src/gallium/auxiliary/util/u_format.h

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  27
  28
  29 #ifndef U_FORMAT_H
  30 #define U_FORMAT_H
  31
  32
  33 #include "pipe/p_format.h"
  34 #include "util/u_debug.h"
  35
  36 #ifdef __cplusplus
  37 extern "C" {
  38 #endif
  39
  40
  41 /**
  42  * Describe how to pack/unpack pixels into/from the prescribed format.
  43  *
  44  * XXX: This could be renamed to something like util_format_pack, or broke down
  45  * in flags inside util_format_block that said exactly what we want.
  46  */
  47 enum util_format_layout {
  48    /**
  49     * Formats with util_format_block::width == util_format_block::height == 1
  50     * that can be described as an ordinary data structure.
  51     */
  52    UTIL_FORMAT_LAYOUT_PLAIN = 0,
  53
  54    /**
  55     * Formats with sub-sampled channels.
  56     *
  57     * This is for formats like YV12 where there is less than one sample per
  58     * pixel.
  59     */
  60    UTIL_FORMAT_LAYOUT_SUBSAMPLED = 3,
  61
  62    /**
  63     * S3 Texture Compression formats.
  64     */
  65    UTIL_FORMAT_LAYOUT_S3TC = 4,
  66
  67    /**
  68     * Red-Green Texture Compression formats.
  69     */
  70    UTIL_FORMAT_LAYOUT_RGTC = 5,
  71
  72    /**
  73     * Everything else that doesn't fit in any of the above layouts.
  74     */
  75    UTIL_FORMAT_LAYOUT_OTHER = 6
  76 };
  77
  78
  79 struct util_format_block
  80 {
  81    /** Block width in pixels */
  82    unsigned width;
  83
  84    /** Block height in pixels */
  85    unsigned height;
  86
  87    /** Block size in bits */
  88    unsigned bits;
  89 };
  90
  91
  92 enum util_format_type {
  93    UTIL_FORMAT_TYPE_VOID = 0,
  94    UTIL_FORMAT_TYPE_UNSIGNED = 1,
  95    UTIL_FORMAT_TYPE_SIGNED = 2,
  96    UTIL_FORMAT_TYPE_FIXED = 3,
  97    UTIL_FORMAT_TYPE_FLOAT = 4
  98 };
  99
 100
 101 enum util_format_swizzle {
 102    UTIL_FORMAT_SWIZZLE_X = 0,
 103    UTIL_FORMAT_SWIZZLE_Y = 1,
 104    UTIL_FORMAT_SWIZZLE_Z = 2,
 105    UTIL_FORMAT_SWIZZLE_W = 3,
 106    UTIL_FORMAT_SWIZZLE_0 = 4,
 107    UTIL_FORMAT_SWIZZLE_1 = 5,
 108    UTIL_FORMAT_SWIZZLE_NONE = 6,
 109    UTIL_FORMAT_SWIZZLE_MAX = 7  /**< Number of enums counter (must be last) */
 110 };
 111
 112
 113 enum util_format_colorspace {
 114    UTIL_FORMAT_COLORSPACE_RGB = 0,
 115    UTIL_FORMAT_COLORSPACE_SRGB = 1,
 116    UTIL_FORMAT_COLORSPACE_YUV = 2,
 117    UTIL_FORMAT_COLORSPACE_ZS = 3
 118 };
 119
 120
 121 struct util_format_channel_description
 122 {
 123    unsigned type:6;        /**< UTIL_FORMAT_TYPE_x */
 124    unsigned normalized:1;
 125    unsigned size:9;        /**< bits per channel */
 126 };
 127
 128
 129 struct util_format_description
 130 {
 131    enum pipe_format format;
 132
 133    const char *name;
 134
 135    /**
 136     * Short name, striped of the prefix, lower case.
 137     */
 138    const char *short_name;
 139
 140    /**
 141     * Pixel block dimensions.
 142     */
 143    struct util_format_block block;
 144
 145    enum util_format_layout layout;
 146
 147    /**
 148     * The number of channels.
 149     */
 150    unsigned nr_channels:3;
 151
 152    /**
 153     * Whether all channels have the same number of (whole) bytes.
 154     */
 155    unsigned is_array:1;
 156
 157    /**
 158     * Whether the pixel format can be described as a bitfield structure.
 159     *
 160     * In particular:
 161     * - pixel depth must be 8, 16, or 32 bits;
 162     * - all channels must be unsigned, signed, or void
 163     */
 164    unsigned is_bitmask:1;
 165
 166    /**
 167     * Whether channels have mixed types (ignoring UTIL_FORMAT_TYPE_VOID).
 168     */
 169    unsigned is_mixed:1;
 170
 171    /**
 172     * Input channel description.
 173     *
 174     * Only valid for UTIL_FORMAT_LAYOUT_PLAIN formats.
 175     */
 176    struct util_format_channel_description channel[4];
 177
 178    /**
 179     * Output channel swizzle.
 180     *
 181     * The order is either:
 182     * - RGBA
 183     * - YUV(A)
 184     * - ZS
 185     * depending on the colorspace.
 186     */
 187    unsigned char swizzle[4];
 188
 189    /**
 190     * Colorspace transformation.
 191     */
 192    enum util_format_colorspace colorspace;
 193
 194    /**
 195     * Unpack pixel blocks to R8G8B8A8_UNORM.
 196     * Note: strides are in bytes.
 197     *
 198     * Only defined for non-depth-stencil formats.
 199     */
 200    void
 201    (*unpack_rgba_8unorm)(uint8_t *dst, unsigned dst_stride,
 202                          const uint8_t *src, unsigned src_stride,
 203                          unsigned width, unsigned height);
 204
 205    /**
 206     * Pack pixel blocks from R8G8B8A8_UNORM.
 207     * Note: strides are in bytes.
 208     *
 209     * Only defined for non-depth-stencil formats.
 210     */
 211    void
 212    (*pack_rgba_8unorm)(uint8_t *dst, unsigned dst_stride,
 213                        const uint8_t *src, unsigned src_stride,
 214                        unsigned width, unsigned height);
 215
 216    /**
 217     * Fetch a single pixel (i, j) from a block.
 218     *
 219     * XXX: Only defined for a very few select formats.
 220     */
 221    void
 222    (*fetch_rgba_8unorm)(uint8_t *dst,
 223                         const uint8_t *src,
 224                         unsigned i, unsigned j);
 225
 226    /**
 227     * Unpack pixel blocks to R32G32B32A32_FLOAT.
 228     * Note: strides are in bytes.
 229     *
 230     * Only defined for non-depth-stencil formats.
 231     */
 232    void
 233    (*unpack_rgba_float)(float *dst, unsigned dst_stride,
 234                         const uint8_t *src, unsigned src_stride,
 235                         unsigned width, unsigned height);
 236
 237    /**
 238     * Pack pixel blocks from R32G32B32A32_FLOAT.
 239     * Note: strides are in bytes.
 240     *
 241     * Only defined for non-depth-stencil formats.
 242     */
 243    void
 244    (*pack_rgba_float)(uint8_t *dst, unsigned dst_stride,
 245                       const float *src, unsigned src_stride,
 246                       unsigned width, unsigned height);
 247
 248    /**
 249     * Fetch a single pixel (i, j) from a block.
 250     *
 251     * Only defined for non-depth-stencil formats.
 252     */
 253    void
 254    (*fetch_rgba_float)(float *dst,
 255                        const uint8_t *src,
 256                        unsigned i, unsigned j);
 257
 258    /**
 259     * Unpack pixels to Z32_UNORM.
 260     * Note: strides are in bytes.
 261     *
 262     * Only defined for depth formats.
 263     */
 264    void
 265    (*unpack_z_32unorm)(uint32_t *dst, unsigned dst_stride,
 266                        const uint8_t *src, unsigned src_stride,
 267                        unsigned width, unsigned height);
 268
 269    /**
 270     * Pack pixels from Z32_FLOAT.
 271     * Note: strides are in bytes.
 272     *
 273     * Only defined for depth formats.
 274     */
 275    void
 276    (*pack_z_32unorm)(uint8_t *dst, unsigned dst_stride,
 277                      const uint32_t *src, unsigned src_stride,
 278                      unsigned width, unsigned height);
 279
 280    /**
 281     * Unpack pixels to Z32_FLOAT.
 282     * Note: strides are in bytes.
 283     *
 284     * Only defined for depth formats.
 285     */
 286    void
 287    (*unpack_z_float)(float *dst, unsigned dst_stride,
 288                      const uint8_t *src, unsigned src_stride,
 289                      unsigned width, unsigned height);
 290
 291    /**
 292     * Pack pixels from Z32_FLOAT.
 293     * Note: strides are in bytes.
 294     *
 295     * Only defined for depth formats.
 296     */
 297    void
 298    (*pack_z_float)(uint8_t *dst, unsigned dst_stride,
 299                    const float *src, unsigned src_stride,
 300                    unsigned width, unsigned height);
 301
 302    /**
 303     * Unpack pixels to S8_USCALED.
 304     * Note: strides are in bytes.
 305     *
 306     * Only defined for stencil formats.
 307     */
 308    void
 309    (*unpack_s_8uscaled)(uint8_t *dst, unsigned dst_stride,
 310                         const uint8_t *src, unsigned src_stride,
 311                         unsigned width, unsigned height);
 312
 313    /**
 314     * Pack pixels from S8_USCALED.
 315     * Note: strides are in bytes.
 316     *
 317     * Only defined for stencil formats.
 318     */
 319    void
 320    (*pack_s_8uscaled)(uint8_t *dst, unsigned dst_stride,
 321                       const uint8_t *src, unsigned src_stride,
 322                       unsigned width, unsigned height);
 323
 324 };
 325
 326
 327 extern const struct util_format_description
 328 util_format_description_table[];
 329
 330
 331 const struct util_format_description *
 332 util_format_description(enum pipe_format format);
 333
 334
 335 /*
 336  * Format query functions.
 337  */
 338
 339 static INLINE const char *
 340 util_format_name(enum pipe_format format)
 341 {
 342    const struct util_format_description *desc = util_format_description(format);
 343
 344    assert(desc);
 345    if (!desc) {
 346       return "PIPE_FORMAT_???";
 347    }
 348
 349    return desc->name;
 350 }
 351
 352 static INLINE const char *
 353 util_format_short_name(enum pipe_format format)
 354 {
 355    const struct util_format_description *desc = util_format_description(format);
 356
 357    assert(desc);
 358    if (!desc) {
 359       return "???";
 360    }
 361
 362    return desc->short_name;
 363 }
 364
 365 /**
 366  * Whether this format is plain, see UTIL_FORMAT_LAYOUT_PLAIN for more info.
 367  */
 368 static INLINE boolean
 369 util_format_is_plain(enum pipe_format format)
 370 {
 371    const struct util_format_description *desc = util_format_description(format);
 372
 373    if (!format) {
 374       return FALSE;
 375    }
 376
 377    return desc->layout == UTIL_FORMAT_LAYOUT_PLAIN ? TRUE : FALSE;
 378 }
 379
 380 static INLINE boolean
 381 util_format_is_compressed(enum pipe_format format)
 382 {
 383    const struct util_format_description *desc = util_format_description(format);
 384
 385    assert(desc);
 386    if (!desc) {
 387       return FALSE;
 388    }
 389
 390    switch (desc->layout) {
 391    case UTIL_FORMAT_LAYOUT_S3TC:
 392    case UTIL_FORMAT_LAYOUT_RGTC:
 393       /* XXX add other formats in the future */
 394       return TRUE;
 395    default:
 396       return FALSE;
 397    }
 398 }
 399
 400 static INLINE boolean
 401 util_format_is_s3tc(enum pipe_format format)
 402 {
 403    const struct util_format_description *desc = util_format_description(format);
 404
 405    assert(desc);
 406    if (!desc) {
 407       return FALSE;
 408    }
 409
 410    return desc->layout == UTIL_FORMAT_LAYOUT_S3TC ? TRUE : FALSE;
 411 }
 412
 413 static INLINE boolean
 414 util_format_is_srgb(enum pipe_format format)
 415 {
 416    const struct util_format_description *desc = util_format_description(format);
 417    return desc->colorspace == UTIL_FORMAT_COLORSPACE_SRGB;
 418 }
 419
 420 static INLINE boolean
 421 util_format_has_depth(const struct util_format_description *desc)
 422 {
 423    return desc->colorspace == UTIL_FORMAT_COLORSPACE_ZS &&
 424           desc->swizzle[0] != UTIL_FORMAT_SWIZZLE_NONE;
 425 }
 426
 427 static INLINE boolean
 428 util_format_has_stencil(const struct util_format_description *desc)
 429 {
 430    return desc->colorspace == UTIL_FORMAT_COLORSPACE_ZS &&
 431           desc->swizzle[1] != UTIL_FORMAT_SWIZZLE_NONE;
 432 }
 433
 434 static INLINE boolean
 435 util_format_is_depth_or_stencil(enum pipe_format format)
 436 {
 437    const struct util_format_description *desc = util_format_description(format);
 438
 439    assert(desc);
 440    if (!desc) {
 441       return FALSE;
 442    }
 443
 444    return util_format_has_depth(desc) ||
 445           util_format_has_stencil(desc);
 446 }
 447
 448 static INLINE boolean
 449 util_format_is_depth_and_stencil(enum pipe_format format)
 450 {
 451    const struct util_format_description *desc = util_format_description(format);
 452
 453    assert(desc);
 454    if (!desc) {
 455       return FALSE;
 456    }
 457
 458    return util_format_has_depth(desc) &&
 459           util_format_has_stencil(desc);
 460 }
 461
 462
 463 /**
 464  * Give the RGBA colormask of the channels that can be represented in this
 465  * format.
 466  *
 467  * That is, the channels whose values are preserved.
 468  */
 469 static INLINE unsigned
 470 util_format_colormask(const struct util_format_description *desc)
 471 {
 472    unsigned colormask;
 473    unsigned chan;
 474
 475    switch (desc->colorspace) {
 476    case UTIL_FORMAT_COLORSPACE_RGB:
 477    case UTIL_FORMAT_COLORSPACE_SRGB:
 478    case UTIL_FORMAT_COLORSPACE_YUV:
 479       colormask = 0;
 480       for (chan = 0; chan < 4; ++chan) {
 481          if (desc->swizzle[chan] < 4) {
 482             colormask |= (1 << chan);
 483          }
 484       }
 485       return colormask;
 486    case UTIL_FORMAT_COLORSPACE_ZS:
 487       return 0;
 488    default:
 489       assert(0);
 490       return 0;
 491    }
 492 }
 493
 494
 495 boolean
 496 util_format_is_float(enum pipe_format format);
 497
 498
 499 boolean
 500 util_format_is_rgb_no_alpha(enum pipe_format format);
 501
 502
 503 boolean
 504 util_format_is_luminance(enum pipe_format format);
 505
 506
 507 boolean
 508 util_format_is_luminance_alpha(enum pipe_format format);
 509
 510
 511 boolean
 512 util_format_is_intensity(enum pipe_format format);
 513
 514
 515 /**
 516  * Whether the src format can be blitted to destation format with a simple
 517  * memcpy.
 518  */
 519 boolean
 520 util_is_format_compatible(const struct util_format_description *src_desc,
 521                           const struct util_format_description *dst_desc);
 522
 523 /**
 524  * Whether the format is supported by Gallium for the given bindings.
 525  * This covers S3TC textures and floating-point render targets.
 526  */
 527 boolean
 528 util_format_is_supported(enum pipe_format format, unsigned bind);
 529
 530 /**
 531  * Whether this format is a rgab8 variant.
 532  *
 533  * That is, any format that matches the
 534  *
 535  *   PIPE_FORMAT_?8?8?8?8_UNORM
 536  */
 537 static INLINE boolean
 538 util_format_is_rgba8_variant(const struct util_format_description *desc)
 539 {
 540    unsigned chan;
 541
 542    if(desc->block.width != 1 ||
 543       desc->block.height != 1 ||
 544       desc->block.bits != 32)
 545       return FALSE;
 546
 547    for(chan = 0; chan < 4; ++chan) {
 548       if(desc->channel[chan].type != UTIL_FORMAT_TYPE_UNSIGNED &&
 549          desc->channel[chan].type != UTIL_FORMAT_TYPE_VOID)
 550          return FALSE;
 551       if(desc->channel[chan].size != 8)
 552          return FALSE;
 553    }
 554
 555    return TRUE;
 556 }
 557
 558
 559 /**
 560  * Return total bits needed for the pixel format per block.
 561  */
 562 static INLINE uint
 563 util_format_get_blocksizebits(enum pipe_format format)
 564 {
 565    const struct util_format_description *desc = util_format_description(format);
 566
 567    assert(desc);
 568    if (!desc) {
 569       return 0;
 570    }
 571
 572    return desc->block.bits;
 573 }
 574
 575 /**
 576  * Return bytes per block (not pixel) for the given format.
 577  */
 578 static INLINE uint
 579 util_format_get_blocksize(enum pipe_format format)
 580 {
 581    uint bits = util_format_get_blocksizebits(format);
 582
 583    assert(bits % 8 == 0);
 584
 585    return bits / 8;
 586 }
 587
 588 static INLINE uint
 589 util_format_get_blockwidth(enum pipe_format format)
 590 {
 591    const struct util_format_description *desc = util_format_description(format);
 592
 593    assert(desc);
 594    if (!desc) {
 595       return 1;
 596    }
 597
 598    return desc->block.width;
 599 }
 600
 601 static INLINE uint
 602 util_format_get_blockheight(enum pipe_format format)
 603 {
 604    const struct util_format_description *desc = util_format_description(format);
 605
 606    assert(desc);
 607    if (!desc) {
 608       return 1;
 609    }
 610
 611    return desc->block.height;
 612 }
 613
 614 static INLINE unsigned
 615 util_format_get_nblocksx(enum pipe_format format,
 616                          unsigned x)
 617 {
 618    unsigned blockwidth = util_format_get_blockwidth(format);
 619    return (x + blockwidth - 1) / blockwidth;
 620 }
 621
 622 static INLINE unsigned
 623 util_format_get_nblocksy(enum pipe_format format,
 624                          unsigned y)
 625 {
 626    unsigned blockheight = util_format_get_blockheight(format);
 627    return (y + blockheight - 1) / blockheight;
 628 }
 629
 630 static INLINE unsigned
 631 util_format_get_nblocks(enum pipe_format format,
 632                         unsigned width,
 633                         unsigned height)
 634 {
 635    return util_format_get_nblocksx(format, width) * util_format_get_nblocksy(format, height);
 636 }
 637
 638 static INLINE size_t
 639 util_format_get_stride(enum pipe_format format,
 640                        unsigned width)
 641 {
 642    return util_format_get_nblocksx(format, width) * util_format_get_blocksize(format);
 643 }
 644
 645 static INLINE size_t
 646 util_format_get_2d_size(enum pipe_format format,
 647                         size_t stride,
 648                         unsigned height)
 649 {
 650    return util_format_get_nblocksy(format, height) * stride;
 651 }
 652
 653 static INLINE uint
 654 util_format_get_component_bits(enum pipe_format format,
 655                                enum util_format_colorspace colorspace,
 656                                uint component)
 657 {
 658    const struct util_format_description *desc = util_format_description(format);
 659    enum util_format_colorspace desc_colorspace;
 660
 661    assert(format);
 662    if (!format) {
 663       return 0;
 664    }
 665
 666    assert(component < 4);
 667
 668    /* Treat RGB and SRGB as equivalent. */
 669    if (colorspace == UTIL_FORMAT_COLORSPACE_SRGB) {
 670       colorspace = UTIL_FORMAT_COLORSPACE_RGB;
 671    }
 672    if (desc->colorspace == UTIL_FORMAT_COLORSPACE_SRGB) {
 673       desc_colorspace = UTIL_FORMAT_COLORSPACE_RGB;
 674    } else {
 675       desc_colorspace = desc->colorspace;
 676    }
 677
 678    if (desc_colorspace != colorspace) {
 679       return 0;
 680    }
 681
 682    switch (desc->swizzle[component]) {
 683    case UTIL_FORMAT_SWIZZLE_X:
 684       return desc->channel[0].size;
 685    case UTIL_FORMAT_SWIZZLE_Y:
 686       return desc->channel[1].size;
 687    case UTIL_FORMAT_SWIZZLE_Z:
 688       return desc->channel[2].size;
 689    case UTIL_FORMAT_SWIZZLE_W:
 690       return desc->channel[3].size;
 691    default:
 692       return 0;
 693    }
 694 }
 695
 696 static INLINE boolean
 697 util_format_has_alpha(enum pipe_format format)
 698 {
 699    const struct util_format_description *desc = util_format_description(format);
 700
 701    assert(format);
 702    if (!format) {
 703       return FALSE;
 704    }
 705
 706    switch (desc->colorspace) {
 707    case UTIL_FORMAT_COLORSPACE_RGB:
 708    case UTIL_FORMAT_COLORSPACE_SRGB:
 709       return desc->swizzle[3] != UTIL_FORMAT_SWIZZLE_1;
 710    case UTIL_FORMAT_COLORSPACE_YUV:
 711       return FALSE;
 712    case UTIL_FORMAT_COLORSPACE_ZS:
 713       return FALSE;
 714    default:
 715       assert(0);
 716       return FALSE;
 717    }
 718 }
 719
 720 /**
 721  * Given a linear RGB colorspace format, return the corresponding SRGB
 722  * format, or PIPE_FORMAT_NONE if none.
 723  */
 724 static INLINE enum pipe_format
 725 util_format_srgb(enum pipe_format format)
 726 {
 727    switch (format) {
 728    case PIPE_FORMAT_L8_UNORM:
 729       return PIPE_FORMAT_L8_SRGB;
 730    case PIPE_FORMAT_L8A8_UNORM:
 731       return PIPE_FORMAT_L8A8_SRGB;
 732    case PIPE_FORMAT_R8G8B8_UNORM:
 733       return PIPE_FORMAT_R8G8B8_SRGB;
 734    case PIPE_FORMAT_A8B8G8R8_UNORM:
 735       return PIPE_FORMAT_A8B8G8R8_SRGB;
 736    case PIPE_FORMAT_X8B8G8R8_UNORM:
 737       return PIPE_FORMAT_X8B8G8R8_SRGB;
 738    case PIPE_FORMAT_B8G8R8A8_UNORM:
 739       return PIPE_FORMAT_B8G8R8A8_SRGB;
 740    case PIPE_FORMAT_B8G8R8X8_UNORM:
 741       return PIPE_FORMAT_B8G8R8X8_SRGB;
 742    case PIPE_FORMAT_A8R8G8B8_UNORM:
 743       return PIPE_FORMAT_A8R8G8B8_SRGB;
 744    case PIPE_FORMAT_X8R8G8B8_UNORM:
 745       return PIPE_FORMAT_X8R8G8B8_SRGB;
 746    case PIPE_FORMAT_DXT1_RGB:
 747       return PIPE_FORMAT_DXT1_SRGB;
 748    case PIPE_FORMAT_DXT1_RGBA:
 749       return PIPE_FORMAT_DXT1_SRGBA;
 750    case PIPE_FORMAT_DXT3_RGBA:
 751       return PIPE_FORMAT_DXT3_SRGBA;
 752    case PIPE_FORMAT_DXT5_RGBA:
 753       return PIPE_FORMAT_DXT5_SRGBA;
 754    default:
 755       return PIPE_FORMAT_NONE;
 756    }
 757 }
 758
 759 /**
 760  * Given an sRGB format, return the corresponding linear colorspace format.
 761  * For non sRGB formats, return the format unchanged.
 762  */
 763 static INLINE enum pipe_format
 764 util_format_linear(enum pipe_format format)
 765 {
 766    switch (format) {
 767    case PIPE_FORMAT_L8_SRGB:
 768       return PIPE_FORMAT_L8_UNORM;
 769    case PIPE_FORMAT_L8A8_SRGB:
 770       return PIPE_FORMAT_L8A8_UNORM;
 771    case PIPE_FORMAT_R8G8B8_SRGB:
 772       return PIPE_FORMAT_R8G8B8_UNORM;
 773    case PIPE_FORMAT_A8B8G8R8_SRGB:
 774       return PIPE_FORMAT_A8B8G8R8_UNORM;
 775    case PIPE_FORMAT_X8B8G8R8_SRGB:
 776       return PIPE_FORMAT_X8B8G8R8_UNORM;
 777    case PIPE_FORMAT_B8G8R8A8_SRGB:
 778       return PIPE_FORMAT_B8G8R8A8_UNORM;
 779    case PIPE_FORMAT_B8G8R8X8_SRGB:
 780       return PIPE_FORMAT_B8G8R8X8_UNORM;
 781    case PIPE_FORMAT_A8R8G8B8_SRGB:
 782       return PIPE_FORMAT_A8R8G8B8_UNORM;
 783    case PIPE_FORMAT_X8R8G8B8_SRGB:
 784       return PIPE_FORMAT_X8R8G8B8_UNORM;
 785    case PIPE_FORMAT_DXT1_SRGB:
 786       return PIPE_FORMAT_DXT1_RGB;
 787    case PIPE_FORMAT_DXT1_SRGBA:
 788       return PIPE_FORMAT_DXT1_RGBA;
 789    case PIPE_FORMAT_DXT3_SRGBA:
 790       return PIPE_FORMAT_DXT3_RGBA;
 791    case PIPE_FORMAT_DXT5_SRGBA:
 792       return PIPE_FORMAT_DXT5_RGBA;
 793    default:
 794       return format;
 795    }
 796 }
 797
 798 /**
 799  * Return the number of components stored.
 800  * Formats with block size != 1x1 will always have 1 component (the block).
 801  */
 802 static INLINE unsigned
 803 util_format_get_nr_components(enum pipe_format format)
 804 {
 805    const struct util_format_description *desc = util_format_description(format);
 806    return desc->nr_channels;
 807 }
 808
 809 /**
 810  * Return the index of the first non-void channel
 811  * -1 if no non-void channels
 812  */
 813 static INLINE int
 814 util_format_get_first_non_void_channel(enum pipe_format format)
 815 {
 816    const struct util_format_description *desc = util_format_description(format);
 817    int i;
 818
 819    for (i = 0; i < 4; i++)
 820       if (desc->channel[i].type != UTIL_FORMAT_TYPE_VOID)
 821          break;
 822
 823    if (i == 4)
 824        return -1;
 825
 826    return i;
 827 }
 828
 829 /*
 830  * Format access functions.
 831  */
 832
 833 void
 834 util_format_read_4f(enum pipe_format format,
 835                     float *dst, unsigned dst_stride,
 836                     const void *src, unsigned src_stride,
 837                     unsigned x, unsigned y, unsigned w, unsigned h);
 838
 839 void
 840 util_format_write_4f(enum pipe_format format,
 841                      const float *src, unsigned src_stride,
 842                      void *dst, unsigned dst_stride,
 843                      unsigned x, unsigned y, unsigned w, unsigned h);
 844
 845 void
 846 util_format_read_4ub(enum pipe_format format,
 847                      uint8_t *dst, unsigned dst_stride,
 848                      const void *src, unsigned src_stride,
 849                      unsigned x, unsigned y, unsigned w, unsigned h);
 850
 851 void
 852 util_format_write_4ub(enum pipe_format format,
 853                       const uint8_t *src, unsigned src_stride,
 854                       void *dst, unsigned dst_stride,
 855                       unsigned x, unsigned y, unsigned w, unsigned h);
 856
 857 /*
 858  * Generic format conversion;
 859  */
 860
 861 boolean
 862 util_format_fits_8unorm(const struct util_format_description *format_desc);
 863
 864 void
 865 util_format_translate(enum pipe_format dst_format,
 866                       void *dst, unsigned dst_stride,
 867                       unsigned dst_x, unsigned dst_y,
 868                       enum pipe_format src_format,
 869                       const void *src, unsigned src_stride,
 870                       unsigned src_x, unsigned src_y,
 871                       unsigned width, unsigned height);
 872
 873 /*
 874  * Swizzle operations.
 875  */
 876
 877 /* Compose two sets of swizzles.
 878  * If V is a 4D vector and the function parameters represent functions that
 879  * swizzle vector components, this holds:
 880  *     swz2(swz1(V)) = dst(V)
 881  */
 882 void util_format_compose_swizzles(const unsigned char swz1[4],
 883                                   const unsigned char swz2[4],
 884                                   unsigned char dst[4]);
 885
 886 void util_format_swizzle_4f(float *dst, const float *src,
 887                             const unsigned char swz[4]);
 888
 889 void util_format_unswizzle_4f(float *dst, const float *src,
 890                               const unsigned char swz[4]);
 891
 892 #ifdef __cplusplus
 893 } // extern "C" {
 894 #endif
 895
 896 #endif /* ! U_FORMAT_H */