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, bytesPerRow;
 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    bytesPerRow = texelBytes * width;
 243
 244    /* memcpy*/
 245    if (dstStride == stride && dstStride == bytesPerRow) {
 246       memcpy(dst, map, bytesPerRow * height);
 247    } else {
 248       for (j = 0; j < height; j++) {
 249          memcpy(dst, map, bytesPerRow);
 250          dst += dstStride;
 251          map += stride;
 252       }
 253    }
 254
 255    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 256    return GL_TRUE;
 257 }
 258
 259
 260 /**
 261  * Optimized path for conversion of depth values to GL_DEPTH_COMPONENT,
 262  * GL_UNSIGNED_INT.
 263  */
 264 static GLboolean
 265 read_uint_depth_pixels( struct gl_context *ctx,
 266                         GLint x, GLint y,
 267                         GLsizei width, GLsizei height,
 268                         GLenum type, GLvoid *pixels,
 269                         const struct gl_pixelstore_attrib *packing )
 270 {
 271    struct gl_framebuffer *fb = ctx->ReadBuffer;
 272    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 273    GLubyte *map, *dst;
 274    int stride, dstStride, j;
 275
 276    if (ctx->Pixel.DepthScale != 1.0F || ctx->Pixel.DepthBias != 0.0F)
 277       return GL_FALSE;
 278
 279    if (packing->SwapBytes)
 280       return GL_FALSE;
 281
 282    if (_mesa_get_format_datatype(rb->Format) != GL_UNSIGNED_NORMALIZED)
 283       return GL_FALSE;
 284
 285    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 286                                &map, &stride);
 287
 288    if (!map) {
 289       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 290       return GL_TRUE;  /* don't bother trying the slow path */
 291    }
 292
 293    dstStride = _mesa_image_row_stride(packing, width, GL_DEPTH_COMPONENT, type);
 294    dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 295                                            GL_DEPTH_COMPONENT, type, 0, 0);
 296
 297    for (j = 0; j < height; j++) {
 298       _mesa_unpack_uint_z_row(rb->Format, width, map, (GLuint *)dst);
 299
 300       map += stride;
 301       dst += dstStride;
 302    }
 303    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 304
 305    return GL_TRUE;
 306 }
 307
 308 /**
 309  * Read pixels for format=GL_DEPTH_COMPONENT.
 310  */
 311 static void
 312 read_depth_pixels( struct gl_context *ctx,
 313                    GLint x, GLint y,
 314                    GLsizei width, GLsizei height,
 315                    GLenum type, GLvoid *pixels,
 316                    const struct gl_pixelstore_attrib *packing )
 317 {
 318    struct gl_framebuffer *fb = ctx->ReadBuffer;
 319    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 320    GLint j;
 321    GLubyte *dst, *map;
 322    int dstStride, stride;
 323    GLfloat *depthValues;
 324
 325    if (!rb)
 326       return;
 327
 328    /* clipping should have been done already */
 329    assert(x >= 0);
 330    assert(y >= 0);
 331    assert(x + width <= (GLint) rb->Width);
 332    assert(y + height <= (GLint) rb->Height);
 333
 334    if (type == GL_UNSIGNED_INT &&
 335        read_uint_depth_pixels(ctx, x, y, width, height, type, pixels, packing)) {
 336       return;
 337    }
 338
 339    dstStride = _mesa_image_row_stride(packing, width, GL_DEPTH_COMPONENT, type);
 340    dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 341                                            GL_DEPTH_COMPONENT, type, 0, 0);
 342
 343    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 344                                &map, &stride);
 345    if (!map) {
 346       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 347       return;
 348    }
 349
 350    depthValues = malloc(width * sizeof(GLfloat));
 351
 352    if (depthValues) {
 353       /* General case (slower) */
 354       for (j = 0; j < height; j++, y++) {
 355          _mesa_unpack_float_z_row(rb->Format, width, map, depthValues);
 356          _mesa_pack_depth_span(ctx, width, dst, type, depthValues, packing);
 357
 358          dst += dstStride;
 359          map += stride;
 360       }
 361    }
 362    else {
 363       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 364    }
 365
 366    free(depthValues);
 367
 368    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 369 }
 370
 371
 372 /**
 373  * Read pixels for format=GL_STENCIL_INDEX.
 374  */
 375 static void
 376 read_stencil_pixels( struct gl_context *ctx,
 377                      GLint x, GLint y,
 378                      GLsizei width, GLsizei height,
 379                      GLenum type, GLvoid *pixels,
 380                      const struct gl_pixelstore_attrib *packing )
 381 {
 382    struct gl_framebuffer *fb = ctx->ReadBuffer;
 383    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 384    GLint j;
 385    GLubyte *map, *stencil;
 386    GLint stride;
 387
 388    if (!rb)
 389       return;
 390
 391    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 392                                &map, &stride);
 393    if (!map) {
 394       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 395       return;
 396    }
 397
 398    stencil = malloc(width * sizeof(GLubyte));
 399
 400    if (stencil) {
 401       /* process image row by row */
 402       for (j = 0; j < height; j++) {
 403          GLvoid *dest;
 404
 405          _mesa_unpack_ubyte_stencil_row(rb->Format, width, map, stencil);
 406          dest = _mesa_image_address2d(packing, pixels, width, height,
 407                                       GL_STENCIL_INDEX, type, j, 0);
 408
 409          _mesa_pack_stencil_span(ctx, width, type, dest, stencil, packing);
 410
 411          map += stride;
 412       }
 413    }
 414    else {
 415       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 416    }
 417
 418    free(stencil);
 419
 420    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 421 }
 422
 423 /*
 424  * Read R, G, B, A, RGB, L, or LA pixels.
 425  */
 426 static void
 427 read_rgba_pixels( struct gl_context *ctx,
 428                   GLint x, GLint y,
 429                   GLsizei width, GLsizei height,
 430                   GLenum format, GLenum type, GLvoid *pixels,
 431                   const struct gl_pixelstore_attrib *packing )
 432 {
 433    GLbitfield transferOps;
 434    bool dst_is_integer, convert_rgb_to_lum, needs_rebase;
 435    int dst_stride, src_stride, rb_stride;
 436    uint32_t dst_format, src_format;
 437    GLubyte *dst, *map;
 438    mesa_format rb_format;
 439    bool needs_rgba;
 440    void *rgba, *src;
 441    bool src_is_uint = false;
 442    uint8_t rebase_swizzle[4];
 443    struct gl_framebuffer *fb = ctx->ReadBuffer;
 444    struct gl_renderbuffer *rb = fb->_ColorReadBuffer;
 445    GLenum dstBaseFormat = _mesa_unpack_format_to_base_format(format);
 446
 447    if (!rb)
 448       return;
 449
 450    transferOps = _mesa_get_readpixels_transfer_ops(ctx, rb->Format, format,
 451                                                    type, GL_FALSE);
 452    /* Describe the dst format */
 453    dst_is_integer = _mesa_is_enum_format_integer(format);
 454    dst_stride = _mesa_image_row_stride(packing, width, format, type);
 455    dst_format = _mesa_format_from_format_and_type(format, type);
 456    convert_rgb_to_lum =
 457       _mesa_need_rgb_to_luminance_conversion(rb->_BaseFormat, dstBaseFormat);
 458    dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 459                                            format, type, 0, 0);
 460
 461    /* Map the source render buffer */
 462    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 463                                &map, &rb_stride);
 464    if (!map) {
 465       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 466       return;
 467    }
 468    rb_format = _mesa_get_srgb_format_linear(rb->Format);
 469
 470    /*
 471     * Depending on the base formats involved in the conversion we might need to
 472     * rebase some values, so for these formats we compute a rebase swizzle.
 473     */
 474    if (rb->_BaseFormat == GL_LUMINANCE || rb->_BaseFormat == GL_INTENSITY) {
 475       needs_rebase = true;
 476       rebase_swizzle[0] = MESA_FORMAT_SWIZZLE_X;
 477       rebase_swizzle[1] = MESA_FORMAT_SWIZZLE_ZERO;
 478       rebase_swizzle[2] = MESA_FORMAT_SWIZZLE_ZERO;
 479       rebase_swizzle[3] = MESA_FORMAT_SWIZZLE_ONE;
 480    } else if (rb->_BaseFormat == GL_LUMINANCE_ALPHA) {
 481       needs_rebase = true;
 482       rebase_swizzle[0] = MESA_FORMAT_SWIZZLE_X;
 483       rebase_swizzle[1] = MESA_FORMAT_SWIZZLE_ZERO;
 484       rebase_swizzle[2] = MESA_FORMAT_SWIZZLE_ZERO;
 485       rebase_swizzle[3] = MESA_FORMAT_SWIZZLE_W;
 486    } else if (_mesa_get_format_base_format(rb_format) != rb->_BaseFormat) {
 487       needs_rebase =
 488          _mesa_compute_rgba2base2rgba_component_mapping(rb->_BaseFormat,
 489                                                         rebase_swizzle);
 490    } else {
 491       needs_rebase = false;
 492    }
 493
 494    /* Since _mesa_format_convert does not handle transferOps we need to handle
 495     * them before we call the function. This requires to convert to RGBA float
 496     * first so we can call _mesa_apply_rgba_transfer_ops. If the dst format is
 497     * integer transferOps do not apply.
 498     *
 499     * Converting to luminance also requires converting to RGBA first, so we can
 500     * then compute luminance values as L=R+G+B. Notice that this is different
 501     * from GetTexImage, where we compute L=R.
 502     */
 503    assert(!transferOps || (transferOps && !dst_is_integer));
 504
 505    needs_rgba = transferOps || convert_rgb_to_lum;
 506    rgba = NULL;
 507    if (needs_rgba) {
 508       uint32_t rgba_format;
 509       int rgba_stride;
 510       bool need_convert;
 511
 512       /* Convert to RGBA float or int/uint depending on the type of the src */
 513       if (dst_is_integer) {
 514          src_is_uint = _mesa_is_format_unsigned(rb_format);
 515          if (src_is_uint) {
 516             rgba_format = RGBA32_UINT;
 517             rgba_stride = width * 4 * sizeof(GLuint);
 518          } else {
 519             rgba_format = RGBA32_INT;
 520             rgba_stride = width * 4 * sizeof(GLint);
 521          }
 522       } else {
 523          rgba_format = RGBA32_FLOAT;
 524          rgba_stride = width * 4 * sizeof(GLfloat);
 525       }
 526
 527       /* If we are lucky and the dst format matches the RGBA format we need to
 528        * convert to, then we can convert directly into the dst buffer and avoid
 529        * the final conversion/copy from the rgba buffer to the dst buffer.
 530        */
 531       if (dst_format == rgba_format &&
 532           dst_stride == rgba_stride) {
 533          need_convert = false;
 534          rgba = dst;
 535       } else {
 536          need_convert = true;
 537          rgba = malloc(height * rgba_stride);
 538          if (!rgba) {
 539             _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 540             goto done_unmap;
 541          }
 542       }
 543
 544       /* Convert to RGBA now */
 545       _mesa_format_convert(rgba, rgba_format, rgba_stride,
 546                            map, rb_format, rb_stride,
 547                            width, height,
 548                            needs_rebase ? rebase_swizzle : NULL);
 549
 550       /* Handle transfer ops if necessary */
 551       if (transferOps)
 552          _mesa_apply_rgba_transfer_ops(ctx, transferOps, width * height, rgba);
 553
 554       /* If we had to rebase, we have already taken care of that */
 555       needs_rebase = false;
 556
 557       /* If we were lucky and our RGBA conversion matches the dst format, then
 558        * we are done.
 559        */
 560       if (!need_convert)
 561          goto done_swap;
 562
 563       /* Otherwise, we need to convert from RGBA to dst next */
 564       src = rgba;
 565       src_format = rgba_format;
 566       src_stride = rgba_stride;
 567    } else {
 568       /* No RGBA conversion needed, convert directly to dst */
 569       src = map;
 570       src_format = rb_format;
 571       src_stride = rb_stride;
 572    }
 573
 574    /* Do the conversion.
 575     *
 576     * If the dst format is Luminance, we need to do the conversion by computing
 577     * L=R+G+B values.
 578     */
 579    if (!convert_rgb_to_lum) {
 580       _mesa_format_convert(dst, dst_format, dst_stride,
 581                            src, src_format, src_stride,
 582                            width, height,
 583                            needs_rebase ? rebase_swizzle : NULL);
 584    } else if (!dst_is_integer) {
 585       /* Compute float Luminance values from RGBA float */
 586       int luminance_stride, luminance_bytes;
 587       void *luminance;
 588       uint32_t luminance_format;
 589
 590       luminance_stride = width * sizeof(GLfloat);
 591       if (format == GL_LUMINANCE_ALPHA)
 592          luminance_stride *= 2;
 593       luminance_bytes = height * luminance_stride;
 594       luminance = malloc(luminance_bytes);
 595       if (!luminance) {
 596          _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 597          free(rgba);
 598          goto done_unmap;
 599       }
 600       _mesa_pack_luminance_from_rgba_float(width * height, src,
 601                                            luminance, format, transferOps);
 602
 603       /* Convert from Luminance float to dst (this will hadle type conversion
 604        * from float to the type of dst if necessary)
 605        */
 606       luminance_format = _mesa_format_from_format_and_type(format, GL_FLOAT);
 607       _mesa_format_convert(dst, dst_format, dst_stride,
 608                            luminance, luminance_format, luminance_stride,
 609                            width, height, NULL);
 610       free(luminance);
 611    } else {
 612       _mesa_pack_luminance_from_rgba_integer(width * height, src, !src_is_uint,
 613                                              dst, format, type);
 614    }
 615
 616    free(rgba);
 617
 618 done_swap:
 619    /* Handle byte swapping if required */
 620    if (packing->SwapBytes) {
 621       _mesa_swap_bytes_2d_image(format, type, packing,
 622                                 width, height, dst, dst);
 623    }
 624
 625 done_unmap:
 626    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 627 }
 628
 629 /**
 630  * For a packed depth/stencil buffer being read as depth/stencil, just memcpy the
 631  * data (possibly swapping 8/24 vs 24/8 as we go).
 632  */
 633 static GLboolean
 634 fast_read_depth_stencil_pixels(struct gl_context *ctx,
 635                                GLint x, GLint y,
 636                                GLsizei width, GLsizei height,
 637                                GLubyte *dst, int dstStride)
 638 {
 639    struct gl_framebuffer *fb = ctx->ReadBuffer;
 640    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 641    struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 642    GLubyte *map;
 643    int stride, i;
 644
 645    if (rb != stencilRb)
 646       return GL_FALSE;
 647
 648    if (rb->Format != MESA_FORMAT_S8_UINT_Z24_UNORM &&
 649        rb->Format != MESA_FORMAT_Z24_UNORM_S8_UINT)
 650       return GL_FALSE;
 651
 652    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 653                                &map, &stride);
 654    if (!map) {
 655       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 656       return GL_TRUE;  /* don't bother trying the slow path */
 657    }
 658
 659    for (i = 0; i < height; i++) {
 660       _mesa_unpack_uint_24_8_depth_stencil_row(rb->Format, width,
 661                                                map, (GLuint *)dst);
 662       map += stride;
 663       dst += dstStride;
 664    }
 665
 666    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 667
 668    return GL_TRUE;
 669 }
 670
 671
 672 /**
 673  * For non-float-depth and stencil buffers being read as 24/8 depth/stencil,
 674  * copy the integer data directly instead of converting depth to float and
 675  * re-packing.
 676  */
 677 static GLboolean
 678 fast_read_depth_stencil_pixels_separate(struct gl_context *ctx,
 679                                         GLint x, GLint y,
 680                                         GLsizei width, GLsizei height,
 681                                         uint32_t *dst, int dstStride)
 682 {
 683    struct gl_framebuffer *fb = ctx->ReadBuffer;
 684    struct gl_renderbuffer *depthRb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 685    struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 686    GLubyte *depthMap, *stencilMap, *stencilVals;
 687    int depthStride, stencilStride, i, j;
 688
 689    if (_mesa_get_format_datatype(depthRb->Format) != GL_UNSIGNED_NORMALIZED)
 690       return GL_FALSE;
 691
 692    ctx->Driver.MapRenderbuffer(ctx, depthRb, x, y, width, height,
 693                                GL_MAP_READ_BIT, &depthMap, &depthStride);
 694    if (!depthMap) {
 695       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 696       return GL_TRUE;  /* don't bother trying the slow path */
 697    }
 698
 699    ctx->Driver.MapRenderbuffer(ctx, stencilRb, x, y, width, height,
 700                                GL_MAP_READ_BIT, &stencilMap, &stencilStride);
 701    if (!stencilMap) {
 702       ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 703       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 704       return GL_TRUE;  /* don't bother trying the slow path */
 705    }
 706
 707    stencilVals = malloc(width * sizeof(GLubyte));
 708
 709    if (stencilVals) {
 710       for (j = 0; j < height; j++) {
 711          _mesa_unpack_uint_z_row(depthRb->Format, width, depthMap, dst);
 712          _mesa_unpack_ubyte_stencil_row(stencilRb->Format, width,
 713                                         stencilMap, stencilVals);
 714
 715          for (i = 0; i < width; i++) {
 716             dst[i] = (dst[i] & 0xffffff00) | stencilVals[i];
 717          }
 718
 719          depthMap += depthStride;
 720          stencilMap += stencilStride;
 721          dst += dstStride / 4;
 722       }
 723    }
 724    else {
 725       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 726    }
 727
 728    free(stencilVals);
 729
 730    ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 731    ctx->Driver.UnmapRenderbuffer(ctx, stencilRb);
 732
 733    return GL_TRUE;
 734 }
 735
 736 static void
 737 slow_read_depth_stencil_pixels_separate(struct gl_context *ctx,
 738                                         GLint x, GLint y,
 739                                         GLsizei width, GLsizei height,
 740                                         GLenum type,
 741                                         const struct gl_pixelstore_attrib *packing,
 742                                         GLubyte *dst, int dstStride)
 743 {
 744    struct gl_framebuffer *fb = ctx->ReadBuffer;
 745    struct gl_renderbuffer *depthRb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 746    struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 747    GLubyte *depthMap, *stencilMap;
 748    int depthStride, stencilStride, j;
 749    GLubyte *stencilVals;
 750    GLfloat *depthVals;
 751
 752
 753    /* The depth and stencil buffers might be separate, or a single buffer.
 754     * If one buffer, only map it once.
 755     */
 756    ctx->Driver.MapRenderbuffer(ctx, depthRb, x, y, width, height,
 757                                GL_MAP_READ_BIT, &depthMap, &depthStride);
 758    if (!depthMap) {
 759       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 760       return;
 761    }
 762
 763    if (stencilRb != depthRb) {
 764       ctx->Driver.MapRenderbuffer(ctx, stencilRb, x, y, width, height,
 765                                   GL_MAP_READ_BIT, &stencilMap,
 766                                   &stencilStride);
 767       if (!stencilMap) {
 768          ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 769          _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 770          return;
 771       }
 772    }
 773    else {
 774       stencilMap = depthMap;
 775       stencilStride = depthStride;
 776    }
 777
 778    stencilVals = malloc(width * sizeof(GLubyte));
 779    depthVals = malloc(width * sizeof(GLfloat));
 780
 781    if (stencilVals && depthVals) {
 782       for (j = 0; j < height; j++) {
 783          _mesa_unpack_float_z_row(depthRb->Format, width, depthMap, depthVals);
 784          _mesa_unpack_ubyte_stencil_row(stencilRb->Format, width,
 785                                         stencilMap, stencilVals);
 786
 787          _mesa_pack_depth_stencil_span(ctx, width, type, (GLuint *)dst,
 788                                        depthVals, stencilVals, packing);
 789
 790          depthMap += depthStride;
 791          stencilMap += stencilStride;
 792          dst += dstStride;
 793       }
 794    }
 795    else {
 796       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 797    }
 798
 799    free(stencilVals);
 800    free(depthVals);
 801
 802    ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 803    if (stencilRb != depthRb) {
 804       ctx->Driver.UnmapRenderbuffer(ctx, stencilRb);
 805    }
 806 }
 807
 808
 809 /**
 810  * Read combined depth/stencil values.
 811  * We'll have already done error checking to be sure the expected
 812  * depth and stencil buffers really exist.
 813  */
 814 static void
 815 read_depth_stencil_pixels(struct gl_context *ctx,
 816                           GLint x, GLint y,
 817                           GLsizei width, GLsizei height,
 818                           GLenum type, GLvoid *pixels,
 819                           const struct gl_pixelstore_attrib *packing )
 820 {
 821    const GLboolean scaleOrBias
 822       = ctx->Pixel.DepthScale != 1.0F || ctx->Pixel.DepthBias != 0.0F;
 823    const GLboolean stencilTransfer = ctx->Pixel.IndexShift
 824       || ctx->Pixel.IndexOffset || ctx->Pixel.MapStencilFlag;
 825    GLubyte *dst;
 826    int dstStride;
 827
 828    dst = (GLubyte *) _mesa_image_address2d(packing, pixels,
 829                                            width, height,
 830                                            GL_DEPTH_STENCIL_EXT,
 831                                            type, 0, 0);
 832    dstStride = _mesa_image_row_stride(packing, width,
 833                                       GL_DEPTH_STENCIL_EXT, type);
 834
 835    /* Fast 24/8 reads. */
 836    if (type == GL_UNSIGNED_INT_24_8 &&
 837        !scaleOrBias && !stencilTransfer && !packing->SwapBytes) {
 838       if (fast_read_depth_stencil_pixels(ctx, x, y, width, height,
 839                                          dst, dstStride))
 840          return;
 841
 842       if (fast_read_depth_stencil_pixels_separate(ctx, x, y, width, height,
 843                                                   (uint32_t *)dst, dstStride))
 844          return;
 845    }
 846
 847    slow_read_depth_stencil_pixels_separate(ctx, x, y, width, height,
 848                                            type, packing,
 849                                            dst, dstStride);
 850 }
 851
 852
 853
 854 /**
 855  * Software fallback routine for ctx->Driver.ReadPixels().
 856  * By time we get here, all error checking will have been done.
 857  */
 858 void
 859 _mesa_readpixels(struct gl_context *ctx,
 860                  GLint x, GLint y, GLsizei width, GLsizei height,
 861                  GLenum format, GLenum type,
 862                  const struct gl_pixelstore_attrib *packing,
 863                  GLvoid *pixels)
 864 {
 865    if (ctx->NewState)
 866       _mesa_update_state(ctx);
 867
 868    pixels = _mesa_map_pbo_dest(ctx, packing, 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, packing);
 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                              packing);
 883          break;
 884       case GL_DEPTH_COMPONENT:
 885          read_depth_pixels(ctx, x, y, width, height, type, pixels,
 886                            packing);
 887          break;
 888       case GL_DEPTH_STENCIL_EXT:
 889          read_depth_stencil_pixels(ctx, x, y, width, height, type, pixels,
 890                                    packing);
 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                           packing);
 896       }
 897
 898       _mesa_unmap_pbo_dest(ctx, packing);
 899    }
 900 }
 901
 902
 903 static GLenum
 904 read_pixels_es3_error_check(GLenum format, GLenum type,
 905                             const struct gl_renderbuffer *rb)
 906 {
 907    const GLenum internalFormat = rb->InternalFormat;
 908    const GLenum data_type = _mesa_get_format_datatype(rb->Format);
 909    GLboolean is_unsigned_int = GL_FALSE;
 910    GLboolean is_signed_int = GL_FALSE;
 911    GLboolean is_float_depth = (internalFormat == GL_DEPTH_COMPONENT32F) ||
 912          (internalFormat == GL_DEPTH32F_STENCIL8);
 913
 914    is_unsigned_int = _mesa_is_enum_format_unsigned_int(internalFormat);
 915    if (!is_unsigned_int) {
 916       is_signed_int = _mesa_is_enum_format_signed_int(internalFormat);
 917    }
 918
 919    switch (format) {
 920    case GL_RGBA:
 921       if (type == GL_FLOAT && data_type == GL_FLOAT)
 922          return GL_NO_ERROR; /* EXT_color_buffer_float */
 923       if (type == GL_UNSIGNED_BYTE && data_type == GL_UNSIGNED_NORMALIZED)
 924          return GL_NO_ERROR;
 925       if (internalFormat == GL_RGB10_A2 &&
 926           type == GL_UNSIGNED_INT_2_10_10_10_REV)
 927          return GL_NO_ERROR;
 928       if (internalFormat == GL_RGB10_A2UI && type == GL_UNSIGNED_BYTE)
 929          return GL_NO_ERROR;
 930       break;
 931    case GL_BGRA:
 932       /* GL_EXT_read_format_bgra */
 933       if (type == GL_UNSIGNED_BYTE ||
 934           type == GL_UNSIGNED_SHORT_4_4_4_4_REV ||
 935           type == GL_UNSIGNED_SHORT_1_5_5_5_REV)
 936          return GL_NO_ERROR;
 937       break;
 938    case GL_RGBA_INTEGER:
 939       if ((is_signed_int && type == GL_INT) ||
 940           (is_unsigned_int && type == GL_UNSIGNED_INT))
 941          return GL_NO_ERROR;
 942       break;
 943    case GL_DEPTH_STENCIL:
 944       switch (type) {
 945       case GL_FLOAT_32_UNSIGNED_INT_24_8_REV:
 946          if (is_float_depth)
 947             return GL_NO_ERROR;
 948          break;
 949       case GL_UNSIGNED_INT_24_8:
 950          if (!is_float_depth)
 951             return GL_NO_ERROR;
 952          break;
 953       default:
 954          return GL_INVALID_ENUM;
 955       }
 956       break;
 957    case GL_DEPTH_COMPONENT:
 958       switch (type) {
 959       case GL_FLOAT:
 960          if (is_float_depth)
 961             return GL_NO_ERROR;
 962          break;
 963       case GL_UNSIGNED_SHORT:
 964       case GL_UNSIGNED_INT:
 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 static ALWAYS_INLINE void
 988 read_pixels(GLint x, GLint y, GLsizei width, GLsizei height, GLenum format,
 989             GLenum type, GLsizei bufSize, GLvoid *pixels, bool no_error)
 990 {
 991    GLenum err = GL_NO_ERROR;
 992    struct gl_renderbuffer *rb;
 993    struct gl_pixelstore_attrib clippedPacking;
 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 (!no_error && (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 (!no_error && 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 (!no_error) {
1024       if (rb == NULL) {
1025          _mesa_error(ctx, GL_INVALID_OPERATION,
1026                      "glReadPixels(read buffer)");
1027          return;
1028       }
1029
1030       /* OpenGL ES 1.x and OpenGL ES 2.0 impose additional restrictions on the
1031        * combinations of format and type that can be used.
1032        *
1033        * Technically, only two combinations are actually allowed:
1034        * GL_RGBA/GL_UNSIGNED_BYTE, and some implementation-specific internal
1035        * preferred combination.  This code doesn't know what that preferred
1036        * combination is, and Mesa can handle anything valid.  Just work instead.
1037        */
1038       if (_mesa_is_gles(ctx)) {
1039          if (ctx->API == API_OPENGLES2 &&
1040              _mesa_is_color_format(format) &&
1041              _mesa_get_color_read_format(ctx, NULL, "glReadPixels") == format &&
1042              _mesa_get_color_read_type(ctx, NULL, "glReadPixels") == type) {
1043             err = GL_NO_ERROR;
1044          } else if (ctx->Version < 30) {
1045             err = _mesa_es_error_check_format_and_type(ctx, format, type, 2);
1046             if (err == GL_NO_ERROR) {
1047                if (type == GL_FLOAT || type == GL_HALF_FLOAT_OES) {
1048                   err = GL_INVALID_OPERATION;
1049                }
1050             }
1051          } else {
1052             err = read_pixels_es3_error_check(format, type, rb);
1053          }
1054
1055          if (err != GL_NO_ERROR) {
1056             _mesa_error(ctx, err, "glReadPixels(invalid format %s and/or type %s)",
1057                         _mesa_enum_to_string(format),
1058                         _mesa_enum_to_string(type));
1059             return;
1060          }
1061       }
1062
1063       err = _mesa_error_check_format_and_type(ctx, format, type);
1064       if (err != GL_NO_ERROR) {
1065          _mesa_error(ctx, err, "glReadPixels(invalid format %s and/or type %s)",
1066                      _mesa_enum_to_string(format),
1067                      _mesa_enum_to_string(type));
1068          return;
1069       }
1070
1071       if (_mesa_is_user_fbo(ctx->ReadBuffer) &&
1072           ctx->ReadBuffer->Visual.samples > 0) {
1073          _mesa_error(ctx, GL_INVALID_OPERATION, "glReadPixels(multisample FBO)");
1074          return;
1075       }
1076
1077       if (!_mesa_source_buffer_exists(ctx, format)) {
1078          _mesa_error(ctx, GL_INVALID_OPERATION, "glReadPixels(no readbuffer)");
1079          return;
1080       }
1081
1082       /* Check that the destination format and source buffer are both
1083        * integer-valued or both non-integer-valued.
1084        */
1085       if (ctx->Extensions.EXT_texture_integer && _mesa_is_color_format(format)) {
1086          const struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
1087          const GLboolean srcInteger = _mesa_is_format_integer_color(rb->Format);
1088          const GLboolean dstInteger = _mesa_is_enum_format_integer(format);
1089          if (dstInteger != srcInteger) {
1090             _mesa_error(ctx, GL_INVALID_OPERATION,
1091                         "glReadPixels(integer / non-integer format mismatch");
1092             return;
1093          }
1094       }
1095    }
1096
1097    /* Do all needed clipping here, so that we can forget about it later */
1098    clippedPacking = ctx->Pack;
1099    if (!_mesa_clip_readpixels(ctx, &x, &y, &width, &height, &clippedPacking))
1100       return; /* nothing to do */
1101
1102    if (!no_error) {
1103       if (!_mesa_validate_pbo_access(2, &ctx->Pack, width, height, 1,
1104                                      format, type, bufSize, pixels)) {
1105          if (_mesa_is_bufferobj(ctx->Pack.BufferObj)) {
1106             _mesa_error(ctx, GL_INVALID_OPERATION,
1107                         "glReadPixels(out of bounds PBO access)");
1108          } else {
1109             _mesa_error(ctx, GL_INVALID_OPERATION,
1110                         "glReadnPixelsARB(out of bounds access:"
1111                         " bufSize (%d) is too small)", bufSize);
1112          }
1113          return;
1114       }
1115
1116       if (_mesa_is_bufferobj(ctx->Pack.BufferObj) &&
1117           _mesa_check_disallowed_mapping(ctx->Pack.BufferObj)) {
1118          /* buffer is mapped - that's an error */
1119          _mesa_error(ctx, GL_INVALID_OPERATION, "glReadPixels(PBO is mapped)");
1120          return;
1121       }
1122    }
1123
1124    ctx->Driver.ReadPixels(ctx, x, y, width, height,
1125                           format, type, &clippedPacking, pixels);
1126 }
1127
1128 void GLAPIENTRY
1129 _mesa_ReadnPixelsARB_no_error(GLint x, GLint y, GLsizei width, GLsizei height,
1130                               GLenum format, GLenum type, GLsizei bufSize,
1131                               GLvoid *pixels)
1132 {
1133    read_pixels(x, y, width, height, format, type, bufSize, pixels, true);
1134 }
1135
1136 void GLAPIENTRY
1137 _mesa_ReadnPixelsARB(GLint x, GLint y, GLsizei width, GLsizei height,
1138                      GLenum format, GLenum type, GLsizei bufSize,
1139                      GLvoid *pixels)
1140 {
1141    read_pixels(x, y, width, height, format, type, bufSize, pixels, false);
1142 }
1143
1144 void GLAPIENTRY
1145 _mesa_ReadPixels_no_error(GLint x, GLint y, GLsizei width, GLsizei height,
1146                           GLenum format, GLenum type, GLvoid *pixels)
1147 {
1148    _mesa_ReadnPixelsARB_no_error(x, y, width, height, format, type, INT_MAX,
1149                                  pixels);
1150 }
1151
1152 void GLAPIENTRY
1153 _mesa_ReadPixels(GLint x, GLint y, GLsizei width, GLsizei height,
1154                  GLenum format, GLenum type, GLvoid *pixels)
1155 {
1156    _mesa_ReadnPixelsARB(x, y, width, height, format, type, INT_MAX, pixels);
1157 }