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 "colormac.h"
  36 #include "context.h"
  37 #include "formats.h"
  38 #include "mtypes.h"
  39 #include "context.h"
  40 #include "texcompress.h"
  41 #include "texcompress_fxt1.h"
  42 #include "texcompress_rgtc.h"
  43 #include "texcompress_s3tc.h"
  44 #include "texcompress_etc.h"
  45 #include "texcompress_bptc.h"
  46
  47
  48 /**
  49  * Get the GL base format of a specified GL compressed texture format
  50  *
  51  * From page 232 of the OpenGL 3.3 (Compatiblity Profile) spec:
  52  *
  53  *     "Compressed Internal Format      Base Internal Format    Type
  54  *     ---------------------------     --------------------    ---------
  55  *     COMPRESSED_ALPHA                ALPHA                   Generic
  56  *     COMPRESSED_LUMINANCE            LUMINANCE               Generic
  57  *     COMPRESSED_LUMINANCE_ALPHA      LUMINANCE_ALPHA         Generic
  58  *     COMPRESSED_INTENSITY            INTENSITY               Generic
  59  *     COMPRESSED_RED                  RED                     Generic
  60  *     COMPRESSED_RG                   RG                      Generic
  61  *     COMPRESSED_RGB                  RGB                     Generic
  62  *     COMPRESSED_RGBA                 RGBA                    Generic
  63  *     COMPRESSED_SRGB                 RGB                     Generic
  64  *     COMPRESSED_SRGB_ALPHA           RGBA                    Generic
  65  *     COMPRESSED_SLUMINANCE           LUMINANCE               Generic
  66  *     COMPRESSED_SLUMINANCE_ALPHA     LUMINANCE_ALPHA         Generic
  67  *     COMPRESSED_RED_RGTC1            RED                     Specific
  68  *     COMPRESSED_SIGNED_RED_RGTC1     RED                     Specific
  69  *     COMPRESSED_RG_RGTC2             RG                      Specific
  70  *     COMPRESSED_SIGNED_RG_RGTC2      RG                      Specific"
  71  *
  72  * \return
  73  * The base format of \c format if \c format is a compressed format (either
  74  * generic or specific.  Otherwise 0 is returned.
  75  */
  76 GLenum
  77 _mesa_gl_compressed_format_base_format(GLenum format)
  78 {
  79    switch (format) {
  80    case GL_COMPRESSED_RED:
  81    case GL_COMPRESSED_R11_EAC:
  82    case GL_COMPRESSED_RED_RGTC1:
  83    case GL_COMPRESSED_SIGNED_R11_EAC:
  84    case GL_COMPRESSED_SIGNED_RED_RGTC1:
  85       return GL_RED;
  86
  87    case GL_COMPRESSED_RG:
  88    case GL_COMPRESSED_RG11_EAC:
  89    case GL_COMPRESSED_RG_RGTC2:
  90    case GL_COMPRESSED_SIGNED_RG11_EAC:
  91    case GL_COMPRESSED_SIGNED_RG_RGTC2:
  92       return GL_RG;
  93
  94    case GL_COMPRESSED_RGB:
  95    case GL_COMPRESSED_SRGB:
  96    case GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT_ARB:
  97    case GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT_ARB:
  98    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
  99    case GL_COMPRESSED_RGB_FXT1_3DFX:
 100    case GL_COMPRESSED_SRGB_S3TC_DXT1_EXT:
 101    case GL_ETC1_RGB8_OES:
 102    case GL_COMPRESSED_RGB8_ETC2:
 103    case GL_COMPRESSED_SRGB8_ETC2:
 104       return GL_RGB;
 105
 106    case GL_COMPRESSED_RGBA:
 107    case GL_COMPRESSED_SRGB_ALPHA:
 108    case GL_COMPRESSED_RGBA_BPTC_UNORM_ARB:
 109    case GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM_ARB:
 110    case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 111    case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
 112    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
 113    case GL_COMPRESSED_RGBA_FXT1_3DFX:
 114    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT:
 115    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT:
 116    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT:
 117    case GL_COMPRESSED_RGBA8_ETC2_EAC:
 118    case GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC:
 119    case GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2:
 120    case GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2:
 121       return GL_RGBA;
 122
 123    case GL_COMPRESSED_ALPHA:
 124       return GL_ALPHA;
 125
 126    case GL_COMPRESSED_LUMINANCE:
 127    case GL_COMPRESSED_SLUMINANCE:
 128    case GL_COMPRESSED_LUMINANCE_LATC1_EXT:
 129    case GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT:
 130       return GL_LUMINANCE;
 131
 132    case GL_COMPRESSED_LUMINANCE_ALPHA:
 133    case GL_COMPRESSED_SLUMINANCE_ALPHA:
 134    case GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT:
 135    case GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT:
 136    case GL_COMPRESSED_LUMINANCE_ALPHA_3DC_ATI:
 137       return GL_LUMINANCE_ALPHA;
 138
 139    case GL_COMPRESSED_INTENSITY:
 140       return GL_INTENSITY;
 141
 142    default:
 143       return 0;
 144    }
 145 }
 146
 147 /**
 148  * Return list of (and count of) all specific texture compression
 149  * formats that are supported.
 150  *
 151  * Some formats are \b not returned by this function.  The
 152  * \c GL_COMPRESSED_TEXTURE_FORMATS query only returns formats that are
 153  * "suitable for general-purpose usage."  All texture compression extensions
 154  * have taken this to mean either linear RGB or linear RGBA.
 155  *
 156  * The GL_ARB_texture_compress_rgtc spec says:
 157  *
 158  *    "19) Should the GL_NUM_COMPRESSED_TEXTURE_FORMATS and
 159  *        GL_COMPRESSED_TEXTURE_FORMATS queries return the RGTC formats?
 160  *
 161  *        RESOLVED:  No.
 162  *
 163  *        The OpenGL 2.1 specification says "The only values returned
 164  *        by this query [GL_COMPRESSED_TEXTURE_FORMATS"] are those
 165  *        corresponding to formats suitable for general-purpose usage.
 166  *        The renderer will not enumerate formats with restrictions that
 167  *        need to be specifically understood prior to use."
 168  *
 169  *        Compressed textures with just red or red-green components are
 170  *        not general-purpose so should not be returned by these queries
 171  *        because they have restrictions.
 172  *
 173  *        Applications that seek to use the RGTC formats should do so
 174  *        by looking for this extension's name in the string returned by
 175  *        glGetString(GL_EXTENSIONS) rather than
 176  *        what GL_NUM_COMPRESSED_TEXTURE_FORMATS and
 177  *        GL_COMPRESSED_TEXTURE_FORMATS return."
 178  *
 179  * There is nearly identical wording in the GL_EXT_texture_compression_rgtc
 180  * spec.
 181  *
 182  * The GL_EXT_texture_rRGB spec says:
 183  *
 184  *    "22) Should the new COMPRESSED_SRGB_* formats be listed in an
 185  *        implementation's GL_COMPRESSED_TEXTURE_FORMATS list?
 186  *
 187  *        RESOLVED:  No.  Section 3.8.1 says formats listed by
 188  *        GL_COMPRESSED_TEXTURE_FORMATS are "suitable for general-purpose
 189  *        usage."  The non-linear distribution of red, green, and
 190  *        blue for these sRGB compressed formats makes them not really
 191  *        general-purpose."
 192  *
 193  * The GL_EXT_texture_compression_latc spec says:
 194  *
 195  *    "16) Should the GL_NUM_COMPRESSED_TEXTURE_FORMATS and
 196  *        GL_COMPRESSED_TEXTURE_FORMATS queries return the LATC formats?
 197  *
 198  *        RESOLVED:  No.
 199  *
 200  *        The OpenGL 2.1 specification says "The only values returned
 201  *        by this query [GL_COMPRESSED_TEXTURE_FORMATS"] are those
 202  *        corresponding to formats suitable for general-purpose usage.
 203  *        The renderer will not enumerate formats with restrictions that
 204  *        need to be specifically understood prior to use."
 205  *
 206  *        Historically, OpenGL implementation have advertised the RGB and
 207  *        RGBA versions of the S3TC extensions compressed format tokens
 208  *        through this mechanism.
 209  *
 210  *        The specification is not sufficiently clear about what "suitable
 211  *        for general-purpose usage" means.  Historically that seems to mean
 212  *        unsigned RGB or unsigned RGBA.  The DXT1 format supporting alpha
 213  *        (GL_COMPRESSED_RGBA_S3TC_DXT1_EXT) is not exposed in the list (at
 214  *        least for NVIDIA drivers) because the alpha is always 1.0 expect
 215  *        when it is 0.0 when RGB is required to be black.  NVIDIA's even
 216  *        limits itself to true linear RGB or RGBA formats, specifically
 217  *        not including EXT_texture_sRGB's sRGB S3TC compressed formats.
 218  *
 219  *        Adding luminance and luminance-alpha texture formats (and
 220  *        certainly signed versions of luminance and luminance-alpha
 221  *        formats!) invites potential comptaibility problems with old
 222  *        applications using this mechanism since old applications are
 223  *        unlikely to expect non-RGB or non-RGBA formats to be advertised
 224  *        through this mechanism.  However no specific misinteractions
 225  *        with old applications is known.
 226  *
 227  *        Applications that seek to use the LATC formats should do so
 228  *        by looking for this extension's name in the string returned by
 229  *        glGetString(GL_EXTENSIONS) rather than
 230  *        what GL_NUM_COMPRESSED_TEXTURE_FORMATS and
 231  *        GL_COMPRESSED_TEXTURE_FORMATS return."
 232  *
 233  * There is no formal spec for GL_ATI_texture_compression_3dc.  Since the
 234  * formats added by this extension are luminance-alpha formats, it is
 235  * reasonable to expect them to follow the same rules as
 236  * GL_EXT_texture_compression_latc.  At the very least, Catalyst 11.6 does not
 237  * expose the 3dc formats through this mechanism.
 238  *
 239  * The spec for GL_ARB_texture_compression_bptc doesn't mention whether it
 240  * should be included in GL_COMPRESSED_TEXTURE_FORMATS. However as it takes a
 241  * very long time to compress the textures in this format it's probably not
 242  * very useful as a general format where the GL will have to compress it on
 243  * the fly.
 244  *
 245  * \param ctx  the GL context
 246  * \param formats  the resulting format list (may be NULL).
 247  *
 248  * \return number of formats.
 249  */
 250 GLuint
 251 _mesa_get_compressed_formats(struct gl_context *ctx, GLint *formats)
 252 {
 253    GLuint n = 0;
 254    if (ctx->Extensions.TDFX_texture_compression_FXT1) {
 255       if (formats) {
 256          formats[n++] = GL_COMPRESSED_RGB_FXT1_3DFX;
 257          formats[n++] = GL_COMPRESSED_RGBA_FXT1_3DFX;
 258       }
 259       else {
 260          n += 2;
 261       }
 262    }
 263
 264    if (ctx->Extensions.EXT_texture_compression_s3tc) {
 265       if (formats) {
 266          formats[n++] = GL_COMPRESSED_RGB_S3TC_DXT1_EXT;
 267          formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
 268          formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
 269       }
 270       else {
 271          n += 3;
 272       }
 273
 274       /* The ES and desktop GL specs diverge here.
 275        *
 276        * In desktop OpenGL, the driver can perform online compression of
 277        * uncompressed texture data.  GL_NUM_COMPRESSED_TEXTURE_FORMATS and
 278        * GL_COMPRESSED_TEXTURE_FORMATS give the application a list of
 279        * formats that it could ask the driver to compress with some
 280        * expectation of quality.  The GL_ARB_texture_compression spec
 281        * calls this "suitable for general-purpose usage."  As noted
 282        * above, this means GL_COMPRESSED_RGBA_S3TC_DXT1_EXT is not
 283        * included in the list.
 284        *
 285        * In OpenGL ES, the driver never performs compression.
 286        * GL_NUM_COMPRESSED_TEXTURE_FORMATS and
 287        * GL_COMPRESSED_TEXTURE_FORMATS give the application a list of
 288        * formats that the driver can receive from the application.  It
 289        * is the *complete* list of formats.  The
 290        * GL_EXT_texture_compression_s3tc spec says:
 291        *
 292        *     "New State for OpenGL ES 2.0.25 and 3.0.2 Specifications
 293        *
 294        *         The queries for NUM_COMPRESSED_TEXTURE_FORMATS and
 295        *         COMPRESSED_TEXTURE_FORMATS include
 296        *         COMPRESSED_RGB_S3TC_DXT1_EXT,
 297        *         COMPRESSED_RGBA_S3TC_DXT1_EXT,
 298        *         COMPRESSED_RGBA_S3TC_DXT3_EXT, and
 299        *         COMPRESSED_RGBA_S3TC_DXT5_EXT."
 300        *
 301        * Note that the addition is only to the OpenGL ES specification!
 302        */
 303       if (_mesa_is_gles(ctx)) {
 304          if (formats) {
 305             formats[n++] = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
 306          } else {
 307             n += 1;
 308          }
 309       }
 310    }
 311
 312    /* The GL_OES_compressed_ETC1_RGB8_texture spec says:
 313     *
 314     *     "New State
 315     *
 316     *         The queries for NUM_COMPRESSED_TEXTURE_FORMATS and
 317     *         COMPRESSED_TEXTURE_FORMATS include ETC1_RGB8_OES."
 318     */
 319    if (_mesa_is_gles(ctx)
 320        && ctx->Extensions.OES_compressed_ETC1_RGB8_texture) {
 321       if (formats) {
 322          formats[n++] = GL_ETC1_RGB8_OES;
 323       }
 324       else {
 325          n += 1;
 326       }
 327    }
 328
 329    if (ctx->API == API_OPENGLES) {
 330       if (formats) {
 331          formats[n++] = GL_PALETTE4_RGB8_OES;
 332          formats[n++] = GL_PALETTE4_RGBA8_OES;
 333          formats[n++] = GL_PALETTE4_R5_G6_B5_OES;
 334          formats[n++] = GL_PALETTE4_RGBA4_OES;
 335          formats[n++] = GL_PALETTE4_RGB5_A1_OES;
 336          formats[n++] = GL_PALETTE8_RGB8_OES;
 337          formats[n++] = GL_PALETTE8_RGBA8_OES;
 338          formats[n++] = GL_PALETTE8_R5_G6_B5_OES;
 339          formats[n++] = GL_PALETTE8_RGBA4_OES;
 340          formats[n++] = GL_PALETTE8_RGB5_A1_OES;
 341       }
 342       else {
 343          n += 10;
 344       }
 345    }
 346
 347    if (_mesa_is_gles3(ctx)) {
 348       if (formats) {
 349          formats[n++] = GL_COMPRESSED_RGB8_ETC2;
 350          formats[n++] = GL_COMPRESSED_SRGB8_ETC2;
 351          formats[n++] = GL_COMPRESSED_RGBA8_ETC2_EAC;
 352          formats[n++] = GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC;
 353          formats[n++] = GL_COMPRESSED_R11_EAC;
 354          formats[n++] = GL_COMPRESSED_RG11_EAC;
 355          formats[n++] = GL_COMPRESSED_SIGNED_R11_EAC;
 356          formats[n++] = GL_COMPRESSED_SIGNED_RG11_EAC;
 357          formats[n++] = GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2;
 358          formats[n++] = GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2;
 359       }
 360       else {
 361          n += 10;
 362       }
 363    }
 364    return n;
 365 }
 366
 367
 368 /**
 369  * Convert a compressed MESA_FORMAT_x to a GLenum.
 370  */
 371 mesa_format
 372 _mesa_glenum_to_compressed_format(GLenum format)
 373 {
 374    switch (format) {
 375    case GL_COMPRESSED_RGB_FXT1_3DFX:
 376       return MESA_FORMAT_RGB_FXT1;
 377    case GL_COMPRESSED_RGBA_FXT1_3DFX:
 378       return MESA_FORMAT_RGBA_FXT1;
 379
 380    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
 381    case GL_RGB_S3TC:
 382       return MESA_FORMAT_RGB_DXT1;
 383    case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 384    case GL_RGB4_S3TC:
 385       return MESA_FORMAT_RGBA_DXT1;
 386    case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
 387    case GL_RGBA_S3TC:
 388       return MESA_FORMAT_RGBA_DXT3;
 389    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
 390    case GL_RGBA4_S3TC:
 391       return MESA_FORMAT_RGBA_DXT5;
 392
 393    case GL_COMPRESSED_SRGB_S3TC_DXT1_EXT:
 394       return MESA_FORMAT_SRGB_DXT1;
 395    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT:
 396       return MESA_FORMAT_SRGBA_DXT1;
 397    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT:
 398       return MESA_FORMAT_SRGBA_DXT3;
 399    case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT:
 400       return MESA_FORMAT_SRGBA_DXT5;
 401
 402    case GL_COMPRESSED_RED_RGTC1:
 403       return MESA_FORMAT_R_RGTC1_UNORM;
 404    case GL_COMPRESSED_SIGNED_RED_RGTC1:
 405       return MESA_FORMAT_R_RGTC1_SNORM;
 406    case GL_COMPRESSED_RG_RGTC2:
 407       return MESA_FORMAT_RG_RGTC2_UNORM;
 408    case GL_COMPRESSED_SIGNED_RG_RGTC2:
 409       return MESA_FORMAT_RG_RGTC2_SNORM;
 410
 411    case GL_COMPRESSED_LUMINANCE_LATC1_EXT:
 412       return MESA_FORMAT_L_LATC1_UNORM;
 413    case GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT:
 414       return MESA_FORMAT_L_LATC1_SNORM;
 415    case GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT:
 416    case GL_COMPRESSED_LUMINANCE_ALPHA_3DC_ATI:
 417       return MESA_FORMAT_LA_LATC2_UNORM;
 418    case GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT:
 419       return MESA_FORMAT_LA_LATC2_SNORM;
 420
 421    case GL_ETC1_RGB8_OES:
 422       return MESA_FORMAT_ETC1_RGB8;
 423    case GL_COMPRESSED_RGB8_ETC2:
 424       return MESA_FORMAT_ETC2_RGB8;
 425    case GL_COMPRESSED_SRGB8_ETC2:
 426       return MESA_FORMAT_ETC2_SRGB8;
 427    case GL_COMPRESSED_RGBA8_ETC2_EAC:
 428       return MESA_FORMAT_ETC2_RGBA8_EAC;
 429    case GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC:
 430       return MESA_FORMAT_ETC2_SRGB8_ALPHA8_EAC;
 431    case GL_COMPRESSED_R11_EAC:
 432       return MESA_FORMAT_ETC2_R11_EAC;
 433    case GL_COMPRESSED_RG11_EAC:
 434       return MESA_FORMAT_ETC2_RG11_EAC;
 435    case GL_COMPRESSED_SIGNED_R11_EAC:
 436       return MESA_FORMAT_ETC2_SIGNED_R11_EAC;
 437    case GL_COMPRESSED_SIGNED_RG11_EAC:
 438       return MESA_FORMAT_ETC2_SIGNED_RG11_EAC;
 439    case GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2:
 440       return MESA_FORMAT_ETC2_RGB8_PUNCHTHROUGH_ALPHA1;
 441    case GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2:
 442       return MESA_FORMAT_ETC2_SRGB8_PUNCHTHROUGH_ALPHA1;
 443
 444    case GL_COMPRESSED_RGBA_BPTC_UNORM:
 445       return MESA_FORMAT_BPTC_RGBA_UNORM;
 446    case GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM:
 447       return MESA_FORMAT_BPTC_SRGB_ALPHA_UNORM;
 448    case GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT:
 449       return MESA_FORMAT_BPTC_RGB_SIGNED_FLOAT;
 450    case GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT:
 451       return MESA_FORMAT_BPTC_RGB_UNSIGNED_FLOAT;
 452
 453    default:
 454       return MESA_FORMAT_NONE;
 455    }
 456 }
 457
 458
 459 /**
 460  * Given a compressed MESA_FORMAT_x value, return the corresponding
 461  * GLenum for that format.
 462  * This is needed for glGetTexLevelParameter(GL_TEXTURE_INTERNAL_FORMAT)
 463  * which must return the specific texture format used when the user might
 464  * have originally specified a generic compressed format in their
 465  * glTexImage2D() call.
 466  * For non-compressed textures, we always return the user-specified
 467  * internal format unchanged.
 468  */
 469 GLenum
 470 _mesa_compressed_format_to_glenum(struct gl_context *ctx, mesa_format mesaFormat)
 471 {
 472    switch (mesaFormat) {
 473    case MESA_FORMAT_RGB_FXT1:
 474       return GL_COMPRESSED_RGB_FXT1_3DFX;
 475    case MESA_FORMAT_RGBA_FXT1:
 476       return GL_COMPRESSED_RGBA_FXT1_3DFX;
 477    case MESA_FORMAT_RGB_DXT1:
 478       return GL_COMPRESSED_RGB_S3TC_DXT1_EXT;
 479    case MESA_FORMAT_RGBA_DXT1:
 480       return GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
 481    case MESA_FORMAT_RGBA_DXT3:
 482       return GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
 483    case MESA_FORMAT_RGBA_DXT5:
 484       return GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
 485    case MESA_FORMAT_SRGB_DXT1:
 486       return GL_COMPRESSED_SRGB_S3TC_DXT1_EXT;
 487    case MESA_FORMAT_SRGBA_DXT1:
 488       return GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT;
 489    case MESA_FORMAT_SRGBA_DXT3:
 490       return GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT;
 491    case MESA_FORMAT_SRGBA_DXT5:
 492       return GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT;
 493    case MESA_FORMAT_R_RGTC1_UNORM:
 494       return GL_COMPRESSED_RED_RGTC1;
 495    case MESA_FORMAT_R_RGTC1_SNORM:
 496       return GL_COMPRESSED_SIGNED_RED_RGTC1;
 497    case MESA_FORMAT_RG_RGTC2_UNORM:
 498       return GL_COMPRESSED_RG_RGTC2;
 499    case MESA_FORMAT_RG_RGTC2_SNORM:
 500       return GL_COMPRESSED_SIGNED_RG_RGTC2;
 501
 502    case MESA_FORMAT_L_LATC1_UNORM:
 503       return GL_COMPRESSED_LUMINANCE_LATC1_EXT;
 504    case MESA_FORMAT_L_LATC1_SNORM:
 505       return GL_COMPRESSED_SIGNED_LUMINANCE_LATC1_EXT;
 506    case MESA_FORMAT_LA_LATC2_UNORM:
 507       return GL_COMPRESSED_LUMINANCE_ALPHA_LATC2_EXT;
 508    case MESA_FORMAT_LA_LATC2_SNORM:
 509       return GL_COMPRESSED_SIGNED_LUMINANCE_ALPHA_LATC2_EXT;
 510
 511    case MESA_FORMAT_ETC1_RGB8:
 512       return GL_ETC1_RGB8_OES;
 513    case MESA_FORMAT_ETC2_RGB8:
 514       return GL_COMPRESSED_RGB8_ETC2;
 515    case MESA_FORMAT_ETC2_SRGB8:
 516       return GL_COMPRESSED_SRGB8_ETC2;
 517    case MESA_FORMAT_ETC2_RGBA8_EAC:
 518       return GL_COMPRESSED_RGBA8_ETC2_EAC;
 519    case MESA_FORMAT_ETC2_SRGB8_ALPHA8_EAC:
 520       return GL_COMPRESSED_SRGB8_ALPHA8_ETC2_EAC;
 521    case MESA_FORMAT_ETC2_R11_EAC:
 522       return GL_COMPRESSED_R11_EAC;
 523    case MESA_FORMAT_ETC2_RG11_EAC:
 524       return GL_COMPRESSED_RG11_EAC;
 525    case MESA_FORMAT_ETC2_SIGNED_R11_EAC:
 526       return GL_COMPRESSED_SIGNED_R11_EAC;
 527    case MESA_FORMAT_ETC2_SIGNED_RG11_EAC:
 528       return GL_COMPRESSED_SIGNED_RG11_EAC;
 529    case MESA_FORMAT_ETC2_RGB8_PUNCHTHROUGH_ALPHA1:
 530       return GL_COMPRESSED_RGB8_PUNCHTHROUGH_ALPHA1_ETC2;
 531    case MESA_FORMAT_ETC2_SRGB8_PUNCHTHROUGH_ALPHA1:
 532       return GL_COMPRESSED_SRGB8_PUNCHTHROUGH_ALPHA1_ETC2;
 533
 534    case MESA_FORMAT_BPTC_RGBA_UNORM:
 535       return GL_COMPRESSED_RGBA_BPTC_UNORM;
 536    case MESA_FORMAT_BPTC_SRGB_ALPHA_UNORM:
 537       return GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM;
 538    case MESA_FORMAT_BPTC_RGB_SIGNED_FLOAT:
 539       return GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT;
 540    case MESA_FORMAT_BPTC_RGB_UNSIGNED_FLOAT:
 541       return GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT;
 542
 543    default:
 544       _mesa_problem(ctx, "Unexpected mesa texture format in"
 545                     " _mesa_compressed_format_to_glenum()");
 546       return 0;
 547    }
 548 }
 549
 550
 551 /*
 552  * Return the address of the pixel at (col, row, img) in a
 553  * compressed texture image.
 554  * \param col, row, img - image position (3D), should be a multiple of the
 555  *                        format's block size.
 556  * \param format - compressed image format
 557  * \param width - image width (stride) in pixels
 558  * \param image - the image address
 559  * \return address of pixel at (row, col, img)
 560  */
 561 GLubyte *
 562 _mesa_compressed_image_address(GLint col, GLint row, GLint img,
 563                                mesa_format mesaFormat,
 564                                GLsizei width, const GLubyte *image)
 565 {
 566    /* XXX only 2D images implemented, not 3D */
 567    const GLuint blockSize = _mesa_get_format_bytes(mesaFormat);
 568    GLuint bw, bh;
 569    GLint offset;
 570
 571    _mesa_get_format_block_size(mesaFormat, &bw, &bh);
 572
 573    ASSERT(col % bw == 0);
 574    ASSERT(row % bh == 0);
 575
 576    offset = ((width + bw - 1) / bw) * (row / bh) + col / bw;
 577    offset *= blockSize;
 578
 579    return (GLubyte *) image + offset;
 580 }
 581
 582
 583 /**
 584  * Return a texel-fetch function for the given format, or NULL if
 585  * invalid format.
 586  */
 587 compressed_fetch_func
 588 _mesa_get_compressed_fetch_func(mesa_format format)
 589 {
 590    switch (format) {
 591    case MESA_FORMAT_RGB_DXT1:
 592    case MESA_FORMAT_RGBA_DXT1:
 593    case MESA_FORMAT_RGBA_DXT3:
 594    case MESA_FORMAT_RGBA_DXT5:
 595    case MESA_FORMAT_SRGB_DXT1:
 596    case MESA_FORMAT_SRGBA_DXT1:
 597    case MESA_FORMAT_SRGBA_DXT3:
 598    case MESA_FORMAT_SRGBA_DXT5:
 599       return _mesa_get_dxt_fetch_func(format);
 600    case MESA_FORMAT_RGB_FXT1:
 601    case MESA_FORMAT_RGBA_FXT1:
 602       return _mesa_get_fxt_fetch_func(format);
 603    case MESA_FORMAT_R_RGTC1_UNORM:
 604    case MESA_FORMAT_L_LATC1_UNORM:
 605    case MESA_FORMAT_R_RGTC1_SNORM:
 606    case MESA_FORMAT_L_LATC1_SNORM:
 607    case MESA_FORMAT_RG_RGTC2_UNORM:
 608    case MESA_FORMAT_LA_LATC2_UNORM:
 609    case MESA_FORMAT_RG_RGTC2_SNORM:
 610    case MESA_FORMAT_LA_LATC2_SNORM:
 611       return _mesa_get_compressed_rgtc_func(format);
 612    case MESA_FORMAT_ETC1_RGB8:
 613       return _mesa_get_etc_fetch_func(format);
 614    case MESA_FORMAT_BPTC_RGBA_UNORM:
 615    case MESA_FORMAT_BPTC_SRGB_ALPHA_UNORM:
 616    case MESA_FORMAT_BPTC_RGB_SIGNED_FLOAT:
 617    case MESA_FORMAT_BPTC_RGB_UNSIGNED_FLOAT:
 618       return _mesa_get_bptc_fetch_func(format);
 619    default:
 620       return NULL;
 621    }
 622 }
 623
 624
 625 /**
 626  * Decompress a compressed texture image, returning a GL_RGBA/GL_FLOAT image.
 627  * \param srcRowStride  stride in bytes between rows of blocks in the
 628  *                      compressed source image.
 629  */
 630 void
 631 _mesa_decompress_image(mesa_format format, GLuint width, GLuint height,
 632                        const GLubyte *src, GLint srcRowStride,
 633                        GLfloat *dest)
 634 {
 635    compressed_fetch_func fetch;
 636    GLuint i, j;
 637    GLuint bytes, bw, bh;
 638    GLint stride;
 639
 640    bytes = _mesa_get_format_bytes(format);
 641    _mesa_get_format_block_size(format, &bw, &bh);
 642
 643    fetch = _mesa_get_compressed_fetch_func(format);
 644    if (!fetch) {
 645       _mesa_problem(NULL, "Unexpected format in _mesa_decompress_image()");
 646       return;
 647    }
 648
 649    stride = srcRowStride * bh / bytes;
 650
 651    for (j = 0; j < height; j++) {
 652       for (i = 0; i < width; i++) {
 653          fetch(src, stride, i, j, dest);
 654          dest += 4;
 655       }
 656    }
 657 }