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_pixeltex.h"
  39 #include "s_span.h"
  40 #include "s_stencil.h"
  41 #include "s_texture.h"
  42 #include "s_zoom.h"
  43
  44
  45
  46 /*
  47  * Determine if there's overlap in an image copy.
  48  * This test also compensates for the fact that copies are done from
  49  * bottom to top and overlaps can sometimes be handled correctly
  50  * without making a temporary image copy.
  51  */
  52 static GLboolean
  53 regions_overlap(GLint srcx, GLint srcy,
  54                 GLint dstx, GLint dsty,
  55                 GLint width, GLint height,
  56                 GLfloat zoomX, GLfloat zoomY)
  57 {
  58    if (zoomX == 1.0 && zoomY == 1.0) {
  59       /* no zoom */
  60       if (srcx >= dstx + width || (srcx + width <= dstx)) {
  61          return GL_FALSE;
  62       }
  63       else if (srcy < dsty) { /* this is OK */
  64          return GL_FALSE;
  65       }
  66       else if (srcy > dsty + height) {
  67          return GL_FALSE;
  68       }
  69       else {
  70          return GL_TRUE;
  71       }
  72    }
  73    else {
  74       /* add one pixel of slop when zooming, just to be safe */
  75       if ((srcx > dstx + (width * zoomX) + 1) || (srcx + width + 1 < dstx)) {
  76          return GL_FALSE;
  77       }
  78       else if ((srcy < dsty) && (srcy + height < dsty + (height * zoomY))) {
  79          return GL_FALSE;
  80       }
  81       else if ((srcy > dsty) && (srcy + height > dsty + (height * zoomY))) {
  82          return GL_FALSE;
  83       }
  84       else {
  85          return GL_TRUE;
  86       }
  87    }
  88 }
  89
  90
  91 /**
  92  * Convert GLfloat[n][4] colors to GLchan[n][4].
  93  * XXX maybe move into image.c
  94  */
  95 static void
  96 float_span_to_chan(GLuint n, CONST GLfloat in[][4], GLchan out[][4])
  97 {
  98    GLuint i;
  99    for (i = 0; i < n; i++) {
 100       UNCLAMPED_FLOAT_TO_CHAN(out[i][RCOMP], in[i][RCOMP]);
 101       UNCLAMPED_FLOAT_TO_CHAN(out[i][GCOMP], in[i][GCOMP]);
 102       UNCLAMPED_FLOAT_TO_CHAN(out[i][BCOMP], in[i][BCOMP]);
 103       UNCLAMPED_FLOAT_TO_CHAN(out[i][ACOMP], in[i][ACOMP]);
 104    }
 105 }
 106
 107
 108 /**
 109  * Convert GLchan[n][4] colors to GLfloat[n][4].
 110  * XXX maybe move into image.c
 111  */
 112 static void
 113 chan_span_to_float(GLuint n, CONST GLchan in[][4], GLfloat out[][4])
 114 {
 115    GLuint i;
 116    for (i = 0; i < n; i++) {
 117       out[i][RCOMP] = CHAN_TO_FLOAT(in[i][RCOMP]);
 118       out[i][GCOMP] = CHAN_TO_FLOAT(in[i][GCOMP]);
 119       out[i][BCOMP] = CHAN_TO_FLOAT(in[i][BCOMP]);
 120       out[i][ACOMP] = CHAN_TO_FLOAT(in[i][ACOMP]);
 121    }
 122 }
 123
 124
 125
 126 /*
 127  * RGBA copypixels with convolution.
 128  */
 129 static void
 130 copy_conv_rgba_pixels(GLcontext *ctx, GLint srcx, GLint srcy,
 131                       GLint width, GLint height, GLint destx, GLint desty)
 132 {
 133    struct gl_renderbuffer *drawRb = NULL;
 134    GLboolean quick_draw;
 135    GLint row;
 136    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 137    const GLuint transferOps = ctx->_ImageTransferState;
 138    GLfloat *dest, *tmpImage, *convImage;
 139    struct sw_span span;
 140
 141    INIT_SPAN(span, GL_BITMAP, 0, 0, SPAN_RGBA);
 142
 143    if (ctx->Depth.Test)
 144       _swrast_span_default_z(ctx, &span);
 145    if (ctx->Fog.Enabled)
 146       _swrast_span_default_fog(ctx, &span);
 147
 148
 149    if (SWRAST_CONTEXT(ctx)->_RasterMask == 0
 150        && !zoom
 151        && destx >= 0
 152        && destx + width <= (GLint) ctx->DrawBuffer->Width) {
 153       quick_draw = GL_TRUE;
 154       drawRb = ctx->DrawBuffer->_ColorDrawBuffers[0][0];
 155    }
 156    else {
 157       quick_draw = GL_FALSE;
 158    }
 159
 160    /* allocate space for GLfloat image */
 161    tmpImage = (GLfloat *) MALLOC(width * height * 4 * sizeof(GLfloat));
 162    if (!tmpImage) {
 163       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glCopyPixels");
 164       return;
 165    }
 166    convImage = (GLfloat *) MALLOC(width * height * 4 * sizeof(GLfloat));
 167    if (!convImage) {
 168       FREE(tmpImage);
 169       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glCopyPixels");
 170       return;
 171    }
 172
 173    /* read source image */
 174    dest = tmpImage;
 175    for (row = 0; row < height; row++) {
 176       GLchan rgba[MAX_WIDTH][4];
 177       /* Read GLchan and convert to GLfloat */
 178       _swrast_read_rgba_span(ctx, ctx->ReadBuffer->_ColorReadBuffer,
 179                              width, srcx, srcy + row, rgba);
 180       chan_span_to_float(width, (CONST GLchan (*)[4]) rgba,
 181                          (GLfloat (*)[4]) dest);
 182       dest += 4 * width;
 183    }
 184
 185    /* do the image transfer ops which preceed convolution */
 186    for (row = 0; row < height; row++) {
 187       GLfloat (*rgba)[4] = (GLfloat (*)[4]) (tmpImage + row * width * 4);
 188       _mesa_apply_rgba_transfer_ops(ctx,
 189                                     transferOps & IMAGE_PRE_CONVOLUTION_BITS,
 190                                     width, rgba);
 191    }
 192
 193    /* do convolution */
 194    if (ctx->Pixel.Convolution2DEnabled) {
 195       _mesa_convolve_2d_image(ctx, &width, &height, tmpImage, convImage);
 196    }
 197    else {
 198       ASSERT(ctx->Pixel.Separable2DEnabled);
 199       _mesa_convolve_sep_image(ctx, &width, &height, tmpImage, convImage);
 200    }
 201    FREE(tmpImage);
 202
 203    /* do remaining post-convolution image transfer ops */
 204    for (row = 0; row < height; row++) {
 205       GLfloat (*rgba)[4] = (GLfloat (*)[4]) (convImage + row * width * 4);
 206       _mesa_apply_rgba_transfer_ops(ctx,
 207                                     transferOps & IMAGE_POST_CONVOLUTION_BITS,
 208                                     width, rgba);
 209    }
 210
 211    /* write the new image */
 212    for (row = 0; row < height; row++) {
 213       const GLfloat *src = convImage + row * width * 4;
 214       GLint dy;
 215
 216       /* convert floats back to chan */
 217       float_span_to_chan(width, (const GLfloat (*)[4]) src, span.array->rgba);
 218
 219       if (ctx->Pixel.PixelTextureEnabled && ctx->Texture._EnabledUnits) {
 220          span.end = width;
 221          _swrast_pixel_texture(ctx, &span);
 222       }
 223
 224       /* write row to framebuffer */
 225
 226       dy = desty + row;
 227       if (quick_draw && dy >= 0 && dy < (GLint) ctx->DrawBuffer->Height) {
 228          drawRb->PutRow(ctx, drawRb, width, destx, dy, span.array->rgba, NULL);
 229       }
 230       else if (zoom) {
 231          span.x = destx;
 232          span.y = dy;
 233          span.end = width;
 234          _swrast_write_zoomed_rgba_span(ctx, &span,
 235                                      (CONST GLchan (*)[4])span.array->rgba,
 236                                      desty, 0);
 237       }
 238       else {
 239          span.x = destx;
 240          span.y = dy;
 241          span.end = width;
 242          _swrast_write_rgba_span(ctx, &span);
 243       }
 244    }
 245
 246    FREE(convImage);
 247 }
 248
 249
 250 /*
 251  * RGBA copypixels
 252  */
 253 static void
 254 copy_rgba_pixels(GLcontext *ctx, GLint srcx, GLint srcy,
 255                  GLint width, GLint height, GLint destx, GLint desty)
 256 {
 257    struct gl_renderbuffer *drawRb;
 258    GLchan *tmpImage,*p;
 259    GLboolean quick_draw;
 260    GLint sy, dy, stepy, j;
 261    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 262    GLint overlapping;
 263    const GLuint transferOps = ctx->_ImageTransferState;
 264    struct sw_span span;
 265
 266    if (!ctx->ReadBuffer->_ColorReadBuffer) {
 267       /* no readbuffer - OK */
 268       return;
 269    }
 270
 271    INIT_SPAN(span, GL_BITMAP, 0, 0, SPAN_RGBA);
 272
 273    if (ctx->Pixel.Convolution2DEnabled || ctx->Pixel.Separable2DEnabled) {
 274       copy_conv_rgba_pixels(ctx, srcx, srcy, width, height, destx, desty);
 275       return;
 276    }
 277
 278    /* Determine if copy should be done bottom-to-top or top-to-bottom */
 279    if (srcy < desty) {
 280       /* top-down  max-to-min */
 281       sy = srcy + height - 1;
 282       dy = desty + height - 1;
 283       stepy = -1;
 284    }
 285    else {
 286       /* bottom-up  min-to-max */
 287       sy = srcy;
 288       dy = desty;
 289       stepy = 1;
 290    }
 291
 292    if (ctx->DrawBuffer == ctx->ReadBuffer) {
 293       overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
 294                                     ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
 295    }
 296    else {
 297       overlapping = GL_FALSE;
 298    }
 299
 300    if (ctx->Depth.Test)
 301       _swrast_span_default_z(ctx, &span);
 302    if (ctx->Fog.Enabled)
 303       _swrast_span_default_fog(ctx, &span);
 304
 305    if (SWRAST_CONTEXT(ctx)->_RasterMask == 0
 306        && !zoom
 307        && destx >= 0
 308        && destx + width <= (GLint) ctx->DrawBuffer->Width) {
 309       quick_draw = GL_TRUE;
 310       drawRb = ctx->DrawBuffer->_ColorDrawBuffers[0][0];
 311    }
 312    else {
 313       quick_draw = GL_FALSE;
 314       drawRb = NULL;
 315    }
 316
 317    if (overlapping) {
 318       GLint ssy = sy;
 319       tmpImage = (GLchan *) MALLOC(width * height * sizeof(GLchan) * 4);
 320       if (!tmpImage) {
 321          _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
 322          return;
 323       }
 324       /* read the source image */
 325       p = tmpImage;
 326       for (j = 0; j < height; j++, ssy += stepy) {
 327          _swrast_read_rgba_span( ctx, ctx->ReadBuffer->_ColorReadBuffer,
 328                                  width, srcx, ssy, (GLchan (*)[4]) p );
 329          p += width * 4;
 330       }
 331       p = tmpImage;
 332    }
 333    else {
 334       tmpImage = NULL;  /* silence compiler warnings */
 335       p = NULL;
 336    }
 337
 338    for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
 339       /* Get source pixels */
 340       if (overlapping) {
 341          /* get from buffered image */
 342          ASSERT(width < MAX_WIDTH);
 343          MEMCPY(span.array->rgba, p, width * sizeof(GLchan) * 4);
 344          p += width * 4;
 345       }
 346       else {
 347          /* get from framebuffer */
 348          ASSERT(width < MAX_WIDTH);
 349          _swrast_read_rgba_span( ctx, ctx->ReadBuffer->_ColorReadBuffer,
 350                                  width, srcx, sy, span.array->rgba );
 351       }
 352
 353       if (transferOps) {
 354          GLfloat rgbaFloat[MAX_WIDTH][4];
 355          /* convert to float, transfer, convert back to chan */
 356          chan_span_to_float(width, (CONST GLchan (*)[4]) span.array->rgba,
 357                             rgbaFloat);
 358          _mesa_apply_rgba_transfer_ops(ctx, transferOps, width, rgbaFloat);
 359          float_span_to_chan(width, (CONST GLfloat (*)[4]) rgbaFloat,
 360                             span.array->rgba);
 361       }
 362
 363       if (ctx->Pixel.PixelTextureEnabled && ctx->Texture._EnabledUnits) {
 364          span.end = width;
 365          _swrast_pixel_texture(ctx, &span);
 366       }
 367
 368       /* Write color span */
 369       if (quick_draw && dy >= 0 && dy < (GLint) ctx->DrawBuffer->Height) {
 370          drawRb->PutRow(ctx, drawRb, width, destx, dy, span.array->rgba, NULL);
 371       }
 372       else if (zoom) {
 373          span.x = destx;
 374          span.y = dy;
 375          span.end = width;
 376          _swrast_write_zoomed_rgba_span(ctx, &span,
 377                                      (CONST GLchan (*)[4]) span.array->rgba,
 378                                      desty, 0);
 379       }
 380       else {
 381          span.x = destx;
 382          span.y = dy;
 383          span.end = width;
 384          _swrast_write_rgba_span(ctx, &span);
 385       }
 386    }
 387
 388    if (overlapping)
 389       FREE(tmpImage);
 390 }
 391
 392
 393 static void
 394 copy_ci_pixels( GLcontext *ctx, GLint srcx, GLint srcy,
 395                 GLint width, GLint height,
 396                 GLint destx, GLint desty )
 397 {
 398    GLuint *tmpImage,*p;
 399    GLint sy, dy, stepy;
 400    GLint j;
 401    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 402    const GLboolean shift_or_offset = ctx->Pixel.IndexShift || ctx->Pixel.IndexOffset;
 403    GLint overlapping;
 404    struct sw_span span;
 405
 406    if (!ctx->ReadBuffer->_ColorReadBuffer) {
 407       /* no readbuffer - OK */
 408       return;
 409    }
 410
 411    INIT_SPAN(span, GL_BITMAP, 0, 0, SPAN_INDEX);
 412
 413    /* Determine if copy should be bottom-to-top or top-to-bottom */
 414    if (srcy<desty) {
 415       /* top-down  max-to-min */
 416       sy = srcy + height - 1;
 417       dy = desty + height - 1;
 418       stepy = -1;
 419    }
 420    else {
 421       /* bottom-up  min-to-max */
 422       sy = srcy;
 423       dy = desty;
 424       stepy = 1;
 425    }
 426
 427    if (ctx->DrawBuffer == ctx->ReadBuffer) {
 428       overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
 429                                     ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
 430    }
 431    else {
 432       overlapping = GL_FALSE;
 433    }
 434
 435    if (ctx->Depth.Test)
 436       _swrast_span_default_z(ctx, &span);
 437    if (ctx->Fog.Enabled)
 438       _swrast_span_default_fog(ctx, &span);
 439
 440    if (overlapping) {
 441       GLint ssy = sy;
 442       tmpImage = (GLuint *) MALLOC(width * height * sizeof(GLuint));
 443       if (!tmpImage) {
 444          _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
 445          return;
 446       }
 447       /* read the image */
 448       p = tmpImage;
 449       for (j = 0; j < height; j++, ssy += stepy) {
 450          _swrast_read_index_span( ctx, ctx->ReadBuffer->_ColorReadBuffer,
 451                                   width, srcx, ssy, p );
 452          p += width;
 453       }
 454       p = tmpImage;
 455    }
 456    else {
 457       tmpImage = NULL;  /* silence compiler warning */
 458       p = NULL;
 459    }
 460
 461    for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
 462       /* Get color indexes */
 463       if (overlapping) {
 464          MEMCPY(span.array->index, p, width * sizeof(GLuint));
 465          p += width;
 466       }
 467       else {
 468          _swrast_read_index_span( ctx, ctx->ReadBuffer->_ColorReadBuffer,
 469                                   width, srcx, sy, span.array->index );
 470       }
 471
 472       /* Apply shift, offset, look-up table */
 473       if (shift_or_offset) {
 474          _mesa_shift_and_offset_ci( ctx, width, span.array->index );
 475       }
 476       if (ctx->Pixel.MapColorFlag) {
 477          _mesa_map_ci( ctx, width, span.array->index );
 478       }
 479
 480       /* write color indexes */
 481       span.x = destx;
 482       span.y = dy;
 483       span.end = width;
 484       if (zoom)
 485          _swrast_write_zoomed_index_span(ctx, &span, desty, 0);
 486       else
 487          _swrast_write_index_span(ctx, &span);
 488    }
 489
 490    if (overlapping)
 491       FREE(tmpImage);
 492 }
 493
 494
 495
 496 /*
 497  * TODO: Optimize!!!!
 498  */
 499 static void
 500 copy_depth_pixels( GLcontext *ctx, GLint srcx, GLint srcy,
 501                    GLint width, GLint height,
 502                    GLint destx, GLint desty )
 503 {
 504    const GLfloat depthMax = ctx->DrawBuffer->_DepthMaxF;
 505    struct gl_renderbuffer *readRb
 506       = ctx->ReadBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
 507    GLfloat *p, *tmpImage;
 508    GLint sy, dy, stepy;
 509    GLint i, j;
 510    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 511    GLint overlapping;
 512    struct sw_span span;
 513
 514    if (!readRb) {
 515       /* no readbuffer - OK */
 516       return;
 517    }
 518
 519    INIT_SPAN(span, GL_BITMAP, 0, 0, SPAN_Z);
 520
 521    if (!ctx->Visual.depthBits) {
 522       _mesa_error( ctx, GL_INVALID_OPERATION, "glCopyPixels" );
 523       return;
 524    }
 525
 526    /* Determine if copy should be bottom-to-top or top-to-bottom */
 527    if (srcy<desty) {
 528       /* top-down  max-to-min */
 529       sy = srcy + height - 1;
 530       dy = desty + height - 1;
 531       stepy = -1;
 532    }
 533    else {
 534       /* bottom-up  min-to-max */
 535       sy = srcy;
 536       dy = desty;
 537       stepy = 1;
 538    }
 539
 540    if (ctx->DrawBuffer == ctx->ReadBuffer) {
 541       overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
 542                                     ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
 543    }
 544    else {
 545       overlapping = GL_FALSE;
 546    }
 547
 548    _swrast_span_default_color(ctx, &span);
 549    if (ctx->Fog.Enabled)
 550       _swrast_span_default_fog(ctx, &span);
 551
 552    if (overlapping) {
 553       GLint ssy = sy;
 554       tmpImage = (GLfloat *) MALLOC(width * height * sizeof(GLfloat));
 555       if (!tmpImage) {
 556          _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
 557          return;
 558       }
 559       p = tmpImage;
 560       for (j = 0; j < height; j++, ssy += stepy) {
 561          _swrast_read_depth_span_float(ctx, readRb, width, srcx, ssy, p);
 562          p += width;
 563       }
 564       p = tmpImage;
 565    }
 566    else {
 567       tmpImage = NULL;  /* silence compiler warning */
 568       p = NULL;
 569    }
 570
 571    for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
 572       GLfloat depth[MAX_WIDTH];
 573       float sum = 0;
 574       /* get depth values */
 575       if (overlapping) {
 576          MEMCPY(depth, p, width * sizeof(GLfloat));
 577          p += width;
 578       }
 579       else {
 580          _swrast_read_depth_span_float(ctx, readRb, width, srcx, sy, depth);
 581       }
 582
 583       /* apply scale and bias */
 584       for (i = 0; i < width; i++) {
 585          GLfloat d = depth[i] * ctx->Pixel.DepthScale + ctx->Pixel.DepthBias;
 586          sum += d;
 587          span.array->z[i] = (GLdepth) (CLAMP(d, 0.0F, 1.0F) * depthMax);
 588       }
 589
 590       /* write depth values */
 591       span.x = destx;
 592       span.y = dy;
 593       span.end = width;
 594       if (ctx->Visual.rgbMode) {
 595          if (zoom)
 596             _swrast_write_zoomed_rgba_span( ctx, &span,
 597                             (const GLchan (*)[4])span.array->rgba, desty, 0 );
 598          else
 599             _swrast_write_rgba_span(ctx, &span);
 600       }
 601       else {
 602          if (zoom)
 603             _swrast_write_zoomed_index_span( ctx, &span, desty, 0 );
 604          else
 605             _swrast_write_index_span(ctx, &span);
 606       }
 607    }
 608
 609    if (overlapping)
 610       FREE(tmpImage);
 611 }
 612
 613
 614
 615 static void
 616 copy_stencil_pixels( GLcontext *ctx, GLint srcx, GLint srcy,
 617                      GLint width, GLint height,
 618                      GLint destx, GLint desty )
 619 {
 620    struct gl_renderbuffer *rb
 621       = ctx->ReadBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
 622    GLint sy, dy, stepy;
 623    GLint j;
 624    GLstencil *p, *tmpImage;
 625    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 626    const GLboolean shift_or_offset = ctx->Pixel.IndexShift || ctx->Pixel.IndexOffset;
 627    GLint overlapping;
 628
 629    if (!ctx->Visual.stencilBits) {
 630       _mesa_error( ctx, GL_INVALID_OPERATION, "glCopyPixels" );
 631       return;
 632    }
 633
 634    if (!rb) {
 635       /* no readbuffer - OK */
 636       return;
 637    }
 638
 639    /* Determine if copy should be bottom-to-top or top-to-bottom */
 640    if (srcy < desty) {
 641       /* top-down  max-to-min */
 642       sy = srcy + height - 1;
 643       dy = desty + height - 1;
 644       stepy = -1;
 645    }
 646    else {
 647       /* bottom-up  min-to-max */
 648       sy = srcy;
 649       dy = desty;
 650       stepy = 1;
 651    }
 652
 653    if (ctx->DrawBuffer == ctx->ReadBuffer) {
 654       overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
 655                                     ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
 656    }
 657    else {
 658       overlapping = GL_FALSE;
 659    }
 660
 661    if (overlapping) {
 662       GLint ssy = sy;
 663       tmpImage = (GLstencil *) MALLOC(width * height * sizeof(GLstencil));
 664       if (!tmpImage) {
 665          _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
 666          return;
 667       }
 668       p = tmpImage;
 669       for (j = 0; j < height; j++, ssy += stepy) {
 670          _swrast_read_stencil_span( ctx, rb, width, srcx, ssy, p );
 671          p += width;
 672       }
 673       p = tmpImage;
 674    }
 675    else {
 676       tmpImage = NULL;  /* silence compiler warning */
 677       p = NULL;
 678    }
 679
 680    for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
 681       GLstencil stencil[MAX_WIDTH];
 682
 683       /* Get stencil values */
 684       if (overlapping) {
 685          MEMCPY(stencil, p, width * sizeof(GLstencil));
 686          p += width;
 687       }
 688       else {
 689          _swrast_read_stencil_span( ctx, rb, width, srcx, sy, stencil );
 690       }
 691
 692       /* Apply shift, offset, look-up table */
 693       if (shift_or_offset) {
 694          _mesa_shift_and_offset_stencil( ctx, width, stencil );
 695       }
 696       if (ctx->Pixel.MapStencilFlag) {
 697          _mesa_map_stencil( ctx, width, stencil );
 698       }
 699
 700       /* Write stencil values */
 701       if (zoom) {
 702          _swrast_write_zoomed_stencil_span( ctx, width, destx, dy,
 703                                           stencil, desty, 0 );
 704       }
 705       else {
 706          _swrast_write_stencil_span( ctx, width, destx, dy, stencil );
 707       }
 708    }
 709
 710    if (overlapping)
 711       FREE(tmpImage);
 712 }
 713
 714
 715
 716 void
 717 _swrast_CopyPixels( GLcontext *ctx,
 718                     GLint srcx, GLint srcy, GLsizei width, GLsizei height,
 719                     GLint destx, GLint desty,
 720                     GLenum type )
 721 {
 722    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 723    RENDER_START(swrast,ctx);
 724
 725    if (swrast->NewState)
 726       _swrast_validate_derived( ctx );
 727
 728    if (type == GL_COLOR && ctx->Visual.rgbMode) {
 729       copy_rgba_pixels( ctx, srcx, srcy, width, height, destx, desty );
 730    }
 731    else if (type == GL_COLOR && !ctx->Visual.rgbMode) {
 732       copy_ci_pixels( ctx, srcx, srcy, width, height, destx, desty );
 733    }
 734    else if (type == GL_DEPTH) {
 735       copy_depth_pixels( ctx, srcx, srcy, width, height, destx, desty );
 736    }
 737    else if (type == GL_STENCIL) {
 738       copy_stencil_pixels( ctx, srcx, srcy, width, height, destx, desty );
 739    }
 740    else {
 741       _mesa_error( ctx, GL_INVALID_ENUM, "glCopyPixels" );
 742    }
 743
 744    RENDER_FINISH(swrast,ctx);
 745 }