196       break;
 197    default:
 198       return 0;
 199    }
 200
 201    return stride;
 202 }
 203
 204
 205 /*
 206  * Return the address of the pixel at (col, row, img) in a
 207  * compressed texture image.
 208  * \param col, row, img - image position (3D)
 209  * \param format - compressed image format
 210  * \param width - image width
 211  * \param image - the image address
 212  * \return address of pixel at (row, col)
 213  */
 214 GLubyte *
 215 _mesa_compressed_image_address(GLint col, GLint row, GLint img,
 216                                GLenum format,
 217                                GLsizei width, const GLubyte *image)
 218 {
 219    GLubyte *addr;
 220
 221    (void) img;
 222
 223    /* We try to spot a "complete" subtexture "above" ROW, COL;
 224     * this texture is given by appropriate rounding of WIDTH x ROW.
 225     * Then we just add the amount left (usually on the left).
 226     *
 227     * Example for X*Y microtiles (Z bytes each)
 228     * offset = Z * (((width + X - 1) / X) * (row / Y) + col / X);
 229     */
 230
 231    switch (format) {
 232    case GL_COMPRESSED_RGB_FXT1_3DFX:
 233    case GL_COMPRESSED_RGBA_FXT1_3DFX:
 234       addr = (GLubyte *) image + 16 * (((width + 7) / 8) * (row / 4) + col / 8);
 235       break;
 236    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
 237    case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 238    case GL_RGB_S3TC:
 239    case GL_RGB4_S3TC:
 240       addr = (GLubyte *) image + 8 * (((width + 3) / 4) * (row / 4) + col / 4);
 241       break;
 242    case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
 243    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
 244    case GL_RGBA_S3TC:
 245    case GL_RGBA4_S3TC:
 246       addr = (GLubyte *) image + 16 * (((width + 3) / 4) * (row / 4) + col / 4);
 247       break;
 248    default:
 249       return 0;
 250    }
 251
 252    return addr;
 253 }