src/mesa/main/readpix.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2008  Brian Paul   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 "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  22  * OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25 #include "glheader.h"
  26 #include "imports.h"
  27 #include "blend.h"
  28 #include "bufferobj.h"
  29 #include "context.h"
  30 #include "enums.h"
  31 #include "readpix.h"
  32 #include "framebuffer.h"
  33 #include "formats.h"
  34 #include "format_unpack.h"
  35 #include "image.h"
  36 #include "mtypes.h"
  37 #include "pack.h"
  38 #include "pbo.h"
  39 #include "state.h"
  40 #include "glformats.h"
  41 #include "fbobject.h"
  42 #include "format_utils.h"
  43 #include "pixeltransfer.h"
  44
  45
  46 /**
  47  * Return true if the conversion L=R+G+B is needed.
  48  */
  49 GLboolean
  50 _mesa_need_rgb_to_luminance_conversion(GLenum srcBaseFormat,
  51                                        GLenum dstBaseFormat)
  52 {
  53    return (srcBaseFormat == GL_RG ||
  54            srcBaseFormat == GL_RGB ||
  55            srcBaseFormat == GL_RGBA) &&
  56           (dstBaseFormat == GL_LUMINANCE ||
  57            dstBaseFormat == GL_LUMINANCE_ALPHA);
  58 }
  59
  60 /**
  61  * Return true if the conversion L,I to RGB conversion is needed.
  62  */
  63 GLboolean
  64 _mesa_need_luminance_to_rgb_conversion(GLenum srcBaseFormat,
  65                                        GLenum dstBaseFormat)
  66 {
  67    return (srcBaseFormat == GL_LUMINANCE ||
  68            srcBaseFormat == GL_LUMINANCE_ALPHA ||
  69            srcBaseFormat == GL_INTENSITY) &&
  70           (dstBaseFormat == GL_GREEN ||
  71            dstBaseFormat == GL_BLUE ||
  72            dstBaseFormat == GL_RG ||
  73            dstBaseFormat == GL_RGB ||
  74            dstBaseFormat == GL_BGR ||
  75            dstBaseFormat == GL_RGBA ||
  76            dstBaseFormat == GL_BGRA);
  77 }
  78
  79 /**
  80  * Return transfer op flags for this ReadPixels operation.
  81  */
  82 GLbitfield
  83 _mesa_get_readpixels_transfer_ops(const struct gl_context *ctx,
  84                                   mesa_format texFormat,
  85                                   GLenum format, GLenum type,
  86                                   GLboolean uses_blit)
  87 {
  88    GLbitfield transferOps = ctx->_ImageTransferState;
  89    GLenum srcBaseFormat = _mesa_get_format_base_format(texFormat);
  90    GLenum dstBaseFormat = _mesa_unpack_format_to_base_format(format);
  91
  92    if (format == GL_DEPTH_COMPONENT ||
  93        format == GL_DEPTH_STENCIL ||
  94        format == GL_STENCIL_INDEX) {
  95       return 0;
  96    }
  97
  98    /* Pixel transfer ops (scale, bias, table lookup) do not apply
  99     * to integer formats.
 100     */
 101    if (_mesa_is_enum_format_integer(format)) {
 102       return 0;
 103    }
 104
 105    if (uses_blit) {
 106       /* For blit-based ReadPixels packing, the clamping is done automatically
 107        * unless the type is float. */
 108       if (_mesa_get_clamp_read_color(ctx, ctx->ReadBuffer) &&
 109           (type == GL_FLOAT || type == GL_HALF_FLOAT)) {
 110          transferOps |= IMAGE_CLAMP_BIT;
 111       }
 112    }
 113    else {
 114       /* For CPU-based ReadPixels packing, the clamping must always be done
 115        * for non-float types, */
 116       if (_mesa_get_clamp_read_color(ctx, ctx->ReadBuffer) ||
 117           (type != GL_FLOAT && type != GL_HALF_FLOAT)) {
 118          transferOps |= IMAGE_CLAMP_BIT;
 119       }
 120    }
 121
 122    /* If the format is unsigned normalized, we can ignore clamping
 123     * because the values are already in the range [0,1] so it won't
 124     * have any effect anyway.
 125     */
 126    if (_mesa_get_format_datatype(texFormat) == GL_UNSIGNED_NORMALIZED &&
 127        !_mesa_need_rgb_to_luminance_conversion(srcBaseFormat, dstBaseFormat)) {
 128       transferOps &= ~IMAGE_CLAMP_BIT;
 129    }
 130
 131    return transferOps;
 132 }
 133
 134
 135 /**
 136  * Return true if memcpy cannot be used for ReadPixels.
 137  *
 138  * If uses_blit is true, the function returns true if a simple 3D engine blit
 139  * cannot be used for ReadPixels packing.
 140  *
 141  * NOTE: This doesn't take swizzling and format conversions between
 142  *       the readbuffer and the pixel pack buffer into account.
 143  */
 144 GLboolean
 145 _mesa_readpixels_needs_slow_path(const struct gl_context *ctx, GLenum format,
 146                                  GLenum type, GLboolean uses_blit)
 147 {
 148    struct gl_renderbuffer *rb =
 149          _mesa_get_read_renderbuffer_for_format(ctx, format);
 150    GLenum dstBaseFormat = _mesa_unpack_format_to_base_format(format);
 151
 152    assert(rb);
 153
 154    /* There are different rules depending on the base format. */
 155    switch (format) {
 156    case GL_DEPTH_STENCIL:
 157       return !_mesa_has_depthstencil_combined(ctx->ReadBuffer) ||
 158              ctx->Pixel.DepthScale != 1.0f || ctx->Pixel.DepthBias != 0.0f ||
 159              ctx->Pixel.IndexShift || ctx->Pixel.IndexOffset ||
 160              ctx->Pixel.MapStencilFlag;
 161
 162    case GL_DEPTH_COMPONENT:
 163       return ctx->Pixel.DepthScale != 1.0f || ctx->Pixel.DepthBias != 0.0f;
 164
 165    case GL_STENCIL_INDEX:
 166       return ctx->Pixel.IndexShift || ctx->Pixel.IndexOffset ||
 167              ctx->Pixel.MapStencilFlag;
 168
 169    default:
 170       /* Color formats. */
 171       if (_mesa_need_rgb_to_luminance_conversion(rb->_BaseFormat,
 172                                                  dstBaseFormat)) {
 173          return GL_TRUE;
 174       }
 175
 176       /* And finally, see if there are any transfer ops. */
 177       return _mesa_get_readpixels_transfer_ops(ctx, rb->Format, format, type,
 178                                                uses_blit) != 0;
 179    }
 180    return GL_FALSE;
 181 }
 182
 183
 184 static GLboolean
 185 readpixels_can_use_memcpy(const struct gl_context *ctx, GLenum format, GLenum type,
 186                           const struct gl_pixelstore_attrib *packing)
 187 {
 188    struct gl_renderbuffer *rb =
 189          _mesa_get_read_renderbuffer_for_format(ctx, format);
 190
 191    assert(rb);
 192
 193    if (_mesa_readpixels_needs_slow_path(ctx, format, type, GL_FALSE)) {
 194       return GL_FALSE;
 195    }
 196
 197    /* The base internal format and the base Mesa format must match. */
 198    if (rb->_BaseFormat != _mesa_get_format_base_format(rb->Format)) {
 199       return GL_FALSE;
 200    }
 201
 202    /* The Mesa format must match the input format and type. */
 203    if (!_mesa_format_matches_format_and_type(rb->Format, format, type,
 204                                              packing->SwapBytes, NULL)) {
 205       return GL_FALSE;
 206    }
 207
 208    return GL_TRUE;
 209 }
 210
 211
 212 static GLboolean
 213 readpixels_memcpy(struct gl_context *ctx,
 214                   GLint x, GLint y,
 215                   GLsizei width, GLsizei height,
 216                   GLenum format, GLenum type,
 217                   GLvoid *pixels,
 218                   const struct gl_pixelstore_attrib *packing)
 219 {
 220    struct gl_renderbuffer *rb =
 221          _mesa_get_read_renderbuffer_for_format(ctx, format);
 222    GLubyte *dst, *map;
 223    int dstStride, stride, j, texelBytes;
 224
 225    /* Fail if memcpy cannot be used. */
 226    if (!readpixels_can_use_memcpy(ctx, format, type, packing)) {
 227       return GL_FALSE;
 228    }
 229
 230    dstStride = _mesa_image_row_stride(packing, width, format, type);
 231    dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 232                                            format, type, 0, 0);
 233
 234    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 235                                &map, &stride);
 236    if (!map) {
 237       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 238       return GL_TRUE;  /* don't bother trying the slow path */
 239    }
 240
 241    texelBytes = _mesa_get_format_bytes(rb->Format);
 242
 243    /* memcpy*/
 244    for (j = 0; j < height; j++) {
 245       memcpy(dst, map, width * texelBytes);
 246       dst += dstStride;
 247       map += stride;
 248    }
 249
 250    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 251    return GL_TRUE;
 252 }
 253
 254
 255 /**
 256  * Optimized path for conversion of depth values to GL_DEPTH_COMPONENT,
 257  * GL_UNSIGNED_INT.
 258  */
 259 static GLboolean
 260 read_uint_depth_pixels( struct gl_context *ctx,
 261                         GLint x, GLint y,
 262                         GLsizei width, GLsizei height,
 263                         GLenum type, GLvoid *pixels,
 264                         const struct gl_pixelstore_attrib *packing )
 265 {
 266    struct gl_framebuffer *fb = ctx->ReadBuffer;
 267    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 268    GLubyte *map, *dst;
 269    int stride, dstStride, j;
 270
 271    if (ctx->Pixel.DepthScale != 1.0F || ctx->Pixel.DepthBias != 0.0F)
 272       return GL_FALSE;
 273
 274    if (packing->SwapBytes)
 275       return GL_FALSE;
 276
 277    if (_mesa_get_format_datatype(rb->Format) != GL_UNSIGNED_NORMALIZED)
 278       return GL_FALSE;
 279
 280    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 281                                &map, &stride);
 282
 283    if (!map) {
 284       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 285       return GL_TRUE;  /* don't bother trying the slow path */
 286    }
 287
 288    dstStride = _mesa_image_row_stride(packing, width, GL_DEPTH_COMPONENT, type);
 289    dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 290                                            GL_DEPTH_COMPONENT, type, 0, 0);
 291
 292    for (j = 0; j < height; j++) {
 293       _mesa_unpack_uint_z_row(rb->Format, width, map, (GLuint *)dst);
 294
 295       map += stride;
 296       dst += dstStride;
 297    }
 298    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 299
 300    return GL_TRUE;
 301 }
 302
 303 /**
 304  * Read pixels for format=GL_DEPTH_COMPONENT.
 305  */
 306 static void
 307 read_depth_pixels( struct gl_context *ctx,
 308                    GLint x, GLint y,
 309                    GLsizei width, GLsizei height,
 310                    GLenum type, GLvoid *pixels,
 311                    const struct gl_pixelstore_attrib *packing )
 312 {
 313    struct gl_framebuffer *fb = ctx->ReadBuffer;
 314    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 315    GLint j;
 316    GLubyte *dst, *map;
 317    int dstStride, stride;
 318    GLfloat *depthValues;
 319
 320    if (!rb)
 321       return;
 322
 323    /* clipping should have been done already */
 324    assert(x >= 0);
 325    assert(y >= 0);
 326    assert(x + width <= (GLint) rb->Width);
 327    assert(y + height <= (GLint) rb->Height);
 328
 329    if (type == GL_UNSIGNED_INT &&
 330        read_uint_depth_pixels(ctx, x, y, width, height, type, pixels, packing)) {
 331       return;
 332    }
 333
 334    dstStride = _mesa_image_row_stride(packing, width, GL_DEPTH_COMPONENT, type);
 335    dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 336                                            GL_DEPTH_COMPONENT, type, 0, 0);
 337
 338    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 339                                &map, &stride);
 340    if (!map) {
 341       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 342       return;
 343    }
 344
 345    depthValues = malloc(width * sizeof(GLfloat));
 346
 347    if (depthValues) {
 348       /* General case (slower) */
 349       for (j = 0; j < height; j++, y++) {
 350          _mesa_unpack_float_z_row(rb->Format, width, map, depthValues);
 351          _mesa_pack_depth_span(ctx, width, dst, type, depthValues, packing);
 352
 353          dst += dstStride;
 354          map += stride;
 355       }
 356    }
 357    else {
 358       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 359    }
 360
 361    free(depthValues);
 362
 363    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 364 }
 365
 366
 367 /**
 368  * Read pixels for format=GL_STENCIL_INDEX.
 369  */
 370 static void
 371 read_stencil_pixels( struct gl_context *ctx,
 372                      GLint x, GLint y,
 373                      GLsizei width, GLsizei height,
 374                      GLenum type, GLvoid *pixels,
 375                      const struct gl_pixelstore_attrib *packing )
 376 {
 377    struct gl_framebuffer *fb = ctx->ReadBuffer;
 378    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 379    GLint j;
 380    GLubyte *map, *stencil;
 381    GLint stride;
 382
 383    if (!rb)
 384       return;
 385
 386    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 387                                &map, &stride);
 388    if (!map) {
 389       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 390       return;
 391    }
 392
 393    stencil = malloc(width * sizeof(GLubyte));
 394
 395    if (stencil) {
 396       /* process image row by row */
 397       for (j = 0; j < height; j++) {
 398          GLvoid *dest;
 399
 400          _mesa_unpack_ubyte_stencil_row(rb->Format, width, map, stencil);
 401          dest = _mesa_image_address2d(packing, pixels, width, height,
 402                                       GL_STENCIL_INDEX, type, j, 0);
 403
 404          _mesa_pack_stencil_span(ctx, width, type, dest, stencil, packing);
 405
 406          map += stride;
 407       }
 408    }
 409    else {
 410       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 411    }
 412
 413    free(stencil);
 414
 415    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 416 }
 417
 418 /*
 419  * Read R, G, B, A, RGB, L, or LA pixels.
 420  */
 421 static void
 422 read_rgba_pixels( struct gl_context *ctx,
 423                   GLint x, GLint y,
 424                   GLsizei width, GLsizei height,
 425                   GLenum format, GLenum type, GLvoid *pixels,
 426                   const struct gl_pixelstore_attrib *packing )
 427 {
 428    GLbitfield transferOps;
 429    bool dst_is_integer, convert_rgb_to_lum, needs_rebase;
 430    int dst_stride, src_stride, rb_stride;
 431    uint32_t dst_format, src_format;
 432    GLubyte *dst, *map;
 433    mesa_format rb_format;
 434    bool needs_rgba;
 435    void *rgba, *src;
 436    bool src_is_uint = false;
 437    uint8_t rebase_swizzle[4];
 438    struct gl_framebuffer *fb = ctx->ReadBuffer;
 439    struct gl_renderbuffer *rb = fb->_ColorReadBuffer;
 440    GLenum dstBaseFormat = _mesa_unpack_format_to_base_format(format);
 441
 442    if (!rb)
 443       return;
 444
 445    transferOps = _mesa_get_readpixels_transfer_ops(ctx, rb->Format, format,
 446                                                    type, GL_FALSE);
 447    /* Describe the dst format */
 448    dst_is_integer = _mesa_is_enum_format_integer(format);
 449    dst_stride = _mesa_image_row_stride(packing, width, format, type);
 450    dst_format = _mesa_format_from_format_and_type(format, type);
 451    convert_rgb_to_lum =
 452       _mesa_need_rgb_to_luminance_conversion(rb->_BaseFormat, dstBaseFormat);
 453    dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 454                                            format, type, 0, 0);
 455
 456    /* Map the source render buffer */
 457    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 458                                &map, &rb_stride);
 459    if (!map) {
 460       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 461       return;
 462    }
 463    rb_format = _mesa_get_srgb_format_linear(rb->Format);
 464
 465    /*
 466     * Depending on the base formats involved in the conversion we might need to
 467     * rebase some values, so for these formats we compute a rebase swizzle.
 468     */
 469    if (rb->_BaseFormat == GL_LUMINANCE || rb->_BaseFormat == GL_INTENSITY) {
 470       needs_rebase = true;
 471       rebase_swizzle[0] = MESA_FORMAT_SWIZZLE_X;
 472       rebase_swizzle[1] = MESA_FORMAT_SWIZZLE_ZERO;
 473       rebase_swizzle[2] = MESA_FORMAT_SWIZZLE_ZERO;
 474       rebase_swizzle[3] = MESA_FORMAT_SWIZZLE_ONE;
 475    } else if (rb->_BaseFormat == GL_LUMINANCE_ALPHA) {
 476       needs_rebase = true;
 477       rebase_swizzle[0] = MESA_FORMAT_SWIZZLE_X;
 478       rebase_swizzle[1] = MESA_FORMAT_SWIZZLE_ZERO;
 479       rebase_swizzle[2] = MESA_FORMAT_SWIZZLE_ZERO;
 480       rebase_swizzle[3] = MESA_FORMAT_SWIZZLE_W;
 481    } else if (_mesa_get_format_base_format(rb_format) != rb->_BaseFormat) {
 482       needs_rebase =
 483          _mesa_compute_rgba2base2rgba_component_mapping(rb->_BaseFormat,
 484                                                         rebase_swizzle);
 485    } else {
 486       needs_rebase = false;
 487    }
 488
 489    /* Since _mesa_format_convert does not handle transferOps we need to handle
 490     * them before we call the function. This requires to convert to RGBA float
 491     * first so we can call _mesa_apply_rgba_transfer_ops. If the dst format is
 492     * integer transferOps do not apply.
 493     *
 494     * Converting to luminance also requires converting to RGBA first, so we can
 495     * then compute luminance values as L=R+G+B. Notice that this is different
 496     * from GetTexImage, where we compute L=R.
 497     */
 498    assert(!transferOps || (transferOps && !dst_is_integer));
 499
 500    needs_rgba = transferOps || convert_rgb_to_lum;
 501    rgba = NULL;
 502    if (needs_rgba) {
 503       uint32_t rgba_format;
 504       int rgba_stride;
 505       bool need_convert;
 506
 507       /* Convert to RGBA float or int/uint depending on the type of the src */
 508       if (dst_is_integer) {
 509          src_is_uint = _mesa_is_format_unsigned(rb_format);
 510          if (src_is_uint) {
 511             rgba_format = RGBA32_UINT;
 512             rgba_stride = width * 4 * sizeof(GLuint);
 513          } else {
 514             rgba_format = RGBA32_INT;
 515             rgba_stride = width * 4 * sizeof(GLint);
 516          }
 517       } else {
 518          rgba_format = RGBA32_FLOAT;
 519          rgba_stride = width * 4 * sizeof(GLfloat);
 520       }
 521
 522       /* If we are lucky and the dst format matches the RGBA format we need to
 523        * convert to, then we can convert directly into the dst buffer and avoid
 524        * the final conversion/copy from the rgba buffer to the dst buffer.
 525        */
 526       if (dst_format == rgba_format &&
 527           dst_stride == rgba_stride) {
 528          need_convert = false;
 529          rgba = dst;
 530       } else {
 531          need_convert = true;
 532          rgba = malloc(height * rgba_stride);
 533          if (!rgba) {
 534             _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 535             goto done_unmap;
 536          }
 537       }
 538
 539       /* Convert to RGBA now */
 540       _mesa_format_convert(rgba, rgba_format, rgba_stride,
 541                            map, rb_format, rb_stride,
 542                            width, height,
 543                            needs_rebase ? rebase_swizzle : NULL);
 544
 545       /* Handle transfer ops if necessary */
 546       if (transferOps)
 547          _mesa_apply_rgba_transfer_ops(ctx, transferOps, width * height, rgba);
 548
 549       /* If we had to rebase, we have already taken care of that */
 550       needs_rebase = false;
 551
 552       /* If we were lucky and our RGBA conversion matches the dst format, then
 553        * we are done.
 554        */
 555       if (!need_convert)
 556          goto done_swap;
 557
 558       /* Otherwise, we need to convert from RGBA to dst next */
 559       src = rgba;
 560       src_format = rgba_format;
 561       src_stride = rgba_stride;
 562    } else {
 563       /* No RGBA conversion needed, convert directly to dst */
 564       src = map;
 565       src_format = rb_format;
 566       src_stride = rb_stride;
 567    }
 568
 569    /* Do the conversion.
 570     *
 571     * If the dst format is Luminance, we need to do the conversion by computing
 572     * L=R+G+B values.
 573     */
 574    if (!convert_rgb_to_lum) {
 575       _mesa_format_convert(dst, dst_format, dst_stride,
 576                            src, src_format, src_stride,
 577                            width, height,
 578                            needs_rebase ? rebase_swizzle : NULL);
 579    } else if (!dst_is_integer) {
 580       /* Compute float Luminance values from RGBA float */
 581       int luminance_stride, luminance_bytes;
 582       void *luminance;
 583       uint32_t luminance_format;
 584
 585       luminance_stride = width * sizeof(GLfloat);
 586       if (format == GL_LUMINANCE_ALPHA)
 587          luminance_stride *= 2;
 588       luminance_bytes = height * luminance_stride;
 589       luminance = malloc(luminance_bytes);
 590       if (!luminance) {
 591          _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 592          free(rgba);
 593          goto done_unmap;
 594       }
 595       _mesa_pack_luminance_from_rgba_float(width * height, src,
 596                                            luminance, format, transferOps);
 597
 598       /* Convert from Luminance float to dst (this will hadle type conversion
 599        * from float to the type of dst if necessary)
 600        */
 601       luminance_format = _mesa_format_from_format_and_type(format, GL_FLOAT);
 602       _mesa_format_convert(dst, dst_format, dst_stride,
 603                            luminance, luminance_format, luminance_stride,
 604                            width, height, NULL);
 605       free(luminance);
 606    } else {
 607       _mesa_pack_luminance_from_rgba_integer(width * height, src, !src_is_uint,
 608                                              dst, format, type);
 609    }
 610
 611    if (rgba)
 612       free(rgba);
 613
 614 done_swap:
 615    /* Handle byte swapping if required */
 616    if (packing->SwapBytes) {
 617       _mesa_swap_bytes_2d_image(format, type, packing,
 618                                 width, height, dst, dst);
 619    }
 620
 621 done_unmap:
 622    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 623 }
 624
 625 /**
 626  * For a packed depth/stencil buffer being read as depth/stencil, just memcpy the
 627  * data (possibly swapping 8/24 vs 24/8 as we go).
 628  */
 629 static GLboolean
 630 fast_read_depth_stencil_pixels(struct gl_context *ctx,
 631                                GLint x, GLint y,
 632                                GLsizei width, GLsizei height,
 633                                GLubyte *dst, int dstStride)
 634 {
 635    struct gl_framebuffer *fb = ctx->ReadBuffer;
 636    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 637    struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 638    GLubyte *map;
 639    int stride, i;
 640
 641    if (rb != stencilRb)
 642       return GL_FALSE;
 643
 644    if (rb->Format != MESA_FORMAT_S8_UINT_Z24_UNORM &&
 645        rb->Format != MESA_FORMAT_Z24_UNORM_S8_UINT)
 646       return GL_FALSE;
 647
 648    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 649                                &map, &stride);
 650    if (!map) {
 651       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 652       return GL_TRUE;  /* don't bother trying the slow path */
 653    }
 654
 655    for (i = 0; i < height; i++) {
 656       _mesa_unpack_uint_24_8_depth_stencil_row(rb->Format, width,
 657                                                map, (GLuint *)dst);
 658       map += stride;
 659       dst += dstStride;
 660    }
 661
 662    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 663
 664    return GL_TRUE;
 665 }
 666
 667
 668 /**
 669  * For non-float-depth and stencil buffers being read as 24/8 depth/stencil,
 670  * copy the integer data directly instead of converting depth to float and
 671  * re-packing.
 672  */
 673 static GLboolean
 674 fast_read_depth_stencil_pixels_separate(struct gl_context *ctx,
 675                                         GLint x, GLint y,
 676                                         GLsizei width, GLsizei height,
 677                                         uint32_t *dst, int dstStride)
 678 {
 679    struct gl_framebuffer *fb = ctx->ReadBuffer;
 680    struct gl_renderbuffer *depthRb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 681    struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 682    GLubyte *depthMap, *stencilMap, *stencilVals;
 683    int depthStride, stencilStride, i, j;
 684
 685    if (_mesa_get_format_datatype(depthRb->Format) != GL_UNSIGNED_NORMALIZED)
 686       return GL_FALSE;
 687
 688    ctx->Driver.MapRenderbuffer(ctx, depthRb, x, y, width, height,
 689                                GL_MAP_READ_BIT, &depthMap, &depthStride);
 690    if (!depthMap) {
 691       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 692       return GL_TRUE;  /* don't bother trying the slow path */
 693    }
 694
 695    ctx->Driver.MapRenderbuffer(ctx, stencilRb, x, y, width, height,
 696                                GL_MAP_READ_BIT, &stencilMap, &stencilStride);
 697    if (!stencilMap) {
 698       ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 699       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 700       return GL_TRUE;  /* don't bother trying the slow path */
 701    }
 702
 703    stencilVals = malloc(width * sizeof(GLubyte));
 704
 705    if (stencilVals) {
 706       for (j = 0; j < height; j++) {
 707          _mesa_unpack_uint_z_row(depthRb->Format, width, depthMap, dst);
 708          _mesa_unpack_ubyte_stencil_row(stencilRb->Format, width,
 709                                         stencilMap, stencilVals);
 710
 711          for (i = 0; i < width; i++) {
 712             dst[i] = (dst[i] & 0xffffff00) | stencilVals[i];
 713          }
 714
 715          depthMap += depthStride;
 716          stencilMap += stencilStride;
 717          dst += dstStride / 4;
 718       }
 719    }
 720    else {
 721       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 722    }
 723
 724    free(stencilVals);
 725
 726    ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 727    ctx->Driver.UnmapRenderbuffer(ctx, stencilRb);
 728
 729    return GL_TRUE;
 730 }
 731
 732 static void
 733 slow_read_depth_stencil_pixels_separate(struct gl_context *ctx,
 734                                         GLint x, GLint y,
 735                                         GLsizei width, GLsizei height,
 736                                         GLenum type,
 737                                         const struct gl_pixelstore_attrib *packing,
 738                                         GLubyte *dst, int dstStride)
 739 {
 740    struct gl_framebuffer *fb = ctx->ReadBuffer;
 741    struct gl_renderbuffer *depthRb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 742    struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 743    GLubyte *depthMap, *stencilMap;
 744    int depthStride, stencilStride, j;
 745    GLubyte *stencilVals;
 746    GLfloat *depthVals;
 747
 748
 749    /* The depth and stencil buffers might be separate, or a single buffer.
 750     * If one buffer, only map it once.
 751     */
 752    ctx->Driver.MapRenderbuffer(ctx, depthRb, x, y, width, height,
 753                                GL_MAP_READ_BIT, &depthMap, &depthStride);
 754    if (!depthMap) {
 755       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 756       return;
 757    }
 758
 759    if (stencilRb != depthRb) {
 760       ctx->Driver.MapRenderbuffer(ctx, stencilRb, x, y, width, height,
 761                                   GL_MAP_READ_BIT, &stencilMap,
 762                                   &stencilStride);
 763       if (!stencilMap) {
 764          ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 765          _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 766          return;
 767       }
 768    }
 769    else {
 770       stencilMap = depthMap;
 771       stencilStride = depthStride;
 772    }
 773
 774    stencilVals = malloc(width * sizeof(GLubyte));
 775    depthVals = malloc(width * sizeof(GLfloat));
 776
 777    if (stencilVals && depthVals) {
 778       for (j = 0; j < height; j++) {
 779          _mesa_unpack_float_z_row(depthRb->Format, width, depthMap, depthVals);
 780          _mesa_unpack_ubyte_stencil_row(stencilRb->Format, width,
 781                                         stencilMap, stencilVals);
 782
 783          _mesa_pack_depth_stencil_span(ctx, width, type, (GLuint *)dst,
 784                                        depthVals, stencilVals, packing);
 785
 786          depthMap += depthStride;
 787          stencilMap += stencilStride;
 788          dst += dstStride;
 789       }
 790    }
 791    else {
 792       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 793    }
 794
 795    free(stencilVals);
 796    free(depthVals);
 797
 798    ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 799    if (stencilRb != depthRb) {
 800       ctx->Driver.UnmapRenderbuffer(ctx, stencilRb);
 801    }
 802 }
 803
 804
 805 /**
 806  * Read combined depth/stencil values.
 807  * We'll have already done error checking to be sure the expected
 808  * depth and stencil buffers really exist.
 809  */
 810 static void
 811 read_depth_stencil_pixels(struct gl_context *ctx,
 812                           GLint x, GLint y,
 813                           GLsizei width, GLsizei height,
 814                           GLenum type, GLvoid *pixels,
 815                           const struct gl_pixelstore_attrib *packing )
 816 {
 817    const GLboolean scaleOrBias
 818       = ctx->Pixel.DepthScale != 1.0F || ctx->Pixel.DepthBias != 0.0F;
 819    const GLboolean stencilTransfer = ctx->Pixel.IndexShift
 820       || ctx->Pixel.IndexOffset || ctx->Pixel.MapStencilFlag;
 821    GLubyte *dst;
 822    int dstStride;
 823
 824    dst = (GLubyte *) _mesa_image_address2d(packing, pixels,
 825                                            width, height,
 826                                            GL_DEPTH_STENCIL_EXT,
 827                                            type, 0, 0);
 828    dstStride = _mesa_image_row_stride(packing, width,
 829                                       GL_DEPTH_STENCIL_EXT, type);
 830
 831    /* Fast 24/8 reads. */
 832    if (type == GL_UNSIGNED_INT_24_8 &&
 833        !scaleOrBias && !stencilTransfer && !packing->SwapBytes) {
 834       if (fast_read_depth_stencil_pixels(ctx, x, y, width, height,
 835                                          dst, dstStride))
 836          return;
 837
 838       if (fast_read_depth_stencil_pixels_separate(ctx, x, y, width, height,
 839                                                   (uint32_t *)dst, dstStride))
 840          return;
 841    }
 842
 843    slow_read_depth_stencil_pixels_separate(ctx, x, y, width, height,
 844                                            type, packing,
 845                                            dst, dstStride);
 846 }
 847
 848
 849
 850 /**
 851  * Software fallback routine for ctx->Driver.ReadPixels().
 852  * By time we get here, all error checking will have been done.
 853  */
 854 void
 855 _mesa_readpixels(struct gl_context *ctx,
 856                  GLint x, GLint y, GLsizei width, GLsizei height,
 857                  GLenum format, GLenum type,
 858                  const struct gl_pixelstore_attrib *packing,
 859                  GLvoid *pixels)
 860 {
 861    if (ctx->NewState)
 862       _mesa_update_state(ctx);
 863
 864    pixels = _mesa_map_pbo_dest(ctx, packing, pixels);
 865
 866    if (pixels) {
 867       /* Try memcpy first. */
 868       if (readpixels_memcpy(ctx, x, y, width, height, format, type,
 869                             pixels, packing)) {
 870          _mesa_unmap_pbo_dest(ctx, packing);
 871          return;
 872       }
 873
 874       /* Otherwise take the slow path. */
 875       switch (format) {
 876       case GL_STENCIL_INDEX:
 877          read_stencil_pixels(ctx, x, y, width, height, type, pixels,
 878                              packing);
 879          break;
 880       case GL_DEPTH_COMPONENT:
 881          read_depth_pixels(ctx, x, y, width, height, type, pixels,
 882                            packing);
 883          break;
 884       case GL_DEPTH_STENCIL_EXT:
 885          read_depth_stencil_pixels(ctx, x, y, width, height, type, pixels,
 886                                    packing);
 887          break;
 888       default:
 889          /* all other formats should be color formats */
 890          read_rgba_pixels(ctx, x, y, width, height, format, type, pixels,
 891                           packing);
 892       }
 893
 894       _mesa_unmap_pbo_dest(ctx, packing);
 895    }
 896 }
 897
 898
 899 static GLenum
 900 read_pixels_es3_error_check(GLenum format, GLenum type,
 901                             const struct gl_renderbuffer *rb)
 902 {
 903    const GLenum internalFormat = rb->InternalFormat;
 904    const GLenum data_type = _mesa_get_format_datatype(rb->Format);
 905    GLboolean is_unsigned_int = GL_FALSE;
 906    GLboolean is_signed_int = GL_FALSE;
 907    GLboolean is_float_depth = (internalFormat == GL_DEPTH_COMPONENT32F) ||
 908          (internalFormat == GL_DEPTH32F_STENCIL8);
 909
 910    is_unsigned_int = _mesa_is_enum_format_unsigned_int(internalFormat);
 911    if (!is_unsigned_int) {
 912       is_signed_int = _mesa_is_enum_format_signed_int(internalFormat);
 913    }
 914
 915    switch (format) {
 916    case GL_RGBA:
 917       if (type == GL_FLOAT && data_type == GL_FLOAT)
 918          return GL_NO_ERROR; /* EXT_color_buffer_float */
 919       if (type == GL_UNSIGNED_BYTE && data_type == GL_UNSIGNED_NORMALIZED)
 920          return GL_NO_ERROR;
 921       if (internalFormat == GL_RGB10_A2 &&
 922           type == GL_UNSIGNED_INT_2_10_10_10_REV)
 923          return GL_NO_ERROR;
 924       if (internalFormat == GL_RGB10_A2UI && type == GL_UNSIGNED_BYTE)
 925          return GL_NO_ERROR;
 926       break;
 927    case GL_BGRA:
 928       /* GL_EXT_read_format_bgra */
 929       if (type == GL_UNSIGNED_BYTE ||
 930           type == GL_UNSIGNED_SHORT_4_4_4_4_REV ||
 931           type == GL_UNSIGNED_SHORT_1_5_5_5_REV)
 932          return GL_NO_ERROR;
 933       break;
 934    case GL_RGBA_INTEGER:
 935       if ((is_signed_int && type == GL_INT) ||
 936           (is_unsigned_int && type == GL_UNSIGNED_INT))
 937          return GL_NO_ERROR;
 938       break;
 939    case GL_DEPTH_STENCIL:
 940       switch (type) {
 941       case GL_FLOAT_32_UNSIGNED_INT_24_8_REV:
 942          if (is_float_depth)
 943             return GL_NO_ERROR;
 944          break;
 945       case GL_UNSIGNED_INT_24_8:
 946          if (!is_float_depth)
 947             return GL_NO_ERROR;
 948          break;
 949       default:
 950          return GL_INVALID_ENUM;
 951       }
 952       break;
 953    case GL_DEPTH_COMPONENT:
 954       switch (type) {
 955       case GL_FLOAT:
 956          if (is_float_depth)
 957             return GL_NO_ERROR;
 958          break;
 959       case GL_UNSIGNED_SHORT:
 960       case GL_UNSIGNED_INT:
 961       case GL_UNSIGNED_INT_24_8:
 962          if (!is_float_depth)
 963             return GL_NO_ERROR;
 964          break;
 965       default:
 966          return GL_INVALID_ENUM;
 967       }
 968       break;
 969    case GL_STENCIL_INDEX:
 970       switch (type) {
 971       case GL_UNSIGNED_BYTE:
 972          return GL_NO_ERROR;
 973       default:
 974          return GL_INVALID_ENUM;
 975       }
 976       break;
 977    }
 978
 979    return GL_INVALID_OPERATION;
 980 }
 981
 982
 983 void GLAPIENTRY
 984 _mesa_ReadnPixelsARB( GLint x, GLint y, GLsizei width, GLsizei height,
 985                       GLenum format, GLenum type, GLsizei bufSize,
 986                       GLvoid *pixels )
 987 {
 988    GLenum err = GL_NO_ERROR;
 989    struct gl_renderbuffer *rb;
 990    struct gl_pixelstore_attrib clippedPacking;
 991
 992    GET_CURRENT_CONTEXT(ctx);
 993
 994    FLUSH_VERTICES(ctx, 0);
 995    FLUSH_CURRENT(ctx, 0);
 996
 997    if (MESA_VERBOSE & VERBOSE_API)
 998       _mesa_debug(ctx, "glReadPixels(%d, %d, %s, %s, %p)\n",
 999                   width, height,
1000                   _mesa_enum_to_string(format),
1001                   _mesa_enum_to_string(type),
1002                   pixels);
1003
1004    if (width < 0 || height < 0) {
1005       _mesa_error( ctx, GL_INVALID_VALUE,
1006                    "glReadPixels(width=%d height=%d)", width, height );
1007       return;
1008    }
1009
1010    if (ctx->NewState)
1011       _mesa_update_state(ctx);
1012
1013    if (ctx->ReadBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
1014       _mesa_error(ctx, GL_INVALID_FRAMEBUFFER_OPERATION_EXT,
1015                   "glReadPixels(incomplete framebuffer)" );
1016       return;
1017    }
1018
1019    rb = _mesa_get_read_renderbuffer_for_format(ctx, format);
1020    if (rb == NULL) {
1021       _mesa_error(ctx, GL_INVALID_OPERATION,
1022                   "glReadPixels(read buffer)");
1023       return;
1024    }
1025
1026    /* OpenGL ES 1.x and OpenGL ES 2.0 impose additional restrictions on the
1027     * combinations of format and type that can be used.
1028     *
1029     * Technically, only two combinations are actually allowed:
1030     * GL_RGBA/GL_UNSIGNED_BYTE, and some implementation-specific internal
1031     * preferred combination.  This code doesn't know what that preferred
1032     * combination is, and Mesa can handle anything valid.  Just work instead.
1033     */
1034    if (_mesa_is_gles(ctx)) {
1035       if (ctx->API == API_OPENGLES2 &&
1036           _mesa_is_color_format(format) &&
1037           _mesa_get_color_read_format(ctx) == format &&
1038           _mesa_get_color_read_type(ctx) == type) {
1039          err = GL_NO_ERROR;
1040       } else if (ctx->Version < 30) {
1041          err = _mesa_es_error_check_format_and_type(ctx, format, type, 2);
1042          if (err == GL_NO_ERROR) {
1043             if (type == GL_FLOAT || type == GL_HALF_FLOAT_OES) {
1044                err = GL_INVALID_OPERATION;
1045             }
1046          }
1047       } else {
1048          err = read_pixels_es3_error_check(format, type, rb);
1049       }
1050
1051       if (err != GL_NO_ERROR) {
1052          _mesa_error(ctx, err, "glReadPixels(invalid format %s and/or type %s)",
1053                      _mesa_enum_to_string(format),
1054                      _mesa_enum_to_string(type));
1055          return;
1056       }
1057    }
1058
1059    err = _mesa_error_check_format_and_type(ctx, format, type);
1060    if (err != GL_NO_ERROR) {
1061       _mesa_error(ctx, err, "glReadPixels(invalid format %s and/or type %s)",
1062                   _mesa_enum_to_string(format),
1063                   _mesa_enum_to_string(type));
1064       return;
1065    }
1066
1067    if (_mesa_is_user_fbo(ctx->ReadBuffer) &&
1068        ctx->ReadBuffer->Visual.samples > 0) {
1069       _mesa_error(ctx, GL_INVALID_OPERATION, "glReadPixels(multisample FBO)");
1070       return;
1071    }
1072
1073    if (!_mesa_source_buffer_exists(ctx, format)) {
1074       _mesa_error(ctx, GL_INVALID_OPERATION, "glReadPixels(no readbuffer)");
1075       return;
1076    }
1077
1078    /* Check that the destination format and source buffer are both
1079     * integer-valued or both non-integer-valued.
1080     */
1081    if (ctx->Extensions.EXT_texture_integer && _mesa_is_color_format(format)) {
1082       const struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
1083       const GLboolean srcInteger = _mesa_is_format_integer_color(rb->Format);
1084       const GLboolean dstInteger = _mesa_is_enum_format_integer(format);
1085       if (dstInteger != srcInteger) {
1086          _mesa_error(ctx, GL_INVALID_OPERATION,
1087                      "glReadPixels(integer / non-integer format mismatch");
1088          return;
1089       }
1090    }
1091
1092    /* Do all needed clipping here, so that we can forget about it later */
1093    clippedPacking = ctx->Pack;
1094    if (!_mesa_clip_readpixels(ctx, &x, &y, &width, &height, &clippedPacking))
1095       return; /* nothing to do */
1096
1097    if (!_mesa_validate_pbo_access(2, &ctx->Pack, width, height, 1,
1098                                   format, type, bufSize, pixels)) {
1099       if (_mesa_is_bufferobj(ctx->Pack.BufferObj)) {
1100          _mesa_error(ctx, GL_INVALID_OPERATION,
1101                      "glReadPixels(out of bounds PBO access)");
1102       } else {
1103          _mesa_error(ctx, GL_INVALID_OPERATION,
1104                      "glReadnPixelsARB(out of bounds access:"
1105                      " bufSize (%d) is too small)", bufSize);
1106       }
1107       return;
1108    }
1109
1110    if (_mesa_is_bufferobj(ctx->Pack.BufferObj) &&
1111        _mesa_check_disallowed_mapping(ctx->Pack.BufferObj)) {
1112       /* buffer is mapped - that's an error */
1113       _mesa_error(ctx, GL_INVALID_OPERATION, "glReadPixels(PBO is mapped)");
1114       return;
1115    }
1116
1117    ctx->Driver.ReadPixels(ctx, x, y, width, height,
1118                           format, type, &clippedPacking, pixels);
1119 }
1120
1121 void GLAPIENTRY
1122 _mesa_ReadPixels( GLint x, GLint y, GLsizei width, GLsizei height,
1123                   GLenum format, GLenum type, GLvoid *pixels )
1124 {
1125    _mesa_ReadnPixelsARB(x, y, width, height, format, type, INT_MAX, pixels);
1126 }