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
 196    /* clipping should have already been done */
 197    ASSERT(x + width <= (GLint) rb->Width);
 198    ASSERT(y + height <= (GLint) rb->Height);
 199
 200    /* check for things we can't handle here */
 201    if (transferOps ||
 202        packing->SwapBytes ||
 203        packing->LsbFirst) {
 204       return GL_FALSE;
 205    }
 206
 207    if (format == GL_RGBA && rb->DataType == type) {
 208       const GLint dstStride = _mesa_image_row_stride(packing, width,
 209                                                      format, type);
 210       GLubyte *dest
 211          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 212                                              format, type, 0, 0);
 213       GLint row;
 214       ASSERT(rb->GetRow);
 215       for (row = 0; row < height; row++) {
 216          rb->GetRow(ctx, rb, width, x, y + row, dest);
 217          dest += dstStride;
 218       }
 219       return GL_TRUE;
 220    }
 221
 222    if (format == GL_RGB &&
 223        rb->DataType == GL_UNSIGNED_BYTE &&
 224        type == GL_UNSIGNED_BYTE) {
 225       const GLint dstStride = _mesa_image_row_stride(packing, width,
 226                                                      format, type);
 227       GLubyte *dest
 228          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 229                                              format, type, 0, 0);
 230       GLint row;
 231       ASSERT(rb->GetRow);
 232       for (row = 0; row < height; row++) {
 233          GLubyte tempRow[MAX_WIDTH][4];
 234          GLint col;
 235          rb->GetRow(ctx, rb, width, x, y + row, tempRow);
 236          /* convert RGBA to RGB */
 237          for (col = 0; col < width; col++) {
 238             dest[col * 3 + 0] = tempRow[col][0];
 239             dest[col * 3 + 1] = tempRow[col][1];
 240             dest[col * 3 + 2] = tempRow[col][2];
 241          }
 242          dest += dstStride;
 243       }
 244       return GL_TRUE;
 245    }
 246
 247    /* not handled */
 248    return GL_FALSE;
 249 }
 250
 251
 252 /**
 253  * When we're using a low-precision color buffer (like 16-bit 5/6/5)
 254  * we have to adjust our color values a bit to pass conformance.
 255  * The problem is when a 5 or 6-bit color value is converted to an 8-bit
 256  * value and then a floating point value, the floating point values don't
 257  * increment uniformly as the 5 or 6-bit value is incremented.
 258  *
 259  * This function adjusts floating point values to compensate.
 260  */
 261 static void
 262 adjust_colors(const struct gl_framebuffer *fb, GLuint n, GLfloat rgba[][4])
 263 {
 264    const GLuint rShift = 8 - fb->Visual.redBits;
 265    const GLuint gShift = 8 - fb->Visual.greenBits;
 266    const GLuint bShift = 8 - fb->Visual.blueBits;
 267    GLfloat rScale = 1.0F / (GLfloat) ((1 << fb->Visual.redBits  ) - 1);
 268    GLfloat gScale = 1.0F / (GLfloat) ((1 << fb->Visual.greenBits) - 1);
 269    GLfloat bScale = 1.0F / (GLfloat) ((1 << fb->Visual.blueBits ) - 1);
 270    GLuint i;
 271
 272    if (fb->Visual.redBits == 0)
 273       rScale = 0;
 274    if (fb->Visual.greenBits == 0)
 275       gScale = 0;
 276    if (fb->Visual.blueBits == 0)
 277       bScale = 0;
 278
 279    for (i = 0; i < n; i++) {
 280       GLint r, g, b;
 281       /* convert float back to ubyte */
 282       CLAMPED_FLOAT_TO_UBYTE(r, rgba[i][RCOMP]);
 283       CLAMPED_FLOAT_TO_UBYTE(g, rgba[i][GCOMP]);
 284       CLAMPED_FLOAT_TO_UBYTE(b, rgba[i][BCOMP]);
 285       /* using only the N most significant bits of the ubyte value, convert to
 286        * float in [0,1].
 287        */
 288       rgba[i][RCOMP] = (GLfloat) (r >> rShift) * rScale;
 289       rgba[i][GCOMP] = (GLfloat) (g >> gShift) * gScale;
 290       rgba[i][BCOMP] = (GLfloat) (b >> bShift) * bScale;
 291    }
 292 }
 293
 294
 295
 296 /*
 297  * Read R, G, B, A, RGB, L, or LA pixels.
 298  */
 299 static void
 300 read_rgba_pixels( GLcontext *ctx,
 301                   GLint x, GLint y,
 302                   GLsizei width, GLsizei height,
 303                   GLenum format, GLenum type, GLvoid *pixels,
 304                   const struct gl_pixelstore_attrib *packing )
 305 {
 306    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 307    GLbitfield transferOps = ctx->_ImageTransferState;
 308    struct gl_framebuffer *fb = ctx->ReadBuffer;
 309    struct gl_renderbuffer *rb = fb->_ColorReadBuffer;
 310
 311    if (!rb)
 312       return;
 313
 314    if (type == GL_FLOAT && ((ctx->Color.ClampReadColor == GL_TRUE) ||
 315                             (ctx->Color.ClampReadColor == GL_FIXED_ONLY_ARB &&
 316                              rb->DataType != GL_FLOAT)))
 317       transferOps |= IMAGE_CLAMP_BIT;
 318
 319    /* Try optimized path first */
 320    if (fast_read_rgba_pixels(ctx, x, y, width, height,
 321                              format, type, pixels, packing, transferOps)) {
 322       return; /* done! */
 323    }
 324
 325    /* width should never be > MAX_WIDTH since we did clipping earlier */
 326    ASSERT(width <= MAX_WIDTH);
 327
 328    if (ctx->Pixel.Convolution2DEnabled || ctx->Pixel.Separable2DEnabled) {
 329       GLfloat *dest, *src, *tmpImage, *convImage;
 330       GLint row;
 331
 332       tmpImage = (GLfloat *) malloc(width * height * 4 * sizeof(GLfloat));
 333       if (!tmpImage) {
 334          _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 335          return;
 336       }
 337       convImage = (GLfloat *) malloc(width * height * 4 * sizeof(GLfloat));
 338       if (!convImage) {
 339          free(tmpImage);
 340          _mesa_error(ctx, GL_OUT_OF_MEMORY, "glReadPixels");
 341          return;
 342       }
 343
 344       /* read full RGBA, FLOAT image */
 345       dest = tmpImage;
 346       for (row = 0; row < height; row++, y++) {
 347          _swrast_read_rgba_span(ctx, rb, width, x, y, GL_FLOAT, dest);
 348          _mesa_apply_rgba_transfer_ops(ctx,
 349                                       transferOps & IMAGE_PRE_CONVOLUTION_BITS,
 350                                       width, (GLfloat (*)[4]) dest);
 351          dest += width * 4;
 352       }
 353
 354       /* do convolution */
 355       if (ctx->Pixel.Convolution2DEnabled) {
 356          _mesa_convolve_2d_image(ctx, &width, &height, tmpImage, convImage);
 357       }
 358       else {
 359          ASSERT(ctx->Pixel.Separable2DEnabled);
 360          _mesa_convolve_sep_image(ctx, &width, &height, tmpImage, convImage);
 361       }
 362       free(tmpImage);
 363
 364       /* finish transfer ops and pack the resulting image */
 365       src = convImage;
 366       for (row = 0; row < height; row++) {
 367          GLvoid *dest;
 368          dest = _mesa_image_address2d(packing, pixels, width, height,
 369                                       format, type, row, 0);
 370          _mesa_pack_rgba_span_float(ctx, width, (GLfloat (*)[4]) src,
 371                                     format, type, dest, packing,
 372                                     transferOps & IMAGE_POST_CONVOLUTION_BITS);
 373          src += width * 4;
 374       }
 375       free(convImage);
 376    }
 377    else {
 378       /* no convolution */
 379       const GLint dstStride
 380          = _mesa_image_row_stride(packing, width, format, type);
 381       GLfloat (*rgba)[4] = swrast->SpanArrays->attribs[FRAG_ATTRIB_COL0];
 382       GLint row;
 383       GLubyte *dst
 384          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 385                                              format, type, 0, 0);
 386
 387       /* make sure we don't apply 1D convolution */
 388       transferOps &= ~(IMAGE_CONVOLUTION_BIT |
 389                        IMAGE_POST_CONVOLUTION_SCALE_BIAS);
 390
 391       for (row = 0; row < height; row++, y++) {
 392
 393          /* Get float rgba pixels */
 394          _swrast_read_rgba_span(ctx, rb, width, x, y, GL_FLOAT, rgba);
 395
 396          /* apply fudge factor for shallow color buffers */
 397          if (fb->Visual.redBits < 8 ||
 398              fb->Visual.greenBits < 8 ||
 399              fb->Visual.blueBits < 8) {
 400             adjust_colors(fb, width, rgba);
 401          }
 402
 403          /* pack the row of RGBA pixels into user's buffer */
 404          _mesa_pack_rgba_span_float(ctx, width, rgba, format, type, dst,
 405                                     packing, transferOps);
 406
 407          dst += dstStride;
 408       }
 409    }
 410 }
 411
 412
 413 /**
 414  * Read combined depth/stencil values.
 415  * We'll have already done error checking to be sure the expected
 416  * depth and stencil buffers really exist.
 417  */
 418 static void
 419 read_depth_stencil_pixels(GLcontext *ctx,
 420                           GLint x, GLint y,
 421                           GLsizei width, GLsizei height,
 422                           GLenum type, GLvoid *pixels,
 423                           const struct gl_pixelstore_attrib *packing )
 424 {
 425    const GLboolean scaleOrBias
 426       = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
 427    const GLboolean stencilTransfer = ctx->Pixel.IndexShift
 428       || ctx->Pixel.IndexOffset || ctx->Pixel.MapStencilFlag;
 429    struct gl_renderbuffer *depthRb, *stencilRb;
 430
 431    depthRb = ctx->ReadBuffer->_DepthBuffer;
 432    stencilRb = ctx->ReadBuffer->_StencilBuffer;
 433
 434    if (!depthRb || !stencilRb)
 435       return;
 436
 437    depthRb = ctx->ReadBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
 438    stencilRb = ctx->ReadBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
 439
 440    if (depthRb->_BaseFormat == GL_DEPTH_STENCIL_EXT &&
 441        stencilRb->_BaseFormat == GL_DEPTH_STENCIL_EXT &&
 442        depthRb == stencilRb &&
 443        !scaleOrBias &&
 444        !stencilTransfer) {
 445       /* This is the ideal case.
 446        * Reading GL_DEPTH_STENCIL pixels from combined depth/stencil buffer.
 447        * Plus, no pixel transfer ops to worry about!
 448        */
 449       GLint i;
 450       GLint dstStride = _mesa_image_row_stride(packing, width,
 451                                                GL_DEPTH_STENCIL_EXT, type);
 452       GLubyte *dst = (GLubyte *) _mesa_image_address2d(packing, pixels,
 453                                                        width, height,
 454                                                        GL_DEPTH_STENCIL_EXT,
 455                                                        type, 0, 0);
 456       for (i = 0; i < height; i++) {
 457          depthRb->GetRow(ctx, depthRb, width, x, y + i, dst);
 458          dst += dstStride;
 459       }
 460    }
 461    else {
 462       /* Reading GL_DEPTH_STENCIL pixels from separate depth/stencil buffers,
 463        * or we need pixel transfer.
 464        */
 465       GLint i;
 466       depthRb = ctx->ReadBuffer->_DepthBuffer;
 467       stencilRb = ctx->ReadBuffer->_StencilBuffer;
 468
 469       for (i = 0; i < height; i++) {
 470          GLstencil stencilVals[MAX_WIDTH];
 471
 472          GLuint *depthStencilDst = (GLuint *)
 473             _mesa_image_address2d(packing, pixels, width, height,
 474                                   GL_DEPTH_STENCIL_EXT, type, i, 0);
 475
 476          _swrast_read_stencil_span(ctx, stencilRb, width,
 477                                    x, y + i, stencilVals);
 478
 479          if (!scaleOrBias && !stencilTransfer
 480              && ctx->ReadBuffer->Visual.depthBits == 24) {
 481             /* ideal case */
 482             GLuint zVals[MAX_WIDTH]; /* 24-bit values! */
 483             GLint j;
 484             ASSERT(depthRb->DataType == GL_UNSIGNED_INT);
 485             /* note, we've already been clipped */
 486             depthRb->GetRow(ctx, depthRb, width, x, y + i, zVals);
 487             for (j = 0; j < width; j++) {
 488                depthStencilDst[j] = (zVals[j] << 8) | (stencilVals[j] & 0xff);
 489             }
 490          }
 491          else {
 492             /* general case */
 493             GLfloat depthVals[MAX_WIDTH];
 494             _swrast_read_depth_span_float(ctx, depthRb, width, x, y + i,
 495                                           depthVals);
 496             _mesa_pack_depth_stencil_span(ctx, width, depthStencilDst,
 497                                           depthVals, stencilVals, packing);
 498          }
 499       }
 500    }
 501 }
 502
 503
 504
 505 /**
 506  * Software fallback routine for ctx->Driver.ReadPixels().
 507  * By time we get here, all error checking will have been done.
 508  */
 509 void
 510 _swrast_ReadPixels( GLcontext *ctx,
 511                     GLint x, GLint y, GLsizei width, GLsizei height,
 512                     GLenum format, GLenum type,
 513                     const struct gl_pixelstore_attrib *packing,
 514                     GLvoid *pixels )
 515 {
 516    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 517    struct gl_pixelstore_attrib clippedPacking = *packing;
 518
 519    if (ctx->NewState)
 520       _mesa_update_state(ctx);
 521
 522    /* Need to do swrast_render_start() before clipping or anything else
 523     * since this is where a driver may grab the hw lock and get an updated
 524     * window size.
 525     */
 526    swrast_render_start(ctx);
 527
 528    if (swrast->NewState)
 529       _swrast_validate_derived( ctx );
 530
 531    /* Do all needed clipping here, so that we can forget about it later */
 532    if (!_mesa_clip_readpixels(ctx, &x, &y, &width, &height, &clippedPacking)) {
 533       /* The ReadPixels region is totally outside the window bounds */
 534       swrast_render_finish(ctx);
 535       return;
 536    }
 537
 538    pixels = _mesa_map_pbo_dest(ctx, &clippedPacking, pixels);
 539    if (!pixels)
 540       return;
 541
 542    switch (format) {
 543       case GL_STENCIL_INDEX:
 544          read_stencil_pixels(ctx, x, y, width, height, type, pixels,
 545                              &clippedPacking);
 546          break;
 547       case GL_DEPTH_COMPONENT:
 548          read_depth_pixels(ctx, x, y, width, height, type, pixels,
 549                            &clippedPacking);
 550          break;
 551       case GL_RED:
 552       case GL_GREEN:
 553       case GL_BLUE:
 554       case GL_ALPHA:
 555       case GL_RGB:
 556       case GL_LUMINANCE:
 557       case GL_LUMINANCE_ALPHA:
 558       case GL_RGBA:
 559       case GL_BGR:
 560       case GL_BGRA:
 561       case GL_ABGR_EXT:
 562          read_rgba_pixels(ctx, x, y, width, height,
 563                           format, type, pixels, &clippedPacking);
 564          break;
 565       case GL_DEPTH_STENCIL_EXT:
 566          read_depth_stencil_pixels(ctx, x, y, width, height,
 567                                    type, pixels, &clippedPacking);
 568          break;
 569       default:
 570          _mesa_problem(ctx, "unexpected format in _swrast_ReadPixels");
 571          /* don't return yet, clean-up */
 572    }
 573
 574    swrast_render_finish(ctx);
 575
 576    _mesa_unmap_pbo_dest(ctx, &clippedPacking);
 577 }