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          need_convert = false;
 528          rgba = dst;
 529       } else {
 530          need_convert = true;
 531          rgba = malloc(height * rgba_stride);
 532          if (!rgba) {
 533             _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 534             goto done_unmap;
 535          }
 536       }
 537
 538       /* Convert to RGBA now */
 539       _mesa_format_convert(rgba, rgba_format, rgba_stride,
 540                            map, rb_format, rb_stride,
 541                            width, height,
 542                            needs_rebase ? rebase_swizzle : NULL);
 543
 544       /* Handle transfer ops if necessary */
 545       if (transferOps)
 546          _mesa_apply_rgba_transfer_ops(ctx, transferOps, width * height, rgba);
 547
 548       /* If we had to rebase, we have already taken care of that */
 549       needs_rebase = false;
 550
 551       /* If we were lucky and our RGBA conversion matches the dst format, then
 552        * we are done.
 553        */
 554       if (!need_convert)
 555          goto done_swap;
 556
 557       /* Otherwise, we need to convert from RGBA to dst next */
 558       src = rgba;
 559       src_format = rgba_format;
 560       src_stride = rgba_stride;
 561    } else {
 562       /* No RGBA conversion needed, convert directly to dst */
 563       src = map;
 564       src_format = rb_format;
 565       src_stride = rb_stride;
 566    }
 567
 568    /* Do the conversion.
 569     *
 570     * If the dst format is Luminance, we need to do the conversion by computing
 571     * L=R+G+B values.
 572     */
 573    if (!convert_rgb_to_lum) {
 574       _mesa_format_convert(dst, dst_format, dst_stride,
 575                            src, src_format, src_stride,
 576                            width, height,
 577                            needs_rebase ? rebase_swizzle : NULL);
 578    } else if (!dst_is_integer) {
 579       /* Compute float Luminance values from RGBA float */
 580       int luminance_stride, luminance_bytes;
 581       void *luminance;
 582       uint32_t luminance_format;
 583
 584       luminance_stride = width * sizeof(GL_FLOAT);
 585       if (format == GL_LUMINANCE_ALPHA)
 586          luminance_stride *= 2;
 587       luminance_bytes = height * luminance_stride;
 588       luminance = malloc(luminance_bytes);
 589       if (!luminance) {
 590          _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 591          free(rgba);
 592          goto done_unmap;
 593       }
 594       _mesa_pack_luminance_from_rgba_float(width * height, src,
 595                                            luminance, format, transferOps);
 596
 597       /* Convert from Luminance float to dst (this will hadle type conversion
 598        * from float to the type of dst if necessary)
 599        */
 600       luminance_format = _mesa_format_from_format_and_type(format, GL_FLOAT);
 601       _mesa_format_convert(dst, dst_format, dst_stride,
 602                            luminance, luminance_format, luminance_stride,
 603                            width, height, NULL);
 604       free(luminance);
 605    } else {
 606       _mesa_pack_luminance_from_rgba_integer(width * height, src, !src_is_uint,
 607                                              dst, format, type);
 608    }
 609
 610    if (rgba)
 611       free(rgba);
 612
 613 done_swap:
 614    /* Handle byte swapping if required */
 615    if (packing->SwapBytes) {
 616       _mesa_swap_bytes_2d_image(format, type, packing,
 617                                 width, height, dst, dst);
 618    }
 619
 620 done_unmap:
 621    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 622 }
 623
 624 /**
 625  * For a packed depth/stencil buffer being read as depth/stencil, just memcpy the
 626  * data (possibly swapping 8/24 vs 24/8 as we go).
 627  */
 628 static GLboolean
 629 fast_read_depth_stencil_pixels(struct gl_context *ctx,
 630                                GLint x, GLint y,
 631                                GLsizei width, GLsizei height,
 632                                GLubyte *dst, int dstStride)
 633 {
 634    struct gl_framebuffer *fb = ctx->ReadBuffer;
 635    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 636    struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 637    GLubyte *map;
 638    int stride, i;
 639
 640    if (rb != stencilRb)
 641       return GL_FALSE;
 642
 643    if (rb->Format != MESA_FORMAT_S8_UINT_Z24_UNORM &&
 644        rb->Format != MESA_FORMAT_Z24_UNORM_S8_UINT)
 645       return GL_FALSE;
 646
 647    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 648                                &map, &stride);
 649    if (!map) {
 650       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 651       return GL_TRUE;  /* don't bother trying the slow path */
 652    }
 653
 654    for (i = 0; i < height; i++) {
 655       _mesa_unpack_uint_24_8_depth_stencil_row(rb->Format, width,
 656                                                map, (GLuint *)dst);
 657       map += stride;
 658       dst += dstStride;
 659    }
 660
 661    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 662
 663    return GL_TRUE;
 664 }
 665
 666
 667 /**
 668  * For non-float-depth and stencil buffers being read as 24/8 depth/stencil,
 669  * copy the integer data directly instead of converting depth to float and
 670  * re-packing.
 671  */
 672 static GLboolean
 673 fast_read_depth_stencil_pixels_separate(struct gl_context *ctx,
 674                                         GLint x, GLint y,
 675                                         GLsizei width, GLsizei height,
 676                                         uint32_t *dst, int dstStride)
 677 {
 678    struct gl_framebuffer *fb = ctx->ReadBuffer;
 679    struct gl_renderbuffer *depthRb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 680    struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 681    GLubyte *depthMap, *stencilMap, *stencilVals;
 682    int depthStride, stencilStride, i, j;
 683
 684    if (_mesa_get_format_datatype(depthRb->Format) != GL_UNSIGNED_NORMALIZED)
 685       return GL_FALSE;
 686
 687    ctx->Driver.MapRenderbuffer(ctx, depthRb, x, y, width, height,
 688                                GL_MAP_READ_BIT, &depthMap, &depthStride);
 689    if (!depthMap) {
 690       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 691       return GL_TRUE;  /* don't bother trying the slow path */
 692    }
 693
 694    ctx->Driver.MapRenderbuffer(ctx, stencilRb, x, y, width, height,
 695                                GL_MAP_READ_BIT, &stencilMap, &stencilStride);
 696    if (!stencilMap) {
 697       ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 698       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 699       return GL_TRUE;  /* don't bother trying the slow path */
 700    }
 701
 702    stencilVals = malloc(width * sizeof(GLubyte));
 703
 704    if (stencilVals) {
 705       for (j = 0; j < height; j++) {
 706          _mesa_unpack_uint_z_row(depthRb->Format, width, depthMap, dst);
 707          _mesa_unpack_ubyte_stencil_row(stencilRb->Format, width,
 708                                         stencilMap, stencilVals);
 709
 710          for (i = 0; i < width; i++) {
 711             dst[i] = (dst[i] & 0xffffff00) | stencilVals[i];
 712          }
 713
 714          depthMap += depthStride;
 715          stencilMap += stencilStride;
 716          dst += dstStride / 4;
 717       }
 718    }
 719    else {
 720       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 721    }
 722
 723    free(stencilVals);
 724
 725    ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 726    ctx->Driver.UnmapRenderbuffer(ctx, stencilRb);
 727
 728    return GL_TRUE;
 729 }
 730
 731 static void
 732 slow_read_depth_stencil_pixels_separate(struct gl_context *ctx,
 733                                         GLint x, GLint y,
 734                                         GLsizei width, GLsizei height,
 735                                         GLenum type,
 736                                         const struct gl_pixelstore_attrib *packing,
 737                                         GLubyte *dst, int dstStride)
 738 {
 739    struct gl_framebuffer *fb = ctx->ReadBuffer;
 740    struct gl_renderbuffer *depthRb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 741    struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 742    GLubyte *depthMap, *stencilMap;
 743    int depthStride, stencilStride, j;
 744    GLubyte *stencilVals;
 745    GLfloat *depthVals;
 746
 747
 748    /* The depth and stencil buffers might be separate, or a single buffer.
 749     * If one buffer, only map it once.
 750     */
 751    ctx->Driver.MapRenderbuffer(ctx, depthRb, x, y, width, height,
 752                                GL_MAP_READ_BIT, &depthMap, &depthStride);
 753    if (!depthMap) {
 754       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 755       return;
 756    }
 757
 758    if (stencilRb != depthRb) {
 759       ctx->Driver.MapRenderbuffer(ctx, stencilRb, x, y, width, height,
 760                                   GL_MAP_READ_BIT, &stencilMap,
 761                                   &stencilStride);
 762       if (!stencilMap) {
 763          ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 764          _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 765          return;
 766       }
 767    }
 768    else {
 769       stencilMap = depthMap;
 770       stencilStride = depthStride;
 771    }
 772
 773    stencilVals = malloc(width * sizeof(GLubyte));
 774    depthVals = malloc(width * sizeof(GLfloat));
 775
 776    if (stencilVals && depthVals) {
 777       for (j = 0; j < height; j++) {
 778          _mesa_unpack_float_z_row(depthRb->Format, width, depthMap, depthVals);
 779          _mesa_unpack_ubyte_stencil_row(stencilRb->Format, width,
 780                                         stencilMap, stencilVals);
 781
 782          _mesa_pack_depth_stencil_span(ctx, width, type, (GLuint *)dst,
 783                                        depthVals, stencilVals, packing);
 784
 785          depthMap += depthStride;
 786          stencilMap += stencilStride;
 787          dst += dstStride;
 788       }
 789    }
 790    else {
 791       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 792    }
 793
 794    free(stencilVals);
 795    free(depthVals);
 796
 797    ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 798    if (stencilRb != depthRb) {
 799       ctx->Driver.UnmapRenderbuffer(ctx, stencilRb);
 800    }
 801 }
 802
 803
 804 /**
 805  * Read combined depth/stencil values.
 806  * We'll have already done error checking to be sure the expected
 807  * depth and stencil buffers really exist.
 808  */
 809 static void
 810 read_depth_stencil_pixels(struct gl_context *ctx,
 811                           GLint x, GLint y,
 812                           GLsizei width, GLsizei height,
 813                           GLenum type, GLvoid *pixels,
 814                           const struct gl_pixelstore_attrib *packing )
 815 {
 816    const GLboolean scaleOrBias
 817       = ctx->Pixel.DepthScale != 1.0F || ctx->Pixel.DepthBias != 0.0F;
 818    const GLboolean stencilTransfer = ctx->Pixel.IndexShift
 819       || ctx->Pixel.IndexOffset || ctx->Pixel.MapStencilFlag;
 820    GLubyte *dst;
 821    int dstStride;
 822
 823    dst = (GLubyte *) _mesa_image_address2d(packing, pixels,
 824                                            width, height,
 825                                            GL_DEPTH_STENCIL_EXT,
 826                                            type, 0, 0);
 827    dstStride = _mesa_image_row_stride(packing, width,
 828                                       GL_DEPTH_STENCIL_EXT, type);
 829
 830    /* Fast 24/8 reads. */
 831    if (type == GL_UNSIGNED_INT_24_8 &&
 832        !scaleOrBias && !stencilTransfer && !packing->SwapBytes) {
 833       if (fast_read_depth_stencil_pixels(ctx, x, y, width, height,
 834                                          dst, dstStride))
 835          return;
 836
 837       if (fast_read_depth_stencil_pixels_separate(ctx, x, y, width, height,
 838                                                   (uint32_t *)dst, dstStride))
 839          return;
 840    }
 841
 842    slow_read_depth_stencil_pixels_separate(ctx, x, y, width, height,
 843                                            type, packing,
 844                                            dst, dstStride);
 845 }
 846
 847
 848
 849 /**
 850  * Software fallback routine for ctx->Driver.ReadPixels().
 851  * By time we get here, all error checking will have been done.
 852  */
 853 void
 854 _mesa_readpixels(struct gl_context *ctx,
 855                  GLint x, GLint y, GLsizei width, GLsizei height,
 856                  GLenum format, GLenum type,
 857                  const struct gl_pixelstore_attrib *packing,
 858                  GLvoid *pixels)
 859 {
 860    struct gl_pixelstore_attrib clippedPacking = *packing;
 861
 862    if (ctx->NewState)
 863       _mesa_update_state(ctx);
 864
 865    /* Do all needed clipping here, so that we can forget about it later */
 866    if (_mesa_clip_readpixels(ctx, &x, &y, &width, &height, &clippedPacking)) {
 867
 868       pixels = _mesa_map_pbo_dest(ctx, &clippedPacking, pixels);
 869
 870       if (pixels) {
 871          /* Try memcpy first. */
 872          if (readpixels_memcpy(ctx, x, y, width, height, format, type,
 873                                pixels, packing)) {
 874             _mesa_unmap_pbo_dest(ctx, &clippedPacking);
 875             return;
 876          }
 877
 878          /* Otherwise take the slow path. */
 879          switch (format) {
 880          case GL_STENCIL_INDEX:
 881             read_stencil_pixels(ctx, x, y, width, height, type, pixels,
 882                                 &clippedPacking);
 883             break;
 884          case GL_DEPTH_COMPONENT:
 885             read_depth_pixels(ctx, x, y, width, height, type, pixels,
 886                               &clippedPacking);
 887             break;
 888          case GL_DEPTH_STENCIL_EXT:
 889             read_depth_stencil_pixels(ctx, x, y, width, height, type, pixels,
 890                                       &clippedPacking);
 891             break;
 892          default:
 893             /* all other formats should be color formats */
 894             read_rgba_pixels(ctx, x, y, width, height, format, type, pixels,
 895                              &clippedPacking);
 896          }
 897
 898          _mesa_unmap_pbo_dest(ctx, &clippedPacking);
 899       }
 900    }
 901 }
 902
 903
 904 static GLenum
 905 read_pixels_es3_error_check(GLenum format, GLenum type,
 906                             const struct gl_renderbuffer *rb)
 907 {
 908    const GLenum internalFormat = rb->InternalFormat;
 909    const GLenum data_type = _mesa_get_format_datatype(rb->Format);
 910    GLboolean is_unsigned_int = GL_FALSE;
 911    GLboolean is_signed_int = GL_FALSE;
 912    GLboolean is_float_depth = (internalFormat == GL_DEPTH_COMPONENT32F) ||
 913          (internalFormat == GL_DEPTH32F_STENCIL8);
 914
 915    is_unsigned_int = _mesa_is_enum_format_unsigned_int(internalFormat);
 916    if (!is_unsigned_int) {
 917       is_signed_int = _mesa_is_enum_format_signed_int(internalFormat);
 918    }
 919
 920    switch (format) {
 921    case GL_RGBA:
 922       if (type == GL_FLOAT && data_type == GL_FLOAT)
 923          return GL_NO_ERROR; /* EXT_color_buffer_float */
 924       if (type == GL_UNSIGNED_BYTE && data_type == GL_UNSIGNED_NORMALIZED)
 925          return GL_NO_ERROR;
 926       if (internalFormat == GL_RGB10_A2 &&
 927           type == GL_UNSIGNED_INT_2_10_10_10_REV)
 928          return GL_NO_ERROR;
 929       if (internalFormat == GL_RGB10_A2UI && type == GL_UNSIGNED_BYTE)
 930          return GL_NO_ERROR;
 931       break;
 932    case GL_BGRA:
 933       /* GL_EXT_read_format_bgra */
 934       if (type == GL_UNSIGNED_BYTE ||
 935           type == GL_UNSIGNED_SHORT_4_4_4_4_REV ||
 936           type == GL_UNSIGNED_SHORT_1_5_5_5_REV)
 937          return GL_NO_ERROR;
 938       break;
 939    case GL_RGBA_INTEGER:
 940       if ((is_signed_int && type == GL_INT) ||
 941           (is_unsigned_int && type == GL_UNSIGNED_INT))
 942          return GL_NO_ERROR;
 943       break;
 944    case GL_DEPTH_STENCIL:
 945       switch (type) {
 946       case GL_FLOAT_32_UNSIGNED_INT_24_8_REV:
 947          if (is_float_depth)
 948             return GL_NO_ERROR;
 949          break;
 950       case GL_UNSIGNED_INT_24_8:
 951          if (!is_float_depth)
 952             return GL_NO_ERROR;
 953          break;
 954       default:
 955          return GL_INVALID_ENUM;
 956       }
 957       break;
 958    case GL_DEPTH_COMPONENT:
 959       switch (type) {
 960       case GL_FLOAT:
 961          if (is_float_depth)
 962             return GL_NO_ERROR;
 963          break;
 964       case GL_UNSIGNED_SHORT:
 965       case GL_UNSIGNED_INT_24_8:
 966          if (!is_float_depth)
 967             return GL_NO_ERROR;
 968          break;
 969       default:
 970          return GL_INVALID_ENUM;
 971       }
 972       break;
 973    case GL_STENCIL_INDEX:
 974       switch (type) {
 975       case GL_UNSIGNED_BYTE:
 976          return GL_NO_ERROR;
 977       default:
 978          return GL_INVALID_ENUM;
 979       }
 980       break;
 981    }
 982
 983    return GL_INVALID_OPERATION;
 984 }
 985
 986
 987 void GLAPIENTRY
 988 _mesa_ReadnPixelsARB( GLint x, GLint y, GLsizei width, GLsizei height,
 989                       GLenum format, GLenum type, GLsizei bufSize,
 990                       GLvoid *pixels )
 991 {
 992    GLenum err = GL_NO_ERROR;
 993    struct gl_renderbuffer *rb;
 994
 995    GET_CURRENT_CONTEXT(ctx);
 996
 997    FLUSH_VERTICES(ctx, 0);
 998    FLUSH_CURRENT(ctx, 0);
 999
1000    if (MESA_VERBOSE & VERBOSE_API)
1001       _mesa_debug(ctx, "glReadPixels(%d, %d, %s, %s, %p)\n",
1002                   width, height,
1003                   _mesa_enum_to_string(format),
1004                   _mesa_enum_to_string(type),
1005                   pixels);
1006
1007    if (width < 0 || height < 0) {
1008       _mesa_error( ctx, GL_INVALID_VALUE,
1009                    "glReadPixels(width=%d height=%d)", width, height );
1010       return;
1011    }
1012
1013    if (ctx->NewState)
1014       _mesa_update_state(ctx);
1015
1016    if (ctx->ReadBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
1017       _mesa_error(ctx, GL_INVALID_FRAMEBUFFER_OPERATION_EXT,
1018                   "glReadPixels(incomplete framebuffer)" );
1019       return;
1020    }
1021
1022    rb = _mesa_get_read_renderbuffer_for_format(ctx, format);
1023    if (rb == NULL) {
1024       _mesa_error(ctx, GL_INVALID_OPERATION,
1025                   "glReadPixels(read buffer)");
1026       return;
1027    }
1028
1029    /* OpenGL ES 1.x and OpenGL ES 2.0 impose additional restrictions on the
1030     * combinations of format and type that can be used.
1031     *
1032     * Technically, only two combinations are actually allowed:
1033     * GL_RGBA/GL_UNSIGNED_BYTE, and some implementation-specific internal
1034     * preferred combination.  This code doesn't know what that preferred
1035     * combination is, and Mesa can handle anything valid.  Just work instead.
1036     */
1037    if (_mesa_is_gles(ctx)) {
1038       if (ctx->API == API_OPENGLES2 &&
1039           _mesa_is_color_format(format) &&
1040           _mesa_get_color_read_format(ctx) == format &&
1041           _mesa_get_color_read_type(ctx) == type) {
1042          err = GL_NO_ERROR;
1043       } else if (ctx->Version < 30) {
1044          err = _mesa_es_error_check_format_and_type(format, type, 2);
1045          if (err == GL_NO_ERROR) {
1046             if (type == GL_FLOAT || type == GL_HALF_FLOAT_OES) {
1047                err = GL_INVALID_OPERATION;
1048             }
1049          }
1050       } else {
1051          err = read_pixels_es3_error_check(format, type, rb);
1052       }
1053
1054       if (err != GL_NO_ERROR) {
1055          _mesa_error(ctx, err, "glReadPixels(invalid format %s and/or type %s)",
1056                      _mesa_enum_to_string(format),
1057                      _mesa_enum_to_string(type));
1058          return;
1059       }
1060    }
1061
1062    err = _mesa_error_check_format_and_type(ctx, format, type);
1063    if (err != GL_NO_ERROR) {
1064       _mesa_error(ctx, err, "glReadPixels(invalid format %s and/or type %s)",
1065                   _mesa_enum_to_string(format),
1066                   _mesa_enum_to_string(type));
1067       return;
1068    }
1069
1070    if (_mesa_is_user_fbo(ctx->ReadBuffer) &&
1071        ctx->ReadBuffer->Visual.samples > 0) {
1072       _mesa_error(ctx, GL_INVALID_OPERATION, "glReadPixels(multisample FBO)");
1073       return;
1074    }
1075
1076    if (!_mesa_source_buffer_exists(ctx, format)) {
1077       _mesa_error(ctx, GL_INVALID_OPERATION, "glReadPixels(no readbuffer)");
1078       return;
1079    }
1080
1081    /* Check that the destination format and source buffer are both
1082     * integer-valued or both non-integer-valued.
1083     */
1084    if (ctx->Extensions.EXT_texture_integer && _mesa_is_color_format(format)) {
1085       const struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
1086       const GLboolean srcInteger = _mesa_is_format_integer_color(rb->Format);
1087       const GLboolean dstInteger = _mesa_is_enum_format_integer(format);
1088       if (dstInteger != srcInteger) {
1089          _mesa_error(ctx, GL_INVALID_OPERATION,
1090                      "glReadPixels(integer / non-integer format mismatch");
1091          return;
1092       }
1093    }
1094
1095    if (width == 0 || height == 0)
1096       return; /* nothing to do */
1097
1098    if (!_mesa_validate_pbo_access(2, &ctx->Pack, width, height, 1,
1099                                   format, type, bufSize, pixels)) {
1100       if (_mesa_is_bufferobj(ctx->Pack.BufferObj)) {
1101          _mesa_error(ctx, GL_INVALID_OPERATION,
1102                      "glReadPixels(out of bounds PBO access)");
1103       } else {
1104          _mesa_error(ctx, GL_INVALID_OPERATION,
1105                      "glReadnPixelsARB(out of bounds access:"
1106                      " bufSize (%d) is too small)", bufSize);
1107       }
1108       return;
1109    }
1110
1111    if (_mesa_is_bufferobj(ctx->Pack.BufferObj) &&
1112        _mesa_check_disallowed_mapping(ctx->Pack.BufferObj)) {
1113       /* buffer is mapped - that's an error */
1114       _mesa_error(ctx, GL_INVALID_OPERATION, "glReadPixels(PBO is mapped)");
1115       return;
1116    }
1117
1118    ctx->Driver.ReadPixels(ctx, x, y, width, height,
1119                           format, type, &ctx->Pack, pixels);
1120 }
1121
1122 void GLAPIENTRY
1123 _mesa_ReadPixels( GLint x, GLint y, GLsizei width, GLsizei height,
1124                   GLenum format, GLenum type, GLvoid *pixels )
1125 {
1126    _mesa_ReadnPixelsARB(x, y, width, height, format, type, INT_MAX, pixels);
1127 }