src/mesa/main/texcompress.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2006  Brian Paul   All Rights Reserved.
   5  * Copyright (c) 2008 VMware, Inc.
   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  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  23  * OTHER DEALINGS IN THE SOFTWARE.
  24  */
  25
  26
  27 /**
  28  * \file texcompress.c
  29  * Helper functions for texture compression.
  30  */
  31
  32
  33 #include "glheader.h"
  34 #include "imports.h"
  35 #include "context.h"
  36 #include "formats.h"
  37 #include "mtypes.h"
  38 #include "context.h"
  39 #include "texcompress.h"
  40 #include "texcompress_fxt1.h"
  41 #include "texcompress_rgtc.h"
  42 #include "texcompress_s3tc.h"
  43 #include "texcompress_etc.h"
  44 #include "texcompress_bptc.h"
  45
  46
  47 /**
  48  * Get the GL base format of a specified GL compressed texture format
  49  *
  50  * From page 232 of the OpenGL 3.3 (Compatiblity Profile) spec:
  51  *
  52  *     "Compressed Internal Format      Base Internal Format    Type
  53  *     ---------------------------     --------------------    ---------
  54  *     COMPRESSED_ALPHA                ALPHA                   Generic
  55  *     COMPRESSED_LUMINANCE            LUMINANCE               Generic
  56  *     COMPRESSED_LUMINANCE_ALPHA      LUMINANCE_ALPHA         Generic
  57  *     COMPRESSED_INTENSITY            INTENSITY               Generic
  58  *     COMPRESSED_RED                  RED                     Generic
  59  *     COMPRESSED_RG                   RG                      Generic
  60  *     COMPRESSED_RGB                  RGB                     Generic
  61  *     COMPRESSED_RGBA                 RGBA                    Generic
  62  *     COMPRESSED_SRGB                 RGB                     Generic
  63  *     COMPRESSED_SRGB_ALPHA           RGBA                    Generic
  64  *     COMPRESSED_SLUMINANCE           LUMINANCE               Generic
  65  *     COMPRESSED_SLUMINANCE_ALPHA     LUMINANCE_ALPHA         Generic
  66  *     COMPRESSED_RED_RGTC1            RED                     Specific
  67  *     COMPRESSED_SIGNED_RED_RGTC1     RED                     Specific
  68  *     COMPRESSED_RG_RGTC2             RG                      Specific
  69  *     COMPRESSED_SIGNED_RG_RGTC2      RG                      Specific"
  70  *
  71  * \return
  72  * The base format of \c format if \c format is a compressed format (either
  73  * generic or specific.  Otherwise 0 is returned.
  74  */
  75 GLenum
  76 _mesa_gl_compressed_format_base_format(GLenum format)
  77 {
  78    switch (format) {
  79    case GL_COMPRESSED_RED:
  80    case GL_COMPRESSED_R11_EAC:
  81    case GL_COMPRESSED_RED_RGTC1:
  82    case GL_COMPRESSED_SIGNED_R11_EAC:
  83    case GL_COMPRESSED_SIGNED_RED_RGTC1:
  84       return GL_RED;
  85
  86    case GL_COMPRESSED_RG:
  87    case GL_COMPRESSED_RG11_EAC:
  88    case GL_COMPRESSED_RG_RGTC2:
  89    case GL_COMPRESSED_SIGNED_RG11_EAC:
  90    case GL_COMPRESSED_SIGNED_RG_RGTC2:
  91       return GL_RG;
  92
  93    case GL_COMPRESSED_RGB:
  94    case GL_COMPRESSED_SRGB:
  95    case GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT_ARB:
  96    case GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT_ARB:
  97    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
  98    case GL_COMPRESSED_RGB_FXT1_3DFX:
  99    case GL_COMPRESSED_SRGB_S3TC_DXT1_EXT:
 100    case GL_ETC1_RGB8_OES:
 101    case GL_COMPRESSED_RGB8_ETC2:
 102    case GL_COMPRESSED_SRGB8_ETC2:
 103    case GL_RGB_S3TC:
 104    case GL_RGB4_S3TC:
 105    case GL_PALETTE4_RGB8_OES:
 106    case GL_PALETTE4_R5_G6_B5_OES:
 107    case GL_PALETTE8_RGB8_OES:
 108    case GL_PALETTE8_R5_G6_B5_OES:
 109       return GL_RGB;
 110
 111    case GL_COMPRESSED_RGBA:
 112    case GL_COMPRESSED_SRGB_ALPHA:
 113    case GL_COMPRESSED_RGBA_BPTC_UNORM_ARB:
 114    case GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM_ARB:
 115    case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 116    case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
 117    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
 118    case GL_COMPRESSED_RGBA_FXT1_3DFX:
 119    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT:
 120    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT:
 121    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT:
 122    case GL_COMPRESSED_RGBA8_ETC2_EAC:
 123    case GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC:
 124    case GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2:
 125    case GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2:
 126    case GL_RGBA_S3TC:
 127    case GL_RGBA4_S3TC:
 128    case GL_PALETTE4_RGBA8_OES:
 129    case GL_PALETTE8_RGB5_A1_OES:
 130    case GL_PALETTE4_RGBA4_OES:
 131    case GL_PALETTE4_RGB5_A1_OES:
 132    case GL_PALETTE8_RGBA8_OES:
 133    case GL_PALETTE8_RGBA4_OES:
 134       return GL_RGBA;
 135
 136    case GL_COMPRESSED_ALPHA:
 137       return GL_ALPHA;
 138
 139    case GL_COMPRESSED_LUMINANCE:
 140    case GL_COMPRESSED_SLUMINANCE:
 141    case GL_COMPRESSED_LUMINANCE_LATC1_EXT:
 142    case GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT:
 143       return GL_LUMINANCE;
 144
 145    case GL_COMPRESSED_LUMINANCE_ALPHA:
 146    case GL_COMPRESSED_SLUMINANCE_ALPHA:
 147    case GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT:
 148    case GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT:
 149    case GL_COMPRESSED_LUMINANCE_ALPHA_3DC_ATI:
 150       return GL_LUMINANCE_ALPHA;
 151
 152    case GL_COMPRESSED_INTENSITY:
 153       return GL_INTENSITY;
 154
 155    default:
 156       return 0;
 157    }
 158 }
 159
 160 /**
 161  * Return list of (and count of) all specific texture compression
 162  * formats that are supported.
 163  *
 164  * Some formats are \b not returned by this function.  The
 165  * \c GL_COMPRESSED_TEXTURE_FORMATS query only returns formats that are
 166  * "suitable for general-purpose usage."  All texture compression extensions
 167  * have taken this to mean either linear RGB or linear RGBA.
 168  *
 169  * The GL_ARB_texture_compress_rgtc spec says:
 170  *
 171  *    "19) Should the GL_NUM_COMPRESSED_TEXTURE_FORMATS and
 172  *        GL_COMPRESSED_TEXTURE_FORMATS queries return the RGTC formats?
 173  *
 174  *        RESOLVED:  No.
 175  *
 176  *        The OpenGL 2.1 specification says "The only values returned
 177  *        by this query [GL_COMPRESSED_TEXTURE_FORMATS"] are those
 178  *        corresponding to formats suitable for general-purpose usage.
 179  *        The renderer will not enumerate formats with restrictions that
 180  *        need to be specifically understood prior to use."
 181  *
 182  *        Compressed textures with just red or red-green components are
 183  *        not general-purpose so should not be returned by these queries
 184  *        because they have restrictions.
 185  *
 186  *        Applications that seek to use the RGTC formats should do so
 187  *        by looking for this extension's name in the string returned by
 188  *        glGetString(GL_EXTENSIONS) rather than
 189  *        what GL_NUM_COMPRESSED_TEXTURE_FORMATS and
 190  *        GL_COMPRESSED_TEXTURE_FORMATS return."
 191  *
 192  * There is nearly identical wording in the GL_EXT_texture_compression_rgtc
 193  * spec.
 194  *
 195  * The GL_EXT_texture_rRGB spec says:
 196  *
 197  *    "22) Should the new COMPRESSED_SRGB_* formats be listed in an
 198  *        implementation's GL_COMPRESSED_TEXTURE_FORMATS list?
 199  *
 200  *        RESOLVED:  No.  Section 3.8.1 says formats listed by
 201  *        GL_COMPRESSED_TEXTURE_FORMATS are "suitable for general-purpose
 202  *        usage."  The non-linear distribution of red, green, and
 203  *        blue for these sRGB compressed formats makes them not really
 204  *        general-purpose."
 205  *
 206  * The GL_EXT_texture_compression_latc spec says:
 207  *
 208  *    "16) Should the GL_NUM_COMPRESSED_TEXTURE_FORMATS and
 209  *        GL_COMPRESSED_TEXTURE_FORMATS queries return the LATC formats?
 210  *
 211  *        RESOLVED:  No.
 212  *
 213  *        The OpenGL 2.1 specification says "The only values returned
 214  *        by this query [GL_COMPRESSED_TEXTURE_FORMATS"] are those
 215  *        corresponding to formats suitable for general-purpose usage.
 216  *        The renderer will not enumerate formats with restrictions that
 217  *        need to be specifically understood prior to use."
 218  *
 219  *        Historically, OpenGL implementation have advertised the RGB and
 220  *        RGBA versions of the S3TC extensions compressed format tokens
 221  *        through this mechanism.
 222  *
 223  *        The specification is not sufficiently clear about what "suitable
 224  *        for general-purpose usage" means.  Historically that seems to mean
 225  *        unsigned RGB or unsigned RGBA.  The DXT1 format supporting alpha
 226  *        (GL_COMPRESSED_RGBA_S3TC_DXT1_EXT) is not exposed in the list (at
 227  *        least for NVIDIA drivers) because the alpha is always 1.0 expect
 228  *        when it is 0.0 when RGB is required to be black.  NVIDIA's even
 229  *        limits itself to true linear RGB or RGBA formats, specifically
 230  *        not including EXT_texture_sRGB's sRGB S3TC compressed formats.
 231  *
 232  *        Adding luminance and luminance-alpha texture formats (and
 233  *        certainly signed versions of luminance and luminance-alpha
 234  *        formats!) invites potential comptaibility problems with old
 235  *        applications using this mechanism since old applications are
 236  *        unlikely to expect non-RGB or non-RGBA formats to be advertised
 237  *        through this mechanism.  However no specific misinteractions
 238  *        with old applications is known.
 239  *
 240  *        Applications that seek to use the LATC formats should do so
 241  *        by looking for this extension's name in the string returned by
 242  *        glGetString(GL_EXTENSIONS) rather than
 243  *        what GL_NUM_COMPRESSED_TEXTURE_FORMATS and
 244  *        GL_COMPRESSED_TEXTURE_FORMATS return."
 245  *
 246  * There is no formal spec for GL_ATI_texture_compression_3dc.  Since the
 247  * formats added by this extension are luminance-alpha formats, it is
 248  * reasonable to expect them to follow the same rules as
 249  * GL_EXT_texture_compression_latc.  At the very least, Catalyst 11.6 does not
 250  * expose the 3dc formats through this mechanism.
 251  *
 252  * The spec for GL_ARB_texture_compression_bptc doesn't mention whether it
 253  * should be included in GL_COMPRESSED_TEXTURE_FORMATS. However as it takes a
 254  * very long time to compress the textures in this format it's probably not
 255  * very useful as a general format where the GL will have to compress it on
 256  * the fly.
 257  *
 258  * \param ctx  the GL context
 259  * \param formats  the resulting format list (may be NULL).
 260  *
 261  * \return number of formats.
 262  */
 263 GLuint
 264 _mesa_get_compressed_formats(struct gl_context *ctx, GLint *formats)
 265 {
 266    GLuint n = 0;
 267    if (_mesa_is_desktop_gl(ctx) &&
 268        ctx->Extensions.TDFX_texture_compression_FXT1) {
 269       if (formats) {
 270          formats[n++] = GL_COMPRESSED_RGB_FXT1_3DFX;
 271          formats[n++] = GL_COMPRESSED_RGBA_FXT1_3DFX;
 272       }
 273       else {
 274          n += 2;
 275       }
 276    }
 277
 278    if (ctx->Extensions.EXT_texture_compression_s3tc) {
 279       if (formats) {
 280          formats[n++] = GL_COMPRESSED_RGB_S3TC_DXT1_EXT;
 281          formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
 282          formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
 283       }
 284       else {
 285          n += 3;
 286       }
 287
 288       /* The ES and desktop GL specs diverge here.
 289        *
 290        * In desktop OpenGL, the driver can perform online compression of
 291        * uncompressed texture data.  GL_NUM_COMPRESSED_TEXTURE_FORMATS and
 292        * GL_COMPRESSED_TEXTURE_FORMATS give the application a list of
 293        * formats that it could ask the driver to compress with some
 294        * expectation of quality.  The GL_ARB_texture_compression spec
 295        * calls this "suitable for general-purpose usage."  As noted
 296        * above, this means GL_COMPRESSED_RGBA_S3TC_DXT1_EXT is not
 297        * included in the list.
 298        *
 299        * In OpenGL ES, the driver never performs compression.
 300        * GL_NUM_COMPRESSED_TEXTURE_FORMATS and
 301        * GL_COMPRESSED_TEXTURE_FORMATS give the application a list of
 302        * formats that the driver can receive from the application.  It
 303        * is the *complete* list of formats.  The
 304        * GL_EXT_texture_compression_s3tc spec says:
 305        *
 306        *     "New State for OpenGL ES 2.0.25 and 3.0.2 Specifications
 307        *
 308        *         The queries for NUM_COMPRESSED_TEXTURE_FORMATS and
 309        *         COMPRESSED_TEXTURE_FORMATS include
 310        *         COMPRESSED_RGB_S3TC_DXT1_EXT,
 311        *         COMPRESSED_RGBA_S3TC_DXT1_EXT,
 312        *         COMPRESSED_RGBA_S3TC_DXT3_EXT, and
 313        *         COMPRESSED_RGBA_S3TC_DXT5_EXT."
 314        *
 315        * Note that the addition is only to the OpenGL ES specification!
 316        */
 317       if (_mesa_is_gles(ctx)) {
 318          if (formats) {
 319             formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
 320          } else {
 321             n += 1;
 322          }
 323       }
 324    }
 325
 326    /* The GL_OES_compressed_ETC1_RGB8_texture spec says:
 327     *
 328     *     "New State
 329     *
 330     *         The queries for NUM_COMPRESSED_TEXTURE_FORMATS and
 331     *         COMPRESSED_TEXTURE_FORMATS include ETC1_RGB8_OES."
 332     */
 333    if (_mesa_is_gles(ctx)
 334        && ctx->Extensions.OES_compressed_ETC1_RGB8_texture) {
 335       if (formats) {
 336          formats[n++] = GL_ETC1_RGB8_OES;
 337       }
 338       else {
 339          n += 1;
 340       }
 341    }
 342
 343    if (ctx->API == API_OPENGLES) {
 344       if (formats) {
 345          formats[n++] = GL_PALETTE4_RGB8_OES;
 346          formats[n++] = GL_PALETTE4_RGBA8_OES;
 347          formats[n++] = GL_PALETTE4_R5_G6_B5_OES;
 348          formats[n++] = GL_PALETTE4_RGBA4_OES;
 349          formats[n++] = GL_PALETTE4_RGB5_A1_OES;
 350          formats[n++] = GL_PALETTE8_RGB8_OES;
 351          formats[n++] = GL_PALETTE8_RGBA8_OES;
 352          formats[n++] = GL_PALETTE8_R5_G6_B5_OES;
 353          formats[n++] = GL_PALETTE8_RGBA4_OES;
 354          formats[n++] = GL_PALETTE8_RGB5_A1_OES;
 355       }
 356       else {
 357          n += 10;
 358       }
 359    }
 360
 361    if (_mesa_is_gles3(ctx)) {
 362       if (formats) {
 363          formats[n++] = GL_COMPRESSED_RGB8_ETC2;
 364          formats[n++] = GL_COMPRESSED_SRGB8_ETC2;
 365          formats[n++] = GL_COMPRESSED_RGBA8_ETC2_EAC;
 366          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC;
 367          formats[n++] = GL_COMPRESSED_R11_EAC;
 368          formats[n++] = GL_COMPRESSED_RG11_EAC;
 369          formats[n++] = GL_COMPRESSED_SIGNED_R11_EAC;
 370          formats[n++] = GL_COMPRESSED_SIGNED_RG11_EAC;
 371          formats[n++] = GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2;
 372          formats[n++] = GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2;
 373       }
 374       else {
 375          n += 10;
 376       }
 377    }
 378
 379    /* The KHR_texture_compression_astc_hdr spec says:
 380     *
 381     *    "Interactions with OpenGL 4.2
 382     *
 383     *        OpenGL 4.2 supports the feature that compressed textures can be
 384     *        compressed online, by passing the compressed texture format enum as
 385     *        the internal format when uploading a texture using TexImage1D,
 386     *        TexImage2D or TexImage3D (see Section 3.9.3, Texture Image
 387     *        Specification, subsection Encoding of Special Internal Formats).
 388     *
 389     *        Due to the complexity of the ASTC compression algorithm, it is not
 390     *        usually suitable for online use, and therefore ASTC support will be
 391     *        limited to pre-compressed textures only. Where on-device compression
 392     *        is required, a domain-specific limited compressor will typically
 393     *        be used, and this is therefore not suitable for implementation in
 394     *        the driver.
 395     *
 396     *        In particular, the ASTC format specifiers will not be added to
 397     *        Table 3.14, and thus will not be accepted by the TexImage*D
 398     *        functions, and will not be returned by the (already deprecated)
 399     *        COMPRESSED_TEXTURE_FORMATS query."
 400     *
 401     * The ES and the desktop specs diverge here. In OpenGL ES, the COMPRESSED_TEXTURE_FORMATS
 402     * query returns the set of supported specific compressed formats.
 403     */
 404    if (ctx->API == API_OPENGLES2 &&
 405        ctx->Extensions.KHR_texture_compression_astc_ldr) {
 406       if (formats) {
 407          formats[n++] = GL_COMPRESSED_RGBA_ASTC_4x4_KHR;
 408          formats[n++] = GL_COMPRESSED_RGBA_ASTC_5x4_KHR;
 409          formats[n++] = GL_COMPRESSED_RGBA_ASTC_5x5_KHR;
 410          formats[n++] = GL_COMPRESSED_RGBA_ASTC_6x5_KHR;
 411          formats[n++] = GL_COMPRESSED_RGBA_ASTC_6x6_KHR;
 412          formats[n++] = GL_COMPRESSED_RGBA_ASTC_8x5_KHR;
 413          formats[n++] = GL_COMPRESSED_RGBA_ASTC_8x6_KHR;
 414          formats[n++] = GL_COMPRESSED_RGBA_ASTC_8x8_KHR;
 415          formats[n++] = GL_COMPRESSED_RGBA_ASTC_10x5_KHR;
 416          formats[n++] = GL_COMPRESSED_RGBA_ASTC_10x6_KHR;
 417          formats[n++] = GL_COMPRESSED_RGBA_ASTC_10x8_KHR;
 418          formats[n++] = GL_COMPRESSED_RGBA_ASTC_10x10_KHR;
 419          formats[n++] = GL_COMPRESSED_RGBA_ASTC_12x10_KHR;
 420          formats[n++] = GL_COMPRESSED_RGBA_ASTC_12x12_KHR;
 421          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_4x4_KHR;
 422          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_5x4_KHR;
 423          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_5x5_KHR;
 424          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_6x5_KHR;
 425          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_6x6_KHR;
 426          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_8x5_KHR;
 427          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_8x6_KHR;
 428          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_8x8_KHR;
 429          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10x5_KHR;
 430          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10x6_KHR;
 431          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10x8_KHR;
 432          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10x10_KHR;
 433          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_12x10_KHR;
 434          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_12x12_KHR;
 435       }
 436       else {
 437          n += 28;
 438       }
 439    }
 440
 441    if (_mesa_is_gles3(ctx) &&
 442        ctx->Extensions.OES_texture_compression_astc) {
 443       if (formats) {
 444          formats[n++] = GL_COMPRESSED_RGBA_ASTC_3x3x3_OES;
 445          formats[n++] = GL_COMPRESSED_RGBA_ASTC_4x3x3_OES;
 446          formats[n++] = GL_COMPRESSED_RGBA_ASTC_4x4x3_OES;
 447          formats[n++] = GL_COMPRESSED_RGBA_ASTC_4x4x4_OES;
 448          formats[n++] = GL_COMPRESSED_RGBA_ASTC_5x4x4_OES;
 449          formats[n++] = GL_COMPRESSED_RGBA_ASTC_5x5x4_OES;
 450          formats[n++] = GL_COMPRESSED_RGBA_ASTC_5x5x5_OES;
 451          formats[n++] = GL_COMPRESSED_RGBA_ASTC_6x5x5_OES;
 452          formats[n++] = GL_COMPRESSED_RGBA_ASTC_6x6x5_OES;
 453          formats[n++] = GL_COMPRESSED_RGBA_ASTC_6x6x6_OES;
 454          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_3x3x3_OES;
 455          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_4x3x3_OES;
 456          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_4x4x3_OES;
 457          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_4x4x4_OES;
 458          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_5x4x4_OES;
 459          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_5x5x4_OES;
 460          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_5x5x5_OES;
 461          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_6x5x5_OES;
 462          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_6x6x5_OES;
 463          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_6x6x6_OES;
 464       }
 465       else {
 466          n += 20;
 467       }
 468    }
 469
 470    return n;
 471 }
 472
 473
 474 /**
 475  * Convert GLenum to a compressed MESA_FORMAT_x.
 476  */
 477 mesa_format
 478 _mesa_glenum_to_compressed_format(GLenum format)
 479 {
 480    switch (format) {
 481    case GL_COMPRESSED_RGB_FXT1_3DFX:
 482       return MESA_FORMAT_RGB_FXT1;
 483    case GL_COMPRESSED_RGBA_FXT1_3DFX:
 484       return MESA_FORMAT_RGBA_FXT1;
 485
 486    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
 487    case GL_RGB_S3TC:
 488    case GL_RGB4_S3TC:
 489       return MESA_FORMAT_RGB_DXT1;
 490    case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 491       return MESA_FORMAT_RGBA_DXT1;
 492    case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
 493    case GL_RGBA_S3TC:
 494    case GL_RGBA4_S3TC:
 495       return MESA_FORMAT_RGBA_DXT3;
 496    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
 497       return MESA_FORMAT_RGBA_DXT5;
 498
 499    case GL_COMPRESSED_SRGB_S3TC_DXT1_EXT:
 500       return MESA_FORMAT_SRGB_DXT1;
 501    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT:
 502       return MESA_FORMAT_SRGBA_DXT1;
 503    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT:
 504       return MESA_FORMAT_SRGBA_DXT3;
 505    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT:
 506       return MESA_FORMAT_SRGBA_DXT5;
 507
 508    case GL_COMPRESSED_RED_RGTC1:
 509       return MESA_FORMAT_R_RGTC1_UNORM;
 510    case GL_COMPRESSED_SIGNED_RED_RGTC1:
 511       return MESA_FORMAT_R_RGTC1_SNORM;
 512    case GL_COMPRESSED_RG_RGTC2:
 513       return MESA_FORMAT_RG_RGTC2_UNORM;
 514    case GL_COMPRESSED_SIGNED_RG_RGTC2:
 515       return MESA_FORMAT_RG_RGTC2_SNORM;
 516
 517    case GL_COMPRESSED_LUMINANCE_LATC1_EXT:
 518       return MESA_FORMAT_L_LATC1_UNORM;
 519    case GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT:
 520       return MESA_FORMAT_L_LATC1_SNORM;
 521    case GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT:
 522    case GL_COMPRESSED_LUMINANCE_ALPHA_3DC_ATI:
 523       return MESA_FORMAT_LA_LATC2_UNORM;
 524    case GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT:
 525       return MESA_FORMAT_LA_LATC2_SNORM;
 526
 527    case GL_ETC1_RGB8_OES:
 528       return MESA_FORMAT_ETC1_RGB8;
 529    case GL_COMPRESSED_RGB8_ETC2:
 530       return MESA_FORMAT_ETC2_RGB8;
 531    case GL_COMPRESSED_SRGB8_ETC2:
 532       return MESA_FORMAT_ETC2_SRGB8;
 533    case GL_COMPRESSED_RGBA8_ETC2_EAC:
 534       return MESA_FORMAT_ETC2_RGBA8_EAC;
 535    case GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC:
 536       return MESA_FORMAT_ETC2_SRGB8_ALPHA8_EAC;
 537    case GL_COMPRESSED_R11_EAC:
 538       return MESA_FORMAT_ETC2_R11_EAC;
 539    case GL_COMPRESSED_RG11_EAC:
 540       return MESA_FORMAT_ETC2_RG11_EAC;
 541    case GL_COMPRESSED_SIGNED_R11_EAC:
 542       return MESA_FORMAT_ETC2_SIGNED_R11_EAC;
 543    case GL_COMPRESSED_SIGNED_RG11_EAC:
 544       return MESA_FORMAT_ETC2_SIGNED_RG11_EAC;
 545    case GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2:
 546       return MESA_FORMAT_ETC2_RGB8_PUNCHTHROUGH_ALPHA1;
 547    case GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2:
 548       return MESA_FORMAT_ETC2_SRGB8_PUNCHTHROUGH_ALPHA1;
 549
 550    case GL_COMPRESSED_RGBA_BPTC_UNORM:
 551       return MESA_FORMAT_BPTC_RGBA_UNORM;
 552    case GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM:
 553       return MESA_FORMAT_BPTC_SRGB_ALPHA_UNORM;
 554    case GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT:
 555       return MESA_FORMAT_BPTC_RGB_SIGNED_FLOAT;
 556    case GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT:
 557       return MESA_FORMAT_BPTC_RGB_UNSIGNED_FLOAT;
 558
 559    case GL_COMPRESSED_RGBA_ASTC_4x4_KHR:
 560       return MESA_FORMAT_RGBA_ASTC_4x4;
 561    case GL_COMPRESSED_RGBA_ASTC_5x4_KHR:
 562       return MESA_FORMAT_RGBA_ASTC_5x4;
 563    case GL_COMPRESSED_RGBA_ASTC_5x5_KHR:
 564       return MESA_FORMAT_RGBA_ASTC_5x5;
 565    case GL_COMPRESSED_RGBA_ASTC_6x5_KHR:
 566       return MESA_FORMAT_RGBA_ASTC_6x5;
 567    case GL_COMPRESSED_RGBA_ASTC_6x6_KHR:
 568       return MESA_FORMAT_RGBA_ASTC_6x6;
 569    case GL_COMPRESSED_RGBA_ASTC_8x5_KHR:
 570       return MESA_FORMAT_RGBA_ASTC_8x5;
 571    case GL_COMPRESSED_RGBA_ASTC_8x6_KHR:
 572       return MESA_FORMAT_RGBA_ASTC_8x6;
 573    case GL_COMPRESSED_RGBA_ASTC_8x8_KHR:
 574       return MESA_FORMAT_RGBA_ASTC_8x8;
 575    case GL_COMPRESSED_RGBA_ASTC_10x5_KHR:
 576       return MESA_FORMAT_RGBA_ASTC_10x5;
 577    case GL_COMPRESSED_RGBA_ASTC_10x6_KHR:
 578       return MESA_FORMAT_RGBA_ASTC_10x6;
 579    case GL_COMPRESSED_RGBA_ASTC_10x8_KHR:
 580       return MESA_FORMAT_RGBA_ASTC_10x8;
 581    case GL_COMPRESSED_RGBA_ASTC_10x10_KHR:
 582       return MESA_FORMAT_RGBA_ASTC_10x10;
 583    case GL_COMPRESSED_RGBA_ASTC_12x10_KHR:
 584       return MESA_FORMAT_RGBA_ASTC_12x10;
 585    case GL_COMPRESSED_RGBA_ASTC_12x12_KHR:
 586       return MESA_FORMAT_RGBA_ASTC_12x12;
 587    case GL_COMPRESSED_SRGB8_ALPHA8_ASTC_4x4_KHR:
 588       return MESA_FORMAT_SRGB8_ALPHA8_ASTC_4x4;
 589    case GL_COMPRESSED_SRGB8_ALPHA8_ASTC_5x4_KHR:
 590       return MESA_FORMAT_SRGB8_ALPHA8_ASTC_5x4;
 591    case GL_COMPRESSED_SRGB8_ALPHA8_ASTC_5x5_KHR:
 592       return MESA_FORMAT_SRGB8_ALPHA8_ASTC_5x5;
 593    case GL_COMPRESSED_SRGB8_ALPHA8_ASTC_6x5_KHR:
 594       return MESA_FORMAT_SRGB8_ALPHA8_ASTC_6x5;
 595    case GL_COMPRESSED_SRGB8_ALPHA8_ASTC_6x6_KHR:
 596       return MESA_FORMAT_SRGB8_ALPHA8_ASTC_6x6;
 597    case GL_COMPRESSED_SRGB8_ALPHA8_ASTC_8x5_KHR:
 598       return MESA_FORMAT_SRGB8_ALPHA8_ASTC_8x5;
 599    case GL_COMPRESSED_SRGB8_ALPHA8_ASTC_8x6_KHR:
 600       return MESA_FORMAT_SRGB8_ALPHA8_ASTC_8x6;
 601    case GL_COMPRESSED_SRGB8_ALPHA8_ASTC_8x8_KHR:
 602       return MESA_FORMAT_SRGB8_ALPHA8_ASTC_8x8;
 603    case GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10x5_KHR:
 604       return MESA_FORMAT_SRGB8_ALPHA8_ASTC_10x5;
 605    case GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10x6_KHR:
 606       return MESA_FORMAT_SRGB8_ALPHA8_ASTC_10x6;
 607    case GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10x8_KHR:
 608       return MESA_FORMAT_SRGB8_ALPHA8_ASTC_10x8;
 609    case GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10x10_KHR:
 610       return MESA_FORMAT_SRGB8_ALPHA8_ASTC_10x10;
 611    case GL_COMPRESSED_SRGB8_ALPHA8_ASTC_12x10_KHR:
 612       return MESA_FORMAT_SRGB8_ALPHA8_ASTC_12x10;
 613    case GL_COMPRESSED_SRGB8_ALPHA8_ASTC_12x12_KHR:
 614       return MESA_FORMAT_SRGB8_ALPHA8_ASTC_12x12;
 615
 616    default:
 617       return MESA_FORMAT_NONE;
 618    }
 619 }
 620
 621
 622 /**
 623  * Given a compressed MESA_FORMAT_x value, return the corresponding
 624  * GLenum for that format.
 625  * This is needed for glGetTexLevelParameter(GL_TEXTURE_INTERNAL_FORMAT)
 626  * which must return the specific texture format used when the user might
 627  * have originally specified a generic compressed format in their
 628  * glTexImage2D() call.
 629  * For non-compressed textures, we always return the user-specified
 630  * internal format unchanged.
 631  */
 632 GLenum
 633 _mesa_compressed_format_to_glenum(struct gl_context *ctx, mesa_format mesaFormat)
 634 {
 635    switch (mesaFormat) {
 636    case MESA_FORMAT_RGB_FXT1:
 637       return GL_COMPRESSED_RGB_FXT1_3DFX;
 638    case MESA_FORMAT_RGBA_FXT1:
 639       return GL_COMPRESSED_RGBA_FXT1_3DFX;
 640    case MESA_FORMAT_RGB_DXT1:
 641       return GL_COMPRESSED_RGB_S3TC_DXT1_EXT;
 642    case MESA_FORMAT_RGBA_DXT1:
 643       return GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
 644    case MESA_FORMAT_RGBA_DXT3:
 645       return GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
 646    case MESA_FORMAT_RGBA_DXT5:
 647       return GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
 648    case MESA_FORMAT_SRGB_DXT1:
 649       return GL_COMPRESSED_SRGB_S3TC_DXT1_EXT;
 650    case MESA_FORMAT_SRGBA_DXT1:
 651       return GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT;
 652    case MESA_FORMAT_SRGBA_DXT3:
 653       return GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT;
 654    case MESA_FORMAT_SRGBA_DXT5:
 655       return GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT;
 656    case MESA_FORMAT_R_RGTC1_UNORM:
 657       return GL_COMPRESSED_RED_RGTC1;
 658    case MESA_FORMAT_R_RGTC1_SNORM:
 659       return GL_COMPRESSED_SIGNED_RED_RGTC1;
 660    case MESA_FORMAT_RG_RGTC2_UNORM:
 661       return GL_COMPRESSED_RG_RGTC2;
 662    case MESA_FORMAT_RG_RGTC2_SNORM:
 663       return GL_COMPRESSED_SIGNED_RG_RGTC2;
 664
 665    case MESA_FORMAT_L_LATC1_UNORM:
 666       return GL_COMPRESSED_LUMINANCE_LATC1_EXT;
 667    case MESA_FORMAT_L_LATC1_SNORM:
 668       return GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT;
 669    case MESA_FORMAT_LA_LATC2_UNORM:
 670       return GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT;
 671    case MESA_FORMAT_LA_LATC2_SNORM:
 672       return GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT;
 673
 674    case MESA_FORMAT_ETC1_RGB8:
 675       return GL_ETC1_RGB8_OES;
 676    case MESA_FORMAT_ETC2_RGB8:
 677       return GL_COMPRESSED_RGB8_ETC2;
 678    case MESA_FORMAT_ETC2_SRGB8:
 679       return GL_COMPRESSED_SRGB8_ETC2;
 680    case MESA_FORMAT_ETC2_RGBA8_EAC:
 681       return GL_COMPRESSED_RGBA8_ETC2_EAC;
 682    case MESA_FORMAT_ETC2_SRGB8_ALPHA8_EAC:
 683       return GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC;
 684    case MESA_FORMAT_ETC2_R11_EAC:
 685       return GL_COMPRESSED_R11_EAC;
 686    case MESA_FORMAT_ETC2_RG11_EAC:
 687       return GL_COMPRESSED_RG11_EAC;
 688    case MESA_FORMAT_ETC2_SIGNED_R11_EAC:
 689       return GL_COMPRESSED_SIGNED_R11_EAC;
 690    case MESA_FORMAT_ETC2_SIGNED_RG11_EAC:
 691       return GL_COMPRESSED_SIGNED_RG11_EAC;
 692    case MESA_FORMAT_ETC2_RGB8_PUNCHTHROUGH_ALPHA1:
 693       return GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2;
 694    case MESA_FORMAT_ETC2_SRGB8_PUNCHTHROUGH_ALPHA1:
 695       return GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2;
 696
 697    case MESA_FORMAT_BPTC_RGBA_UNORM:
 698       return GL_COMPRESSED_RGBA_BPTC_UNORM;
 699    case MESA_FORMAT_BPTC_SRGB_ALPHA_UNORM:
 700       return GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM;
 701    case MESA_FORMAT_BPTC_RGB_SIGNED_FLOAT:
 702       return GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT;
 703    case MESA_FORMAT_BPTC_RGB_UNSIGNED_FLOAT:
 704       return GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT;
 705
 706    case MESA_FORMAT_RGBA_ASTC_4x4:
 707       return GL_COMPRESSED_RGBA_ASTC_4x4_KHR;
 708    case MESA_FORMAT_RGBA_ASTC_5x4:
 709       return GL_COMPRESSED_RGBA_ASTC_5x4_KHR;
 710    case MESA_FORMAT_RGBA_ASTC_5x5:
 711       return GL_COMPRESSED_RGBA_ASTC_5x5_KHR;
 712    case MESA_FORMAT_RGBA_ASTC_6x5:
 713       return GL_COMPRESSED_RGBA_ASTC_6x5_KHR;
 714    case MESA_FORMAT_RGBA_ASTC_6x6:
 715       return GL_COMPRESSED_RGBA_ASTC_6x6_KHR;
 716    case MESA_FORMAT_RGBA_ASTC_8x5:
 717       return GL_COMPRESSED_RGBA_ASTC_8x5_KHR;
 718    case MESA_FORMAT_RGBA_ASTC_8x6:
 719       return GL_COMPRESSED_RGBA_ASTC_8x6_KHR;
 720    case MESA_FORMAT_RGBA_ASTC_8x8:
 721       return GL_COMPRESSED_RGBA_ASTC_8x8_KHR;
 722    case MESA_FORMAT_RGBA_ASTC_10x5:
 723       return GL_COMPRESSED_RGBA_ASTC_10x5_KHR;
 724    case MESA_FORMAT_RGBA_ASTC_10x6:
 725       return GL_COMPRESSED_RGBA_ASTC_10x6_KHR;
 726    case MESA_FORMAT_RGBA_ASTC_10x8:
 727       return GL_COMPRESSED_RGBA_ASTC_10x8_KHR;
 728    case MESA_FORMAT_RGBA_ASTC_10x10:
 729       return GL_COMPRESSED_RGBA_ASTC_10x10_KHR;
 730    case MESA_FORMAT_RGBA_ASTC_12x10:
 731       return GL_COMPRESSED_RGBA_ASTC_12x10_KHR;
 732    case MESA_FORMAT_RGBA_ASTC_12x12:
 733       return GL_COMPRESSED_RGBA_ASTC_12x12_KHR;
 734    case MESA_FORMAT_SRGB8_ALPHA8_ASTC_4x4:
 735       return GL_COMPRESSED_SRGB8_ALPHA8_ASTC_4x4_KHR;
 736    case MESA_FORMAT_SRGB8_ALPHA8_ASTC_5x4:
 737       return GL_COMPRESSED_SRGB8_ALPHA8_ASTC_5x4_KHR;
 738    case MESA_FORMAT_SRGB8_ALPHA8_ASTC_5x5:
 739       return GL_COMPRESSED_SRGB8_ALPHA8_ASTC_5x5_KHR;
 740    case MESA_FORMAT_SRGB8_ALPHA8_ASTC_6x5:
 741       return GL_COMPRESSED_SRGB8_ALPHA8_ASTC_6x5_KHR;
 742    case MESA_FORMAT_SRGB8_ALPHA8_ASTC_6x6:
 743       return GL_COMPRESSED_SRGB8_ALPHA8_ASTC_6x6_KHR;
 744    case MESA_FORMAT_SRGB8_ALPHA8_ASTC_8x5:
 745       return GL_COMPRESSED_SRGB8_ALPHA8_ASTC_8x5_KHR;
 746    case MESA_FORMAT_SRGB8_ALPHA8_ASTC_8x6:
 747       return GL_COMPRESSED_SRGB8_ALPHA8_ASTC_8x6_KHR;
 748    case MESA_FORMAT_SRGB8_ALPHA8_ASTC_8x8:
 749       return GL_COMPRESSED_SRGB8_ALPHA8_ASTC_8x8_KHR;
 750    case MESA_FORMAT_SRGB8_ALPHA8_ASTC_10x5:
 751       return GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10x5_KHR;
 752    case MESA_FORMAT_SRGB8_ALPHA8_ASTC_10x6:
 753       return GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10x6_KHR;
 754    case MESA_FORMAT_SRGB8_ALPHA8_ASTC_10x8:
 755       return GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10x8_KHR;
 756    case MESA_FORMAT_SRGB8_ALPHA8_ASTC_10x10:
 757       return GL_COMPRESSED_SRGB8_ALPHA8_ASTC_10x10_KHR;
 758    case MESA_FORMAT_SRGB8_ALPHA8_ASTC_12x10:
 759       return GL_COMPRESSED_SRGB8_ALPHA8_ASTC_12x10_KHR;
 760    case MESA_FORMAT_SRGB8_ALPHA8_ASTC_12x12:
 761       return GL_COMPRESSED_SRGB8_ALPHA8_ASTC_12x12_KHR;
 762
 763    default:
 764       _mesa_problem(ctx, "Unexpected mesa texture format in"
 765                     " _mesa_compressed_format_to_glenum()");
 766       return 0;
 767    }
 768 }
 769
 770
 771 /*
 772  * Return the address of the pixel at (col, row, img) in a
 773  * compressed texture image.
 774  * \param col, row, img - image position (3D), should be a multiple of the
 775  *                        format's block size.
 776  * \param format - compressed image format
 777  * \param width - image width (stride) in pixels
 778  * \param image - the image address
 779  * \return address of pixel at (row, col, img)
 780  */
 781 GLubyte *
 782 _mesa_compressed_image_address(GLint col, GLint row, GLint img,
 783                                mesa_format mesaFormat,
 784                                GLsizei width, const GLubyte *image)
 785 {
 786    /* XXX only 2D images implemented, not 3D */
 787    const GLuint blockSize = _mesa_get_format_bytes(mesaFormat);
 788    GLuint bw, bh;
 789    GLint offset;
 790
 791    _mesa_get_format_block_size(mesaFormat, &bw, &bh);
 792
 793    assert(col % bw == 0);
 794    assert(row % bh == 0);
 795
 796    offset = ((width + bw - 1) / bw) * (row / bh) + col / bw;
 797    offset *= blockSize;
 798
 799    return (GLubyte *) image + offset;
 800 }
 801
 802
 803 /**
 804  * Return a texel-fetch function for the given format, or NULL if
 805  * invalid format.
 806  */
 807 compressed_fetch_func
 808 _mesa_get_compressed_fetch_func(mesa_format format)
 809 {
 810    switch (_mesa_get_format_layout(format)) {
 811    case MESA_FORMAT_LAYOUT_S3TC:
 812       return _mesa_get_dxt_fetch_func(format);
 813    case MESA_FORMAT_LAYOUT_FXT1:
 814       return _mesa_get_fxt_fetch_func(format);
 815    case MESA_FORMAT_LAYOUT_RGTC:
 816    case MESA_FORMAT_LAYOUT_LATC:
 817       return _mesa_get_compressed_rgtc_func(format);
 818    case MESA_FORMAT_LAYOUT_ETC1:
 819       return _mesa_get_etc_fetch_func(format);
 820    case MESA_FORMAT_LAYOUT_BPTC:
 821       return _mesa_get_bptc_fetch_func(format);
 822    default:
 823       return NULL;
 824    }
 825 }
 826
 827
 828 /**
 829  * Decompress a compressed texture image, returning a GL_RGBA/GL_FLOAT image.
 830  * \param srcRowStride  stride in bytes between rows of blocks in the
 831  *                      compressed source image.
 832  */
 833 void
 834 _mesa_decompress_image(mesa_format format, GLuint width, GLuint height,
 835                        const GLubyte *src, GLint srcRowStride,
 836                        GLfloat *dest)
 837 {
 838    compressed_fetch_func fetch;
 839    GLuint i, j;
 840    GLuint bytes, bw, bh;
 841    GLint stride;
 842
 843    bytes = _mesa_get_format_bytes(format);
 844    _mesa_get_format_block_size(format, &bw, &bh);
 845
 846    fetch = _mesa_get_compressed_fetch_func(format);
 847    if (!fetch) {
 848       _mesa_problem(NULL, "Unexpected format in _mesa_decompress_image()");
 849       return;
 850    }
 851
 852    stride = srcRowStride * bh / bytes;
 853
 854    for (j = 0; j < height; j++) {
 855       for (i = 0; i < width; i++) {
 856          fetch(src, stride, i, j, dest);
 857          dest += 4;
 858       }
 859    }
 860 }