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 static GLboolean
  50 need_rgb_to_luminance_conversion(mesa_format texFormat, GLenum format)
  51 {
  52    GLenum baseTexFormat = _mesa_get_format_base_format(texFormat);
  53
  54    return (baseTexFormat == GL_RG ||
  55            baseTexFormat == GL_RGB ||
  56            baseTexFormat == GL_RGBA) &&
  57           (format == GL_LUMINANCE || format == GL_LUMINANCE_ALPHA);
  58 }
  59
  60
  61 /**
  62  * Return transfer op flags for this ReadPixels operation.
  63  */
  64 static GLbitfield
  65 get_readpixels_transfer_ops(const struct gl_context *ctx, mesa_format texFormat,
  66                             GLenum format, GLenum type, GLboolean uses_blit)
  67 {
  68    GLbitfield transferOps = ctx->_ImageTransferState;
  69
  70    if (format == GL_DEPTH_COMPONENT ||
  71        format == GL_DEPTH_STENCIL ||
  72        format == GL_STENCIL_INDEX) {
  73       return 0;
  74    }
  75
  76    /* Pixel transfer ops (scale, bias, table lookup) do not apply
  77     * to integer formats.
  78     */
  79    if (_mesa_is_enum_format_integer(format)) {
  80       return 0;
  81    }
  82
  83    if (uses_blit) {
  84       /* For blit-based ReadPixels packing, the clamping is done automatically
  85        * unless the type is float. */
  86       if (_mesa_get_clamp_read_color(ctx) &&
  87           (type == GL_FLOAT || type == GL_HALF_FLOAT)) {
  88          transferOps |= IMAGE_CLAMP_BIT;
  89       }
  90    }
  91    else {
  92       /* For CPU-based ReadPixels packing, the clamping must always be done
  93        * for non-float types, */
  94       if (_mesa_get_clamp_read_color(ctx) ||
  95           (type != GL_FLOAT && type != GL_HALF_FLOAT)) {
  96          transferOps |= IMAGE_CLAMP_BIT;
  97       }
  98    }
  99
 100    /* If the format is unsigned normalized, we can ignore clamping
 101     * because the values are already in the range [0,1] so it won't
 102     * have any effect anyway.
 103     */
 104    if (_mesa_get_format_datatype(texFormat) == GL_UNSIGNED_NORMALIZED &&
 105        !need_rgb_to_luminance_conversion(texFormat, format)) {
 106       transferOps &= ~IMAGE_CLAMP_BIT;
 107    }
 108
 109    return transferOps;
 110 }
 111
 112
 113 /**
 114  * Return true if memcpy cannot be used for ReadPixels.
 115  *
 116  * If uses_blit is true, the function returns true if a simple 3D engine blit
 117  * cannot be used for ReadPixels packing.
 118  *
 119  * NOTE: This doesn't take swizzling and format conversions between
 120  *       the readbuffer and the pixel pack buffer into account.
 121  */
 122 GLboolean
 123 _mesa_readpixels_needs_slow_path(const struct gl_context *ctx, GLenum format,
 124                                  GLenum type, GLboolean uses_blit)
 125 {
 126    struct gl_renderbuffer *rb =
 127          _mesa_get_read_renderbuffer_for_format(ctx, format);
 128    GLenum srcType;
 129
 130    ASSERT(rb);
 131
 132    /* There are different rules depending on the base format. */
 133    switch (format) {
 134    case GL_DEPTH_STENCIL:
 135       return !_mesa_has_depthstencil_combined(ctx->ReadBuffer) ||
 136              ctx->Pixel.DepthScale != 1.0f || ctx->Pixel.DepthBias != 0.0f ||
 137              ctx->Pixel.IndexShift || ctx->Pixel.IndexOffset ||
 138              ctx->Pixel.MapStencilFlag;
 139
 140    case GL_DEPTH_COMPONENT:
 141       return ctx->Pixel.DepthScale != 1.0f || ctx->Pixel.DepthBias != 0.0f;
 142
 143    case GL_STENCIL_INDEX:
 144       return ctx->Pixel.IndexShift || ctx->Pixel.IndexOffset ||
 145              ctx->Pixel.MapStencilFlag;
 146
 147    default:
 148       /* Color formats. */
 149       if (need_rgb_to_luminance_conversion(rb->Format, format)) {
 150          return GL_TRUE;
 151       }
 152
 153       /* Conversion between signed and unsigned integers needs masking
 154        * (it isn't just memcpy). */
 155       srcType = _mesa_get_format_datatype(rb->Format);
 156
 157       if ((srcType == GL_INT &&
 158            (type == GL_UNSIGNED_INT ||
 159             type == GL_UNSIGNED_SHORT ||
 160             type == GL_UNSIGNED_BYTE)) ||
 161           (srcType == GL_UNSIGNED_INT &&
 162            (type == GL_INT ||
 163             type == GL_SHORT ||
 164             type == GL_BYTE))) {
 165          return GL_TRUE;
 166       }
 167
 168       /* And finally, see if there are any transfer ops. */
 169       return get_readpixels_transfer_ops(ctx, rb->Format, format, type,
 170                                          uses_blit) != 0;
 171    }
 172    return GL_FALSE;
 173 }
 174
 175
 176 static GLboolean
 177 readpixels_can_use_memcpy(const struct gl_context *ctx, GLenum format, GLenum type,
 178                           const struct gl_pixelstore_attrib *packing)
 179 {
 180    struct gl_renderbuffer *rb =
 181          _mesa_get_read_renderbuffer_for_format(ctx, format);
 182
 183    ASSERT(rb);
 184
 185    if (_mesa_readpixels_needs_slow_path(ctx, format, type, GL_FALSE)) {
 186       return GL_FALSE;
 187    }
 188
 189    /* The base internal format and the base Mesa format must match. */
 190    if (rb->_BaseFormat != _mesa_get_format_base_format(rb->Format)) {
 191       return GL_FALSE;
 192    }
 193
 194    /* The Mesa format must match the input format and type. */
 195    if (!_mesa_format_matches_format_and_type(rb->Format, format, type,
 196                                              packing->SwapBytes)) {
 197       return GL_FALSE;
 198    }
 199
 200    return GL_TRUE;
 201 }
 202
 203
 204 static GLboolean
 205 readpixels_memcpy(struct gl_context *ctx,
 206                   GLint x, GLint y,
 207                   GLsizei width, GLsizei height,
 208                   GLenum format, GLenum type,
 209                   GLvoid *pixels,
 210                   const struct gl_pixelstore_attrib *packing)
 211 {
 212    struct gl_renderbuffer *rb =
 213          _mesa_get_read_renderbuffer_for_format(ctx, format);
 214    GLubyte *dst, *map;
 215    int dstStride, stride, j, texelBytes;
 216
 217    /* Fail if memcpy cannot be used. */
 218    if (!readpixels_can_use_memcpy(ctx, format, type, packing)) {
 219       return GL_FALSE;
 220    }
 221
 222    dstStride = _mesa_image_row_stride(packing, width, format, type);
 223    dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 224                                            format, type, 0, 0);
 225
 226    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 227                                &map, &stride);
 228    if (!map) {
 229       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 230       return GL_TRUE;  /* don't bother trying the slow path */
 231    }
 232
 233    texelBytes = _mesa_get_format_bytes(rb->Format);
 234
 235    /* memcpy*/
 236    for (j = 0; j < height; j++) {
 237       memcpy(dst, map, width * texelBytes);
 238       dst += dstStride;
 239       map += stride;
 240    }
 241
 242    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 243    return GL_TRUE;
 244 }
 245
 246
 247 /**
 248  * Optimized path for conversion of depth values to GL_DEPTH_COMPONENT,
 249  * GL_UNSIGNED_INT.
 250  */
 251 static GLboolean
 252 read_uint_depth_pixels( struct gl_context *ctx,
 253                         GLint x, GLint y,
 254                         GLsizei width, GLsizei height,
 255                         GLenum type, GLvoid *pixels,
 256                         const struct gl_pixelstore_attrib *packing )
 257 {
 258    struct gl_framebuffer *fb = ctx->ReadBuffer;
 259    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 260    GLubyte *map, *dst;
 261    int stride, dstStride, j;
 262
 263    if (ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0)
 264       return GL_FALSE;
 265
 266    if (packing->SwapBytes)
 267       return GL_FALSE;
 268
 269    if (_mesa_get_format_datatype(rb->Format) != GL_UNSIGNED_NORMALIZED)
 270       return GL_FALSE;
 271
 272    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 273                                &map, &stride);
 274
 275    if (!map) {
 276       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 277       return GL_TRUE;  /* don't bother trying the slow path */
 278    }
 279
 280    dstStride = _mesa_image_row_stride(packing, width, GL_DEPTH_COMPONENT, type);
 281    dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 282                                            GL_DEPTH_COMPONENT, type, 0, 0);
 283
 284    for (j = 0; j < height; j++) {
 285       _mesa_unpack_uint_z_row(rb->Format, width, map, (GLuint *)dst);
 286
 287       map += stride;
 288       dst += dstStride;
 289    }
 290    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 291
 292    return GL_TRUE;
 293 }
 294
 295 /**
 296  * Read pixels for format=GL_DEPTH_COMPONENT.
 297  */
 298 static void
 299 read_depth_pixels( struct gl_context *ctx,
 300                    GLint x, GLint y,
 301                    GLsizei width, GLsizei height,
 302                    GLenum type, GLvoid *pixels,
 303                    const struct gl_pixelstore_attrib *packing )
 304 {
 305    struct gl_framebuffer *fb = ctx->ReadBuffer;
 306    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 307    GLint j;
 308    GLubyte *dst, *map;
 309    int dstStride, stride;
 310    GLfloat *depthValues;
 311
 312    if (!rb)
 313       return;
 314
 315    /* clipping should have been done already */
 316    ASSERT(x >= 0);
 317    ASSERT(y >= 0);
 318    ASSERT(x + width <= (GLint) rb->Width);
 319    ASSERT(y + height <= (GLint) rb->Height);
 320
 321    if (type == GL_UNSIGNED_INT &&
 322        read_uint_depth_pixels(ctx, x, y, width, height, type, pixels, packing)) {
 323       return;
 324    }
 325
 326    dstStride = _mesa_image_row_stride(packing, width, GL_DEPTH_COMPONENT, type);
 327    dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 328                                            GL_DEPTH_COMPONENT, type, 0, 0);
 329
 330    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 331                                &map, &stride);
 332    if (!map) {
 333       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 334       return;
 335    }
 336
 337    depthValues = malloc(width * sizeof(GLfloat));
 338
 339    if (depthValues) {
 340       /* General case (slower) */
 341       for (j = 0; j < height; j++, y++) {
 342          _mesa_unpack_float_z_row(rb->Format, width, map, depthValues);
 343          _mesa_pack_depth_span(ctx, width, dst, type, depthValues, packing);
 344
 345          dst += dstStride;
 346          map += stride;
 347       }
 348    }
 349    else {
 350       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 351    }
 352
 353    free(depthValues);
 354
 355    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 356 }
 357
 358
 359 /**
 360  * Read pixels for format=GL_STENCIL_INDEX.
 361  */
 362 static void
 363 read_stencil_pixels( struct gl_context *ctx,
 364                      GLint x, GLint y,
 365                      GLsizei width, GLsizei height,
 366                      GLenum type, GLvoid *pixels,
 367                      const struct gl_pixelstore_attrib *packing )
 368 {
 369    struct gl_framebuffer *fb = ctx->ReadBuffer;
 370    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 371    GLint j;
 372    GLubyte *map, *stencil;
 373    GLint stride;
 374
 375    if (!rb)
 376       return;
 377
 378    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 379                                &map, &stride);
 380    if (!map) {
 381       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 382       return;
 383    }
 384
 385    stencil = malloc(width * sizeof(GLubyte));
 386
 387    if (stencil) {
 388       /* process image row by row */
 389       for (j = 0; j < height; j++) {
 390          GLvoid *dest;
 391
 392          _mesa_unpack_ubyte_stencil_row(rb->Format, width, map, stencil);
 393          dest = _mesa_image_address2d(packing, pixels, width, height,
 394                                       GL_STENCIL_INDEX, type, j, 0);
 395
 396          _mesa_pack_stencil_span(ctx, width, type, dest, stencil, packing);
 397
 398          map += stride;
 399       }
 400    }
 401    else {
 402       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 403    }
 404
 405    free(stencil);
 406
 407    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 408 }
 409
 410 /*
 411  * Read R, G, B, A, RGB, L, or LA pixels.
 412  */
 413 static void
 414 read_rgba_pixels( struct gl_context *ctx,
 415                   GLint x, GLint y,
 416                   GLsizei width, GLsizei height,
 417                   GLenum format, GLenum type, GLvoid *pixels,
 418                   const struct gl_pixelstore_attrib *packing )
 419 {
 420    GLbitfield transferOps;
 421    bool dst_is_integer, dst_is_luminance, needs_rebase;
 422    int dst_stride, src_stride, rb_stride;
 423    uint32_t dst_format, src_format;
 424    GLubyte *dst, *map;
 425    mesa_format rb_format;
 426    bool needs_rgba;
 427    void *rgba, *src;
 428    bool src_is_uint = false;
 429    uint8_t rebase_swizzle[4];
 430    struct gl_framebuffer *fb = ctx->ReadBuffer;
 431    struct gl_renderbuffer *rb = fb->_ColorReadBuffer;
 432
 433    if (!rb)
 434       return;
 435
 436    transferOps = get_readpixels_transfer_ops(ctx, rb->Format, format, type,
 437                                              GL_FALSE);
 438    /* Describe the dst format */
 439    dst_is_integer = _mesa_is_enum_format_integer(format);
 440    dst_stride = _mesa_image_row_stride(packing, width, format, type);
 441    dst_format = _mesa_format_from_format_and_type(format, type);
 442    dst_is_luminance = format == GL_LUMINANCE ||
 443                       format == GL_LUMINANCE_ALPHA ||
 444                       format == GL_LUMINANCE_INTEGER_EXT ||
 445                       format == GL_LUMINANCE_ALPHA_INTEGER_EXT;
 446    dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 447                                            format, type, 0, 0);
 448
 449    /* Map the source render buffer */
 450    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 451                                &map, &rb_stride);
 452    if (!map) {
 453       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 454       return;
 455    }
 456    rb_format = _mesa_get_srgb_format_linear(rb->Format);
 457
 458    /*
 459     * Depending on the base formats involved in the conversion we might need to
 460     * rebase some values, so for these formats we compute a rebase swizzle.
 461     */
 462    if (rb->_BaseFormat == GL_LUMINANCE || rb->_BaseFormat == GL_INTENSITY) {
 463       needs_rebase = true;
 464       rebase_swizzle[0] = MESA_FORMAT_SWIZZLE_X;
 465       rebase_swizzle[1] = MESA_FORMAT_SWIZZLE_ZERO;
 466       rebase_swizzle[2] = MESA_FORMAT_SWIZZLE_ZERO;
 467       rebase_swizzle[3] = MESA_FORMAT_SWIZZLE_ONE;
 468    } else if (rb->_BaseFormat == GL_LUMINANCE_ALPHA) {
 469       needs_rebase = true;
 470       rebase_swizzle[0] = MESA_FORMAT_SWIZZLE_X;
 471       rebase_swizzle[1] = MESA_FORMAT_SWIZZLE_ZERO;
 472       rebase_swizzle[2] = MESA_FORMAT_SWIZZLE_ZERO;
 473       rebase_swizzle[3] = MESA_FORMAT_SWIZZLE_W;
 474    } else if (_mesa_get_format_base_format(rb_format) != rb->_BaseFormat) {
 475       needs_rebase =
 476          _mesa_compute_rgba2base2rgba_component_mapping(rb->_BaseFormat,
 477                                                         rebase_swizzle);
 478    } else {
 479       needs_rebase = false;
 480    }
 481
 482    /* Since _mesa_format_convert does not handle transferOps we need to handle
 483     * them before we call the function. This requires to convert to RGBA float
 484     * first so we can call _mesa_apply_rgba_transfer_ops. If the dst format is
 485     * integer transferOps do not apply.
 486     *
 487     * Converting to luminance also requires converting to RGBA first, so we can
 488     * then compute luminance values as L=R+G+B. Notice that this is different
 489     * from GetTexImage, where we compute L=R.
 490     */
 491    assert(!transferOps || (transferOps && !dst_is_integer));
 492
 493    needs_rgba = transferOps || dst_is_luminance;
 494    rgba = NULL;
 495    if (needs_rgba) {
 496       uint32_t rgba_format;
 497       int rgba_stride;
 498       bool need_convert;
 499
 500       /* Convert to RGBA float or int/uint depending on the type of the src */
 501       if (dst_is_integer) {
 502          src_is_uint = _mesa_is_format_unsigned(rb_format);
 503          if (src_is_uint) {
 504             rgba_format = RGBA32_UINT;
 505             rgba_stride = width * 4 * sizeof(GLuint);
 506          } else {
 507             rgba_format = RGBA32_INT;
 508             rgba_stride = width * 4 * sizeof(GLint);
 509          }
 510       } else {
 511          rgba_format = RGBA32_FLOAT;
 512          rgba_stride = width * 4 * sizeof(GLfloat);
 513       }
 514
 515       /* If we are lucky and the dst format matches the RGBA format we need to
 516        * convert to, then we can convert directly into the dst buffer and avoid
 517        * the final conversion/copy from the rgba buffer to the dst buffer.
 518        */
 519       if (dst_format == rgba_format) {
 520          need_convert = false;
 521          rgba = dst;
 522       } else {
 523          need_convert = true;
 524          rgba = malloc(height * rgba_stride);
 525          if (!rgba) {
 526             _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 527             goto done_unmap;
 528          }
 529       }
 530
 531       /* Convert to RGBA now */
 532       _mesa_format_convert(rgba, rgba_format, rgba_stride,
 533                            map, rb_format, rb_stride,
 534                            width, height,
 535                            needs_rebase ? rebase_swizzle : NULL);
 536
 537       /* Handle transfer ops if necessary */
 538       if (transferOps)
 539          _mesa_apply_rgba_transfer_ops(ctx, transferOps, width * height, rgba);
 540
 541       /* If we had to rebase, we have already taken care of that */
 542       needs_rebase = false;
 543
 544       /* If we were lucky and our RGBA conversion matches the dst format, then
 545        * we are done.
 546        */
 547       if (!need_convert)
 548          goto done_swap;
 549
 550       /* Otherwise, we need to convert from RGBA to dst next */
 551       src = rgba;
 552       src_format = rgba_format;
 553       src_stride = rgba_stride;
 554    } else {
 555       /* No RGBA conversion needed, convert directly to dst */
 556       src = map;
 557       src_format = rb_format;
 558       src_stride = rb_stride;
 559    }
 560
 561    /* Do the conversion.
 562     *
 563     * If the dst format is Luminance, we need to do the conversion by computing
 564     * L=R+G+B values.
 565     */
 566    if (!dst_is_luminance) {
 567       _mesa_format_convert(dst, dst_format, dst_stride,
 568                            src, src_format, src_stride,
 569                            width, height,
 570                            needs_rebase ? rebase_swizzle : NULL);
 571    } else if (!dst_is_integer) {
 572       /* Compute float Luminance values from RGBA float */
 573       int luminance_stride, luminance_bytes;
 574       void *luminance;
 575       uint32_t luminance_format;
 576
 577       luminance_stride = width * sizeof(GL_FLOAT);
 578       if (format == GL_LUMINANCE_ALPHA)
 579          luminance_stride *= 2;
 580       luminance_bytes = height * luminance_stride;
 581       luminance = malloc(luminance_bytes);
 582       if (!luminance) {
 583          _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 584          free(rgba);
 585          goto done_unmap;
 586       }
 587       _mesa_pack_luminance_from_rgba_float(width * height, src,
 588                                            luminance, format, transferOps);
 589
 590       /* Convert from Luminance float to dst (this will hadle type conversion
 591        * from float to the type of dst if necessary)
 592        */
 593       luminance_format = _mesa_format_from_format_and_type(format, GL_FLOAT);
 594       _mesa_format_convert(dst, dst_format, dst_stride,
 595                            luminance, luminance_format, luminance_stride,
 596                            width, height, NULL);
 597    } else {
 598       _mesa_pack_luminance_from_rgba_integer(width * height, src, !src_is_uint,
 599                                              dst, format, type);
 600    }
 601
 602    if (rgba)
 603       free(rgba);
 604
 605 done_swap:
 606    /* Handle byte swapping if required */
 607    if (packing->SwapBytes) {
 608       int components = _mesa_components_in_format(format);
 609       GLint swapSize = _mesa_sizeof_packed_type(type);
 610       if (swapSize == 2)
 611          _mesa_swap2((GLushort *) dst, width * height * components);
 612       else if (swapSize == 4)
 613          _mesa_swap4((GLuint *) dst, width * height * components);
 614    }
 615
 616 done_unmap:
 617    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 618 }
 619
 620 /**
 621  * For a packed depth/stencil buffer being read as depth/stencil, just memcpy the
 622  * data (possibly swapping 8/24 vs 24/8 as we go).
 623  */
 624 static GLboolean
 625 fast_read_depth_stencil_pixels(struct gl_context *ctx,
 626                                GLint x, GLint y,
 627                                GLsizei width, GLsizei height,
 628                                GLubyte *dst, int dstStride)
 629 {
 630    struct gl_framebuffer *fb = ctx->ReadBuffer;
 631    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 632    struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 633    GLubyte *map;
 634    int stride, i;
 635
 636    if (rb != stencilRb)
 637       return GL_FALSE;
 638
 639    if (rb->Format != MESA_FORMAT_S8_UINT_Z24_UNORM &&
 640        rb->Format != MESA_FORMAT_Z24_UNORM_S8_UINT)
 641       return GL_FALSE;
 642
 643    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 644                                &map, &stride);
 645    if (!map) {
 646       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 647       return GL_TRUE;  /* don't bother trying the slow path */
 648    }
 649
 650    for (i = 0; i < height; i++) {
 651       _mesa_unpack_uint_24_8_depth_stencil_row(rb->Format, width,
 652                                                map, (GLuint *)dst);
 653       map += stride;
 654       dst += dstStride;
 655    }
 656
 657    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 658
 659    return GL_TRUE;
 660 }
 661
 662
 663 /**
 664  * For non-float-depth and stencil buffers being read as 24/8 depth/stencil,
 665  * copy the integer data directly instead of converting depth to float and
 666  * re-packing.
 667  */
 668 static GLboolean
 669 fast_read_depth_stencil_pixels_separate(struct gl_context *ctx,
 670                                         GLint x, GLint y,
 671                                         GLsizei width, GLsizei height,
 672                                         uint32_t *dst, int dstStride)
 673 {
 674    struct gl_framebuffer *fb = ctx->ReadBuffer;
 675    struct gl_renderbuffer *depthRb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 676    struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 677    GLubyte *depthMap, *stencilMap, *stencilVals;
 678    int depthStride, stencilStride, i, j;
 679
 680    if (_mesa_get_format_datatype(depthRb->Format) != GL_UNSIGNED_NORMALIZED)
 681       return GL_FALSE;
 682
 683    ctx->Driver.MapRenderbuffer(ctx, depthRb, x, y, width, height,
 684                                GL_MAP_READ_BIT, &depthMap, &depthStride);
 685    if (!depthMap) {
 686       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 687       return GL_TRUE;  /* don't bother trying the slow path */
 688    }
 689
 690    ctx->Driver.MapRenderbuffer(ctx, stencilRb, x, y, width, height,
 691                                GL_MAP_READ_BIT, &stencilMap, &stencilStride);
 692    if (!stencilMap) {
 693       ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 694       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 695       return GL_TRUE;  /* don't bother trying the slow path */
 696    }
 697
 698    stencilVals = malloc(width * sizeof(GLubyte));
 699
 700    if (stencilVals) {
 701       for (j = 0; j < height; j++) {
 702          _mesa_unpack_uint_z_row(depthRb->Format, width, depthMap, dst);
 703          _mesa_unpack_ubyte_stencil_row(stencilRb->Format, width,
 704                                         stencilMap, stencilVals);
 705
 706          for (i = 0; i < width; i++) {
 707             dst[i] = (dst[i] & 0xffffff00) | stencilVals[i];
 708          }
 709
 710          depthMap += depthStride;
 711          stencilMap += stencilStride;
 712          dst += dstStride / 4;
 713       }
 714    }
 715    else {
 716       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 717    }
 718
 719    free(stencilVals);
 720
 721    ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 722    ctx->Driver.UnmapRenderbuffer(ctx, stencilRb);
 723
 724    return GL_TRUE;
 725 }
 726
 727 static void
 728 slow_read_depth_stencil_pixels_separate(struct gl_context *ctx,
 729                                         GLint x, GLint y,
 730                                         GLsizei width, GLsizei height,
 731                                         GLenum type,
 732                                         const struct gl_pixelstore_attrib *packing,
 733                                         GLubyte *dst, int dstStride)
 734 {
 735    struct gl_framebuffer *fb = ctx->ReadBuffer;
 736    struct gl_renderbuffer *depthRb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 737    struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 738    GLubyte *depthMap, *stencilMap;
 739    int depthStride, stencilStride, j;
 740    GLubyte *stencilVals;
 741    GLfloat *depthVals;
 742
 743
 744    /* The depth and stencil buffers might be separate, or a single buffer.
 745     * If one buffer, only map it once.
 746     */
 747    ctx->Driver.MapRenderbuffer(ctx, depthRb, x, y, width, height,
 748                                GL_MAP_READ_BIT, &depthMap, &depthStride);
 749    if (!depthMap) {
 750       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 751       return;
 752    }
 753
 754    if (stencilRb != depthRb) {
 755       ctx->Driver.MapRenderbuffer(ctx, stencilRb, x, y, width, height,
 756                                   GL_MAP_READ_BIT, &stencilMap,
 757                                   &stencilStride);
 758       if (!stencilMap) {
 759          ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 760          _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 761          return;
 762       }
 763    }
 764    else {
 765       stencilMap = depthMap;
 766       stencilStride = depthStride;
 767    }
 768
 769    stencilVals = malloc(width * sizeof(GLubyte));
 770    depthVals = malloc(width * sizeof(GLfloat));
 771
 772    if (stencilVals && depthVals) {
 773       for (j = 0; j < height; j++) {
 774          _mesa_unpack_float_z_row(depthRb->Format, width, depthMap, depthVals);
 775          _mesa_unpack_ubyte_stencil_row(stencilRb->Format, width,
 776                                         stencilMap, stencilVals);
 777
 778          _mesa_pack_depth_stencil_span(ctx, width, type, (GLuint *)dst,
 779                                        depthVals, stencilVals, packing);
 780
 781          depthMap += depthStride;
 782          stencilMap += stencilStride;
 783          dst += dstStride;
 784       }
 785    }
 786    else {
 787       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 788    }
 789
 790    free(stencilVals);
 791    free(depthVals);
 792
 793    ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 794    if (stencilRb != depthRb) {
 795       ctx->Driver.UnmapRenderbuffer(ctx, stencilRb);
 796    }
 797 }
 798
 799
 800 /**
 801  * Read combined depth/stencil values.
 802  * We'll have already done error checking to be sure the expected
 803  * depth and stencil buffers really exist.
 804  */
 805 static void
 806 read_depth_stencil_pixels(struct gl_context *ctx,
 807                           GLint x, GLint y,
 808                           GLsizei width, GLsizei height,
 809                           GLenum type, GLvoid *pixels,
 810                           const struct gl_pixelstore_attrib *packing )
 811 {
 812    const GLboolean scaleOrBias
 813       = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
 814    const GLboolean stencilTransfer = ctx->Pixel.IndexShift
 815       || ctx->Pixel.IndexOffset || ctx->Pixel.MapStencilFlag;
 816    GLubyte *dst;
 817    int dstStride;
 818
 819    dst = (GLubyte *) _mesa_image_address2d(packing, pixels,
 820                                            width, height,
 821                                            GL_DEPTH_STENCIL_EXT,
 822                                            type, 0, 0);
 823    dstStride = _mesa_image_row_stride(packing, width,
 824                                       GL_DEPTH_STENCIL_EXT, type);
 825
 826    /* Fast 24/8 reads. */
 827    if (type == GL_UNSIGNED_INT_24_8 &&
 828        !scaleOrBias && !stencilTransfer && !packing->SwapBytes) {
 829       if (fast_read_depth_stencil_pixels(ctx, x, y, width, height,
 830                                          dst, dstStride))
 831          return;
 832
 833       if (fast_read_depth_stencil_pixels_separate(ctx, x, y, width, height,
 834                                                   (uint32_t *)dst, dstStride))
 835          return;
 836    }
 837
 838    slow_read_depth_stencil_pixels_separate(ctx, x, y, width, height,
 839                                            type, packing,
 840                                            dst, dstStride);
 841 }
 842
 843
 844
 845 /**
 846  * Software fallback routine for ctx->Driver.ReadPixels().
 847  * By time we get here, all error checking will have been done.
 848  */
 849 void
 850 _mesa_readpixels(struct gl_context *ctx,
 851                  GLint x, GLint y, GLsizei width, GLsizei height,
 852                  GLenum format, GLenum type,
 853                  const struct gl_pixelstore_attrib *packing,
 854                  GLvoid *pixels)
 855 {
 856    struct gl_pixelstore_attrib clippedPacking = *packing;
 857
 858    if (ctx->NewState)
 859       _mesa_update_state(ctx);
 860
 861    /* Do all needed clipping here, so that we can forget about it later */
 862    if (_mesa_clip_readpixels(ctx, &x, &y, &width, &height, &clippedPacking)) {
 863
 864       pixels = _mesa_map_pbo_dest(ctx, &clippedPacking, 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, &clippedPacking);
 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                                 &clippedPacking);
 879             break;
 880          case GL_DEPTH_COMPONENT:
 881             read_depth_pixels(ctx, x, y, width, height, type, pixels,
 882                               &clippedPacking);
 883             break;
 884          case GL_DEPTH_STENCIL_EXT:
 885             read_depth_stencil_pixels(ctx, x, y, width, height, type, pixels,
 886                                       &clippedPacking);
 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                              &clippedPacking);
 892          }
 893
 894          _mesa_unmap_pbo_dest(ctx, &clippedPacking);
 895       }
 896    }
 897 }
 898
 899
 900 static GLenum
 901 read_pixels_es3_error_check(GLenum format, GLenum type,
 902                             const struct gl_renderbuffer *rb)
 903 {
 904    const GLenum internalFormat = rb->InternalFormat;
 905    const GLenum data_type = _mesa_get_format_datatype(rb->Format);
 906    GLboolean is_unsigned_int = GL_FALSE;
 907    GLboolean is_signed_int = GL_FALSE;
 908
 909    if (!_mesa_is_color_format(internalFormat)) {
 910       return GL_INVALID_OPERATION;
 911    }
 912
 913    is_unsigned_int = _mesa_is_enum_format_unsigned_int(internalFormat);
 914    if (!is_unsigned_int) {
 915       is_signed_int = _mesa_is_enum_format_signed_int(internalFormat);
 916    }
 917
 918    switch (format) {
 919    case GL_RGBA:
 920       if (type == GL_FLOAT && data_type == GL_FLOAT)
 921          return GL_NO_ERROR; /* EXT_color_buffer_float */
 922       if (type == GL_UNSIGNED_BYTE && data_type == GL_UNSIGNED_NORMALIZED)
 923          return GL_NO_ERROR;
 924       if (internalFormat == GL_RGB10_A2 &&
 925           type == GL_UNSIGNED_INT_2_10_10_10_REV)
 926          return GL_NO_ERROR;
 927       if (internalFormat == GL_RGB10_A2UI && type == GL_UNSIGNED_BYTE)
 928          return GL_NO_ERROR;
 929       break;
 930    case GL_BGRA:
 931       /* GL_EXT_read_format_bgra */
 932       if (type == GL_UNSIGNED_BYTE ||
 933           type == GL_UNSIGNED_SHORT_4_4_4_4_REV ||
 934           type == GL_UNSIGNED_SHORT_1_5_5_5_REV)
 935          return GL_NO_ERROR;
 936       break;
 937    case GL_RGBA_INTEGER:
 938       if ((is_signed_int && type == GL_INT) ||
 939           (is_unsigned_int && type == GL_UNSIGNED_INT))
 940          return GL_NO_ERROR;
 941       break;
 942    }
 943
 944    return GL_INVALID_OPERATION;
 945 }
 946
 947
 948 void GLAPIENTRY
 949 _mesa_ReadnPixelsARB( GLint x, GLint y, GLsizei width, GLsizei height,
 950                       GLenum format, GLenum type, GLsizei bufSize,
 951                       GLvoid *pixels )
 952 {
 953    GLenum err = GL_NO_ERROR;
 954    struct gl_renderbuffer *rb;
 955
 956    GET_CURRENT_CONTEXT(ctx);
 957
 958    FLUSH_VERTICES(ctx, 0);
 959    FLUSH_CURRENT(ctx, 0);
 960
 961    if (MESA_VERBOSE & VERBOSE_API)
 962       _mesa_debug(ctx, "glReadPixels(%d, %d, %s, %s, %p)\n",
 963                   width, height,
 964                   _mesa_lookup_enum_by_nr(format),
 965                   _mesa_lookup_enum_by_nr(type),
 966                   pixels);
 967
 968    if (width < 0 || height < 0) {
 969       _mesa_error( ctx, GL_INVALID_VALUE,
 970                    "glReadPixels(width=%d height=%d)", width, height );
 971       return;
 972    }
 973
 974    if (ctx->NewState)
 975       _mesa_update_state(ctx);
 976
 977    if (ctx->ReadBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 978       _mesa_error(ctx, GL_INVALID_FRAMEBUFFER_OPERATION_EXT,
 979                   "glReadPixels(incomplete framebuffer)" );
 980       return;
 981    }
 982
 983    rb = _mesa_get_read_renderbuffer_for_format(ctx, format);
 984    if (rb == NULL) {
 985       _mesa_error(ctx, GL_INVALID_OPERATION,
 986                   "glReadPixels(read buffer)");
 987       return;
 988    }
 989
 990    /* OpenGL ES 1.x and OpenGL ES 2.0 impose additional restrictions on the
 991     * combinations of format and type that can be used.
 992     *
 993     * Technically, only two combinations are actually allowed:
 994     * GL_RGBA/GL_UNSIGNED_BYTE, and some implementation-specific internal
 995     * preferred combination.  This code doesn't know what that preferred
 996     * combination is, and Mesa can handle anything valid.  Just work instead.
 997     */
 998    if (_mesa_is_gles(ctx)) {
 999       if (ctx->API == API_OPENGLES2 &&
1000           _mesa_is_color_format(format) &&
1001           _mesa_get_color_read_format(ctx) == format &&
1002           _mesa_get_color_read_type(ctx) == type) {
1003          err = GL_NO_ERROR;
1004       } else if (ctx->Version < 30) {
1005          err = _mesa_es_error_check_format_and_type(format, type, 2);
1006          if (err == GL_NO_ERROR) {
1007             if (type == GL_FLOAT || type == GL_HALF_FLOAT_OES) {
1008                err = GL_INVALID_OPERATION;
1009             }
1010          }
1011       } else {
1012          err = read_pixels_es3_error_check(format, type, rb);
1013       }
1014
1015       if (err == GL_NO_ERROR && (format == GL_DEPTH_COMPONENT
1016           || format == GL_DEPTH_STENCIL)) {
1017          err = GL_INVALID_ENUM;
1018       }
1019
1020       if (err != GL_NO_ERROR) {
1021          _mesa_error(ctx, err, "glReadPixels(invalid format %s and/or type %s)",
1022                      _mesa_lookup_enum_by_nr(format),
1023                      _mesa_lookup_enum_by_nr(type));
1024          return;
1025       }
1026    }
1027
1028    err = _mesa_error_check_format_and_type(ctx, format, type);
1029    if (err != GL_NO_ERROR) {
1030       _mesa_error(ctx, err, "glReadPixels(invalid format %s and/or type %s)",
1031                   _mesa_lookup_enum_by_nr(format),
1032                   _mesa_lookup_enum_by_nr(type));
1033       return;
1034    }
1035
1036    if (_mesa_is_user_fbo(ctx->ReadBuffer) &&
1037        ctx->ReadBuffer->Visual.samples > 0) {
1038       _mesa_error(ctx, GL_INVALID_OPERATION, "glReadPixels(multisample FBO)");
1039       return;
1040    }
1041
1042    if (!_mesa_source_buffer_exists(ctx, format)) {
1043       _mesa_error(ctx, GL_INVALID_OPERATION, "glReadPixels(no readbuffer)");
1044       return;
1045    }
1046
1047    /* Check that the destination format and source buffer are both
1048     * integer-valued or both non-integer-valued.
1049     */
1050    if (ctx->Extensions.EXT_texture_integer && _mesa_is_color_format(format)) {
1051       const struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
1052       const GLboolean srcInteger = _mesa_is_format_integer_color(rb->Format);
1053       const GLboolean dstInteger = _mesa_is_enum_format_integer(format);
1054       if (dstInteger != srcInteger) {
1055          _mesa_error(ctx, GL_INVALID_OPERATION,
1056                      "glReadPixels(integer / non-integer format mismatch");
1057          return;
1058       }
1059    }
1060
1061    if (width == 0 || height == 0)
1062       return; /* nothing to do */
1063
1064    if (!_mesa_validate_pbo_access(2, &ctx->Pack, width, height, 1,
1065                                   format, type, bufSize, pixels)) {
1066       if (_mesa_is_bufferobj(ctx->Pack.BufferObj)) {
1067          _mesa_error(ctx, GL_INVALID_OPERATION,
1068                      "glReadPixels(out of bounds PBO access)");
1069       } else {
1070          _mesa_error(ctx, GL_INVALID_OPERATION,
1071                      "glReadnPixelsARB(out of bounds access:"
1072                      " bufSize (%d) is too small)", bufSize);
1073       }
1074       return;
1075    }
1076
1077    if (_mesa_is_bufferobj(ctx->Pack.BufferObj) &&
1078        _mesa_check_disallowed_mapping(ctx->Pack.BufferObj)) {
1079       /* buffer is mapped - that's an error */
1080       _mesa_error(ctx, GL_INVALID_OPERATION, "glReadPixels(PBO is mapped)");
1081       return;
1082    }
1083
1084    ctx->Driver.ReadPixels(ctx, x, y, width, height,
1085                           format, type, &ctx->Pack, pixels);
1086 }
1087
1088 void GLAPIENTRY
1089 _mesa_ReadPixels( GLint x, GLint y, GLsizei width, GLsizei height,
1090                   GLenum format, GLenum type, GLvoid *pixels )
1091 {
1092    _mesa_ReadnPixelsARB(x, y, width, height, format, type, INT_MAX, pixels);
1093 }