src/mesa/main/texfetch.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  7.7
   4  *
   5  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
   6  * Copyright (c) 2009  VMware, Inc.
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a
   9  * copy of this software and associated documentation files (the "Software"),
  10  * to deal in the Software without restriction, including without limitation
  11  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  12  * and/or sell copies of the Software, and to permit persons to whom the
  13  * Software is furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included
  16  * in all copies or substantial portions 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 MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  21  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  22  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  23  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  24  */
  25
  26
  27 /**
  28  * \file texfetch.c
  29  *
  30  * Texel fetch/store functions
  31  *
  32  * \author Gareth Hughes
  33  */
  34
  35
  36 #include "colormac.h"
  37 #include "context.h"
  38 #include "texcompress.h"
  39 #include "texcompress_fxt1.h"
  40 #include "texcompress_s3tc.h"
  41 #include "texfetch.h"
  42
  43
  44 /**
  45  * Convert an 8-bit sRGB value from non-linear space to a
  46  * linear RGB value in [0, 1].
  47  * Implemented with a 256-entry lookup table.
  48  */
  49 static INLINE GLfloat
  50 nonlinear_to_linear(GLubyte cs8)
  51 {
  52    static GLfloat table[256];
  53    static GLboolean tableReady = GL_FALSE;
  54    if (!tableReady) {
  55       /* compute lookup table now */
  56       GLuint i;
  57       for (i = 0; i < 256; i++) {
  58          const GLfloat cs = UBYTE_TO_FLOAT(i);
  59          if (cs <= 0.04045) {
  60             table[i] = cs / 12.92f;
  61          }
  62          else {
  63             table[i] = (GLfloat) _mesa_pow((cs + 0.055) / 1.055, 2.4);
  64          }
  65       }
  66       tableReady = GL_TRUE;
  67    }
  68    return table[cs8];
  69 }
  70
  71
  72
  73 /* Texel fetch routines for all supported formats
  74  */
  75 #define DIM 1
  76 #include "texfetch_tmp.h"
  77
  78 #define DIM 2
  79 #include "texfetch_tmp.h"
  80
  81 #define DIM 3
  82 #include "texfetch_tmp.h"
  83
  84 /**
  85  * Null texel fetch function.
  86  *
  87  * Have to have this so the FetchTexel function pointer is never NULL.
  88  */
  89 static void fetch_null_texelf( const struct gl_texture_image *texImage,
  90                                GLint i, GLint j, GLint k, GLfloat *texel )
  91 {
  92    (void) texImage; (void) i; (void) j; (void) k;
  93    texel[RCOMP] = 0.0;
  94    texel[GCOMP] = 0.0;
  95    texel[BCOMP] = 0.0;
  96    texel[ACOMP] = 0.0;
  97    _mesa_warning(NULL, "fetch_null_texelf() called!");
  98 }
  99
 100 static void store_null_texel(struct gl_texture_image *texImage,
 101                              GLint i, GLint j, GLint k, const void *texel)
 102 {
 103    (void) texImage;
 104    (void) i;
 105    (void) j;
 106    (void) k;
 107    (void) texel;
 108    /* no-op */
 109 }
 110
 111
 112
 113 /**
 114  * Table to map MESA_FORMAT_ to texel fetch/store funcs.
 115  * XXX this is somewhat temporary.
 116  */
 117 static struct {
 118    gl_format Name;
 119    FetchTexelFuncF Fetch1D;
 120    FetchTexelFuncF Fetch2D;
 121    FetchTexelFuncF Fetch3D;
 122    StoreTexelFunc StoreTexel;
 123 }
 124 texfetch_funcs[MESA_FORMAT_COUNT] =
 125 {
 126    {
 127       MESA_FORMAT_NONE,
 128       fetch_null_texelf,
 129       fetch_null_texelf,
 130       fetch_null_texelf,
 131       store_null_texel
 132    },
 133
 134    {
 135       MESA_FORMAT_RGBA8888,
 136       fetch_texel_1d_f_rgba8888,
 137       fetch_texel_2d_f_rgba8888,
 138       fetch_texel_3d_f_rgba8888,
 139       store_texel_rgba8888
 140    },
 141    {
 142       MESA_FORMAT_RGBA8888_REV,
 143       fetch_texel_1d_f_rgba8888_rev,
 144       fetch_texel_2d_f_rgba8888_rev,
 145       fetch_texel_3d_f_rgba8888_rev,
 146       store_texel_rgba8888_rev
 147    },
 148    {
 149       MESA_FORMAT_ARGB8888,
 150       fetch_texel_1d_f_argb8888,
 151       fetch_texel_2d_f_argb8888,
 152       fetch_texel_3d_f_argb8888,
 153       store_texel_argb8888
 154    },
 155    {
 156       MESA_FORMAT_ARGB8888_REV,
 157       fetch_texel_1d_f_argb8888_rev,
 158       fetch_texel_2d_f_argb8888_rev,
 159       fetch_texel_3d_f_argb8888_rev,
 160       store_texel_argb8888_rev
 161    },
 162    {
 163       MESA_FORMAT_XRGB8888,
 164       fetch_texel_1d_f_xrgb8888,
 165       fetch_texel_2d_f_xrgb8888,
 166       fetch_texel_3d_f_xrgb8888,
 167       store_texel_xrgb8888
 168    },
 169    {
 170       MESA_FORMAT_XRGB8888_REV,
 171       fetch_texel_1d_f_xrgb8888_rev,
 172       fetch_texel_2d_f_xrgb8888_rev,
 173       fetch_texel_3d_f_xrgb8888_rev,
 174       store_texel_xrgb8888_rev,
 175    },
 176    {
 177       MESA_FORMAT_RGB888,
 178       fetch_texel_1d_f_rgb888,
 179       fetch_texel_2d_f_rgb888,
 180       fetch_texel_3d_f_rgb888,
 181       store_texel_rgb888
 182    },
 183    {
 184       MESA_FORMAT_BGR888,
 185       fetch_texel_1d_f_bgr888,
 186       fetch_texel_2d_f_bgr888,
 187       fetch_texel_3d_f_bgr888,
 188       store_texel_bgr888
 189    },
 190    {
 191       MESA_FORMAT_RGB565,
 192       fetch_texel_1d_f_rgb565,
 193       fetch_texel_2d_f_rgb565,
 194       fetch_texel_3d_f_rgb565,
 195       store_texel_rgb565
 196    },
 197    {
 198       MESA_FORMAT_RGB565_REV,
 199       fetch_texel_1d_f_rgb565_rev,
 200       fetch_texel_2d_f_rgb565_rev,
 201       fetch_texel_3d_f_rgb565_rev,
 202       store_texel_rgb565_rev
 203    },
 204    {
 205       MESA_FORMAT_ARGB4444,
 206       fetch_texel_1d_f_argb4444,
 207       fetch_texel_2d_f_argb4444,
 208       fetch_texel_3d_f_argb4444,
 209       store_texel_argb4444
 210    },
 211    {
 212       MESA_FORMAT_ARGB4444_REV,
 213       fetch_texel_1d_f_argb4444_rev,
 214       fetch_texel_2d_f_argb4444_rev,
 215       fetch_texel_3d_f_argb4444_rev,
 216       store_texel_argb4444_rev
 217    },
 218    {
 219       MESA_FORMAT_RGBA5551,
 220       fetch_texel_1d_f_rgba5551,
 221       fetch_texel_2d_f_rgba5551,
 222       fetch_texel_3d_f_rgba5551,
 223       store_texel_rgba5551
 224    },
 225    {
 226       MESA_FORMAT_ARGB1555,
 227       fetch_texel_1d_f_argb1555,
 228       fetch_texel_2d_f_argb1555,
 229       fetch_texel_3d_f_argb1555,
 230       store_texel_argb1555
 231    },
 232    {
 233       MESA_FORMAT_ARGB1555_REV,
 234       fetch_texel_1d_f_argb1555_rev,
 235       fetch_texel_2d_f_argb1555_rev,
 236       fetch_texel_3d_f_argb1555_rev,
 237       store_texel_argb1555_rev
 238    },
 239    {
 240       MESA_FORMAT_AL88,
 241       fetch_texel_1d_f_al88,
 242       fetch_texel_2d_f_al88,
 243       fetch_texel_3d_f_al88,
 244       store_texel_al88
 245    },
 246    {
 247       MESA_FORMAT_AL88_REV,
 248       fetch_texel_1d_f_al88_rev,
 249       fetch_texel_2d_f_al88_rev,
 250       fetch_texel_3d_f_al88_rev,
 251       store_texel_al88_rev
 252    },
 253    {
 254       MESA_FORMAT_AL1616,
 255       fetch_texel_1d_f_al1616,
 256       fetch_texel_2d_f_al1616,
 257       fetch_texel_3d_f_al1616,
 258       store_texel_al1616
 259    },
 260    {
 261       MESA_FORMAT_AL1616_REV,
 262       fetch_texel_1d_f_al1616_rev,
 263       fetch_texel_2d_f_al1616_rev,
 264       fetch_texel_3d_f_al1616_rev,
 265       store_texel_al1616_rev
 266    },
 267    {
 268       MESA_FORMAT_RGB332,
 269       fetch_texel_1d_f_rgb332,
 270       fetch_texel_2d_f_rgb332,
 271       fetch_texel_3d_f_rgb332,
 272       store_texel_rgb332
 273    },
 274    {
 275       MESA_FORMAT_A8,
 276       fetch_texel_1d_f_a8,
 277       fetch_texel_2d_f_a8,
 278       fetch_texel_3d_f_a8,
 279       store_texel_a8
 280    },
 281    {
 282       MESA_FORMAT_L8,
 283       fetch_texel_1d_f_l8,
 284       fetch_texel_2d_f_l8,
 285       fetch_texel_3d_f_l8,
 286       store_texel_l8
 287    },
 288    {
 289       MESA_FORMAT_I8,
 290       fetch_texel_1d_f_i8,
 291       fetch_texel_2d_f_i8,
 292       fetch_texel_3d_f_i8,
 293       store_texel_i8
 294    },
 295    {
 296       MESA_FORMAT_CI8,
 297       fetch_texel_1d_f_ci8,
 298       fetch_texel_2d_f_ci8,
 299       fetch_texel_3d_f_ci8,
 300       store_texel_ci8
 301    },
 302    {
 303       MESA_FORMAT_YCBCR,
 304       fetch_texel_1d_f_ycbcr,
 305       fetch_texel_2d_f_ycbcr,
 306       fetch_texel_3d_f_ycbcr,
 307       store_texel_ycbcr
 308    },
 309    {
 310       MESA_FORMAT_YCBCR_REV,
 311       fetch_texel_1d_f_ycbcr_rev,
 312       fetch_texel_2d_f_ycbcr_rev,
 313       fetch_texel_3d_f_ycbcr_rev,
 314       store_texel_ycbcr_rev
 315    },
 316    {
 317       MESA_FORMAT_Z24_S8,
 318       fetch_texel_1d_f_z24_s8,
 319       fetch_texel_2d_f_z24_s8,
 320       fetch_texel_3d_f_z24_s8,
 321       store_texel_z24_s8
 322    },
 323    {
 324       MESA_FORMAT_S8_Z24,
 325       fetch_texel_1d_f_s8_z24,
 326       fetch_texel_2d_f_s8_z24,
 327       fetch_texel_3d_f_s8_z24,
 328       store_texel_s8_z24
 329    },
 330    {
 331       MESA_FORMAT_Z16,
 332       fetch_texel_1d_f_z16,
 333       fetch_texel_2d_f_z16,
 334       fetch_texel_3d_f_z16,
 335       store_texel_z16
 336    },
 337    {
 338       MESA_FORMAT_X8_Z24,
 339       fetch_texel_1d_f_s8_z24,
 340       fetch_texel_2d_f_s8_z24,
 341       fetch_texel_3d_f_s8_z24,
 342       store_texel_s8_z24
 343    },
 344    {
 345       MESA_FORMAT_Z24_X8,
 346       fetch_texel_1d_f_z24_s8,
 347       fetch_texel_2d_f_z24_s8,
 348       fetch_texel_3d_f_z24_s8,
 349       store_texel_z24_s8
 350    },
 351    {
 352       MESA_FORMAT_Z32,
 353       fetch_texel_1d_f_z32,
 354       fetch_texel_2d_f_z32,
 355       fetch_texel_3d_f_z32,
 356       store_texel_z32
 357    },
 358    {
 359       MESA_FORMAT_S8,
 360       NULL,
 361       NULL,
 362       NULL,
 363       NULL
 364    },
 365    {
 366       MESA_FORMAT_SRGB8,
 367       fetch_texel_1d_srgb8,
 368       fetch_texel_2d_srgb8,
 369       fetch_texel_3d_srgb8,
 370       store_texel_srgb8
 371    },
 372    {
 373       MESA_FORMAT_SRGBA8,
 374       fetch_texel_1d_srgba8,
 375       fetch_texel_2d_srgba8,
 376       fetch_texel_3d_srgba8,
 377       store_texel_srgba8
 378    },
 379    {
 380       MESA_FORMAT_SARGB8,
 381       fetch_texel_1d_sargb8,
 382       fetch_texel_2d_sargb8,
 383       fetch_texel_3d_sargb8,
 384       store_texel_sargb8
 385    },
 386    {
 387       MESA_FORMAT_SL8,
 388       fetch_texel_1d_sl8,
 389       fetch_texel_2d_sl8,
 390       fetch_texel_3d_sl8,
 391       store_texel_sl8
 392    },
 393    {
 394       MESA_FORMAT_SLA8,
 395       fetch_texel_1d_sla8,
 396       fetch_texel_2d_sla8,
 397       fetch_texel_3d_sla8,
 398       store_texel_sla8
 399    },
 400    {
 401       MESA_FORMAT_SRGB_DXT1,
 402       NULL,
 403       _mesa_fetch_texel_2d_f_srgb_dxt1,
 404       NULL,
 405       NULL
 406    },
 407    {
 408       MESA_FORMAT_SRGBA_DXT1,
 409       NULL,
 410       _mesa_fetch_texel_2d_f_srgba_dxt1,
 411       NULL,
 412       NULL
 413    },
 414    {
 415       MESA_FORMAT_SRGBA_DXT3,
 416       NULL,
 417       _mesa_fetch_texel_2d_f_srgba_dxt3,
 418       NULL,
 419       NULL
 420    },
 421    {
 422       MESA_FORMAT_SRGBA_DXT5,
 423       NULL,
 424       _mesa_fetch_texel_2d_f_srgba_dxt5,
 425       NULL,
 426       NULL
 427    },
 428
 429    {
 430       MESA_FORMAT_RGB_FXT1,
 431       NULL,
 432       _mesa_fetch_texel_2d_f_rgb_fxt1,
 433       NULL,
 434       NULL
 435    },
 436    {
 437       MESA_FORMAT_RGBA_FXT1,
 438       NULL,
 439       _mesa_fetch_texel_2d_f_rgba_fxt1,
 440       NULL,
 441       NULL
 442    },
 443    {
 444       MESA_FORMAT_RGB_DXT1,
 445       NULL,
 446       _mesa_fetch_texel_2d_f_rgb_dxt1,
 447       NULL,
 448       NULL
 449    },
 450    {
 451       MESA_FORMAT_RGBA_DXT1,
 452       NULL,
 453       _mesa_fetch_texel_2d_f_rgba_dxt1,
 454       NULL,
 455       NULL
 456    },
 457    {
 458       MESA_FORMAT_RGBA_DXT3,
 459       NULL,
 460       _mesa_fetch_texel_2d_f_rgba_dxt3,
 461       NULL,
 462       NULL
 463    },
 464    {
 465       MESA_FORMAT_RGBA_DXT5,
 466       NULL,
 467       _mesa_fetch_texel_2d_f_rgba_dxt5,
 468       NULL,
 469       NULL
 470    },
 471    {
 472       MESA_FORMAT_RGBA_FLOAT32,
 473       fetch_texel_1d_f_rgba_f32,
 474       fetch_texel_2d_f_rgba_f32,
 475       fetch_texel_3d_f_rgba_f32,
 476       store_texel_rgba_f32
 477    },
 478    {
 479       MESA_FORMAT_RGBA_FLOAT16,
 480       fetch_texel_1d_f_rgba_f16,
 481       fetch_texel_2d_f_rgba_f16,
 482       fetch_texel_3d_f_rgba_f16,
 483       store_texel_rgba_f16
 484    },
 485    {
 486       MESA_FORMAT_RGB_FLOAT32,
 487       fetch_texel_1d_f_rgb_f32,
 488       fetch_texel_2d_f_rgb_f32,
 489       fetch_texel_3d_f_rgb_f32,
 490       store_texel_rgb_f32
 491    },
 492    {
 493       MESA_FORMAT_RGB_FLOAT16,
 494       fetch_texel_1d_f_rgb_f16,
 495       fetch_texel_2d_f_rgb_f16,
 496       fetch_texel_3d_f_rgb_f16,
 497       store_texel_rgb_f16
 498    },
 499    {
 500       MESA_FORMAT_ALPHA_FLOAT32,
 501       fetch_texel_1d_f_alpha_f32,
 502       fetch_texel_2d_f_alpha_f32,
 503       fetch_texel_3d_f_alpha_f32,
 504       store_texel_alpha_f32
 505    },
 506    {
 507       MESA_FORMAT_ALPHA_FLOAT16,
 508       fetch_texel_1d_f_alpha_f16,
 509       fetch_texel_2d_f_alpha_f16,
 510       fetch_texel_3d_f_alpha_f16,
 511       store_texel_alpha_f16
 512    },
 513    {
 514       MESA_FORMAT_LUMINANCE_FLOAT32,
 515       fetch_texel_1d_f_luminance_f32,
 516       fetch_texel_2d_f_luminance_f32,
 517       fetch_texel_3d_f_luminance_f32,
 518       store_texel_luminance_f32
 519    },
 520    {
 521       MESA_FORMAT_LUMINANCE_FLOAT16,
 522       fetch_texel_1d_f_luminance_f16,
 523       fetch_texel_2d_f_luminance_f16,
 524       fetch_texel_3d_f_luminance_f16,
 525       store_texel_luminance_f16
 526    },
 527    {
 528       MESA_FORMAT_LUMINANCE_ALPHA_FLOAT32,
 529       fetch_texel_1d_f_luminance_alpha_f32,
 530       fetch_texel_2d_f_luminance_alpha_f32,
 531       fetch_texel_3d_f_luminance_alpha_f32,
 532       store_texel_luminance_alpha_f32
 533    },
 534    {
 535       MESA_FORMAT_LUMINANCE_ALPHA_FLOAT16,
 536       fetch_texel_1d_f_luminance_alpha_f16,
 537       fetch_texel_2d_f_luminance_alpha_f16,
 538       fetch_texel_3d_f_luminance_alpha_f16,
 539       store_texel_luminance_alpha_f16
 540    },
 541    {
 542       MESA_FORMAT_INTENSITY_FLOAT32,
 543       fetch_texel_1d_f_intensity_f32,
 544       fetch_texel_2d_f_intensity_f32,
 545       fetch_texel_3d_f_intensity_f32,
 546       store_texel_intensity_f32
 547    },
 548    {
 549       MESA_FORMAT_INTENSITY_FLOAT16,
 550       fetch_texel_1d_f_intensity_f16,
 551       fetch_texel_2d_f_intensity_f16,
 552       fetch_texel_3d_f_intensity_f16,
 553       store_texel_intensity_f16
 554    },
 555    {
 556       MESA_FORMAT_DUDV8,
 557       fetch_texel_1d_dudv8,
 558       fetch_texel_2d_dudv8,
 559       fetch_texel_3d_dudv8,
 560       NULL
 561    },
 562    {
 563       MESA_FORMAT_SIGNED_RGBA8888,
 564       fetch_texel_1d_signed_rgba8888,
 565       fetch_texel_2d_signed_rgba8888,
 566       fetch_texel_3d_signed_rgba8888,
 567       store_texel_signed_rgba8888
 568    },
 569    {
 570       MESA_FORMAT_SIGNED_RGBA8888_REV,
 571       fetch_texel_1d_signed_rgba8888_rev,
 572       fetch_texel_2d_signed_rgba8888_rev,
 573       fetch_texel_3d_signed_rgba8888_rev,
 574       store_texel_signed_rgba8888_rev
 575    },
 576    {
 577       MESA_FORMAT_SIGNED_RGBA_16,
 578       NULL, /* XXX to do */
 579       NULL,
 580       NULL,
 581       NULL
 582    },
 583 };
 584
 585
 586 static FetchTexelFuncF
 587 _mesa_get_texel_fetch_func(gl_format format, GLuint dims)
 588 {
 589 #ifdef DEBUG
 590    /* check that the table entries are sorted by format name */
 591    gl_format fmt;
 592    for (fmt = 0; fmt < MESA_FORMAT_COUNT; fmt++) {
 593       assert(texfetch_funcs[fmt].Name == fmt);
 594    }
 595 #endif
 596
 597    assert(Elements(texfetch_funcs) == MESA_FORMAT_COUNT);
 598    assert(format < MESA_FORMAT_COUNT);
 599
 600    switch (dims) {
 601    case 1:
 602       return texfetch_funcs[format].Fetch1D;
 603    case 2:
 604       return texfetch_funcs[format].Fetch2D;
 605    case 3:
 606       return texfetch_funcs[format].Fetch3D;
 607    default:
 608       assert(0 && "bad dims in _mesa_get_texel_fetch_func");
 609       return NULL;
 610    }
 611 }
 612
 613
 614 StoreTexelFunc
 615 _mesa_get_texel_store_func(gl_format format)
 616 {
 617    assert(format < MESA_FORMAT_COUNT);
 618    return texfetch_funcs[format].StoreTexel;
 619 }
 620
 621
 622 /**
 623  * Adaptor for fetching a GLchan texel from a float-valued texture.
 624  */
 625 static void
 626 fetch_texel_float_to_chan(const struct gl_texture_image *texImage,
 627                           GLint i, GLint j, GLint k, GLchan *texelOut)
 628 {
 629    GLfloat temp[4];
 630    GLenum baseFormat = _mesa_get_format_base_format(texImage->TexFormat);
 631
 632    ASSERT(texImage->FetchTexelf);
 633    texImage->FetchTexelf(texImage, i, j, k, temp);
 634    if (baseFormat == GL_DEPTH_COMPONENT ||
 635        baseFormat == GL_DEPTH_STENCIL_EXT) {
 636       /* just one channel */
 637       UNCLAMPED_FLOAT_TO_CHAN(texelOut[0], temp[0]);
 638    }
 639    else {
 640       /* four channels */
 641       UNCLAMPED_FLOAT_TO_CHAN(texelOut[0], temp[0]);
 642       UNCLAMPED_FLOAT_TO_CHAN(texelOut[1], temp[1]);
 643       UNCLAMPED_FLOAT_TO_CHAN(texelOut[2], temp[2]);
 644       UNCLAMPED_FLOAT_TO_CHAN(texelOut[3], temp[3]);
 645    }
 646 }
 647
 648
 649 #if 0
 650 /**
 651  * Adaptor for fetching a float texel from a GLchan-valued texture.
 652  */
 653 static void
 654 fetch_texel_chan_to_float(const struct gl_texture_image *texImage,
 655                           GLint i, GLint j, GLint k, GLfloat *texelOut)
 656 {
 657    GLchan temp[4];
 658    GLenum baseFormat = _mesa_get_format_base_format(texImage->TexFormat);
 659
 660    ASSERT(texImage->FetchTexelc);
 661    texImage->FetchTexelc(texImage, i, j, k, temp);
 662    if (baseFormat == GL_DEPTH_COMPONENT ||
 663        baseFormat == GL_DEPTH_STENCIL_EXT) {
 664       /* just one channel */
 665       texelOut[0] = CHAN_TO_FLOAT(temp[0]);
 666    }
 667    else {
 668       /* four channels */
 669       texelOut[0] = CHAN_TO_FLOAT(temp[0]);
 670       texelOut[1] = CHAN_TO_FLOAT(temp[1]);
 671       texelOut[2] = CHAN_TO_FLOAT(temp[2]);
 672       texelOut[3] = CHAN_TO_FLOAT(temp[3]);
 673    }
 674 }
 675 #endif
 676
 677
 678 /**
 679  * Initialize the texture image's FetchTexelc and FetchTexelf methods.
 680  */
 681 void
 682 _mesa_set_fetch_functions(struct gl_texture_image *texImage, GLuint dims)
 683 {
 684    ASSERT(dims == 1 || dims == 2 || dims == 3);
 685    ASSERT(texImage->TexFormat);
 686
 687    if (!texImage->FetchTexelf) {
 688       texImage->FetchTexelf =
 689          _mesa_get_texel_fetch_func(texImage->TexFormat, dims);
 690    }
 691
 692    /* now check if we need to use a float/chan adaptor */
 693    if (!texImage->FetchTexelc) {
 694       texImage->FetchTexelc = fetch_texel_float_to_chan;
 695    }
 696
 697    ASSERT(texImage->FetchTexelc);
 698    ASSERT(texImage->FetchTexelf);
 699 }