src/mesa/state_tracker/st_format.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
   4  * All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  21  * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
  22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28
  29 /**
  30  * Texture Image-related functions.
  31  * \author Brian Paul
  32  */
  33
  34 #include "main/imports.h"
  35 #include "main/context.h"
  36 #include "main/texstore.h"
  37 #include "main/texformat.h"
  38 #include "main/enums.h"
  39 #include "main/macros.h"
  40
  41 #include "pipe/p_context.h"
  42 #include "pipe/p_defines.h"
  43 #include "st_context.h"
  44 #include "st_format.h"
  45
  46 static GLuint
  47 format_bits(
  48    pipe_format_rgbazs_t  info,
  49    GLuint comp )
  50 {
  51    GLuint   size;
  52
  53    if (pf_swizzle_x(info) == comp) {
  54       size = pf_size_x(info);
  55    }
  56    else if (pf_swizzle_y(info) == comp) {
  57       size = pf_size_y(info);
  58    }
  59    else if (pf_swizzle_z(info) == comp) {
  60       size = pf_size_z(info);
  61    }
  62    else if (pf_swizzle_w(info) == comp) {
  63       size = pf_size_w(info);
  64    }
  65    else {
  66       size = 0;
  67    }
  68    return size << (pf_exp8(info) * 3);
  69 }
  70
  71 static GLuint
  72 format_max_bits(
  73    pipe_format_rgbazs_t  info )
  74 {
  75    GLuint   size = format_bits( info, PIPE_FORMAT_COMP_R );
  76
  77    size = MAX2( size, format_bits( info, PIPE_FORMAT_COMP_G ) );
  78    size = MAX2( size, format_bits( info, PIPE_FORMAT_COMP_B ) );
  79    size = MAX2( size, format_bits( info, PIPE_FORMAT_COMP_A ) );
  80    size = MAX2( size, format_bits( info, PIPE_FORMAT_COMP_Z ) );
  81    size = MAX2( size, format_bits( info, PIPE_FORMAT_COMP_S ) );
  82    return size;
  83 }
  84
  85 static GLuint
  86 format_size(
  87    pipe_format_rgbazs_t  info )
  88 {
  89    return
  90       format_bits( info, PIPE_FORMAT_COMP_R ) +
  91       format_bits( info, PIPE_FORMAT_COMP_G ) +
  92       format_bits( info, PIPE_FORMAT_COMP_B ) +
  93       format_bits( info, PIPE_FORMAT_COMP_A ) +
  94       format_bits( info, PIPE_FORMAT_COMP_Z ) +
  95       format_bits( info, PIPE_FORMAT_COMP_S );
  96 }
  97
  98 /*
  99  * XXX temporary here
 100  */
 101 GLboolean
 102 st_get_format_info(
 103    GLuint format,
 104    struct pipe_format_info *pinfo )
 105 {
 106    if (pf_layout(format) == PIPE_FORMAT_LAYOUT_RGBAZS) {
 107       pipe_format_rgbazs_t info;
 108
 109       info = format;
 110
 111 #if 0
 112       {
 113          char  fmtname[256];
 114
 115          pf_sprint_name( fmtname, format );
 116          printf(
 117             "%s\n",
 118             fmtname );
 119       }
 120 #endif
 121
 122       /* Data type */
 123       if (format == PIPE_FORMAT_U_A1_R5_G5_B5 || format == PIPE_FORMAT_U_R5_G6_B5) {
 124          pinfo->datatype = GL_UNSIGNED_SHORT;
 125       }
 126       else {
 127          GLuint size;
 128
 129          size = format_max_bits( info );
 130          if (size == 8) {
 131             if (pf_type(info) == PIPE_FORMAT_TYPE_UNORM)
 132                pinfo->datatype = GL_UNSIGNED_BYTE;
 133             else
 134                pinfo->datatype = GL_BYTE;
 135          }
 136          else if (size == 16) {
 137             if (pf_type(info) == PIPE_FORMAT_TYPE_UNORM)
 138                pinfo->datatype = GL_UNSIGNED_SHORT;
 139             else
 140                pinfo->datatype = GL_SHORT;
 141          }
 142          else {
 143             assert( size <= 32 );
 144             if (pf_type(info) == PIPE_FORMAT_TYPE_UNORM)
 145                pinfo->datatype = GL_UNSIGNED_INT;
 146             else
 147                pinfo->datatype = GL_INT;
 148          }
 149       }
 150
 151       /* Component bits */
 152       pinfo->red_bits = format_bits( info, PIPE_FORMAT_COMP_R );
 153       pinfo->green_bits = format_bits( info, PIPE_FORMAT_COMP_G );
 154       pinfo->blue_bits = format_bits( info, PIPE_FORMAT_COMP_B );
 155       pinfo->alpha_bits = format_bits( info, PIPE_FORMAT_COMP_A );
 156       pinfo->depth_bits = format_bits( info, PIPE_FORMAT_COMP_Z );
 157       pinfo->stencil_bits = format_bits( info, PIPE_FORMAT_COMP_S );
 158       pinfo->luminance_bits = 0;
 159       pinfo->intensity_bits = 0;
 160
 161       /* Format size */
 162       pinfo->size = format_size( info ) / 8;
 163
 164       /* Luminance & Intensity bits */
 165       if( pf_swizzle_x(info) == PIPE_FORMAT_COMP_R &&
 166           pf_swizzle_y(info) == PIPE_FORMAT_COMP_R &&
 167           pf_swizzle_z(info) == PIPE_FORMAT_COMP_R ) {
 168          if( pf_swizzle_w(info) == PIPE_FORMAT_COMP_R ) {
 169             pinfo->intensity_bits = pinfo->red_bits;
 170          }
 171          else {
 172             pinfo->luminance_bits = pinfo->red_bits;
 173          }
 174          pinfo->red_bits = 0;
 175       }
 176
 177       /* Base format */
 178       if (pinfo->depth_bits) {
 179          if (pinfo->stencil_bits) {
 180             pinfo->base_format = GL_DEPTH_STENCIL_EXT;
 181          }
 182          else {
 183             pinfo->base_format = GL_DEPTH_COMPONENT;
 184          }
 185       }
 186       else if (pinfo->stencil_bits) {
 187          pinfo->base_format = GL_STENCIL_INDEX;
 188       }
 189       else {
 190          pinfo->base_format = GL_RGBA;
 191       }
 192    }
 193    else {
 194       pipe_format_ycbcr_t info;
 195
 196       assert( pf_layout(format) == PIPE_FORMAT_LAYOUT_YCBCR );
 197
 198       info = format;
 199
 200       /* TODO */
 201       assert( 0 );
 202    }
 203
 204 #if 0
 205    printf(
 206       "ST_FORMAT: R(%u), G(%u), B(%u), A(%u), Z(%u), S(%u)\n",
 207       pinfo->red_bits,
 208       pinfo->green_bits,
 209       pinfo->blue_bits,
 210       pinfo->alpha_bits,
 211       pinfo->depth_bits,
 212       pinfo->stencil_bits );
 213 #endif
 214
 215    pinfo->format = format;
 216
 217    return GL_TRUE;
 218 }
 219
 220
 221 /**
 222  * Return bytes per pixel for the given format.
 223  */
 224 GLuint
 225 st_sizeof_format(GLuint pipeFormat)
 226 {
 227    struct pipe_format_info info;
 228    if (!st_get_format_info( pipeFormat, &info )) {
 229       assert( 0 );
 230       return 0;
 231    }
 232    return info.size;
 233 }
 234
 235
 236 /**
 237  * Return bytes per pixel for the given format.
 238  */
 239 GLenum
 240 st_format_datatype(GLuint pipeFormat)
 241 {
 242    struct pipe_format_info info;
 243    if (!st_get_format_info( pipeFormat, &info )) {
 244       assert( 0 );
 245       return 0;
 246    }
 247    return info.datatype;
 248 }
 249
 250
 251 GLuint
 252 st_mesa_format_to_pipe_format(GLuint mesaFormat)
 253 {
 254    switch (mesaFormat) {
 255       /* fix this */
 256    case MESA_FORMAT_ARGB8888_REV:
 257    case MESA_FORMAT_ARGB8888:
 258       return PIPE_FORMAT_U_A8_R8_G8_B8;
 259    case MESA_FORMAT_ARGB4444:
 260       return PIPE_FORMAT_U_A4_R4_G4_B4;
 261    case MESA_FORMAT_AL88:
 262       return PIPE_FORMAT_U_A8_L8;
 263    case MESA_FORMAT_A8:
 264       return PIPE_FORMAT_U_A8;
 265    case MESA_FORMAT_L8:
 266       return PIPE_FORMAT_U_L8;
 267    case MESA_FORMAT_I8:
 268       return PIPE_FORMAT_U_I8;
 269    case MESA_FORMAT_Z16:
 270       return PIPE_FORMAT_U_Z16;
 271    default:
 272       assert(0);
 273       return 0;
 274    }
 275 }
 276
 277 /**
 278  * Search list of formats for first RGBA format.
 279  */
 280 static GLuint
 281 default_rgba_format(
 282    struct pipe_context *pipe )
 283 {
 284    if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_R8_G8_B8_A8 )) {
 285       return PIPE_FORMAT_U_R8_G8_B8_A8;
 286    }
 287    if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A8_R8_G8_B8 )) {
 288       return PIPE_FORMAT_U_A8_R8_G8_B8;
 289    }
 290    if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_R5_G6_B5 )) {
 291       return PIPE_FORMAT_U_R5_G6_B5;
 292    }
 293    return PIPE_FORMAT_NONE;
 294 }
 295
 296
 297 /**
 298  * Search list of formats for first RGBA format with >8 bits/channel.
 299  */
 300 static GLuint
 301 default_deep_rgba_format(
 302    struct pipe_context *pipe )
 303 {
 304    if (pipe->is_format_supported( pipe, PIPE_FORMAT_S_R16_G16_B16_A16 )) {
 305       return PIPE_FORMAT_S_R16_G16_B16_A16;
 306    }
 307    return PIPE_FORMAT_NONE;
 308 }
 309
 310
 311 /**
 312  * Search list of formats for first depth/Z format.
 313  */
 314 static GLuint
 315 default_depth_format(
 316    struct pipe_context *pipe )
 317 {
 318    if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_Z16 )) {
 319       return PIPE_FORMAT_U_Z16;
 320    }
 321    if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_Z32 )) {
 322       return PIPE_FORMAT_U_Z32;
 323    }
 324    if (pipe->is_format_supported( pipe, PIPE_FORMAT_S8_Z24 )) {
 325       return PIPE_FORMAT_S8_Z24;
 326    }
 327    if (pipe->is_format_supported( pipe, PIPE_FORMAT_Z24_S8 )) {
 328       return PIPE_FORMAT_Z24_S8;
 329    }
 330    return PIPE_FORMAT_NONE;
 331 }
 332
 333 /**
 334  * Choose the PIPE_FORMAT_ to use for storing a texture image based
 335  * on the user's internalFormat, format and type parameters.
 336  * We query the pipe device for a list of formats which it supports
 337  * and choose from them.
 338  * If we find a device that needs a more intricate selection mechanism,
 339  * this function _could_ get pushed down into the pipe device.
 340  *
 341  * Note: also used for glRenderbufferStorageEXT()
 342  *
 343  * Note: format and type may be GL_NONE (see renderbuffers)
 344  *
 345  * \return PIPE_FORMAT_NONE if error/problem.
 346  */
 347 GLuint
 348 st_choose_pipe_format(struct pipe_context *pipe, GLint internalFormat,
 349                       GLenum format, GLenum type)
 350 {
 351    switch (internalFormat) {
 352    case 4:
 353    case GL_RGBA:
 354    case GL_COMPRESSED_RGBA:
 355       if (format == GL_BGRA) {
 356          if (type == GL_UNSIGNED_BYTE || type == GL_UNSIGNED_INT_8_8_8_8_REV) {
 357             if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A8_R8_G8_B8 ))
 358                return PIPE_FORMAT_U_A8_R8_G8_B8;
 359          }
 360          else if (type == GL_UNSIGNED_SHORT_4_4_4_4_REV) {
 361             if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A4_R4_G4_B4 ))
 362                return PIPE_FORMAT_U_A4_R4_G4_B4;
 363          }
 364          else if (type == GL_UNSIGNED_SHORT_1_5_5_5_REV) {
 365             if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A1_R5_G5_B5 ))
 366                return PIPE_FORMAT_U_A1_R5_G5_B5;
 367          }
 368       }
 369       return default_rgba_format( pipe );
 370
 371    case 3:
 372    case GL_RGB:
 373    case GL_COMPRESSED_RGB:
 374       if (format == GL_RGB && type == GL_UNSIGNED_SHORT_5_6_5) {
 375          if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_R5_G6_B5 ))
 376             return PIPE_FORMAT_U_R5_G6_B5;
 377       }
 378       return default_rgba_format( pipe );
 379
 380    case GL_RGBA8:
 381    case GL_RGB10_A2:
 382    case GL_RGBA12:
 383       return default_rgba_format( pipe );
 384    case GL_RGBA16:
 385       return default_deep_rgba_format( pipe );
 386
 387    case GL_RGBA4:
 388    case GL_RGBA2:
 389       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A4_R4_G4_B4 ))
 390          return PIPE_FORMAT_U_A4_R4_G4_B4;
 391       return default_rgba_format( pipe );
 392
 393    case GL_RGB5_A1:
 394       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A1_R5_G5_B5 ))
 395          return PIPE_FORMAT_U_A1_R5_G5_B5;
 396       return default_rgba_format( pipe );
 397
 398    case GL_RGB8:
 399    case GL_RGB10:
 400    case GL_RGB12:
 401    case GL_RGB16:
 402       return default_rgba_format( pipe );
 403
 404    case GL_RGB5:
 405    case GL_RGB4:
 406    case GL_R3_G3_B2:
 407       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A1_R5_G5_B5 ))
 408          return PIPE_FORMAT_U_A1_R5_G5_B5;
 409       return default_rgba_format( pipe );
 410
 411    case GL_ALPHA:
 412    case GL_ALPHA4:
 413    case GL_ALPHA8:
 414    case GL_ALPHA12:
 415    case GL_ALPHA16:
 416    case GL_COMPRESSED_ALPHA:
 417       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A8 ))
 418          return PIPE_FORMAT_U_A8;
 419       return default_rgba_format( pipe );
 420
 421    case 1:
 422    case GL_LUMINANCE:
 423    case GL_LUMINANCE4:
 424    case GL_LUMINANCE8:
 425    case GL_LUMINANCE12:
 426    case GL_LUMINANCE16:
 427    case GL_COMPRESSED_LUMINANCE:
 428       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A8 ))
 429          return PIPE_FORMAT_U_A8;
 430       return default_rgba_format( pipe );
 431
 432    case 2:
 433    case GL_LUMINANCE_ALPHA:
 434    case GL_LUMINANCE4_ALPHA4:
 435    case GL_LUMINANCE6_ALPHA2:
 436    case GL_LUMINANCE8_ALPHA8:
 437    case GL_LUMINANCE12_ALPHA4:
 438    case GL_LUMINANCE12_ALPHA12:
 439    case GL_LUMINANCE16_ALPHA16:
 440    case GL_COMPRESSED_LUMINANCE_ALPHA:
 441       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A8_L8 ))
 442          return PIPE_FORMAT_U_A8_L8;
 443       return default_rgba_format( pipe );
 444
 445    case GL_INTENSITY:
 446    case GL_INTENSITY4:
 447    case GL_INTENSITY8:
 448    case GL_INTENSITY12:
 449    case GL_INTENSITY16:
 450    case GL_COMPRESSED_INTENSITY:
 451       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_I8 ))
 452          return PIPE_FORMAT_U_I8;
 453       return default_rgba_format( pipe );
 454
 455    case GL_YCBCR_MESA:
 456       if (type == GL_UNSIGNED_SHORT_8_8_MESA || type == GL_UNSIGNED_BYTE) {
 457          if (pipe->is_format_supported( pipe, PIPE_FORMAT_YCBCR ))
 458             return PIPE_FORMAT_YCBCR;
 459       }
 460       else {
 461          if (pipe->is_format_supported( pipe, PIPE_FORMAT_YCBCR_REV ))
 462             return PIPE_FORMAT_YCBCR_REV;
 463       }
 464       return PIPE_FORMAT_NONE;
 465
 466 #if 0
 467    case GL_COMPRESSED_RGB_FXT1_3DFX:
 468       return &_mesa_texformat_rgb_fxt1;
 469    case GL_COMPRESSED_RGBA_FXT1_3DFX:
 470       return &_mesa_texformat_rgba_fxt1;
 471
 472    case GL_RGB_S3TC:
 473    case GL_RGB4_S3TC:
 474    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
 475       return &_mesa_texformat_rgb_dxt1;
 476
 477    case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 478       return &_mesa_texformat_rgba_dxt1;
 479
 480    case GL_RGBA_S3TC:
 481    case GL_RGBA4_S3TC:
 482    case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
 483       return &_mesa_texformat_rgba_dxt3;
 484
 485    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
 486       return &_mesa_texformat_rgba_dxt5;
 487 #endif
 488
 489    case GL_DEPTH_COMPONENT16:
 490       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_Z16 ))
 491          return PIPE_FORMAT_U_Z16;
 492       /* fall-through */
 493    case GL_DEPTH_COMPONENT24:
 494       if (pipe->is_format_supported( pipe, PIPE_FORMAT_S8_Z24 ))
 495          return PIPE_FORMAT_S8_Z24;
 496       if (pipe->is_format_supported( pipe, PIPE_FORMAT_Z24_S8 ))
 497          return PIPE_FORMAT_Z24_S8;
 498       /* fall-through */
 499    case GL_DEPTH_COMPONENT32:
 500       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_Z32 ))
 501          return PIPE_FORMAT_U_Z32;
 502       /* fall-through */
 503    case GL_DEPTH_COMPONENT:
 504       return default_depth_format( pipe );
 505
 506    case GL_STENCIL_INDEX:
 507    case GL_STENCIL_INDEX1_EXT:
 508    case GL_STENCIL_INDEX4_EXT:
 509    case GL_STENCIL_INDEX8_EXT:
 510    case GL_STENCIL_INDEX16_EXT:
 511       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_S8 ))
 512          return PIPE_FORMAT_U_S8;
 513       if (pipe->is_format_supported( pipe, PIPE_FORMAT_S8_Z24 ))
 514          return PIPE_FORMAT_S8_Z24;
 515       if (pipe->is_format_supported( pipe, PIPE_FORMAT_Z24_S8 ))
 516          return PIPE_FORMAT_Z24_S8;
 517       return PIPE_FORMAT_NONE;
 518
 519    case GL_DEPTH_STENCIL_EXT:
 520    case GL_DEPTH24_STENCIL8_EXT:
 521       if (pipe->is_format_supported( pipe, PIPE_FORMAT_S8_Z24 ))
 522          return PIPE_FORMAT_S8_Z24;
 523       if (pipe->is_format_supported( pipe, PIPE_FORMAT_Z24_S8 ))
 524          return PIPE_FORMAT_Z24_S8;
 525       return PIPE_FORMAT_NONE;
 526
 527    default:
 528       return PIPE_FORMAT_NONE;
 529    }
 530 }
 531
 532
 533
 534 /* It works out that this function is fine for all the supported
 535  * hardware.  However, there is still a need to map the formats onto
 536  * hardware descriptors.
 537  */
 538 /* Note that the i915 can actually support many more formats than
 539  * these if we take the step of simply swizzling the colors
 540  * immediately after sampling...
 541  */
 542 const struct gl_texture_format *
 543 st_ChooseTextureFormat(GLcontext * ctx, GLint internalFormat,
 544                          GLenum format, GLenum type)
 545 {
 546 #if 0
 547    struct intel_context *intel = intel_context(ctx);
 548    const GLboolean do32bpt = (intel->intelScreen->front.cpp == 4);
 549 #else
 550    const GLboolean do32bpt = 1;
 551 #endif
 552
 553    switch (internalFormat) {
 554    case 4:
 555    case GL_RGBA:
 556    case GL_COMPRESSED_RGBA:
 557       if (format == GL_BGRA) {
 558          if (type == GL_UNSIGNED_BYTE || type == GL_UNSIGNED_INT_8_8_8_8_REV) {
 559             return &_mesa_texformat_argb8888;
 560          }
 561          else if (type == GL_UNSIGNED_SHORT_4_4_4_4_REV) {
 562             return &_mesa_texformat_argb4444;
 563          }
 564          else if (type == GL_UNSIGNED_SHORT_1_5_5_5_REV) {
 565             return &_mesa_texformat_argb1555;
 566          }
 567       }
 568       return do32bpt ? &_mesa_texformat_argb8888 : &_mesa_texformat_argb4444;
 569
 570    case 3:
 571    case GL_RGB:
 572    case GL_COMPRESSED_RGB:
 573       if (format == GL_RGB && type == GL_UNSIGNED_SHORT_5_6_5) {
 574          return &_mesa_texformat_rgb565;
 575       }
 576       return do32bpt ? &_mesa_texformat_argb8888 : &_mesa_texformat_rgb565;
 577
 578    case GL_RGBA8:
 579    case GL_RGB10_A2:
 580    case GL_RGBA12:
 581    case GL_RGBA16:
 582       return do32bpt ? &_mesa_texformat_argb8888 : &_mesa_texformat_argb4444;
 583
 584    case GL_RGBA4:
 585    case GL_RGBA2:
 586       return &_mesa_texformat_argb4444;
 587
 588    case GL_RGB5_A1:
 589       return &_mesa_texformat_argb1555;
 590
 591    case GL_RGB8:
 592    case GL_RGB10:
 593    case GL_RGB12:
 594    case GL_RGB16:
 595       return &_mesa_texformat_argb8888;
 596
 597    case GL_RGB5:
 598    case GL_RGB4:
 599    case GL_R3_G3_B2:
 600       return &_mesa_texformat_rgb565;
 601
 602    case GL_ALPHA:
 603    case GL_ALPHA4:
 604    case GL_ALPHA8:
 605    case GL_ALPHA12:
 606    case GL_ALPHA16:
 607    case GL_COMPRESSED_ALPHA:
 608       return &_mesa_texformat_a8;
 609
 610    case 1:
 611    case GL_LUMINANCE:
 612    case GL_LUMINANCE4:
 613    case GL_LUMINANCE8:
 614    case GL_LUMINANCE12:
 615    case GL_LUMINANCE16:
 616    case GL_COMPRESSED_LUMINANCE:
 617       return &_mesa_texformat_l8;
 618
 619    case 2:
 620    case GL_LUMINANCE_ALPHA:
 621    case GL_LUMINANCE4_ALPHA4:
 622    case GL_LUMINANCE6_ALPHA2:
 623    case GL_LUMINANCE8_ALPHA8:
 624    case GL_LUMINANCE12_ALPHA4:
 625    case GL_LUMINANCE12_ALPHA12:
 626    case GL_LUMINANCE16_ALPHA16:
 627    case GL_COMPRESSED_LUMINANCE_ALPHA:
 628       return &_mesa_texformat_al88;
 629
 630    case GL_INTENSITY:
 631    case GL_INTENSITY4:
 632    case GL_INTENSITY8:
 633    case GL_INTENSITY12:
 634    case GL_INTENSITY16:
 635    case GL_COMPRESSED_INTENSITY:
 636       return &_mesa_texformat_i8;
 637
 638    case GL_YCBCR_MESA:
 639       if (type == GL_UNSIGNED_SHORT_8_8_MESA || type == GL_UNSIGNED_BYTE)
 640          return &_mesa_texformat_ycbcr;
 641       else
 642          return &_mesa_texformat_ycbcr_rev;
 643
 644    case GL_COMPRESSED_RGB_FXT1_3DFX:
 645       return &_mesa_texformat_rgb_fxt1;
 646    case GL_COMPRESSED_RGBA_FXT1_3DFX:
 647       return &_mesa_texformat_rgba_fxt1;
 648
 649    case GL_RGB_S3TC:
 650    case GL_RGB4_S3TC:
 651    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
 652       return &_mesa_texformat_rgb_dxt1;
 653
 654    case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 655       return &_mesa_texformat_rgba_dxt1;
 656
 657    case GL_RGBA_S3TC:
 658    case GL_RGBA4_S3TC:
 659    case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
 660       return &_mesa_texformat_rgba_dxt3;
 661
 662    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
 663       return &_mesa_texformat_rgba_dxt5;
 664
 665    case GL_DEPTH_COMPONENT:
 666    case GL_DEPTH_COMPONENT16:
 667    case GL_DEPTH_COMPONENT24:
 668    case GL_DEPTH_COMPONENT32:
 669       return &_mesa_texformat_z16;
 670
 671    case GL_DEPTH_STENCIL_EXT:
 672    case GL_DEPTH24_STENCIL8_EXT:
 673       return &_mesa_texformat_z24_s8;
 674
 675    default:
 676       fprintf(stderr, "unexpected texture format %s in %s\n",
 677               _mesa_lookup_enum_by_nr(internalFormat), __FUNCTION__);
 678       return NULL;
 679    }
 680
 681    return NULL;                 /* never get here */
 682 }