src/mesa/swrast/s_copypix.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.5
   4  *
   5  * Copyright (C) 1999-2005  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 "glheader.h"
  27 #include "context.h"
  28 #include "colormac.h"
  29 #include "convolve.h"
  30 #include "histogram.h"
  31 #include "image.h"
  32 #include "macros.h"
  33 #include "imports.h"
  34 #include "pixel.h"
  35
  36 #include "s_context.h"
  37 #include "s_depth.h"
  38 #include "s_span.h"
  39 #include "s_stencil.h"
  40 #include "s_zoom.h"
  41
  42
  43
  44 /*
  45  * Determine if there's overlap in an image copy.
  46  * This test also compensates for the fact that copies are done from
  47  * bottom to top and overlaps can sometimes be handled correctly
  48  * without making a temporary image copy.
  49  */
  50 static GLboolean
  51 regions_overlap(GLint srcx, GLint srcy,
  52                 GLint dstx, GLint dsty,
  53                 GLint width, GLint height,
  54                 GLfloat zoomX, GLfloat zoomY)
  55 {
  56    if (zoomX == 1.0 && zoomY == 1.0) {
  57       /* no zoom */
  58       if (srcx >= dstx + width || (srcx + width <= dstx)) {
  59          return GL_FALSE;
  60       }
  61       else if (srcy < dsty) { /* this is OK */
  62          return GL_FALSE;
  63       }
  64       else if (srcy > dsty + height) {
  65          return GL_FALSE;
  66       }
  67       else {
  68          return GL_TRUE;
  69       }
  70    }
  71    else {
  72       /* add one pixel of slop when zooming, just to be safe */
  73       if ((srcx > dstx + (width * zoomX) + 1) || (srcx + width + 1 < dstx)) {
  74          return GL_FALSE;
  75       }
  76       else if ((srcy < dsty) && (srcy + height < dsty + (height * zoomY))) {
  77          return GL_FALSE;
  78       }
  79       else if ((srcy > dsty) && (srcy + height > dsty + (height * zoomY))) {
  80          return GL_FALSE;
  81       }
  82       else {
  83          return GL_TRUE;
  84       }
  85    }
  86 }
  87
  88
  89 /**
  90  * Convert GLfloat[n][4] colors to GLchan[n][4].
  91  * XXX maybe move into image.c
  92  */
  93 static void
  94 float_span_to_chan(GLuint n, CONST GLfloat in[][4], GLchan out[][4])
  95 {
  96    GLuint i;
  97    for (i = 0; i < n; i++) {
  98       UNCLAMPED_FLOAT_TO_CHAN(out[i][RCOMP], in[i][RCOMP]);
  99       UNCLAMPED_FLOAT_TO_CHAN(out[i][GCOMP], in[i][GCOMP]);
 100       UNCLAMPED_FLOAT_TO_CHAN(out[i][BCOMP], in[i][BCOMP]);
 101       UNCLAMPED_FLOAT_TO_CHAN(out[i][ACOMP], in[i][ACOMP]);
 102    }
 103 }
 104
 105
 106 /**
 107  * Convert GLchan[n][4] colors to GLfloat[n][4].
 108  * XXX maybe move into image.c
 109  */
 110 static void
 111 chan_span_to_float(GLuint n, CONST GLchan in[][4], GLfloat out[][4])
 112 {
 113    GLuint i;
 114    for (i = 0; i < n; i++) {
 115       out[i][RCOMP] = CHAN_TO_FLOAT(in[i][RCOMP]);
 116       out[i][GCOMP] = CHAN_TO_FLOAT(in[i][GCOMP]);
 117       out[i][BCOMP] = CHAN_TO_FLOAT(in[i][BCOMP]);
 118       out[i][ACOMP] = CHAN_TO_FLOAT(in[i][ACOMP]);
 119    }
 120 }
 121
 122
 123
 124 /*
 125  * RGBA copypixels with convolution.
 126  */
 127 static void
 128 copy_conv_rgba_pixels(GLcontext *ctx, GLint srcx, GLint srcy,
 129                       GLint width, GLint height, GLint destx, GLint desty)
 130 {
 131    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 132    struct gl_renderbuffer *drawRb = NULL;
 133    GLboolean quick_draw;
 134    GLint row;
 135    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 136    const GLuint transferOps = ctx->_ImageTransferState;
 137    GLfloat *dest, *tmpImage, *convImage;
 138    struct sw_span span;
 139
 140    INIT_SPAN(span, GL_BITMAP, 0, 0, SPAN_RGBA);
 141
 142    if (ctx->Depth.Test)
 143       _swrast_span_default_z(ctx, &span);
 144    if (swrast->_FogEnabled)
 145       _swrast_span_default_fog(ctx, &span);
 146
 147
 148    if (SWRAST_CONTEXT(ctx)->_RasterMask == 0
 149        && !zoom
 150        && destx >= 0
 151        && destx + width <= (GLint) ctx->DrawBuffer->Width) {
 152       quick_draw = GL_TRUE;
 153       drawRb = ctx->DrawBuffer->_ColorDrawBuffers[0][0];
 154    }
 155    else {
 156       quick_draw = GL_FALSE;
 157    }
 158
 159    /* allocate space for GLfloat image */
 160    tmpImage = (GLfloat *) _mesa_malloc(width * height * 4 * sizeof(GLfloat));
 161    if (!tmpImage) {
 162       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glCopyPixels");
 163       return;
 164    }
 165    convImage = (GLfloat *) _mesa_malloc(width * height * 4 * sizeof(GLfloat));
 166    if (!convImage) {
 167       _mesa_free(tmpImage);
 168       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glCopyPixels");
 169       return;
 170    }
 171
 172    /* read source image */
 173    dest = tmpImage;
 174    for (row = 0; row < height; row++) {
 175       GLchan rgba[MAX_WIDTH][4];
 176       /* Read GLchan and convert to GLfloat */
 177       _swrast_read_rgba_span(ctx, ctx->ReadBuffer->_ColorReadBuffer,
 178                              width, srcx, srcy + row, rgba);
 179       chan_span_to_float(width, (CONST GLchan (*)[4]) rgba,
 180                          (GLfloat (*)[4]) dest);
 181       dest += 4 * width;
 182    }
 183
 184    /* do the image transfer ops which preceed convolution */
 185    for (row = 0; row < height; row++) {
 186       GLfloat (*rgba)[4] = (GLfloat (*)[4]) (tmpImage + row * width * 4);
 187       _mesa_apply_rgba_transfer_ops(ctx,
 188                                     transferOps & IMAGE_PRE_CONVOLUTION_BITS,
 189                                     width, rgba);
 190    }
 191
 192    /* do convolution */
 193    if (ctx->Pixel.Convolution2DEnabled) {
 194       _mesa_convolve_2d_image(ctx, &width, &height, tmpImage, convImage);
 195    }
 196    else {
 197       ASSERT(ctx->Pixel.Separable2DEnabled);
 198       _mesa_convolve_sep_image(ctx, &width, &height, tmpImage, convImage);
 199    }
 200    _mesa_free(tmpImage);
 201
 202    /* do remaining post-convolution image transfer ops */
 203    for (row = 0; row < height; row++) {
 204       GLfloat (*rgba)[4] = (GLfloat (*)[4]) (convImage + row * width * 4);
 205       _mesa_apply_rgba_transfer_ops(ctx,
 206                                     transferOps & IMAGE_POST_CONVOLUTION_BITS,
 207                                     width, rgba);
 208    }
 209
 210    /* write the new image */
 211    for (row = 0; row < height; row++) {
 212       const GLfloat *src = convImage + row * width * 4;
 213       GLint dy;
 214
 215       /* convert floats back to chan */
 216       float_span_to_chan(width, (const GLfloat (*)[4]) src, span.array->rgba);
 217
 218       /* write row to framebuffer */
 219       dy = desty + row;
 220       if (quick_draw && dy >= 0 && dy < (GLint) ctx->DrawBuffer->Height) {
 221          drawRb->PutRow(ctx, drawRb, width, destx, dy, span.array->rgba, NULL);
 222       }
 223       else {
 224          span.x = destx;
 225          span.y = dy;
 226          span.end = width;
 227          if (zoom) {
 228             _swrast_write_zoomed_rgba_span(ctx, destx, desty, &span,
 229                                         (CONST GLchan (*)[4])span.array->rgba);
 230          }
 231          else {
 232             _swrast_write_rgba_span(ctx, &span);
 233          }
 234       }
 235    }
 236
 237    _mesa_free(convImage);
 238 }
 239
 240
 241 /*
 242  * RGBA copypixels
 243  */
 244 static void
 245 copy_rgba_pixels(GLcontext *ctx, GLint srcx, GLint srcy,
 246                  GLint width, GLint height, GLint destx, GLint desty)
 247 {
 248    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 249    struct gl_renderbuffer *drawRb;
 250    GLchan *tmpImage,*p;
 251    GLboolean quick_draw;
 252    GLint sy, dy, stepy, j;
 253    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 254    GLint overlapping;
 255    const GLuint transferOps = ctx->_ImageTransferState;
 256    struct sw_span span;
 257
 258    if (!ctx->ReadBuffer->_ColorReadBuffer) {
 259       /* no readbuffer - OK */
 260       return;
 261    }
 262
 263    INIT_SPAN(span, GL_BITMAP, 0, 0, SPAN_RGBA);
 264
 265    if (ctx->Pixel.Convolution2DEnabled || ctx->Pixel.Separable2DEnabled) {
 266       copy_conv_rgba_pixels(ctx, srcx, srcy, width, height, destx, desty);
 267       return;
 268    }
 269
 270    /* Determine if copy should be done bottom-to-top or top-to-bottom */
 271    if (srcy < desty) {
 272       /* top-down  max-to-min */
 273       sy = srcy + height - 1;
 274       dy = desty + height - 1;
 275       stepy = -1;
 276    }
 277    else {
 278       /* bottom-up  min-to-max */
 279       sy = srcy;
 280       dy = desty;
 281       stepy = 1;
 282    }
 283
 284    if (ctx->DrawBuffer == ctx->ReadBuffer) {
 285       overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
 286                                     ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
 287    }
 288    else {
 289       overlapping = GL_FALSE;
 290    }
 291
 292    if (ctx->Depth.Test)
 293       _swrast_span_default_z(ctx, &span);
 294    if (swrast->_FogEnabled)
 295       _swrast_span_default_fog(ctx, &span);
 296
 297    if (SWRAST_CONTEXT(ctx)->_RasterMask == 0
 298        && !zoom
 299        && destx >= 0
 300        && destx + width <= (GLint) ctx->DrawBuffer->Width) {
 301       quick_draw = GL_TRUE;
 302       drawRb = ctx->DrawBuffer->_ColorDrawBuffers[0][0];
 303    }
 304    else {
 305       quick_draw = GL_FALSE;
 306       drawRb = NULL;
 307    }
 308
 309    if (overlapping) {
 310       GLint ssy = sy;
 311       tmpImage = (GLchan *) _mesa_malloc(width * height * sizeof(GLchan) * 4);
 312       if (!tmpImage) {
 313          _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
 314          return;
 315       }
 316       /* read the source image */
 317       p = tmpImage;
 318       for (j = 0; j < height; j++, ssy += stepy) {
 319          _swrast_read_rgba_span( ctx, ctx->ReadBuffer->_ColorReadBuffer,
 320                                  width, srcx, ssy, (GLchan (*)[4]) p );
 321          p += width * 4;
 322       }
 323       p = tmpImage;
 324    }
 325    else {
 326       tmpImage = NULL;  /* silence compiler warnings */
 327       p = NULL;
 328    }
 329
 330    for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
 331       /* Get source pixels */
 332       if (overlapping) {
 333          /* get from buffered image */
 334          ASSERT(width < MAX_WIDTH);
 335          _mesa_memcpy(span.array->rgba, p, width * sizeof(GLchan) * 4);
 336          p += width * 4;
 337       }
 338       else {
 339          /* get from framebuffer */
 340          ASSERT(width < MAX_WIDTH);
 341          _swrast_read_rgba_span( ctx, ctx->ReadBuffer->_ColorReadBuffer,
 342                                  width, srcx, sy, span.array->rgba );
 343       }
 344
 345       if (transferOps) {
 346          GLfloat rgbaFloat[MAX_WIDTH][4];
 347          /* convert to float, transfer, convert back to chan */
 348          chan_span_to_float(width, (CONST GLchan (*)[4]) span.array->rgba,
 349                             rgbaFloat);
 350          _mesa_apply_rgba_transfer_ops(ctx, transferOps, width, rgbaFloat);
 351          float_span_to_chan(width, (CONST GLfloat (*)[4]) rgbaFloat,
 352                             span.array->rgba);
 353       }
 354
 355       /* Write color span */
 356       if (quick_draw && dy >= 0 && dy < (GLint) ctx->DrawBuffer->Height) {
 357          drawRb->PutRow(ctx, drawRb, width, destx, dy, span.array->rgba, NULL);
 358       }
 359       else {
 360          span.x = destx;
 361          span.y = dy;
 362          span.end = width;
 363          if (zoom) {
 364             _swrast_write_zoomed_rgba_span(ctx, destx, desty, &span,
 365                                        (CONST GLchan (*)[4]) span.array->rgba);
 366          }
 367          else {
 368             _swrast_write_rgba_span(ctx, &span);
 369          }
 370       }
 371    }
 372
 373    if (overlapping)
 374       _mesa_free(tmpImage);
 375 }
 376
 377
 378 static void
 379 copy_ci_pixels( GLcontext *ctx, GLint srcx, GLint srcy,
 380                 GLint width, GLint height,
 381                 GLint destx, GLint desty )
 382 {
 383    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 384    GLuint *tmpImage,*p;
 385    GLint sy, dy, stepy;
 386    GLint j;
 387    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 388    const GLboolean shift_or_offset = ctx->Pixel.IndexShift || ctx->Pixel.IndexOffset;
 389    GLint overlapping;
 390    struct sw_span span;
 391
 392    if (!ctx->ReadBuffer->_ColorReadBuffer) {
 393       /* no readbuffer - OK */
 394       return;
 395    }
 396
 397    INIT_SPAN(span, GL_BITMAP, 0, 0, SPAN_INDEX);
 398
 399    /* Determine if copy should be bottom-to-top or top-to-bottom */
 400    if (srcy<desty) {
 401       /* top-down  max-to-min */
 402       sy = srcy + height - 1;
 403       dy = desty + height - 1;
 404       stepy = -1;
 405    }
 406    else {
 407       /* bottom-up  min-to-max */
 408       sy = srcy;
 409       dy = desty;
 410       stepy = 1;
 411    }
 412
 413    if (ctx->DrawBuffer == ctx->ReadBuffer) {
 414       overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
 415                                     ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
 416    }
 417    else {
 418       overlapping = GL_FALSE;
 419    }
 420
 421    if (ctx->Depth.Test)
 422       _swrast_span_default_z(ctx, &span);
 423    if (swrast->_FogEnabled)
 424       _swrast_span_default_fog(ctx, &span);
 425
 426    if (overlapping) {
 427       GLint ssy = sy;
 428       tmpImage = (GLuint *) _mesa_malloc(width * height * sizeof(GLuint));
 429       if (!tmpImage) {
 430          _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
 431          return;
 432       }
 433       /* read the image */
 434       p = tmpImage;
 435       for (j = 0; j < height; j++, ssy += stepy) {
 436          _swrast_read_index_span( ctx, ctx->ReadBuffer->_ColorReadBuffer,
 437                                   width, srcx, ssy, p );
 438          p += width;
 439       }
 440       p = tmpImage;
 441    }
 442    else {
 443       tmpImage = NULL;  /* silence compiler warning */
 444       p = NULL;
 445    }
 446
 447    for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
 448       /* Get color indexes */
 449       if (overlapping) {
 450          _mesa_memcpy(span.array->index, p, width * sizeof(GLuint));
 451          p += width;
 452       }
 453       else {
 454          _swrast_read_index_span( ctx, ctx->ReadBuffer->_ColorReadBuffer,
 455                                   width, srcx, sy, span.array->index );
 456       }
 457
 458       /* Apply shift, offset, look-up table */
 459       if (shift_or_offset) {
 460          _mesa_shift_and_offset_ci( ctx, width, span.array->index );
 461       }
 462       if (ctx->Pixel.MapColorFlag) {
 463          _mesa_map_ci( ctx, width, span.array->index );
 464       }
 465
 466       /* write color indexes */
 467       span.x = destx;
 468       span.y = dy;
 469       span.end = width;
 470       if (zoom)
 471          _swrast_write_zoomed_index_span(ctx, destx, desty, &span);
 472       else
 473          _swrast_write_index_span(ctx, &span);
 474    }
 475
 476    if (overlapping)
 477       _mesa_free(tmpImage);
 478 }
 479
 480
 481
 482 /*
 483  * TODO: Optimize!!!!
 484  */
 485 static void
 486 copy_depth_pixels( GLcontext *ctx, GLint srcx, GLint srcy,
 487                    GLint width, GLint height,
 488                    GLint destx, GLint desty )
 489 {
 490    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 491    struct gl_framebuffer *fb = ctx->ReadBuffer;
 492    struct gl_renderbuffer *readRb = fb->_DepthBuffer;
 493    const GLfloat depthMax = fb->_DepthMaxF;
 494    GLfloat *p, *tmpImage;
 495    GLint sy, dy, stepy;
 496    GLint i, j;
 497    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 498    GLint overlapping;
 499    struct sw_span span;
 500
 501    if (!readRb) {
 502       /* no readbuffer - OK */
 503       return;
 504    }
 505
 506    INIT_SPAN(span, GL_BITMAP, 0, 0, SPAN_Z);
 507
 508    /* Determine if copy should be bottom-to-top or top-to-bottom */
 509    if (srcy<desty) {
 510       /* top-down  max-to-min */
 511       sy = srcy + height - 1;
 512       dy = desty + height - 1;
 513       stepy = -1;
 514    }
 515    else {
 516       /* bottom-up  min-to-max */
 517       sy = srcy;
 518       dy = desty;
 519       stepy = 1;
 520    }
 521
 522    if (ctx->DrawBuffer == ctx->ReadBuffer) {
 523       overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
 524                                     ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
 525    }
 526    else {
 527       overlapping = GL_FALSE;
 528    }
 529
 530    _swrast_span_default_color(ctx, &span);
 531    if (swrast->_FogEnabled)
 532       _swrast_span_default_fog(ctx, &span);
 533
 534    if (overlapping) {
 535       GLint ssy = sy;
 536       tmpImage = (GLfloat *) _mesa_malloc(width * height * sizeof(GLfloat));
 537       if (!tmpImage) {
 538          _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
 539          return;
 540       }
 541       p = tmpImage;
 542       for (j = 0; j < height; j++, ssy += stepy) {
 543          _swrast_read_depth_span_float(ctx, readRb, width, srcx, ssy, p);
 544          p += width;
 545       }
 546       p = tmpImage;
 547    }
 548    else {
 549       tmpImage = NULL;  /* silence compiler warning */
 550       p = NULL;
 551    }
 552
 553    for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
 554       GLfloat depth[MAX_WIDTH];
 555       /* get depth values */
 556       if (overlapping) {
 557          _mesa_memcpy(depth, p, width * sizeof(GLfloat));
 558          p += width;
 559       }
 560       else {
 561          _swrast_read_depth_span_float(ctx, readRb, width, srcx, sy, depth);
 562       }
 563
 564       /* apply scale and bias */
 565       for (i = 0; i < width; i++) {
 566          GLfloat d = depth[i] * ctx->Pixel.DepthScale + ctx->Pixel.DepthBias;
 567          span.array->z[i] = (GLuint) (CLAMP(d, 0.0F, 1.0F) * depthMax);
 568       }
 569
 570       /* write depth values */
 571       span.x = destx;
 572       span.y = dy;
 573       span.end = width;
 574       if (fb->Visual.rgbMode) {
 575          if (zoom)
 576             _swrast_write_zoomed_rgba_span(ctx, destx, desty, &span,
 577                                        (const GLchan (*)[4]) span.array->rgba);
 578          else
 579             _swrast_write_rgba_span(ctx, &span);
 580       }
 581       else {
 582          if (zoom)
 583             _swrast_write_zoomed_index_span(ctx, destx, desty, &span);
 584          else
 585             _swrast_write_index_span(ctx, &span);
 586       }
 587    }
 588
 589    if (overlapping)
 590       _mesa_free(tmpImage);
 591 }
 592
 593
 594
 595 static void
 596 copy_stencil_pixels( GLcontext *ctx, GLint srcx, GLint srcy,
 597                      GLint width, GLint height,
 598                      GLint destx, GLint desty )
 599 {
 600    struct gl_framebuffer *fb = ctx->ReadBuffer;
 601    struct gl_renderbuffer *rb = fb->_StencilBuffer;
 602    GLint sy, dy, stepy;
 603    GLint j;
 604    GLstencil *p, *tmpImage;
 605    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 606    const GLboolean shift_or_offset = ctx->Pixel.IndexShift || ctx->Pixel.IndexOffset;
 607    GLint overlapping;
 608
 609    if (!rb) {
 610       /* no readbuffer - OK */
 611       return;
 612    }
 613
 614    /* Determine if copy should be bottom-to-top or top-to-bottom */
 615    if (srcy < desty) {
 616       /* top-down  max-to-min */
 617       sy = srcy + height - 1;
 618       dy = desty + height - 1;
 619       stepy = -1;
 620    }
 621    else {
 622       /* bottom-up  min-to-max */
 623       sy = srcy;
 624       dy = desty;
 625       stepy = 1;
 626    }
 627
 628    if (ctx->DrawBuffer == ctx->ReadBuffer) {
 629       overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
 630                                     ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
 631    }
 632    else {
 633       overlapping = GL_FALSE;
 634    }
 635
 636    if (overlapping) {
 637       GLint ssy = sy;
 638       tmpImage = (GLstencil *) _mesa_malloc(width * height * sizeof(GLstencil));
 639       if (!tmpImage) {
 640          _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
 641          return;
 642       }
 643       p = tmpImage;
 644       for (j = 0; j < height; j++, ssy += stepy) {
 645          _swrast_read_stencil_span( ctx, rb, width, srcx, ssy, p );
 646          p += width;
 647       }
 648       p = tmpImage;
 649    }
 650    else {
 651       tmpImage = NULL;  /* silence compiler warning */
 652       p = NULL;
 653    }
 654
 655    for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
 656       GLstencil stencil[MAX_WIDTH];
 657
 658       /* Get stencil values */
 659       if (overlapping) {
 660          _mesa_memcpy(stencil, p, width * sizeof(GLstencil));
 661          p += width;
 662       }
 663       else {
 664          _swrast_read_stencil_span( ctx, rb, width, srcx, sy, stencil );
 665       }
 666
 667       /* Apply shift, offset, look-up table */
 668       if (shift_or_offset) {
 669          _mesa_shift_and_offset_stencil( ctx, width, stencil );
 670       }
 671       if (ctx->Pixel.MapStencilFlag) {
 672          _mesa_map_stencil( ctx, width, stencil );
 673       }
 674
 675       /* Write stencil values */
 676       if (zoom) {
 677          _swrast_write_zoomed_stencil_span(ctx, destx, desty, width,
 678                                            destx, dy, stencil);
 679       }
 680       else {
 681          _swrast_write_stencil_span( ctx, width, destx, dy, stencil );
 682       }
 683    }
 684
 685    if (overlapping)
 686       _mesa_free(tmpImage);
 687 }
 688
 689
 690 /**
 691  * This isn't terribly efficient.  If a driver really has combined
 692  * depth/stencil buffers the driver should implement an optimized
 693  * CopyPixels function.
 694  */
 695 static void
 696 copy_depth_stencil_pixels(GLcontext *ctx,
 697                           const GLint srcX, const GLint srcY,
 698                           const GLint width, const GLint height,
 699                           const GLint destX, const GLint destY)
 700 {
 701    struct gl_renderbuffer *stencilReadRb, *depthReadRb, *depthDrawRb;
 702    GLint sy, dy, stepy;
 703    GLint j;
 704    GLstencil *tempStencilImage = NULL, *stencilPtr = NULL;
 705    GLfloat *tempDepthImage = NULL, *depthPtr = NULL;
 706    const GLfloat depthScale = ctx->DrawBuffer->_DepthMaxF;
 707    const GLuint stencilMask = ctx->Stencil.WriteMask[0];
 708    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 709    const GLboolean shiftOrOffset
 710       = ctx->Pixel.IndexShift || ctx->Pixel.IndexOffset;
 711    const GLboolean scaleOrBias
 712       = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
 713    GLint overlapping;
 714
 715    depthDrawRb = ctx->DrawBuffer->_DepthBuffer;
 716    depthReadRb = ctx->ReadBuffer->_DepthBuffer;
 717    stencilReadRb = ctx->ReadBuffer->_StencilBuffer;
 718
 719    ASSERT(depthDrawRb);
 720    ASSERT(depthReadRb);
 721    ASSERT(stencilReadRb);
 722
 723    /* Determine if copy should be bottom-to-top or top-to-bottom */
 724    if (srcY < destY) {
 725       /* top-down  max-to-min */
 726       sy = srcY + height - 1;
 727       dy = destY + height - 1;
 728       stepy = -1;
 729    }
 730    else {
 731       /* bottom-up  min-to-max */
 732       sy = srcY;
 733       dy = destY;
 734       stepy = 1;
 735    }
 736
 737    if (ctx->DrawBuffer == ctx->ReadBuffer) {
 738       overlapping = regions_overlap(srcX, srcY, destX, destY, width, height,
 739                                     ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
 740    }
 741    else {
 742       overlapping = GL_FALSE;
 743    }
 744
 745    if (overlapping) {
 746       GLint ssy = sy;
 747
 748       if (stencilMask != 0x0) {
 749          tempStencilImage
 750             = (GLstencil *) _mesa_malloc(width * height * sizeof(GLstencil));
 751          if (!tempStencilImage) {
 752             _mesa_error(ctx, GL_OUT_OF_MEMORY, "glCopyPixels");
 753             return;
 754          }
 755
 756          /* get copy of stencil pixels */
 757          stencilPtr = tempStencilImage;
 758          for (j = 0; j < height; j++, ssy += stepy) {
 759             _swrast_read_stencil_span(ctx, stencilReadRb,
 760                                       width, srcX, ssy, stencilPtr);
 761             stencilPtr += width;
 762          }
 763          stencilPtr = tempStencilImage;
 764       }
 765
 766       if (ctx->Depth.Mask) {
 767          tempDepthImage
 768             = (GLfloat *) _mesa_malloc(width * height * sizeof(GLfloat));
 769          if (!tempDepthImage) {
 770             _mesa_error(ctx, GL_OUT_OF_MEMORY, "glCopyPixels");
 771             _mesa_free(tempStencilImage);
 772             return;
 773          }
 774
 775          /* get copy of depth pixels */
 776          depthPtr = tempDepthImage;
 777          for (j = 0; j < height; j++, ssy += stepy) {
 778             _swrast_read_depth_span_float(ctx, depthReadRb,
 779                                           width, srcX, ssy, depthPtr);
 780             depthPtr += width;
 781          }
 782          depthPtr = tempDepthImage;
 783       }
 784    }
 785
 786    for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
 787       if (stencilMask != 0x0) {
 788          GLstencil stencil[MAX_WIDTH];
 789
 790          /* Get stencil values */
 791          if (overlapping) {
 792             _mesa_memcpy(stencil, stencilPtr, width * sizeof(GLstencil));
 793             stencilPtr += width;
 794          }
 795          else {
 796             _swrast_read_stencil_span(ctx, stencilReadRb,
 797                                       width, srcX, sy, stencil);
 798          }
 799
 800          /* Apply shift, offset, look-up table */
 801          if (shiftOrOffset) {
 802             _mesa_shift_and_offset_stencil(ctx, width, stencil);
 803          }
 804          if (ctx->Pixel.MapStencilFlag) {
 805             _mesa_map_stencil(ctx, width, stencil);
 806          }
 807
 808          /* Write values */
 809          if (zoom) {
 810             _swrast_write_zoomed_stencil_span(ctx, destX, destY, width,
 811                                               destX, dy, stencil);
 812          }
 813          else {
 814             _swrast_write_stencil_span( ctx, width, destX, dy, stencil );
 815          }
 816       }
 817
 818       if (ctx->Depth.Mask) {
 819          GLfloat depth[MAX_WIDTH];
 820          GLuint zVals32[MAX_WIDTH];
 821          GLushort zVals16[MAX_WIDTH];
 822          GLvoid *zVals;
 823          GLuint zBytes;
 824
 825          /* get depth values */
 826          if (overlapping) {
 827             _mesa_memcpy(depth, depthPtr, width * sizeof(GLfloat));
 828             depthPtr += width;
 829          }
 830          else {
 831             _swrast_read_depth_span_float(ctx, depthReadRb,
 832                                           width, srcX, sy, depth);
 833          }
 834
 835          /* scale & bias */
 836          if (scaleOrBias) {
 837             _mesa_scale_and_bias_depth(ctx, width, depth);
 838          }
 839          /* convert to integer Z values */
 840          if (depthDrawRb->DataType == GL_UNSIGNED_SHORT) {
 841             GLint k;
 842             for (k = 0; k < width; k++)
 843                zVals16[k] = (GLushort) (depth[k] * depthScale);
 844             zVals = zVals16;
 845             zBytes = 2;
 846          }
 847          else {
 848             GLint k;
 849             for (k = 0; k < width; k++)
 850                zVals32[k] = (GLuint) (depth[k] * depthScale);
 851             zVals = zVals32;
 852             zBytes = 4;
 853          }
 854
 855          /* Write values */
 856          if (zoom) {
 857             _swrast_write_zoomed_z_span(ctx, destX, destY, width,
 858                                         destX, dy, zVals);
 859          }
 860          else {
 861             _swrast_put_row(ctx, depthDrawRb, width, destX, dy, zVals, zBytes);
 862          }
 863       }
 864    }
 865
 866    if (tempStencilImage)
 867       _mesa_free(tempStencilImage);
 868
 869    if (tempDepthImage)
 870       _mesa_free(tempDepthImage);
 871 }
 872
 873
 874 /**
 875  * Do software-based glCopyPixels.
 876  * By time we get here, all parameters will have been error-checked.
 877  */
 878 void
 879 _swrast_CopyPixels( GLcontext *ctx,
 880                     GLint srcx, GLint srcy, GLsizei width, GLsizei height,
 881                     GLint destx, GLint desty, GLenum type )
 882 {
 883    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 884    RENDER_START(swrast,ctx);
 885
 886    if (swrast->NewState)
 887       _swrast_validate_derived( ctx );
 888
 889    switch (type) {
 890    case GL_COLOR:
 891       if (ctx->Visual.rgbMode) {
 892          copy_rgba_pixels( ctx, srcx, srcy, width, height, destx, desty );
 893       }
 894       else {
 895          copy_ci_pixels( ctx, srcx, srcy, width, height, destx, desty );
 896       }
 897       break;
 898    case GL_DEPTH:
 899       copy_depth_pixels( ctx, srcx, srcy, width, height, destx, desty );
 900       break;
 901    case GL_STENCIL:
 902       copy_stencil_pixels( ctx, srcx, srcy, width, height, destx, desty );
 903       break;
 904    case GL_DEPTH_STENCIL_EXT:
 905       copy_depth_stencil_pixels(ctx, srcx, srcy, width, height, destx, desty);
 906       break;
 907    default:
 908       _mesa_problem(ctx, "unexpected type in _swrast_CopyPixels");
 909    }
 910
 911    RENDER_FINISH(swrast,ctx);
 912 }