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(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 ||
  58            format == GL_LUMINANCE_ALPHA ||
  59            format == GL_LUMINANCE_INTEGER_EXT ||
  60            format == GL_LUMINANCE_ALPHA_INTEGER_EXT);
  61 }
  62
  63
  64 /**
  65  * Return transfer op flags for this ReadPixels operation.
  66  */
  67 static GLbitfield
  68 get_readpixels_transfer_ops(const struct gl_context *ctx, mesa_format texFormat,
  69                             GLenum format, GLenum type, GLboolean uses_blit)
  70 {
  71    GLbitfield transferOps = ctx->_ImageTransferState;
  72
  73    if (format == GL_DEPTH_COMPONENT ||
  74        format == GL_DEPTH_STENCIL ||
  75        format == GL_STENCIL_INDEX) {
  76       return 0;
  77    }
  78
  79    /* Pixel transfer ops (scale, bias, table lookup) do not apply
  80     * to integer formats.
  81     */
  82    if (_mesa_is_enum_format_integer(format)) {
  83       return 0;
  84    }
  85
  86    if (uses_blit) {
  87       /* For blit-based ReadPixels packing, the clamping is done automatically
  88        * unless the type is float. */
  89       if (_mesa_get_clamp_read_color(ctx, ctx->ReadBuffer) &&
  90           (type == GL_FLOAT || type == GL_HALF_FLOAT)) {
  91          transferOps |= IMAGE_CLAMP_BIT;
  92       }
  93    }
  94    else {
  95       /* For CPU-based ReadPixels packing, the clamping must always be done
  96        * for non-float types, */
  97       if (_mesa_get_clamp_read_color(ctx, ctx->ReadBuffer) ||
  98           (type != GL_FLOAT && type != GL_HALF_FLOAT)) {
  99          transferOps |= IMAGE_CLAMP_BIT;
 100       }
 101    }
 102
 103    /* If the format is unsigned normalized, we can ignore clamping
 104     * because the values are already in the range [0,1] so it won't
 105     * have any effect anyway.
 106     */
 107    if (_mesa_get_format_datatype(texFormat) == GL_UNSIGNED_NORMALIZED &&
 108        !_mesa_need_rgb_to_luminance_conversion(texFormat, format)) {
 109       transferOps &= ~IMAGE_CLAMP_BIT;
 110    }
 111
 112    return transferOps;
 113 }
 114
 115
 116 /**
 117  * Return true if memcpy cannot be used for ReadPixels.
 118  *
 119  * If uses_blit is true, the function returns true if a simple 3D engine blit
 120  * cannot be used for ReadPixels packing.
 121  *
 122  * NOTE: This doesn't take swizzling and format conversions between
 123  *       the readbuffer and the pixel pack buffer into account.
 124  */
 125 GLboolean
 126 _mesa_readpixels_needs_slow_path(const struct gl_context *ctx, GLenum format,
 127                                  GLenum type, GLboolean uses_blit)
 128 {
 129    struct gl_renderbuffer *rb =
 130          _mesa_get_read_renderbuffer_for_format(ctx, format);
 131    GLenum srcType;
 132
 133    assert(rb);
 134
 135    /* There are different rules depending on the base format. */
 136    switch (format) {
 137    case GL_DEPTH_STENCIL:
 138       return !_mesa_has_depthstencil_combined(ctx->ReadBuffer) ||
 139              ctx->Pixel.DepthScale != 1.0f || ctx->Pixel.DepthBias != 0.0f ||
 140              ctx->Pixel.IndexShift || ctx->Pixel.IndexOffset ||
 141              ctx->Pixel.MapStencilFlag;
 142
 143    case GL_DEPTH_COMPONENT:
 144       return ctx->Pixel.DepthScale != 1.0f || ctx->Pixel.DepthBias != 0.0f;
 145
 146    case GL_STENCIL_INDEX:
 147       return ctx->Pixel.IndexShift || ctx->Pixel.IndexOffset ||
 148              ctx->Pixel.MapStencilFlag;
 149
 150    default:
 151       /* Color formats. */
 152       if (_mesa_need_rgb_to_luminance_conversion(rb->Format, format)) {
 153          return GL_TRUE;
 154       }
 155
 156       /* Conversion between signed and unsigned integers needs masking
 157        * (it isn't just memcpy). */
 158       srcType = _mesa_get_format_datatype(rb->Format);
 159
 160       if ((srcType == GL_INT &&
 161            (type == GL_UNSIGNED_INT ||
 162             type == GL_UNSIGNED_SHORT ||
 163             type == GL_UNSIGNED_BYTE)) ||
 164           (srcType == GL_UNSIGNED_INT &&
 165            (type == GL_INT ||
 166             type == GL_SHORT ||
 167             type == GL_BYTE))) {
 168          return GL_TRUE;
 169       }
 170
 171       /* And finally, see if there are any transfer ops. */
 172       return get_readpixels_transfer_ops(ctx, rb->Format, format, type,
 173                                          uses_blit) != 0;
 174    }
 175    return GL_FALSE;
 176 }
 177
 178
 179 static GLboolean
 180 readpixels_can_use_memcpy(const struct gl_context *ctx, GLenum format, GLenum type,
 181                           const struct gl_pixelstore_attrib *packing)
 182 {
 183    struct gl_renderbuffer *rb =
 184          _mesa_get_read_renderbuffer_for_format(ctx, format);
 185
 186    assert(rb);
 187
 188    if (_mesa_readpixels_needs_slow_path(ctx, format, type, GL_FALSE)) {
 189       return GL_FALSE;
 190    }
 191
 192    /* The base internal format and the base Mesa format must match. */
 193    if (rb->_BaseFormat != _mesa_get_format_base_format(rb->Format)) {
 194       return GL_FALSE;
 195    }
 196
 197    /* The Mesa format must match the input format and type. */
 198    if (!_mesa_format_matches_format_and_type(rb->Format, format, type,
 199                                              packing->SwapBytes)) {
 200       return GL_FALSE;
 201    }
 202
 203    return GL_TRUE;
 204 }
 205
 206
 207 static GLboolean
 208 readpixels_memcpy(struct gl_context *ctx,
 209                   GLint x, GLint y,
 210                   GLsizei width, GLsizei height,
 211                   GLenum format, GLenum type,
 212                   GLvoid *pixels,
 213                   const struct gl_pixelstore_attrib *packing)
 214 {
 215    struct gl_renderbuffer *rb =
 216          _mesa_get_read_renderbuffer_for_format(ctx, format);
 217    GLubyte *dst, *map;
 218    int dstStride, stride, j, texelBytes;
 219
 220    /* Fail if memcpy cannot be used. */
 221    if (!readpixels_can_use_memcpy(ctx, format, type, packing)) {
 222       return GL_FALSE;
 223    }
 224
 225    dstStride = _mesa_image_row_stride(packing, width, format, type);
 226    dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 227                                            format, type, 0, 0);
 228
 229    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 230                                &map, &stride);
 231    if (!map) {
 232       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 233       return GL_TRUE;  /* don't bother trying the slow path */
 234    }
 235
 236    texelBytes = _mesa_get_format_bytes(rb->Format);
 237
 238    /* memcpy*/
 239    for (j = 0; j < height; j++) {
 240       memcpy(dst, map, width * texelBytes);
 241       dst += dstStride;
 242       map += stride;
 243    }
 244
 245    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 246    return GL_TRUE;
 247 }
 248
 249
 250 /**
 251  * Optimized path for conversion of depth values to GL_DEPTH_COMPONENT,
 252  * GL_UNSIGNED_INT.
 253  */
 254 static GLboolean
 255 read_uint_depth_pixels( struct gl_context *ctx,
 256                         GLint x, GLint y,
 257                         GLsizei width, GLsizei height,
 258                         GLenum type, GLvoid *pixels,
 259                         const struct gl_pixelstore_attrib *packing )
 260 {
 261    struct gl_framebuffer *fb = ctx->ReadBuffer;
 262    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 263    GLubyte *map, *dst;
 264    int stride, dstStride, j;
 265
 266    if (ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0)
 267       return GL_FALSE;
 268
 269    if (packing->SwapBytes)
 270       return GL_FALSE;
 271
 272    if (_mesa_get_format_datatype(rb->Format) != GL_UNSIGNED_NORMALIZED)
 273       return GL_FALSE;
 274
 275    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 276                                &map, &stride);
 277
 278    if (!map) {
 279       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 280       return GL_TRUE;  /* don't bother trying the slow path */
 281    }
 282
 283    dstStride = _mesa_image_row_stride(packing, width, GL_DEPTH_COMPONENT, type);
 284    dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 285                                            GL_DEPTH_COMPONENT, type, 0, 0);
 286
 287    for (j = 0; j < height; j++) {
 288       _mesa_unpack_uint_z_row(rb->Format, width, map, (GLuint *)dst);
 289
 290       map += stride;
 291       dst += dstStride;
 292    }
 293    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 294
 295    return GL_TRUE;
 296 }
 297
 298 /**
 299  * Read pixels for format=GL_DEPTH_COMPONENT.
 300  */
 301 static void
 302 read_depth_pixels( struct gl_context *ctx,
 303                    GLint x, GLint y,
 304                    GLsizei width, GLsizei height,
 305                    GLenum type, GLvoid *pixels,
 306                    const struct gl_pixelstore_attrib *packing )
 307 {
 308    struct gl_framebuffer *fb = ctx->ReadBuffer;
 309    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 310    GLint j;
 311    GLubyte *dst, *map;
 312    int dstStride, stride;
 313    GLfloat *depthValues;
 314
 315    if (!rb)
 316       return;
 317
 318    /* clipping should have been done already */
 319    assert(x >= 0);
 320    assert(y >= 0);
 321    assert(x + width <= (GLint) rb->Width);
 322    assert(y + height <= (GLint) rb->Height);
 323
 324    if (type == GL_UNSIGNED_INT &&
 325        read_uint_depth_pixels(ctx, x, y, width, height, type, pixels, packing)) {
 326       return;
 327    }
 328
 329    dstStride = _mesa_image_row_stride(packing, width, GL_DEPTH_COMPONENT, type);
 330    dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 331                                            GL_DEPTH_COMPONENT, type, 0, 0);
 332
 333    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 334                                &map, &stride);
 335    if (!map) {
 336       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 337       return;
 338    }
 339
 340    depthValues = malloc(width * sizeof(GLfloat));
 341
 342    if (depthValues) {
 343       /* General case (slower) */
 344       for (j = 0; j < height; j++, y++) {
 345          _mesa_unpack_float_z_row(rb->Format, width, map, depthValues);
 346          _mesa_pack_depth_span(ctx, width, dst, type, depthValues, packing);
 347
 348          dst += dstStride;
 349          map += stride;
 350       }
 351    }
 352    else {
 353       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 354    }
 355
 356    free(depthValues);
 357
 358    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 359 }
 360
 361
 362 /**
 363  * Read pixels for format=GL_STENCIL_INDEX.
 364  */
 365 static void
 366 read_stencil_pixels( struct gl_context *ctx,
 367                      GLint x, GLint y,
 368                      GLsizei width, GLsizei height,
 369                      GLenum type, GLvoid *pixels,
 370                      const struct gl_pixelstore_attrib *packing )
 371 {
 372    struct gl_framebuffer *fb = ctx->ReadBuffer;
 373    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 374    GLint j;
 375    GLubyte *map, *stencil;
 376    GLint stride;
 377
 378    if (!rb)
 379       return;
 380
 381    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 382                                &map, &stride);
 383    if (!map) {
 384       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 385       return;
 386    }
 387
 388    stencil = malloc(width * sizeof(GLubyte));
 389
 390    if (stencil) {
 391       /* process image row by row */
 392       for (j = 0; j < height; j++) {
 393          GLvoid *dest;
 394
 395          _mesa_unpack_ubyte_stencil_row(rb->Format, width, map, stencil);
 396          dest = _mesa_image_address2d(packing, pixels, width, height,
 397                                       GL_STENCIL_INDEX, type, j, 0);
 398
 399          _mesa_pack_stencil_span(ctx, width, type, dest, stencil, packing);
 400
 401          map += stride;
 402       }
 403    }
 404    else {
 405       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 406    }
 407
 408    free(stencil);
 409
 410    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 411 }
 412
 413 /*
 414  * Read R, G, B, A, RGB, L, or LA pixels.
 415  */
 416 static void
 417 read_rgba_pixels( struct gl_context *ctx,
 418                   GLint x, GLint y,
 419                   GLsizei width, GLsizei height,
 420                   GLenum format, GLenum type, GLvoid *pixels,
 421                   const struct gl_pixelstore_attrib *packing )
 422 {
 423    GLbitfield transferOps;
 424    bool dst_is_integer, convert_rgb_to_lum, needs_rebase;
 425    int dst_stride, src_stride, rb_stride;
 426    uint32_t dst_format, src_format;
 427    GLubyte *dst, *map;
 428    mesa_format rb_format;
 429    bool needs_rgba;
 430    void *rgba, *src;
 431    bool src_is_uint = false;
 432    uint8_t rebase_swizzle[4];
 433    struct gl_framebuffer *fb = ctx->ReadBuffer;
 434    struct gl_renderbuffer *rb = fb->_ColorReadBuffer;
 435
 436    if (!rb)
 437       return;
 438
 439    transferOps = get_readpixels_transfer_ops(ctx, rb->Format, format, type,
 440                                              GL_FALSE);
 441    /* Describe the dst format */
 442    dst_is_integer = _mesa_is_enum_format_integer(format);
 443    dst_stride = _mesa_image_row_stride(packing, width, format, type);
 444    dst_format = _mesa_format_from_format_and_type(format, type);
 445    convert_rgb_to_lum =
 446       _mesa_need_rgb_to_luminance_conversion(rb->Format, format);
 447    dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 448                                            format, type, 0, 0);
 449
 450    /* Map the source render buffer */
 451    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 452                                &map, &rb_stride);
 453    if (!map) {
 454       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 455       return;
 456    }
 457    rb_format = _mesa_get_srgb_format_linear(rb->Format);
 458
 459    /*
 460     * Depending on the base formats involved in the conversion we might need to
 461     * rebase some values, so for these formats we compute a rebase swizzle.
 462     */
 463    if (rb->_BaseFormat == GL_LUMINANCE || rb->_BaseFormat == GL_INTENSITY) {
 464       needs_rebase = true;
 465       rebase_swizzle[0] = MESA_FORMAT_SWIZZLE_X;
 466       rebase_swizzle[1] = MESA_FORMAT_SWIZZLE_ZERO;
 467       rebase_swizzle[2] = MESA_FORMAT_SWIZZLE_ZERO;
 468       rebase_swizzle[3] = MESA_FORMAT_SWIZZLE_ONE;
 469    } else if (rb->_BaseFormat == GL_LUMINANCE_ALPHA) {
 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_W;
 475    } else if (_mesa_get_format_base_format(rb_format) != rb->_BaseFormat) {
 476       needs_rebase =
 477          _mesa_compute_rgba2base2rgba_component_mapping(rb->_BaseFormat,
 478                                                         rebase_swizzle);
 479    } else {
 480       needs_rebase = false;
 481    }
 482
 483    /* Since _mesa_format_convert does not handle transferOps we need to handle
 484     * them before we call the function. This requires to convert to RGBA float
 485     * first so we can call _mesa_apply_rgba_transfer_ops. If the dst format is
 486     * integer transferOps do not apply.
 487     *
 488     * Converting to luminance also requires converting to RGBA first, so we can
 489     * then compute luminance values as L=R+G+B. Notice that this is different
 490     * from GetTexImage, where we compute L=R.
 491     */
 492    assert(!transferOps || (transferOps && !dst_is_integer));
 493
 494    needs_rgba = transferOps || convert_rgb_to_lum;
 495    rgba = NULL;
 496    if (needs_rgba) {
 497       uint32_t rgba_format;
 498       int rgba_stride;
 499       bool need_convert;
 500
 501       /* Convert to RGBA float or int/uint depending on the type of the src */
 502       if (dst_is_integer) {
 503          src_is_uint = _mesa_is_format_unsigned(rb_format);
 504          if (src_is_uint) {
 505             rgba_format = RGBA32_UINT;
 506             rgba_stride = width * 4 * sizeof(GLuint);
 507          } else {
 508             rgba_format = RGBA32_INT;
 509             rgba_stride = width * 4 * sizeof(GLint);
 510          }
 511       } else {
 512          rgba_format = RGBA32_FLOAT;
 513          rgba_stride = width * 4 * sizeof(GLfloat);
 514       }
 515
 516       /* If we are lucky and the dst format matches the RGBA format we need to
 517        * convert to, then we can convert directly into the dst buffer and avoid
 518        * the final conversion/copy from the rgba buffer to the dst buffer.
 519        */
 520       if (dst_format == rgba_format) {
 521          need_convert = false;
 522          rgba = dst;
 523       } else {
 524          need_convert = true;
 525          rgba = malloc(height * rgba_stride);
 526          if (!rgba) {
 527             _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 528             goto done_unmap;
 529          }
 530       }
 531
 532       /* Convert to RGBA now */
 533       _mesa_format_convert(rgba, rgba_format, rgba_stride,
 534                            map, rb_format, rb_stride,
 535                            width, height,
 536                            needs_rebase ? rebase_swizzle : NULL);
 537
 538       /* Handle transfer ops if necessary */
 539       if (transferOps)
 540          _mesa_apply_rgba_transfer_ops(ctx, transferOps, width * height, rgba);
 541
 542       /* If we had to rebase, we have already taken care of that */
 543       needs_rebase = false;
 544
 545       /* If we were lucky and our RGBA conversion matches the dst format, then
 546        * we are done.
 547        */
 548       if (!need_convert)
 549          goto done_swap;
 550
 551       /* Otherwise, we need to convert from RGBA to dst next */
 552       src = rgba;
 553       src_format = rgba_format;
 554       src_stride = rgba_stride;
 555    } else {
 556       /* No RGBA conversion needed, convert directly to dst */
 557       src = map;
 558       src_format = rb_format;
 559       src_stride = rb_stride;
 560    }
 561
 562    /* Do the conversion.
 563     *
 564     * If the dst format is Luminance, we need to do the conversion by computing
 565     * L=R+G+B values.
 566     */
 567    if (!convert_rgb_to_lum) {
 568       _mesa_format_convert(dst, dst_format, dst_stride,
 569                            src, src_format, src_stride,
 570                            width, height,
 571                            needs_rebase ? rebase_swizzle : NULL);
 572    } else if (!dst_is_integer) {
 573       /* Compute float Luminance values from RGBA float */
 574       int luminance_stride, luminance_bytes;
 575       void *luminance;
 576       uint32_t luminance_format;
 577
 578       luminance_stride = width * sizeof(GL_FLOAT);
 579       if (format == GL_LUMINANCE_ALPHA)
 580          luminance_stride *= 2;
 581       luminance_bytes = height * luminance_stride;
 582       luminance = malloc(luminance_bytes);
 583       if (!luminance) {
 584          _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 585          free(rgba);
 586          goto done_unmap;
 587       }
 588       _mesa_pack_luminance_from_rgba_float(width * height, src,
 589                                            luminance, format, transferOps);
 590
 591       /* Convert from Luminance float to dst (this will hadle type conversion
 592        * from float to the type of dst if necessary)
 593        */
 594       luminance_format = _mesa_format_from_format_and_type(format, GL_FLOAT);
 595       _mesa_format_convert(dst, dst_format, dst_stride,
 596                            luminance, luminance_format, luminance_stride,
 597                            width, height, NULL);
 598       free(luminance);
 599    } else {
 600       _mesa_pack_luminance_from_rgba_integer(width * height, src, !src_is_uint,
 601                                              dst, format, type);
 602    }
 603
 604    if (rgba)
 605       free(rgba);
 606
 607 done_swap:
 608    /* Handle byte swapping if required */
 609    if (packing->SwapBytes) {
 610       GLint swapSize = _mesa_sizeof_packed_type(type);
 611       if (swapSize == 2 || swapSize == 4) {
 612          int swapsPerPixel = _mesa_bytes_per_pixel(format, type) / swapSize;
 613          assert(_mesa_bytes_per_pixel(format, type) % swapSize == 0);
 614          if (swapSize == 2)
 615             _mesa_swap2((GLushort *) dst, width * height * swapsPerPixel);
 616          else if (swapSize == 4)
 617             _mesa_swap4((GLuint *) dst, width * height * swapsPerPixel);
 618       }
 619    }
 620
 621 done_unmap:
 622    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 623 }
 624
 625 /**
 626  * For a packed depth/stencil buffer being read as depth/stencil, just memcpy the
 627  * data (possibly swapping 8/24 vs 24/8 as we go).
 628  */
 629 static GLboolean
 630 fast_read_depth_stencil_pixels(struct gl_context *ctx,
 631                                GLint x, GLint y,
 632                                GLsizei width, GLsizei height,
 633                                GLubyte *dst, int dstStride)
 634 {
 635    struct gl_framebuffer *fb = ctx->ReadBuffer;
 636    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 637    struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 638    GLubyte *map;
 639    int stride, i;
 640
 641    if (rb != stencilRb)
 642       return GL_FALSE;
 643
 644    if (rb->Format != MESA_FORMAT_S8_UINT_Z24_UNORM &&
 645        rb->Format != MESA_FORMAT_Z24_UNORM_S8_UINT)
 646       return GL_FALSE;
 647
 648    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 649                                &map, &stride);
 650    if (!map) {
 651       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 652       return GL_TRUE;  /* don't bother trying the slow path */
 653    }
 654
 655    for (i = 0; i < height; i++) {
 656       _mesa_unpack_uint_24_8_depth_stencil_row(rb->Format, width,
 657                                                map, (GLuint *)dst);
 658       map += stride;
 659       dst += dstStride;
 660    }
 661
 662    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 663
 664    return GL_TRUE;
 665 }
 666
 667
 668 /**
 669  * For non-float-depth and stencil buffers being read as 24/8 depth/stencil,
 670  * copy the integer data directly instead of converting depth to float and
 671  * re-packing.
 672  */
 673 static GLboolean
 674 fast_read_depth_stencil_pixels_separate(struct gl_context *ctx,
 675                                         GLint x, GLint y,
 676                                         GLsizei width, GLsizei height,
 677                                         uint32_t *dst, int dstStride)
 678 {
 679    struct gl_framebuffer *fb = ctx->ReadBuffer;
 680    struct gl_renderbuffer *depthRb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 681    struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 682    GLubyte *depthMap, *stencilMap, *stencilVals;
 683    int depthStride, stencilStride, i, j;
 684
 685    if (_mesa_get_format_datatype(depthRb->Format) != GL_UNSIGNED_NORMALIZED)
 686       return GL_FALSE;
 687
 688    ctx->Driver.MapRenderbuffer(ctx, depthRb, x, y, width, height,
 689                                GL_MAP_READ_BIT, &depthMap, &depthStride);
 690    if (!depthMap) {
 691       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 692       return GL_TRUE;  /* don't bother trying the slow path */
 693    }
 694
 695    ctx->Driver.MapRenderbuffer(ctx, stencilRb, x, y, width, height,
 696                                GL_MAP_READ_BIT, &stencilMap, &stencilStride);
 697    if (!stencilMap) {
 698       ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 699       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 700       return GL_TRUE;  /* don't bother trying the slow path */
 701    }
 702
 703    stencilVals = malloc(width * sizeof(GLubyte));
 704
 705    if (stencilVals) {
 706       for (j = 0; j < height; j++) {
 707          _mesa_unpack_uint_z_row(depthRb->Format, width, depthMap, dst);
 708          _mesa_unpack_ubyte_stencil_row(stencilRb->Format, width,
 709                                         stencilMap, stencilVals);
 710
 711          for (i = 0; i < width; i++) {
 712             dst[i] = (dst[i] & 0xffffff00) | stencilVals[i];
 713          }
 714
 715          depthMap += depthStride;
 716          stencilMap += stencilStride;
 717          dst += dstStride / 4;
 718       }
 719    }
 720    else {
 721       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 722    }
 723
 724    free(stencilVals);
 725
 726    ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 727    ctx->Driver.UnmapRenderbuffer(ctx, stencilRb);
 728
 729    return GL_TRUE;
 730 }
 731
 732 static void
 733 slow_read_depth_stencil_pixels_separate(struct gl_context *ctx,
 734                                         GLint x, GLint y,
 735                                         GLsizei width, GLsizei height,
 736                                         GLenum type,
 737                                         const struct gl_pixelstore_attrib *packing,
 738                                         GLubyte *dst, int dstStride)
 739 {
 740    struct gl_framebuffer *fb = ctx->ReadBuffer;
 741    struct gl_renderbuffer *depthRb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 742    struct gl_renderbuffer *stencilRb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 743    GLubyte *depthMap, *stencilMap;
 744    int depthStride, stencilStride, j;
 745    GLubyte *stencilVals;
 746    GLfloat *depthVals;
 747
 748
 749    /* The depth and stencil buffers might be separate, or a single buffer.
 750     * If one buffer, only map it once.
 751     */
 752    ctx->Driver.MapRenderbuffer(ctx, depthRb, x, y, width, height,
 753                                GL_MAP_READ_BIT, &depthMap, &depthStride);
 754    if (!depthMap) {
 755       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 756       return;
 757    }
 758
 759    if (stencilRb != depthRb) {
 760       ctx->Driver.MapRenderbuffer(ctx, stencilRb, x, y, width, height,
 761                                   GL_MAP_READ_BIT, &stencilMap,
 762                                   &stencilStride);
 763       if (!stencilMap) {
 764          ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 765          _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 766          return;
 767       }
 768    }
 769    else {
 770       stencilMap = depthMap;
 771       stencilStride = depthStride;
 772    }
 773
 774    stencilVals = malloc(width * sizeof(GLubyte));
 775    depthVals = malloc(width * sizeof(GLfloat));
 776
 777    if (stencilVals && depthVals) {
 778       for (j = 0; j < height; j++) {
 779          _mesa_unpack_float_z_row(depthRb->Format, width, depthMap, depthVals);
 780          _mesa_unpack_ubyte_stencil_row(stencilRb->Format, width,
 781                                         stencilMap, stencilVals);
 782
 783          _mesa_pack_depth_stencil_span(ctx, width, type, (GLuint *)dst,
 784                                        depthVals, stencilVals, packing);
 785
 786          depthMap += depthStride;
 787          stencilMap += stencilStride;
 788          dst += dstStride;
 789       }
 790    }
 791    else {
 792       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 793    }
 794
 795    free(stencilVals);
 796    free(depthVals);
 797
 798    ctx->Driver.UnmapRenderbuffer(ctx, depthRb);
 799    if (stencilRb != depthRb) {
 800       ctx->Driver.UnmapRenderbuffer(ctx, stencilRb);
 801    }
 802 }
 803
 804
 805 /**
 806  * Read combined depth/stencil values.
 807  * We'll have already done error checking to be sure the expected
 808  * depth and stencil buffers really exist.
 809  */
 810 static void
 811 read_depth_stencil_pixels(struct gl_context *ctx,
 812                           GLint x, GLint y,
 813                           GLsizei width, GLsizei height,
 814                           GLenum type, GLvoid *pixels,
 815                           const struct gl_pixelstore_attrib *packing )
 816 {
 817    const GLboolean scaleOrBias
 818       = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
 819    const GLboolean stencilTransfer = ctx->Pixel.IndexShift
 820       || ctx->Pixel.IndexOffset || ctx->Pixel.MapStencilFlag;
 821    GLubyte *dst;
 822    int dstStride;
 823
 824    dst = (GLubyte *) _mesa_image_address2d(packing, pixels,
 825                                            width, height,
 826                                            GL_DEPTH_STENCIL_EXT,
 827                                            type, 0, 0);
 828    dstStride = _mesa_image_row_stride(packing, width,
 829                                       GL_DEPTH_STENCIL_EXT, type);
 830
 831    /* Fast 24/8 reads. */
 832    if (type == GL_UNSIGNED_INT_24_8 &&
 833        !scaleOrBias && !stencilTransfer && !packing->SwapBytes) {
 834       if (fast_read_depth_stencil_pixels(ctx, x, y, width, height,
 835                                          dst, dstStride))
 836          return;
 837
 838       if (fast_read_depth_stencil_pixels_separate(ctx, x, y, width, height,
 839                                                   (uint32_t *)dst, dstStride))
 840          return;
 841    }
 842
 843    slow_read_depth_stencil_pixels_separate(ctx, x, y, width, height,
 844                                            type, packing,
 845                                            dst, dstStride);
 846 }
 847
 848
 849
 850 /**
 851  * Software fallback routine for ctx->Driver.ReadPixels().
 852  * By time we get here, all error checking will have been done.
 853  */
 854 void
 855 _mesa_readpixels(struct gl_context *ctx,
 856                  GLint x, GLint y, GLsizei width, GLsizei height,
 857                  GLenum format, GLenum type,
 858                  const struct gl_pixelstore_attrib *packing,
 859                  GLvoid *pixels)
 860 {
 861    struct gl_pixelstore_attrib clippedPacking = *packing;
 862
 863    if (ctx->NewState)
 864       _mesa_update_state(ctx);
 865
 866    /* Do all needed clipping here, so that we can forget about it later */
 867    if (_mesa_clip_readpixels(ctx, &x, &y, &width, &height, &clippedPacking)) {
 868
 869       pixels = _mesa_map_pbo_dest(ctx, &clippedPacking, pixels);
 870
 871       if (pixels) {
 872          /* Try memcpy first. */
 873          if (readpixels_memcpy(ctx, x, y, width, height, format, type,
 874                                pixels, packing)) {
 875             _mesa_unmap_pbo_dest(ctx, &clippedPacking);
 876             return;
 877          }
 878
 879          /* Otherwise take the slow path. */
 880          switch (format) {
 881          case GL_STENCIL_INDEX:
 882             read_stencil_pixels(ctx, x, y, width, height, type, pixels,
 883                                 &clippedPacking);
 884             break;
 885          case GL_DEPTH_COMPONENT:
 886             read_depth_pixels(ctx, x, y, width, height, type, pixels,
 887                               &clippedPacking);
 888             break;
 889          case GL_DEPTH_STENCIL_EXT:
 890             read_depth_stencil_pixels(ctx, x, y, width, height, type, pixels,
 891                                       &clippedPacking);
 892             break;
 893          default:
 894             /* all other formats should be color formats */
 895             read_rgba_pixels(ctx, x, y, width, height, format, type, pixels,
 896                              &clippedPacking);
 897          }
 898
 899          _mesa_unmap_pbo_dest(ctx, &clippedPacking);
 900       }
 901    }
 902 }
 903
 904
 905 static GLenum
 906 read_pixels_es3_error_check(GLenum format, GLenum type,
 907                             const struct gl_renderbuffer *rb)
 908 {
 909    const GLenum internalFormat = rb->InternalFormat;
 910    const GLenum data_type = _mesa_get_format_datatype(rb->Format);
 911    GLboolean is_unsigned_int = GL_FALSE;
 912    GLboolean is_signed_int = GL_FALSE;
 913
 914    if (!_mesa_is_color_format(internalFormat)) {
 915       return GL_INVALID_OPERATION;
 916    }
 917
 918    is_unsigned_int = _mesa_is_enum_format_unsigned_int(internalFormat);
 919    if (!is_unsigned_int) {
 920       is_signed_int = _mesa_is_enum_format_signed_int(internalFormat);
 921    }
 922
 923    switch (format) {
 924    case GL_RGBA:
 925       if (type == GL_FLOAT && data_type == GL_FLOAT)
 926          return GL_NO_ERROR; /* EXT_color_buffer_float */
 927       if (type == GL_UNSIGNED_BYTE && data_type == GL_UNSIGNED_NORMALIZED)
 928          return GL_NO_ERROR;
 929       if (internalFormat == GL_RGB10_A2 &&
 930           type == GL_UNSIGNED_INT_2_10_10_10_REV)
 931          return GL_NO_ERROR;
 932       if (internalFormat == GL_RGB10_A2UI && type == GL_UNSIGNED_BYTE)
 933          return GL_NO_ERROR;
 934       break;
 935    case GL_BGRA:
 936       /* GL_EXT_read_format_bgra */
 937       if (type == GL_UNSIGNED_BYTE ||
 938           type == GL_UNSIGNED_SHORT_4_4_4_4_REV ||
 939           type == GL_UNSIGNED_SHORT_1_5_5_5_REV)
 940          return GL_NO_ERROR;
 941       break;
 942    case GL_RGBA_INTEGER:
 943       if ((is_signed_int && type == GL_INT) ||
 944           (is_unsigned_int && type == GL_UNSIGNED_INT))
 945          return GL_NO_ERROR;
 946       break;
 947    }
 948
 949    return GL_INVALID_OPERATION;
 950 }
 951
 952
 953 void GLAPIENTRY
 954 _mesa_ReadnPixelsARB( GLint x, GLint y, GLsizei width, GLsizei height,
 955                       GLenum format, GLenum type, GLsizei bufSize,
 956                       GLvoid *pixels )
 957 {
 958    GLenum err = GL_NO_ERROR;
 959    struct gl_renderbuffer *rb;
 960
 961    GET_CURRENT_CONTEXT(ctx);
 962
 963    FLUSH_VERTICES(ctx, 0);
 964    FLUSH_CURRENT(ctx, 0);
 965
 966    if (MESA_VERBOSE & VERBOSE_API)
 967       _mesa_debug(ctx, "glReadPixels(%d, %d, %s, %s, %p)\n",
 968                   width, height,
 969                   _mesa_lookup_enum_by_nr(format),
 970                   _mesa_lookup_enum_by_nr(type),
 971                   pixels);
 972
 973    if (width < 0 || height < 0) {
 974       _mesa_error( ctx, GL_INVALID_VALUE,
 975                    "glReadPixels(width=%d height=%d)", width, height );
 976       return;
 977    }
 978
 979    if (ctx->NewState)
 980       _mesa_update_state(ctx);
 981
 982    if (ctx->ReadBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 983       _mesa_error(ctx, GL_INVALID_FRAMEBUFFER_OPERATION_EXT,
 984                   "glReadPixels(incomplete framebuffer)" );
 985       return;
 986    }
 987
 988    rb = _mesa_get_read_renderbuffer_for_format(ctx, format);
 989    if (rb == NULL) {
 990       _mesa_error(ctx, GL_INVALID_OPERATION,
 991                   "glReadPixels(read buffer)");
 992       return;
 993    }
 994
 995    /* OpenGL ES 1.x and OpenGL ES 2.0 impose additional restrictions on the
 996     * combinations of format and type that can be used.
 997     *
 998     * Technically, only two combinations are actually allowed:
 999     * GL_RGBA/GL_UNSIGNED_BYTE, and some implementation-specific internal
1000     * preferred combination.  This code doesn't know what that preferred
1001     * combination is, and Mesa can handle anything valid.  Just work instead.
1002     */
1003    if (_mesa_is_gles(ctx)) {
1004       if (ctx->API == API_OPENGLES2 &&
1005           _mesa_is_color_format(format) &&
1006           _mesa_get_color_read_format(ctx) == format &&
1007           _mesa_get_color_read_type(ctx) == type) {
1008          err = GL_NO_ERROR;
1009       } else if (ctx->Version < 30) {
1010          err = _mesa_es_error_check_format_and_type(format, type, 2);
1011          if (err == GL_NO_ERROR) {
1012             if (type == GL_FLOAT || type == GL_HALF_FLOAT_OES) {
1013                err = GL_INVALID_OPERATION;
1014             }
1015          }
1016       } else {
1017          err = read_pixels_es3_error_check(format, type, rb);
1018       }
1019
1020       if (err == GL_NO_ERROR && (format == GL_DEPTH_COMPONENT
1021           || format == GL_DEPTH_STENCIL)) {
1022          err = GL_INVALID_ENUM;
1023       }
1024
1025       if (err != GL_NO_ERROR) {
1026          _mesa_error(ctx, err, "glReadPixels(invalid format %s and/or type %s)",
1027                      _mesa_lookup_enum_by_nr(format),
1028                      _mesa_lookup_enum_by_nr(type));
1029          return;
1030       }
1031    }
1032
1033    err = _mesa_error_check_format_and_type(ctx, format, type);
1034    if (err != GL_NO_ERROR) {
1035       _mesa_error(ctx, err, "glReadPixels(invalid format %s and/or type %s)",
1036                   _mesa_lookup_enum_by_nr(format),
1037                   _mesa_lookup_enum_by_nr(type));
1038       return;
1039    }
1040
1041    if (_mesa_is_user_fbo(ctx->ReadBuffer) &&
1042        ctx->ReadBuffer->Visual.samples > 0) {
1043       _mesa_error(ctx, GL_INVALID_OPERATION, "glReadPixels(multisample FBO)");
1044       return;
1045    }
1046
1047    if (!_mesa_source_buffer_exists(ctx, format)) {
1048       _mesa_error(ctx, GL_INVALID_OPERATION, "glReadPixels(no readbuffer)");
1049       return;
1050    }
1051
1052    /* Check that the destination format and source buffer are both
1053     * integer-valued or both non-integer-valued.
1054     */
1055    if (ctx->Extensions.EXT_texture_integer && _mesa_is_color_format(format)) {
1056       const struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
1057       const GLboolean srcInteger = _mesa_is_format_integer_color(rb->Format);
1058       const GLboolean dstInteger = _mesa_is_enum_format_integer(format);
1059       if (dstInteger != srcInteger) {
1060          _mesa_error(ctx, GL_INVALID_OPERATION,
1061                      "glReadPixels(integer / non-integer format mismatch");
1062          return;
1063       }
1064    }
1065
1066    if (width == 0 || height == 0)
1067       return; /* nothing to do */
1068
1069    if (!_mesa_validate_pbo_access(2, &ctx->Pack, width, height, 1,
1070                                   format, type, bufSize, pixels)) {
1071       if (_mesa_is_bufferobj(ctx->Pack.BufferObj)) {
1072          _mesa_error(ctx, GL_INVALID_OPERATION,
1073                      "glReadPixels(out of bounds PBO access)");
1074       } else {
1075          _mesa_error(ctx, GL_INVALID_OPERATION,
1076                      "glReadnPixelsARB(out of bounds access:"
1077                      " bufSize (%d) is too small)", bufSize);
1078       }
1079       return;
1080    }
1081
1082    if (_mesa_is_bufferobj(ctx->Pack.BufferObj) &&
1083        _mesa_check_disallowed_mapping(ctx->Pack.BufferObj)) {
1084       /* buffer is mapped - that's an error */
1085       _mesa_error(ctx, GL_INVALID_OPERATION, "glReadPixels(PBO is mapped)");
1086       return;
1087    }
1088
1089    ctx->Driver.ReadPixels(ctx, x, y, width, height,
1090                           format, type, &ctx->Pack, pixels);
1091 }
1092
1093 void GLAPIENTRY
1094 _mesa_ReadPixels( GLint x, GLint y, GLsizei width, GLsizei height,
1095                   GLenum format, GLenum type, GLvoid *pixels )
1096 {
1097    _mesa_ReadnPixelsARB(x, y, width, height, format, type, INT_MAX, pixels);
1098 }