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    switch (format) {
 100    case GL_COMPRESSED_RGB_FXT1_3DFX:
 101    case GL_COMPRESSED_RGBA_FXT1_3DFX:
 102       /* round up to multiple of 4 */
 103       size = ((width + 7) / 8) * ((height + 3) / 4) * 16;
 104       return size;
 105    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
 106    case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 107       /* round up width, height to next multiple of 4 */
 108       width = (width + 3) & ~3;
 109       height = (height + 3) & ~3;
 110       ASSERT(depth == 1);
 111       /* 8 bytes per 4x4 tile of RGB[A] texels */
 112       size = (width * height * 8) / 16;
 113       /* Textures smaller than 4x4 will effectively be made into 4x4 and
 114        * take 8 bytes.
 115        */
 116       if (size < 8)
 117          size = 8;
 118       return size;
 119    case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
 120    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
 121       /* round up width, height to next multiple of 4 */
 122       width = (width + 3) & ~3;
 123       height = (height + 3) & ~3;
 124       ASSERT(depth == 1);
 125       /* 16 bytes per 4x4 tile of RGBA texels */
 126       size = width * height; /* simple! */
 127       /* Textures smaller than 4x4 will effectively be made into 4x4 and
 128        * take 16 bytes.
 129        */
 130       if (size < 16)
 131          size = 16;
 132       return size;
 133    default:
 134       _mesa_problem(ctx, "bad texformat in compressed_texture_size");
 135       return 0;
 136    }
 137 }
 138
 139
 140 /**
 141  * Compute the bytes per row in a compressed texture image.
 142  * We use this for computing the destination address for sub-texture updates.
 143  * \param format  one of the specific texture compression formats
 144  * \param width  image width in pixels
 145  * \return stride, in bytes, between rows for compressed image
 146  */
 147 GLint
 148 _mesa_compressed_row_stride(GLenum format, GLsizei width)
 149 {
 150    GLint bytesPerTile, stride;
 151
 152    switch (format) {
 153    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
 154    case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 155       bytesPerTile = 8;
 156       break;
 157    case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
 158    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
 159       bytesPerTile = 16;
 160       break;
 161    default:
 162       return 0;
 163    }
 164
 165    stride = ((width + 3) / 4) * bytesPerTile;
 166    return stride;
 167 }
 168
 169
 170 /**
 171  * Return the address of the pixel at (col, row, img) in a
 172  * compressed texture image.
 173  *
 174  * \param col image position.
 175  * \param row image position.
 176  * \param img image position.
 177  * \param format compressed image format.
 178  * \param width image width.
 179  * \param image the image address.
 180  *
 181  * \return address of pixel at (row, col).
 182  */
 183 GLubyte *
 184 _mesa_compressed_image_address(GLint col, GLint row, GLint img,
 185                                GLenum format,
 186                                GLsizei width, const GLubyte *image)
 187 {
 188    GLint bytesPerTile, stride;
 189    GLubyte *addr;
 190
 191    ASSERT((row & 3) == 0);
 192    ASSERT((col & 3) == 0);
 193    (void) img;
 194
 195    switch (format) {
 196    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
 197    case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 198       bytesPerTile = 8;
 199       break;
 200    case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
 201    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
 202       bytesPerTile = 16;
 203       break;
 204    default:
 205       return 0;
 206    }
 207
 208    stride = ((width + 3) / 4) * bytesPerTile;
 209
 210    addr = (GLubyte *) image + (row / 4) * stride + (col / 4) * bytesPerTile;
 211    return addr;
 212 }
 213
 214
 215 /**
 216  * \param srcRowStride source stride, in pixels
 217  */
 218 void
 219 _mesa_compress_teximage( GLcontext *ctx, GLsizei width, GLsizei height,
 220                          GLenum srcFormat, const GLchan *source,
 221                          GLint srcRowStride,
 222                          const struct gl_texture_format *dstFormat,
 223                          GLubyte *dest, GLint dstRowStride )
 224 {
 225    switch (dstFormat->MesaFormat) {
 226    default:
 227       _mesa_problem(ctx, "Bad dstFormat in _mesa_compress_teximage()");
 228       return;
 229    }
 230 }