src/mesa/swrast/s_readpix.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  7.0.3
   4  *
   5  * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25
  26 #include "main/glheader.h"
  27 #include "main/bufferobj.h"
  28 #include "main/colormac.h"
  29 #include "main/convolve.h"
  30 #include "main/feedback.h"
  31 #include "main/formats.h"
  32 #include "main/image.h"
  33 #include "main/macros.h"
  34 #include "main/imports.h"
  35 #include "main/state.h"
  36
  37 #include "s_context.h"
  38 #include "s_depth.h"
  39 #include "s_span.h"
  40 #include "s_stencil.h"
  41
  42
  43 /**
  44  * Read pixels for format=GL_DEPTH_COMPONENT.
  45  */
  46 static void
  47 read_depth_pixels( GLcontext *ctx,
  48                    GLint x, GLint y,
  49                    GLsizei width, GLsizei height,
  50                    GLenum type, GLvoid *pixels,
  51                    const struct gl_pixelstore_attrib *packing )
  52 {
  53    struct gl_framebuffer *fb = ctx->ReadBuffer;
  54    struct gl_renderbuffer *rb = fb->_DepthBuffer;
  55    const GLboolean biasOrScale
  56       = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
  57
  58    if (!rb)
  59       return;
  60
  61    /* clipping should have been done already */
  62    ASSERT(x >= 0);
  63    ASSERT(y >= 0);
  64    ASSERT(x + width <= (GLint) rb->Width);
  65    ASSERT(y + height <= (GLint) rb->Height);
  66    /* width should never be > MAX_WIDTH since we did clipping earlier */
  67    ASSERT(width <= MAX_WIDTH);
  68
  69    if (type == GL_UNSIGNED_SHORT && fb->Visual.depthBits == 16
  70        && !biasOrScale && !packing->SwapBytes) {
  71       /* Special case: directly read 16-bit unsigned depth values. */
  72       GLint j;
  73       ASSERT(rb->Format == MESA_FORMAT_Z16);
  74       ASSERT(rb->DataType == GL_UNSIGNED_SHORT);
  75       for (j = 0; j < height; j++, y++) {
  76          void *dest =_mesa_image_address2d(packing, pixels, width, height,
  77                                            GL_DEPTH_COMPONENT, type, j, 0);
  78          rb->GetRow(ctx, rb, width, x, y, dest);
  79       }
  80    }
  81    else if (type == GL_UNSIGNED_INT && fb->Visual.depthBits == 24
  82             && !biasOrScale && !packing->SwapBytes) {
  83       /* Special case: directly read 24-bit unsigned depth values. */
  84       GLint j;
  85       ASSERT(rb->Format == MESA_FORMAT_X8_Z24 ||
  86              rb->Format == MESA_FORMAT_S8_Z24 ||
  87              rb->Format == MESA_FORMAT_Z24_X8 ||
  88              rb->Format == MESA_FORMAT_Z24_S8);
  89       ASSERT(rb->DataType == GL_UNSIGNED_INT ||
  90              rb->DataType == GL_UNSIGNED_INT_24_8);
  91       for (j = 0; j < height; j++, y++) {
  92          GLuint *dest = (GLuint *)
  93             _mesa_image_address2d(packing, pixels, width, height,
  94                                   GL_DEPTH_COMPONENT, type, j, 0);
  95          GLint k;
  96          rb->GetRow(ctx, rb, width, x, y, dest);
  97          /* convert range from 24-bit to 32-bit */
  98          if (rb->Format == MESA_FORMAT_X8_Z24 ||
  99              rb->Format == MESA_FORMAT_S8_Z24) {
 100             for (k = 0; k < width; k++) {
 101                /* Note: put MSByte of 24-bit value into LSByte */
 102                dest[k] = (dest[k] << 8) | ((dest[k] >> 16) & 0xff);
 103             }
 104          }
 105          else {
 106             for (k = 0; k < width; k++) {
 107                /* Note: fill in LSByte by replication */
 108                dest[k] = dest[k] | ((dest[k] >> 8) & 0xff);
 109             }
 110          }
 111       }
 112    }
 113    else if (type == GL_UNSIGNED_INT && fb->Visual.depthBits == 32
 114             && !biasOrScale && !packing->SwapBytes) {
 115       /* Special case: directly read 32-bit unsigned depth values. */
 116       GLint j;
 117       ASSERT(rb->Format == MESA_FORMAT_Z32);
 118       ASSERT(rb->DataType == GL_UNSIGNED_INT);
 119       for (j = 0; j < height; j++, y++) {
 120          void *dest = _mesa_image_address2d(packing, pixels, width, height,
 121                                             GL_DEPTH_COMPONENT, type, j, 0);
 122          rb->GetRow(ctx, rb, width, x, y, dest);
 123       }
 124    }
 125    else {
 126       /* General case (slower) */
 127       GLint j;
 128       for (j = 0; j < height; j++, y++) {
 129          GLfloat depthValues[MAX_WIDTH];
 130          GLvoid *dest = _mesa_image_address2d(packing, pixels, width, height,
 131                                               GL_DEPTH_COMPONENT, type, j, 0);
 132          _swrast_read_depth_span_float(ctx, rb, width, x, y, depthValues);
 133          _mesa_pack_depth_span(ctx, width, dest, type, depthValues, packing);
 134       }
 135    }
 136 }
 137
 138
 139 /**
 140  * Read pixels for format=GL_STENCIL_INDEX.
 141  */
 142 static void
 143 read_stencil_pixels( GLcontext *ctx,
 144                      GLint x, GLint y,
 145                      GLsizei width, GLsizei height,
 146                      GLenum type, GLvoid *pixels,
 147                      const struct gl_pixelstore_attrib *packing )
 148 {
 149    struct gl_framebuffer *fb = ctx->ReadBuffer;
 150    struct gl_renderbuffer *rb = fb->_StencilBuffer;
 151    GLint j;
 152
 153    if (!rb)
 154       return;
 155
 156    /* width should never be > MAX_WIDTH since we did clipping earlier */
 157    ASSERT(width <= MAX_WIDTH);
 158
 159    /* process image row by row */
 160    for (j=0;j<height;j++,y++) {
 161       GLvoid *dest;
 162       GLstencil stencil[MAX_WIDTH];
 163
 164       _swrast_read_stencil_span(ctx, rb, width, x, y, stencil);
 165
 166       dest = _mesa_image_address2d(packing, pixels, width, height,
 167                                    GL_STENCIL_INDEX, type, j, 0);
 168
 169       _mesa_pack_stencil_span(ctx, width, type, dest, stencil, packing);
 170    }
 171 }
 172
 173
 174
 175 /**
 176  * Optimized glReadPixels for particular pixel formats when pixel
 177  * scaling, biasing, mapping, etc. are disabled.
 178  * \return GL_TRUE if success, GL_FALSE if unable to do the readpixels
 179  */
 180 static GLboolean
 181 fast_read_rgba_pixels( GLcontext *ctx,
 182                        GLint x, GLint y,
 183                        GLsizei width, GLsizei height,
 184                        GLenum format, GLenum type,
 185                        GLvoid *pixels,
 186                        const struct gl_pixelstore_attrib *packing,
 187                        GLbitfield transferOps)
 188 {
 189    struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
 190
 191    if (!rb)
 192       return GL_FALSE;
 193
 194    ASSERT(rb->_BaseFormat == GL_RGBA || rb->_BaseFormat == GL_RGB ||
 195           rb->_BaseFormat == GL_ALPHA);
 196
 197    /* clipping should have already been done */
 198    ASSERT(x + width <= (GLint) rb->Width);
 199    ASSERT(y + height <= (GLint) rb->Height);
 200
 201    /* check for things we can't handle here */
 202    if (transferOps ||
 203        packing->SwapBytes ||
 204        packing->LsbFirst) {
 205       return GL_FALSE;
 206    }
 207
 208    if (format == GL_RGBA && rb->DataType == type) {
 209       const GLint dstStride = _mesa_image_row_stride(packing, width,
 210                                                      format, type);
 211       GLubyte *dest
 212          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 213                                              format, type, 0, 0);
 214       GLint row;
 215       ASSERT(rb->GetRow);
 216       for (row = 0; row < height; row++) {
 217          rb->GetRow(ctx, rb, width, x, y + row, dest);
 218          dest += dstStride;
 219       }
 220       return GL_TRUE;
 221    }
 222
 223    if (format == GL_RGB &&
 224        rb->DataType == GL_UNSIGNED_BYTE &&
 225        type == GL_UNSIGNED_BYTE) {
 226       const GLint dstStride = _mesa_image_row_stride(packing, width,
 227                                                      format, type);
 228       GLubyte *dest
 229          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 230                                              format, type, 0, 0);
 231       GLint row;
 232       ASSERT(rb->GetRow);
 233       for (row = 0; row < height; row++) {
 234          GLubyte tempRow[MAX_WIDTH][4];
 235          GLint col;
 236          rb->GetRow(ctx, rb, width, x, y + row, tempRow);
 237          /* convert RGBA to RGB */
 238          for (col = 0; col < width; col++) {
 239             dest[col * 3 + 0] = tempRow[col][0];
 240             dest[col * 3 + 1] = tempRow[col][1];
 241             dest[col * 3 + 2] = tempRow[col][2];
 242          }
 243          dest += dstStride;
 244       }
 245       return GL_TRUE;
 246    }
 247
 248    /* not handled */
 249    return GL_FALSE;
 250 }
 251
 252
 253 /**
 254  * When we're using a low-precision color buffer (like 16-bit 5/6/5)
 255  * we have to adjust our color values a bit to pass conformance.
 256  * The problem is when a 5 or 6-bit color value is converted to an 8-bit
 257  * value and then a floating point value, the floating point values don't
 258  * increment uniformly as the 5 or 6-bit value is incremented.
 259  *
 260  * This function adjusts floating point values to compensate.
 261  */
 262 static void
 263 adjust_colors(const struct gl_framebuffer *fb, GLuint n, GLfloat rgba[][4])
 264 {
 265    const GLuint rShift = 8 - fb->Visual.redBits;
 266    const GLuint gShift = 8 - fb->Visual.greenBits;
 267    const GLuint bShift = 8 - fb->Visual.blueBits;
 268    GLfloat rScale = 1.0F / (GLfloat) ((1 << fb->Visual.redBits  ) - 1);
 269    GLfloat gScale = 1.0F / (GLfloat) ((1 << fb->Visual.greenBits) - 1);
 270    GLfloat bScale = 1.0F / (GLfloat) ((1 << fb->Visual.blueBits ) - 1);
 271    GLuint i;
 272
 273    if (fb->Visual.redBits == 0)
 274       rScale = 0;
 275    if (fb->Visual.greenBits == 0)
 276       gScale = 0;
 277    if (fb->Visual.blueBits == 0)
 278       bScale = 0;
 279
 280    for (i = 0; i < n; i++) {
 281       GLint r, g, b;
 282       /* convert float back to ubyte */
 283       CLAMPED_FLOAT_TO_UBYTE(r, rgba[i][RCOMP]);
 284       CLAMPED_FLOAT_TO_UBYTE(g, rgba[i][GCOMP]);
 285       CLAMPED_FLOAT_TO_UBYTE(b, rgba[i][BCOMP]);
 286       /* using only the N most significant bits of the ubyte value, convert to
 287        * float in [0,1].
 288        */
 289       rgba[i][RCOMP] = (GLfloat) (r >> rShift) * rScale;
 290       rgba[i][GCOMP] = (GLfloat) (g >> gShift) * gScale;
 291       rgba[i][BCOMP] = (GLfloat) (b >> bShift) * bScale;
 292    }
 293 }
 294
 295
 296
 297 /*
 298  * Read R, G, B, A, RGB, L, or LA pixels.
 299  */
 300 static void
 301 read_rgba_pixels( GLcontext *ctx,
 302                   GLint x, GLint y,
 303                   GLsizei width, GLsizei height,
 304                   GLenum format, GLenum type, GLvoid *pixels,
 305                   const struct gl_pixelstore_attrib *packing )
 306 {
 307    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 308    GLbitfield transferOps = ctx->_ImageTransferState;
 309    struct gl_framebuffer *fb = ctx->ReadBuffer;
 310    struct gl_renderbuffer *rb = fb->_ColorReadBuffer;
 311
 312    if (!rb)
 313       return;
 314
 315    if (type == GL_FLOAT && ((ctx->Color.ClampReadColor == GL_TRUE) ||
 316                             (ctx->Color.ClampReadColor == GL_FIXED_ONLY_ARB &&
 317                              rb->DataType != GL_FLOAT)))
 318       transferOps |= IMAGE_CLAMP_BIT;
 319
 320    /* Try optimized path first */
 321    if (fast_read_rgba_pixels(ctx, x, y, width, height,
 322                              format, type, pixels, packing, transferOps)) {
 323       return; /* done! */
 324    }
 325
 326    /* width should never be > MAX_WIDTH since we did clipping earlier */
 327    ASSERT(width <= MAX_WIDTH);
 328
 329    if (ctx->Pixel.Convolution2DEnabled || ctx->Pixel.Separable2DEnabled) {
 330       GLfloat *dest, *src, *tmpImage, *convImage;
 331       GLint row;
 332
 333       tmpImage = (GLfloat *) malloc(width * height * 4 * sizeof(GLfloat));
 334       if (!tmpImage) {
 335          _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 336          return;
 337       }
 338       convImage = (GLfloat *) malloc(width * height * 4 * sizeof(GLfloat));
 339       if (!convImage) {
 340          free(tmpImage);
 341          _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 342          return;
 343       }
 344
 345       /* read full RGBA, FLOAT image */
 346       dest = tmpImage;
 347       for (row = 0; row < height; row++, y++) {
 348          _swrast_read_rgba_span(ctx, rb, width, x, y, GL_FLOAT, dest);
 349          _mesa_apply_rgba_transfer_ops(ctx,
 350                                       transferOps & IMAGE_PRE_CONVOLUTION_BITS,
 351                                       width, (GLfloat (*)[4]) dest);
 352          dest += width * 4;
 353       }
 354
 355       /* do convolution */
 356       if (ctx->Pixel.Convolution2DEnabled) {
 357          _mesa_convolve_2d_image(ctx, &width, &height, tmpImage, convImage);
 358       }
 359       else {
 360          ASSERT(ctx->Pixel.Separable2DEnabled);
 361          _mesa_convolve_sep_image(ctx, &width, &height, tmpImage, convImage);
 362       }
 363       free(tmpImage);
 364
 365       /* finish transfer ops and pack the resulting image */
 366       src = convImage;
 367       for (row = 0; row < height; row++) {
 368          GLvoid *dest;
 369          dest = _mesa_image_address2d(packing, pixels, width, height,
 370                                       format, type, row, 0);
 371          _mesa_pack_rgba_span_float(ctx, width, (GLfloat (*)[4]) src,
 372                                     format, type, dest, packing,
 373                                     transferOps & IMAGE_POST_CONVOLUTION_BITS);
 374          src += width * 4;
 375       }
 376       free(convImage);
 377    }
 378    else {
 379       /* no convolution */
 380       const GLint dstStride
 381          = _mesa_image_row_stride(packing, width, format, type);
 382       GLfloat (*rgba)[4] = swrast->SpanArrays->attribs[FRAG_ATTRIB_COL0];
 383       GLint row;
 384       GLubyte *dst
 385          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 386                                              format, type, 0, 0);
 387
 388       /* make sure we don't apply 1D convolution */
 389       transferOps &= ~(IMAGE_CONVOLUTION_BIT |
 390                        IMAGE_POST_CONVOLUTION_SCALE_BIAS);
 391
 392       for (row = 0; row < height; row++, y++) {
 393
 394          /* Get float rgba pixels */
 395          _swrast_read_rgba_span(ctx, rb, width, x, y, GL_FLOAT, rgba);
 396
 397          /* apply fudge factor for shallow color buffers */
 398          if (fb->Visual.redBits < 8 ||
 399              fb->Visual.greenBits < 8 ||
 400              fb->Visual.blueBits < 8) {
 401             adjust_colors(fb, width, rgba);
 402          }
 403
 404          /* pack the row of RGBA pixels into user's buffer */
 405          _mesa_pack_rgba_span_float(ctx, width, rgba, format, type, dst,
 406                                     packing, transferOps);
 407
 408          dst += dstStride;
 409       }
 410    }
 411 }
 412
 413
 414 /**
 415  * Read combined depth/stencil values.
 416  * We'll have already done error checking to be sure the expected
 417  * depth and stencil buffers really exist.
 418  */
 419 static void
 420 read_depth_stencil_pixels(GLcontext *ctx,
 421                           GLint x, GLint y,
 422                           GLsizei width, GLsizei height,
 423                           GLenum type, GLvoid *pixels,
 424                           const struct gl_pixelstore_attrib *packing )
 425 {
 426    const GLboolean scaleOrBias
 427       = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
 428    const GLboolean stencilTransfer = ctx->Pixel.IndexShift
 429       || ctx->Pixel.IndexOffset || ctx->Pixel.MapStencilFlag;
 430    struct gl_renderbuffer *depthRb, *stencilRb;
 431
 432    depthRb = ctx->ReadBuffer->_DepthBuffer;
 433    stencilRb = ctx->ReadBuffer->_StencilBuffer;
 434
 435    if (!depthRb || !stencilRb)
 436       return;
 437
 438    depthRb = ctx->ReadBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
 439    stencilRb = ctx->ReadBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
 440
 441    if (depthRb->_BaseFormat == GL_DEPTH_STENCIL_EXT &&
 442        stencilRb->_BaseFormat == GL_DEPTH_STENCIL_EXT &&
 443        depthRb == stencilRb &&
 444        !scaleOrBias &&
 445        !stencilTransfer) {
 446       /* This is the ideal case.
 447        * Reading GL_DEPTH_STENCIL pixels from combined depth/stencil buffer.
 448        * Plus, no pixel transfer ops to worry about!
 449        */
 450       GLint i;
 451       GLint dstStride = _mesa_image_row_stride(packing, width,
 452                                                GL_DEPTH_STENCIL_EXT, type);
 453       GLubyte *dst = (GLubyte *) _mesa_image_address2d(packing, pixels,
 454                                                        width, height,
 455                                                        GL_DEPTH_STENCIL_EXT,
 456                                                        type, 0, 0);
 457       for (i = 0; i < height; i++) {
 458          depthRb->GetRow(ctx, depthRb, width, x, y + i, dst);
 459          dst += dstStride;
 460       }
 461    }
 462    else {
 463       /* Reading GL_DEPTH_STENCIL pixels from separate depth/stencil buffers,
 464        * or we need pixel transfer.
 465        */
 466       GLint i;
 467       depthRb = ctx->ReadBuffer->_DepthBuffer;
 468       stencilRb = ctx->ReadBuffer->_StencilBuffer;
 469
 470       for (i = 0; i < height; i++) {
 471          GLstencil stencilVals[MAX_WIDTH];
 472
 473          GLuint *depthStencilDst = (GLuint *)
 474             _mesa_image_address2d(packing, pixels, width, height,
 475                                   GL_DEPTH_STENCIL_EXT, type, i, 0);
 476
 477          _swrast_read_stencil_span(ctx, stencilRb, width,
 478                                    x, y + i, stencilVals);
 479
 480          if (!scaleOrBias && !stencilTransfer
 481              && ctx->ReadBuffer->Visual.depthBits == 24) {
 482             /* ideal case */
 483             GLuint zVals[MAX_WIDTH]; /* 24-bit values! */
 484             GLint j;
 485             ASSERT(depthRb->DataType == GL_UNSIGNED_INT);
 486             /* note, we've already been clipped */
 487             depthRb->GetRow(ctx, depthRb, width, x, y + i, zVals);
 488             for (j = 0; j < width; j++) {
 489                depthStencilDst[j] = (zVals[j] << 8) | (stencilVals[j] & 0xff);
 490             }
 491          }
 492          else {
 493             /* general case */
 494             GLfloat depthVals[MAX_WIDTH];
 495             _swrast_read_depth_span_float(ctx, depthRb, width, x, y + i,
 496                                           depthVals);
 497             _mesa_pack_depth_stencil_span(ctx, width, depthStencilDst,
 498                                           depthVals, stencilVals, packing);
 499          }
 500       }
 501    }
 502 }
 503
 504
 505
 506 /**
 507  * Software fallback routine for ctx->Driver.ReadPixels().
 508  * By time we get here, all error checking will have been done.
 509  */
 510 void
 511 _swrast_ReadPixels( GLcontext *ctx,
 512                     GLint x, GLint y, GLsizei width, GLsizei height,
 513                     GLenum format, GLenum type,
 514                     const struct gl_pixelstore_attrib *packing,
 515                     GLvoid *pixels )
 516 {
 517    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 518    struct gl_pixelstore_attrib clippedPacking = *packing;
 519
 520    if (ctx->NewState)
 521       _mesa_update_state(ctx);
 522
 523    /* Need to do swrast_render_start() before clipping or anything else
 524     * since this is where a driver may grab the hw lock and get an updated
 525     * window size.
 526     */
 527    swrast_render_start(ctx);
 528
 529    if (swrast->NewState)
 530       _swrast_validate_derived( ctx );
 531
 532    /* Do all needed clipping here, so that we can forget about it later */
 533    if (!_mesa_clip_readpixels(ctx, &x, &y, &width, &height, &clippedPacking)) {
 534       /* The ReadPixels region is totally outside the window bounds */
 535       swrast_render_finish(ctx);
 536       return;
 537    }
 538
 539    pixels = _mesa_map_pbo_dest(ctx, &clippedPacking, pixels);
 540    if (!pixels)
 541       return;
 542
 543    switch (format) {
 544       case GL_STENCIL_INDEX:
 545          read_stencil_pixels(ctx, x, y, width, height, type, pixels,
 546                              &clippedPacking);
 547          break;
 548       case GL_DEPTH_COMPONENT:
 549          read_depth_pixels(ctx, x, y, width, height, type, pixels,
 550                            &clippedPacking);
 551          break;
 552       case GL_RED:
 553       case GL_GREEN:
 554       case GL_BLUE:
 555       case GL_ALPHA:
 556       case GL_RGB:
 557       case GL_LUMINANCE:
 558       case GL_LUMINANCE_ALPHA:
 559       case GL_RGBA:
 560       case GL_BGR:
 561       case GL_BGRA:
 562       case GL_ABGR_EXT:
 563          read_rgba_pixels(ctx, x, y, width, height,
 564                           format, type, pixels, &clippedPacking);
 565          break;
 566       case GL_DEPTH_STENCIL_EXT:
 567          read_depth_stencil_pixels(ctx, x, y, width, height,
 568                                    type, pixels, &clippedPacking);
 569          break;
 570       default:
 571          _mesa_problem(ctx, "unexpected format in _swrast_ReadPixels");
 572          /* don't return yet, clean-up */
 573    }
 574
 575    swrast_render_finish(ctx);
 576
 577    _mesa_unmap_pbo_dest(ctx, &clippedPacking);
 578 }