src/mesa/main/texcompress.c

   1 /**
   2  * \file texcompress.c
   3  * Compressed textures functions.
   4  */
   5
   6 /*
   7  * Mesa 3-D graphics library
   8  * Version:  5.1
   9  *
  10  * Copyright (C) 1999-2003  Brian Paul   All Rights Reserved.
  11  *
  12  * Permission is hereby granted, free of charge, to any person obtaining a
  13  * copy of this software and associated documentation files (the "Software"),
  14  * to deal in the Software without restriction, including without limitation
  15  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  16  * and/or sell copies of the Software, and to permit persons to whom the
  17  * Software is furnished to do so, subject to the following conditions:
  18  *
  19  * The above copyright notice and this permission notice shall be included
  20  * in all copies or substantial portions of the Software.
  21  *
  22  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  23  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  25  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  26  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  27  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28  */
  29
  30
  31 #include "glheader.h"
  32 #include "imports.h"
  33 #include "context.h"
  34 #include "image.h"
  35 #include "texcompress.h"
  36 #include "texformat.h"
  37
  38
  39 /**
  40  * Get the list of supported internal compression formats.
  41  *
  42  * \param ctx GL context.
  43  * \param formats the resulting format list (may be NULL).
  44  *
  45  * \return number of formats.
  46  */
  47 GLuint
  48 _mesa_get_compressed_formats( GLcontext *ctx, GLint *formats )
  49 {
  50    GLuint n = 0;
  51    if (ctx->Extensions.ARB_texture_compression) {
  52       if (ctx->Extensions.TDFX_texture_compression_FXT1) {
  53          if (formats) {
  54             formats[n++] = GL_COMPRESSED_RGB_FXT1_3DFX;
  55             formats[n++] = GL_COMPRESSED_RGBA_FXT1_3DFX;
  56          }
  57          else {
  58             n += 2;
  59          }
  60       }
  61       if (ctx->Extensions.EXT_texture_compression_s3tc) {
  62          if (formats) {
  63             formats[n++] = GL_COMPRESSED_RGB_S3TC_DXT1_EXT;
  64             /* Skip this one because it has a restriction (all transparent
  65              * pixels become black).  See the texture compressions spec for
  66              * a detailed explanation.  This is what NVIDIA does.
  67             formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
  68             */
  69             formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
  70             formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
  71          }
  72          else {
  73             n += 3;
  74          }
  75       }
  76    }
  77    return n;
  78 }
  79
  80
  81 /**
  82  * Return bytes of storage needed for the given texture size and
  83  * compressed format.
  84  *
  85  * \param width texture width in texels.
  86  * \param height texture height in texels.
  87  * \param depth texture depth in texels.
  88  * \param texFormat one of the compressed format enums
  89  *
  90  * \return size in bytes, or zero if bad \p texFormat.
  91  */
  92 GLuint
  93 _mesa_compressed_texture_size( GLcontext *ctx,
  94                                GLsizei width, GLsizei height, GLsizei depth,
  95                                GLenum format )
  96 {
  97    GLuint size;
  98
  99    if (ctx->Driver.CompressedTextureSize) {
 100       return ctx->Driver.CompressedTextureSize(ctx, width, height, depth, format);
 101    }
 102
 103    switch (format) {
 104    case GL_COMPRESSED_RGB_FXT1_3DFX:
 105    case GL_COMPRESSED_RGBA_FXT1_3DFX:
 106       /* round up to multiples of 8, 4 */
 107       size = ((width + 7) / 8) * ((height + 3) / 4) * 16;
 108       /* Textures smaller than 8x4 will effectively be made into 8x4 and
 109        * take 16 bytes.
 110        */
 111       if (size < 16)
 112          size = 16;
 113       return size;
 114    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
 115    case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 116       /* round up width, height to next multiple of 4 */
 117       width = (width + 3) & ~3;
 118       height = (height + 3) & ~3;
 119       ASSERT(depth == 1);
 120       /* 8 bytes per 4x4 tile of RGB[A] texels */
 121       size = (width * height * 8) / 16;
 122       /* Textures smaller than 4x4 will effectively be made into 4x4 and
 123        * take 8 bytes.
 124        */
 125       if (size < 8)
 126          size = 8;
 127       return size;
 128    case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
 129    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
 130       /* round up width, height to next multiple of 4 */
 131       width = (width + 3) & ~3;
 132       height = (height + 3) & ~3;
 133       ASSERT(depth == 1);
 134       /* 16 bytes per 4x4 tile of RGBA texels */
 135       size = width * height; /* simple! */
 136       /* Textures smaller than 4x4 will effectively be made into 4x4 and
 137        * take 16 bytes.
 138        */
 139       if (size < 16)
 140          size = 16;
 141       return size;
 142    default:
 143       _mesa_problem(ctx, "bad texformat in compressed_texture_size");
 144       return 0;
 145    }
 146 }
 147
 148
 149 /**
 150  * Compute the bytes per row in a compressed texture image.
 151  * We use this for computing the destination address for sub-texture updates.
 152  * \param format  one of the specific texture compression formats
 153  * \param width  image width in pixels
 154  * \return stride, in bytes, between rows for compressed image
 155  */
 156 GLint
 157 _mesa_compressed_row_stride(GLenum format, GLsizei width)
 158 {
 159    GLint bytesPerTile, stride;
 160
 161    switch (format) {
 162    case GL_COMPRESSED_RGB_FXT1_3DFX:
 163    case GL_COMPRESSED_RGBA_FXT1_3DFX:
 164       bytesPerTile = 16;
 165       break;
 166    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
 167    case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 168       bytesPerTile = 8;
 169       break;
 170    case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
 171    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
 172       bytesPerTile = 16;
 173       break;
 174    default:
 175       return 0;
 176    }
 177
 178    stride = ((width + 3) / 4) * bytesPerTile;
 179    return stride;
 180 }
 181
 182
 183 /**
 184  * Return the address of the pixel at (col, row, img) in a
 185  * compressed texture image.
 186  *
 187  * \param col image position.
 188  * \param row image position.
 189  * \param img image position.
 190  * \param format compressed image format.
 191  * \param width image width.
 192  * \param image the image address.
 193  *
 194  * \return address of pixel at (row, col).
 195  */
 196 GLubyte *
 197 _mesa_compressed_image_address(GLint col, GLint row, GLint img,
 198                                GLenum format,
 199                                GLsizei width, const GLubyte *image)
 200 {
 201    GLint bytesPerTile, stride;
 202    GLubyte *addr;
 203
 204    ASSERT((row & 3) == 0);
 205    ASSERT((col & 3) == 0);
 206    (void) img;
 207
 208    switch (format) {
 209    case GL_COMPRESSED_RGB_FXT1_3DFX:
 210    case GL_COMPRESSED_RGBA_FXT1_3DFX:
 211       bytesPerTile = 16;
 212       break;
 213    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
 214    case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 215       bytesPerTile = 8;
 216       break;
 217    case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
 218    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
 219       bytesPerTile = 16;
 220       break;
 221    default:
 222       return 0;
 223    }
 224
 225    stride = ((width + 3) / 4) * bytesPerTile;
 226
 227    addr = (GLubyte *) image + (row / 4) * stride + (col / 4) * bytesPerTile;
 228    return addr;
 229 }
 230
 231
 232 /**
 233  * \param srcRowStride source stride, in pixels
 234  */
 235 void
 236 _mesa_compress_teximage( GLcontext *ctx, GLsizei width, GLsizei height,
 237                          GLenum srcFormat, const GLchan *source,
 238                          GLint srcRowStride,
 239                          const struct gl_texture_format *dstFormat,
 240                          GLubyte *dest, GLint dstRowStride )
 241 {
 242    switch (dstFormat->MesaFormat) {
 243    default:
 244       _mesa_problem(ctx, "Bad dstFormat in _mesa_compress_teximage()");
 245       return;
 246    }
 247 }