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_AL88:
 260       return PIPE_FORMAT_U_A8_L8;
 261    case MESA_FORMAT_A8:
 262       return PIPE_FORMAT_U_A8;
 263    case MESA_FORMAT_L8:
 264       return PIPE_FORMAT_U_L8;
 265    case MESA_FORMAT_I8:
 266       return PIPE_FORMAT_U_I8;
 267    case MESA_FORMAT_Z16:
 268       return PIPE_FORMAT_U_Z16;
 269    default:
 270       assert(0);
 271       return 0;
 272    }
 273 }
 274
 275 /**
 276  * Search list of formats for first RGBA format.
 277  */
 278 static GLuint
 279 default_rgba_format(
 280    struct pipe_context *pipe )
 281 {
 282    if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_R8_G8_B8_A8 )) {
 283       return PIPE_FORMAT_U_R8_G8_B8_A8;
 284    }
 285    if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A8_R8_G8_B8 )) {
 286       return PIPE_FORMAT_U_A8_R8_G8_B8;
 287    }
 288    if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_R5_G6_B5 )) {
 289       return PIPE_FORMAT_U_R5_G6_B5;
 290    }
 291    return PIPE_FORMAT_NONE;
 292 }
 293
 294
 295 /**
 296  * Search list of formats for first RGBA format with >8 bits/channel.
 297  */
 298 static GLuint
 299 default_deep_rgba_format(
 300    struct pipe_context *pipe )
 301 {
 302    if (pipe->is_format_supported( pipe, PIPE_FORMAT_S_R16_G16_B16_A16 )) {
 303       return PIPE_FORMAT_S_R16_G16_B16_A16;
 304    }
 305    return PIPE_FORMAT_NONE;
 306 }
 307
 308
 309 /**
 310  * Search list of formats for first depth/Z format.
 311  */
 312 static GLuint
 313 default_depth_format(
 314    struct pipe_context *pipe )
 315 {
 316    if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_Z16 )) {
 317       return PIPE_FORMAT_U_Z16;
 318    }
 319    if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_Z32 )) {
 320       return PIPE_FORMAT_U_Z32;
 321    }
 322    if (pipe->is_format_supported( pipe, PIPE_FORMAT_S8_Z24 )) {
 323       return PIPE_FORMAT_S8_Z24;
 324    }
 325    if (pipe->is_format_supported( pipe, PIPE_FORMAT_Z24_S8 )) {
 326       return PIPE_FORMAT_Z24_S8;
 327    }
 328    return PIPE_FORMAT_NONE;
 329 }
 330
 331 /**
 332  * Choose the PIPE_FORMAT_ to use for storing a texture image based
 333  * on the user's internalFormat, format and type parameters.
 334  * We query the pipe device for a list of formats which it supports
 335  * and choose from them.
 336  * If we find a device that needs a more intricate selection mechanism,
 337  * this function _could_ get pushed down into the pipe device.
 338  *
 339  * Note: also used for glRenderbufferStorageEXT()
 340  *
 341  * Note: format and type may be GL_NONE (see renderbuffers)
 342  *
 343  * \return PIPE_FORMAT_NONE if error/problem.
 344  */
 345 GLuint
 346 st_choose_pipe_format(struct pipe_context *pipe, GLint internalFormat,
 347                       GLenum format, GLenum type)
 348 {
 349    switch (internalFormat) {
 350    case 4:
 351    case GL_RGBA:
 352    case GL_COMPRESSED_RGBA:
 353       if (format == GL_BGRA) {
 354          if (type == GL_UNSIGNED_BYTE || type == GL_UNSIGNED_INT_8_8_8_8_REV) {
 355             if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A8_R8_G8_B8 ))
 356                return PIPE_FORMAT_U_A8_R8_G8_B8;
 357          }
 358          else if (type == GL_UNSIGNED_SHORT_4_4_4_4_REV) {
 359             if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A4_R4_G4_B4 ))
 360                return PIPE_FORMAT_U_A4_R4_G4_B4;
 361          }
 362          else if (type == GL_UNSIGNED_SHORT_1_5_5_5_REV) {
 363             if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A1_R5_G5_B5 ))
 364                return PIPE_FORMAT_U_A1_R5_G5_B5;
 365          }
 366       }
 367       return default_rgba_format( pipe );
 368
 369    case 3:
 370    case GL_RGB:
 371    case GL_COMPRESSED_RGB:
 372       if (format == GL_RGB && type == GL_UNSIGNED_SHORT_5_6_5) {
 373          if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_R5_G6_B5 ))
 374             return PIPE_FORMAT_U_R5_G6_B5;
 375       }
 376       return default_rgba_format( pipe );
 377
 378    case GL_RGBA8:
 379    case GL_RGB10_A2:
 380    case GL_RGBA12:
 381       return default_rgba_format( pipe );
 382    case GL_RGBA16:
 383       return default_deep_rgba_format( pipe );
 384
 385    case GL_RGBA4:
 386    case GL_RGBA2:
 387       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A4_R4_G4_B4 ))
 388          return PIPE_FORMAT_U_A4_R4_G4_B4;
 389       return default_rgba_format( pipe );
 390
 391    case GL_RGB5_A1:
 392       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A1_R5_G5_B5 ))
 393          return PIPE_FORMAT_U_A1_R5_G5_B5;
 394       return default_rgba_format( pipe );
 395
 396    case GL_RGB8:
 397    case GL_RGB10:
 398    case GL_RGB12:
 399    case GL_RGB16:
 400       return default_rgba_format( pipe );
 401
 402    case GL_RGB5:
 403    case GL_RGB4:
 404    case GL_R3_G3_B2:
 405       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A1_R5_G5_B5 ))
 406          return PIPE_FORMAT_U_A1_R5_G5_B5;
 407       return default_rgba_format( pipe );
 408
 409    case GL_ALPHA:
 410    case GL_ALPHA4:
 411    case GL_ALPHA8:
 412    case GL_ALPHA12:
 413    case GL_ALPHA16:
 414    case GL_COMPRESSED_ALPHA:
 415       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A8 ))
 416          return PIPE_FORMAT_U_A8;
 417       return default_rgba_format( pipe );
 418
 419    case 1:
 420    case GL_LUMINANCE:
 421    case GL_LUMINANCE4:
 422    case GL_LUMINANCE8:
 423    case GL_LUMINANCE12:
 424    case GL_LUMINANCE16:
 425    case GL_COMPRESSED_LUMINANCE:
 426       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A8 ))
 427          return PIPE_FORMAT_U_A8;
 428       return default_rgba_format( pipe );
 429
 430    case 2:
 431    case GL_LUMINANCE_ALPHA:
 432    case GL_LUMINANCE4_ALPHA4:
 433    case GL_LUMINANCE6_ALPHA2:
 434    case GL_LUMINANCE8_ALPHA8:
 435    case GL_LUMINANCE12_ALPHA4:
 436    case GL_LUMINANCE12_ALPHA12:
 437    case GL_LUMINANCE16_ALPHA16:
 438    case GL_COMPRESSED_LUMINANCE_ALPHA:
 439       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_A8_L8 ))
 440          return PIPE_FORMAT_U_A8_L8;
 441       return default_rgba_format( pipe );
 442
 443    case GL_INTENSITY:
 444    case GL_INTENSITY4:
 445    case GL_INTENSITY8:
 446    case GL_INTENSITY12:
 447    case GL_INTENSITY16:
 448    case GL_COMPRESSED_INTENSITY:
 449       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_I8 ))
 450          return PIPE_FORMAT_U_I8;
 451       return default_rgba_format( pipe );
 452
 453    case GL_YCBCR_MESA:
 454       if (type == GL_UNSIGNED_SHORT_8_8_MESA || type == GL_UNSIGNED_BYTE) {
 455          if (pipe->is_format_supported( pipe, PIPE_FORMAT_YCBCR ))
 456             return PIPE_FORMAT_YCBCR;
 457       }
 458       else {
 459          if (pipe->is_format_supported( pipe, PIPE_FORMAT_YCBCR_REV ))
 460             return PIPE_FORMAT_YCBCR_REV;
 461       }
 462       return PIPE_FORMAT_NONE;
 463
 464 #if 0
 465    case GL_COMPRESSED_RGB_FXT1_3DFX:
 466       return &_mesa_texformat_rgb_fxt1;
 467    case GL_COMPRESSED_RGBA_FXT1_3DFX:
 468       return &_mesa_texformat_rgba_fxt1;
 469
 470    case GL_RGB_S3TC:
 471    case GL_RGB4_S3TC:
 472    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
 473       return &_mesa_texformat_rgb_dxt1;
 474
 475    case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 476       return &_mesa_texformat_rgba_dxt1;
 477
 478    case GL_RGBA_S3TC:
 479    case GL_RGBA4_S3TC:
 480    case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
 481       return &_mesa_texformat_rgba_dxt3;
 482
 483    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
 484       return &_mesa_texformat_rgba_dxt5;
 485 #endif
 486
 487    case GL_DEPTH_COMPONENT16:
 488       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_Z16 ))
 489          return PIPE_FORMAT_U_Z16;
 490       /* fall-through */
 491    case GL_DEPTH_COMPONENT24:
 492       if (pipe->is_format_supported( pipe, PIPE_FORMAT_S8_Z24 ))
 493          return PIPE_FORMAT_S8_Z24;
 494       if (pipe->is_format_supported( pipe, PIPE_FORMAT_Z24_S8 ))
 495          return PIPE_FORMAT_Z24_S8;
 496       /* fall-through */
 497    case GL_DEPTH_COMPONENT32:
 498       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_Z32 ))
 499          return PIPE_FORMAT_U_Z32;
 500       /* fall-through */
 501    case GL_DEPTH_COMPONENT:
 502       return default_depth_format( pipe );
 503
 504    case GL_STENCIL_INDEX:
 505    case GL_STENCIL_INDEX1_EXT:
 506    case GL_STENCIL_INDEX4_EXT:
 507    case GL_STENCIL_INDEX8_EXT:
 508    case GL_STENCIL_INDEX16_EXT:
 509       if (pipe->is_format_supported( pipe, PIPE_FORMAT_U_S8 ))
 510          return PIPE_FORMAT_U_S8;
 511       if (pipe->is_format_supported( pipe, PIPE_FORMAT_S8_Z24 ))
 512          return PIPE_FORMAT_S8_Z24;
 513       if (pipe->is_format_supported( pipe, PIPE_FORMAT_Z24_S8 ))
 514          return PIPE_FORMAT_Z24_S8;
 515       return PIPE_FORMAT_NONE;
 516
 517    case GL_DEPTH_STENCIL_EXT:
 518    case GL_DEPTH24_STENCIL8_EXT:
 519       if (pipe->is_format_supported( pipe, PIPE_FORMAT_S8_Z24 ))
 520          return PIPE_FORMAT_S8_Z24;
 521       if (pipe->is_format_supported( pipe, PIPE_FORMAT_Z24_S8 ))
 522          return PIPE_FORMAT_Z24_S8;
 523       return PIPE_FORMAT_NONE;
 524
 525    default:
 526       return PIPE_FORMAT_NONE;
 527    }
 528 }
 529
 530
 531
 532 /* It works out that this function is fine for all the supported
 533  * hardware.  However, there is still a need to map the formats onto
 534  * hardware descriptors.
 535  */
 536 /* Note that the i915 can actually support many more formats than
 537  * these if we take the step of simply swizzling the colors
 538  * immediately after sampling...
 539  */
 540 const struct gl_texture_format *
 541 st_ChooseTextureFormat(GLcontext * ctx, GLint internalFormat,
 542                          GLenum format, GLenum type)
 543 {
 544 #if 0
 545    struct intel_context *intel = intel_context(ctx);
 546    const GLboolean do32bpt = (intel->intelScreen->front.cpp == 4);
 547 #else
 548    const GLboolean do32bpt = 1;
 549 #endif
 550
 551    switch (internalFormat) {
 552    case 4:
 553    case GL_RGBA:
 554    case GL_COMPRESSED_RGBA:
 555       if (format == GL_BGRA) {
 556          if (type == GL_UNSIGNED_BYTE || type == GL_UNSIGNED_INT_8_8_8_8_REV) {
 557             return &_mesa_texformat_argb8888;
 558          }
 559          else if (type == GL_UNSIGNED_SHORT_4_4_4_4_REV) {
 560             return &_mesa_texformat_argb4444;
 561          }
 562          else if (type == GL_UNSIGNED_SHORT_1_5_5_5_REV) {
 563             return &_mesa_texformat_argb1555;
 564          }
 565       }
 566       return do32bpt ? &_mesa_texformat_argb8888 : &_mesa_texformat_argb4444;
 567
 568    case 3:
 569    case GL_RGB:
 570    case GL_COMPRESSED_RGB:
 571       if (format == GL_RGB && type == GL_UNSIGNED_SHORT_5_6_5) {
 572          return &_mesa_texformat_rgb565;
 573       }
 574       return do32bpt ? &_mesa_texformat_argb8888 : &_mesa_texformat_rgb565;
 575
 576    case GL_RGBA8:
 577    case GL_RGB10_A2:
 578    case GL_RGBA12:
 579    case GL_RGBA16:
 580       return do32bpt ? &_mesa_texformat_argb8888 : &_mesa_texformat_argb4444;
 581
 582    case GL_RGBA4:
 583    case GL_RGBA2:
 584       return &_mesa_texformat_argb4444;
 585
 586    case GL_RGB5_A1:
 587       return &_mesa_texformat_argb1555;
 588
 589    case GL_RGB8:
 590    case GL_RGB10:
 591    case GL_RGB12:
 592    case GL_RGB16:
 593       return &_mesa_texformat_argb8888;
 594
 595    case GL_RGB5:
 596    case GL_RGB4:
 597    case GL_R3_G3_B2:
 598       return &_mesa_texformat_rgb565;
 599
 600    case GL_ALPHA:
 601    case GL_ALPHA4:
 602    case GL_ALPHA8:
 603    case GL_ALPHA12:
 604    case GL_ALPHA16:
 605    case GL_COMPRESSED_ALPHA:
 606       return &_mesa_texformat_a8;
 607
 608    case 1:
 609    case GL_LUMINANCE:
 610    case GL_LUMINANCE4:
 611    case GL_LUMINANCE8:
 612    case GL_LUMINANCE12:
 613    case GL_LUMINANCE16:
 614    case GL_COMPRESSED_LUMINANCE:
 615       return &_mesa_texformat_l8;
 616
 617    case 2:
 618    case GL_LUMINANCE_ALPHA:
 619    case GL_LUMINANCE4_ALPHA4:
 620    case GL_LUMINANCE6_ALPHA2:
 621    case GL_LUMINANCE8_ALPHA8:
 622    case GL_LUMINANCE12_ALPHA4:
 623    case GL_LUMINANCE12_ALPHA12:
 624    case GL_LUMINANCE16_ALPHA16:
 625    case GL_COMPRESSED_LUMINANCE_ALPHA:
 626       return &_mesa_texformat_al88;
 627
 628    case GL_INTENSITY:
 629    case GL_INTENSITY4:
 630    case GL_INTENSITY8:
 631    case GL_INTENSITY12:
 632    case GL_INTENSITY16:
 633    case GL_COMPRESSED_INTENSITY:
 634       return &_mesa_texformat_i8;
 635
 636    case GL_YCBCR_MESA:
 637       if (type == GL_UNSIGNED_SHORT_8_8_MESA || type == GL_UNSIGNED_BYTE)
 638          return &_mesa_texformat_ycbcr;
 639       else
 640          return &_mesa_texformat_ycbcr_rev;
 641
 642    case GL_COMPRESSED_RGB_FXT1_3DFX:
 643       return &_mesa_texformat_rgb_fxt1;
 644    case GL_COMPRESSED_RGBA_FXT1_3DFX:
 645       return &_mesa_texformat_rgba_fxt1;
 646
 647    case GL_RGB_S3TC:
 648    case GL_RGB4_S3TC:
 649    case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
 650       return &_mesa_texformat_rgb_dxt1;
 651
 652    case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 653       return &_mesa_texformat_rgba_dxt1;
 654
 655    case GL_RGBA_S3TC:
 656    case GL_RGBA4_S3TC:
 657    case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
 658       return &_mesa_texformat_rgba_dxt3;
 659
 660    case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
 661       return &_mesa_texformat_rgba_dxt5;
 662
 663    case GL_DEPTH_COMPONENT:
 664    case GL_DEPTH_COMPONENT16:
 665    case GL_DEPTH_COMPONENT24:
 666    case GL_DEPTH_COMPONENT32:
 667       return &_mesa_texformat_z16;
 668
 669    case GL_DEPTH_STENCIL_EXT:
 670    case GL_DEPTH24_STENCIL8_EXT:
 671       return &_mesa_texformat_z24_s8;
 672
 673    default:
 674       fprintf(stderr, "unexpected texture format %s in %s\n",
 675               _mesa_lookup_enum_by_nr(internalFormat), __FUNCTION__);
 676       return NULL;
 677    }
 678
 679    return NULL;                 /* never get here */
 680 }