src/mesa/swrast/s_copypix.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.3
   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    GLboolean changeBuffer;
 137    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 138    const GLuint transferOps = ctx->_ImageTransferState;
 139    GLfloat *dest, *tmpImage, *convImage;
 140    struct sw_span span;
 141
 142    INIT_SPAN(span, GL_BITMAP, 0, 0, SPAN_RGBA);
 143
 144    if (ctx->Depth.Test)
 145       _swrast_span_default_z(ctx, &span);
 146    if (ctx->Fog.Enabled)
 147       _swrast_span_default_fog(ctx, &span);
 148
 149
 150    if (SWRAST_CONTEXT(ctx)->_RasterMask == 0
 151        && !zoom
 152        && destx >= 0
 153        && destx + width <= (GLint) ctx->DrawBuffer->Width) {
 154       quick_draw = GL_TRUE;
 155       drawRb = ctx->DrawBuffer->_ColorDrawBuffers[0][0];
 156    }
 157    else {
 158       quick_draw = GL_FALSE;
 159    }
 160
 161    /* If read and draw buffer are different we must do buffer switching */
 162    changeBuffer = ctx->Pixel.ReadBuffer != ctx->Color.DrawBuffer[0]
 163                || ctx->DrawBuffer != ctx->ReadBuffer;
 164
 165
 166    /* allocate space for GLfloat image */
 167    tmpImage = (GLfloat *) MALLOC(width * height * 4 * sizeof(GLfloat));
 168    if (!tmpImage) {
 169       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glCopyPixels");
 170       return;
 171    }
 172    convImage = (GLfloat *) MALLOC(width * height * 4 * sizeof(GLfloat));
 173    if (!convImage) {
 174       FREE(tmpImage);
 175       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glCopyPixels");
 176       return;
 177    }
 178
 179    if (changeBuffer) {
 180       /* choose the read buffer */
 181       _swrast_use_read_buffer(ctx);
 182    }
 183
 184    /* read source image */
 185    dest = tmpImage;
 186    for (row = 0; row < height; row++) {
 187       GLchan rgba[MAX_WIDTH][4];
 188       /* Read GLchan and convert to GLfloat */
 189       _swrast_read_rgba_span(ctx, ctx->ReadBuffer->_ColorReadBuffer,
 190                              width, srcx, srcy + row, rgba);
 191       chan_span_to_float(width, (CONST GLchan (*)[4]) rgba,
 192                          (GLfloat (*)[4]) dest);
 193       dest += 4 * width;
 194    }
 195
 196    if (changeBuffer) {
 197       /* restore default src/dst buffer */
 198       _swrast_use_draw_buffer(ctx);
 199    }
 200
 201    /* do the image transfer ops which preceed convolution */
 202    for (row = 0; row < height; row++) {
 203       GLfloat (*rgba)[4] = (GLfloat (*)[4]) (tmpImage + row * width * 4);
 204       _mesa_apply_rgba_transfer_ops(ctx,
 205                                     transferOps & IMAGE_PRE_CONVOLUTION_BITS,
 206                                     width, rgba);
 207    }
 208
 209    /* do convolution */
 210    if (ctx->Pixel.Convolution2DEnabled) {
 211       _mesa_convolve_2d_image(ctx, &width, &height, tmpImage, convImage);
 212    }
 213    else {
 214       ASSERT(ctx->Pixel.Separable2DEnabled);
 215       _mesa_convolve_sep_image(ctx, &width, &height, tmpImage, convImage);
 216    }
 217    FREE(tmpImage);
 218
 219    /* do remaining post-convolution image transfer ops */
 220    for (row = 0; row < height; row++) {
 221       GLfloat (*rgba)[4] = (GLfloat (*)[4]) (convImage + row * width * 4);
 222       _mesa_apply_rgba_transfer_ops(ctx,
 223                                     transferOps & IMAGE_POST_CONVOLUTION_BITS,
 224                                     width, rgba);
 225    }
 226
 227    /* write the new image */
 228    for (row = 0; row < height; row++) {
 229       const GLfloat *src = convImage + row * width * 4;
 230       GLint dy;
 231
 232       /* convert floats back to chan */
 233       float_span_to_chan(width, (const GLfloat (*)[4]) src, span.array->rgba);
 234
 235       if (ctx->Pixel.PixelTextureEnabled && ctx->Texture._EnabledUnits) {
 236          span.end = width;
 237          _swrast_pixel_texture(ctx, &span);
 238       }
 239
 240       /* write row to framebuffer */
 241
 242       dy = desty + row;
 243       if (quick_draw && dy >= 0 && dy < (GLint) ctx->DrawBuffer->Height) {
 244          drawRb->PutRow(ctx, drawRb, width, destx, dy, span.array->rgba, NULL);
 245       }
 246       else if (zoom) {
 247          span.x = destx;
 248          span.y = dy;
 249          span.end = width;
 250          _swrast_write_zoomed_rgba_span(ctx, &span,
 251                                      (CONST GLchan (*)[4])span.array->rgba,
 252                                      desty, 0);
 253       }
 254       else {
 255          span.x = destx;
 256          span.y = dy;
 257          span.end = width;
 258          _swrast_write_rgba_span(ctx, &span);
 259       }
 260    }
 261
 262    FREE(convImage);
 263 }
 264
 265
 266 /*
 267  * RGBA copypixels
 268  */
 269 static void
 270 copy_rgba_pixels(GLcontext *ctx, GLint srcx, GLint srcy,
 271                  GLint width, GLint height, GLint destx, GLint desty)
 272 {
 273    struct gl_renderbuffer *drawRb;
 274    GLchan *tmpImage,*p;
 275    GLboolean quick_draw;
 276    GLint sy, dy, stepy, j;
 277    GLboolean changeBuffer;
 278    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 279    GLint overlapping;
 280    const GLuint transferOps = ctx->_ImageTransferState;
 281    struct sw_span span;
 282
 283    if (!ctx->ReadBuffer->_ColorReadBuffer) {
 284       /* no readbuffer - OK */
 285       return;
 286    }
 287
 288    INIT_SPAN(span, GL_BITMAP, 0, 0, SPAN_RGBA);
 289
 290    if (ctx->Pixel.Convolution2DEnabled || ctx->Pixel.Separable2DEnabled) {
 291       copy_conv_rgba_pixels(ctx, srcx, srcy, width, height, destx, desty);
 292       return;
 293    }
 294
 295    /* Determine if copy should be done bottom-to-top or top-to-bottom */
 296    if (srcy < desty) {
 297       /* top-down  max-to-min */
 298       sy = srcy + height - 1;
 299       dy = desty + height - 1;
 300       stepy = -1;
 301    }
 302    else {
 303       /* bottom-up  min-to-max */
 304       sy = srcy;
 305       dy = desty;
 306       stepy = 1;
 307    }
 308
 309    if (ctx->DrawBuffer == ctx->ReadBuffer) {
 310       overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
 311                                     ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
 312    }
 313    else {
 314       overlapping = GL_FALSE;
 315    }
 316
 317    if (ctx->Depth.Test)
 318       _swrast_span_default_z(ctx, &span);
 319    if (ctx->Fog.Enabled)
 320       _swrast_span_default_fog(ctx, &span);
 321
 322    if (SWRAST_CONTEXT(ctx)->_RasterMask == 0
 323        && !zoom
 324        && destx >= 0
 325        && destx + width <= (GLint) ctx->DrawBuffer->Width) {
 326       quick_draw = GL_TRUE;
 327       drawRb = ctx->DrawBuffer->_ColorDrawBuffers[0][0];
 328    }
 329    else {
 330       quick_draw = GL_FALSE;
 331       drawRb = NULL;
 332    }
 333
 334    /* If read and draw buffer are different we must do buffer switching */
 335    changeBuffer = ctx->Pixel.ReadBuffer != ctx->Color.DrawBuffer[0]
 336                   || ctx->DrawBuffer != ctx->ReadBuffer;
 337
 338    if (overlapping) {
 339       GLint ssy = sy;
 340       tmpImage = (GLchan *) MALLOC(width * height * sizeof(GLchan) * 4);
 341       if (!tmpImage) {
 342          _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
 343          return;
 344       }
 345       /* setup source */
 346       if (changeBuffer)
 347          _swrast_use_read_buffer(ctx);
 348       /* read the source image */
 349       p = tmpImage;
 350       for (j = 0; j < height; j++, ssy += stepy) {
 351          _swrast_read_rgba_span( ctx, ctx->ReadBuffer->_ColorReadBuffer,
 352                                  width, srcx, ssy, (GLchan (*)[4]) p );
 353          p += width * 4;
 354       }
 355       p = tmpImage;
 356       /* restore dest */
 357       if (changeBuffer) {
 358          _swrast_use_draw_buffer(ctx);
 359          changeBuffer = GL_FALSE;
 360       }
 361    }
 362    else {
 363       tmpImage = NULL;  /* silence compiler warnings */
 364       p = NULL;
 365    }
 366
 367    for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
 368       /* Get source pixels */
 369       if (overlapping) {
 370          /* get from buffered image */
 371          ASSERT(width < MAX_WIDTH);
 372          MEMCPY(span.array->rgba, p, width * sizeof(GLchan) * 4);
 373          p += width * 4;
 374       }
 375       else {
 376          /* get from framebuffer */
 377          if (changeBuffer)
 378             _swrast_use_read_buffer(ctx);
 379          ASSERT(width < MAX_WIDTH);
 380          _swrast_read_rgba_span( ctx, ctx->ReadBuffer->_ColorReadBuffer,
 381                                  width, srcx, sy, span.array->rgba );
 382          if (changeBuffer)
 383             _swrast_use_draw_buffer(ctx);
 384       }
 385
 386       if (transferOps) {
 387          DEFMARRAY(GLfloat, rgbaFloat, MAX_WIDTH, 4);  /* mac 32k limitation */
 388          CHECKARRAY(rgbaFloat, return);
 389
 390          /* convert to float, transfer, convert back to chan */
 391          chan_span_to_float(width, (CONST GLchan (*)[4]) span.array->rgba,
 392                             rgbaFloat);
 393          _mesa_apply_rgba_transfer_ops(ctx, transferOps, width, rgbaFloat);
 394          float_span_to_chan(width, (CONST GLfloat (*)[4]) rgbaFloat,
 395                             span.array->rgba);
 396
 397          UNDEFARRAY(rgbaFloat);  /* mac 32k limitation */
 398       }
 399
 400       if (ctx->Pixel.PixelTextureEnabled && ctx->Texture._EnabledUnits) {
 401          span.end = width;
 402          _swrast_pixel_texture(ctx, &span);
 403       }
 404
 405       /* Write color span */
 406       if (quick_draw && dy >= 0 && dy < (GLint) ctx->DrawBuffer->Height) {
 407          drawRb->PutRow(ctx, drawRb, width, destx, dy, span.array->rgba, NULL);
 408       }
 409       else if (zoom) {
 410          span.x = destx;
 411          span.y = dy;
 412          span.end = width;
 413          _swrast_write_zoomed_rgba_span(ctx, &span,
 414                                      (CONST GLchan (*)[4]) span.array->rgba,
 415                                      desty, 0);
 416       }
 417       else {
 418          span.x = destx;
 419          span.y = dy;
 420          span.end = width;
 421          _swrast_write_rgba_span(ctx, &span);
 422       }
 423    }
 424
 425    if (overlapping)
 426       FREE(tmpImage);
 427 }
 428
 429
 430 static void
 431 copy_ci_pixels( GLcontext *ctx, GLint srcx, GLint srcy,
 432                 GLint width, GLint height,
 433                 GLint destx, GLint desty )
 434 {
 435    GLuint *tmpImage,*p;
 436    GLint sy, dy, stepy;
 437    GLint j;
 438    GLboolean changeBuffer;
 439    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 440    const GLboolean shift_or_offset = ctx->Pixel.IndexShift || ctx->Pixel.IndexOffset;
 441    GLint overlapping;
 442    struct sw_span span;
 443
 444    if (!ctx->ReadBuffer->_ColorReadBuffer) {
 445       /* no readbuffer - OK */
 446       return;
 447    }
 448
 449    INIT_SPAN(span, GL_BITMAP, 0, 0, SPAN_INDEX);
 450
 451    /* Determine if copy should be bottom-to-top or top-to-bottom */
 452    if (srcy<desty) {
 453       /* top-down  max-to-min */
 454       sy = srcy + height - 1;
 455       dy = desty + height - 1;
 456       stepy = -1;
 457    }
 458    else {
 459       /* bottom-up  min-to-max */
 460       sy = srcy;
 461       dy = desty;
 462       stepy = 1;
 463    }
 464
 465    if (ctx->DrawBuffer == ctx->ReadBuffer) {
 466       overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
 467                                     ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
 468    }
 469    else {
 470       overlapping = GL_FALSE;
 471    }
 472
 473    if (ctx->Depth.Test)
 474       _swrast_span_default_z(ctx, &span);
 475    if (ctx->Fog.Enabled)
 476       _swrast_span_default_fog(ctx, &span);
 477
 478    /* If read and draw buffer are different we must do buffer switching */
 479    changeBuffer = ctx->Pixel.ReadBuffer != ctx->Color.DrawBuffer[0]
 480                || ctx->DrawBuffer != ctx->ReadBuffer;
 481
 482    if (overlapping) {
 483       GLint ssy = sy;
 484       tmpImage = (GLuint *) MALLOC(width * height * sizeof(GLuint));
 485       if (!tmpImage) {
 486          _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
 487          return;
 488       }
 489       /* setup source */
 490       if (changeBuffer)
 491          _swrast_use_read_buffer(ctx);
 492       /* read the image */
 493       p = tmpImage;
 494       for (j = 0; j < height; j++, ssy += stepy) {
 495          _swrast_read_index_span( ctx, ctx->ReadBuffer->_ColorReadBuffer,
 496                                   width, srcx, ssy, p );
 497          p += width;
 498       }
 499       p = tmpImage;
 500       /* restore to draw buffer */
 501       if (changeBuffer) {
 502          _swrast_use_draw_buffer(ctx);
 503          changeBuffer = GL_FALSE;
 504       }
 505    }
 506    else {
 507       tmpImage = NULL;  /* silence compiler warning */
 508       p = NULL;
 509    }
 510
 511    for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
 512       /* Get color indexes */
 513       if (overlapping) {
 514          MEMCPY(span.array->index, p, width * sizeof(GLuint));
 515          p += width;
 516       }
 517       else {
 518          if (changeBuffer)
 519             _swrast_use_read_buffer(ctx);
 520          _swrast_read_index_span( ctx, ctx->ReadBuffer->_ColorReadBuffer,
 521                                   width, srcx, sy, span.array->index );
 522          if (changeBuffer)
 523             _swrast_use_draw_buffer(ctx);
 524       }
 525
 526       /* Apply shift, offset, look-up table */
 527       if (shift_or_offset) {
 528          _mesa_shift_and_offset_ci( ctx, width, span.array->index );
 529       }
 530       if (ctx->Pixel.MapColorFlag) {
 531          _mesa_map_ci( ctx, width, span.array->index );
 532       }
 533
 534       /* write color indexes */
 535       span.x = destx;
 536       span.y = dy;
 537       span.end = width;
 538       if (zoom)
 539          _swrast_write_zoomed_index_span(ctx, &span, desty, 0);
 540       else
 541          _swrast_write_index_span(ctx, &span);
 542    }
 543
 544    if (overlapping)
 545       FREE(tmpImage);
 546 }
 547
 548
 549
 550 /*
 551  * TODO: Optimize!!!!
 552  */
 553 static void
 554 copy_depth_pixels( GLcontext *ctx, GLint srcx, GLint srcy,
 555                    GLint width, GLint height,
 556                    GLint destx, GLint desty )
 557 {
 558    const GLfloat depthMax = ctx->DrawBuffer->_DepthMaxF;
 559    struct gl_renderbuffer *readRb
 560       = ctx->ReadBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
 561    GLfloat *p, *tmpImage;
 562    GLint sy, dy, stepy;
 563    GLint i, j;
 564    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 565    GLint overlapping;
 566    struct sw_span span;
 567
 568    if (!readRb) {
 569       /* no readbuffer - OK */
 570       return;
 571    }
 572
 573    INIT_SPAN(span, GL_BITMAP, 0, 0, SPAN_Z);
 574
 575    if (!ctx->Visual.depthBits) {
 576       _mesa_error( ctx, GL_INVALID_OPERATION, "glCopyPixels" );
 577       return;
 578    }
 579
 580    /* Determine if copy should be bottom-to-top or top-to-bottom */
 581    if (srcy<desty) {
 582       /* top-down  max-to-min */
 583       sy = srcy + height - 1;
 584       dy = desty + height - 1;
 585       stepy = -1;
 586    }
 587    else {
 588       /* bottom-up  min-to-max */
 589       sy = srcy;
 590       dy = desty;
 591       stepy = 1;
 592    }
 593
 594    if (ctx->DrawBuffer == ctx->ReadBuffer) {
 595       overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
 596                                     ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
 597    }
 598    else {
 599       overlapping = GL_FALSE;
 600    }
 601
 602    _swrast_span_default_color(ctx, &span);
 603    if (ctx->Fog.Enabled)
 604       _swrast_span_default_fog(ctx, &span);
 605
 606    if (overlapping) {
 607       GLint ssy = sy;
 608       tmpImage = (GLfloat *) MALLOC(width * height * sizeof(GLfloat));
 609       if (!tmpImage) {
 610          _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
 611          return;
 612       }
 613       p = tmpImage;
 614       for (j = 0; j < height; j++, ssy += stepy) {
 615          _swrast_read_depth_span_float(ctx, readRb, width, srcx, ssy, p);
 616          p += width;
 617       }
 618       p = tmpImage;
 619    }
 620    else {
 621       tmpImage = NULL;  /* silence compiler warning */
 622       p = NULL;
 623    }
 624
 625    for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
 626       GLfloat depth[MAX_WIDTH];
 627       float sum = 0;
 628       /* get depth values */
 629       if (overlapping) {
 630          MEMCPY(depth, p, width * sizeof(GLfloat));
 631          p += width;
 632       }
 633       else {
 634          _swrast_read_depth_span_float(ctx, readRb, width, srcx, sy, depth);
 635       }
 636
 637       /* apply scale and bias */
 638       for (i = 0; i < width; i++) {
 639          GLfloat d = depth[i] * ctx->Pixel.DepthScale + ctx->Pixel.DepthBias;
 640          sum += d;
 641          span.array->z[i] = (GLdepth) (CLAMP(d, 0.0F, 1.0F) * depthMax);
 642       }
 643
 644       /* write depth values */
 645       span.x = destx;
 646       span.y = dy;
 647       span.end = width;
 648       if (ctx->Visual.rgbMode) {
 649          if (zoom)
 650             _swrast_write_zoomed_rgba_span( ctx, &span,
 651                             (const GLchan (*)[4])span.array->rgba, desty, 0 );
 652          else
 653             _swrast_write_rgba_span(ctx, &span);
 654       }
 655       else {
 656          if (zoom)
 657             _swrast_write_zoomed_index_span( ctx, &span, desty, 0 );
 658          else
 659             _swrast_write_index_span(ctx, &span);
 660       }
 661    }
 662
 663    if (overlapping)
 664       FREE(tmpImage);
 665 }
 666
 667
 668
 669 static void
 670 copy_stencil_pixels( GLcontext *ctx, GLint srcx, GLint srcy,
 671                      GLint width, GLint height,
 672                      GLint destx, GLint desty )
 673 {
 674    struct gl_renderbuffer *rb
 675       = ctx->ReadBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
 676    GLint sy, dy, stepy;
 677    GLint j;
 678    GLstencil *p, *tmpImage;
 679    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 680    const GLboolean shift_or_offset = ctx->Pixel.IndexShift || ctx->Pixel.IndexOffset;
 681    GLint overlapping;
 682
 683    if (!ctx->Visual.stencilBits) {
 684       _mesa_error( ctx, GL_INVALID_OPERATION, "glCopyPixels" );
 685       return;
 686    }
 687
 688    if (!rb) {
 689       /* no readbuffer - OK */
 690       return;
 691    }
 692
 693    /* Determine if copy should be bottom-to-top or top-to-bottom */
 694    if (srcy < desty) {
 695       /* top-down  max-to-min */
 696       sy = srcy + height - 1;
 697       dy = desty + height - 1;
 698       stepy = -1;
 699    }
 700    else {
 701       /* bottom-up  min-to-max */
 702       sy = srcy;
 703       dy = desty;
 704       stepy = 1;
 705    }
 706
 707    if (ctx->DrawBuffer == ctx->ReadBuffer) {
 708       overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
 709                                     ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
 710    }
 711    else {
 712       overlapping = GL_FALSE;
 713    }
 714
 715    if (overlapping) {
 716       GLint ssy = sy;
 717       tmpImage = (GLstencil *) MALLOC(width * height * sizeof(GLstencil));
 718       if (!tmpImage) {
 719          _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
 720          return;
 721       }
 722       p = tmpImage;
 723       for (j = 0; j < height; j++, ssy += stepy) {
 724          _swrast_read_stencil_span( ctx, rb, width, srcx, ssy, p );
 725          p += width;
 726       }
 727       p = tmpImage;
 728    }
 729    else {
 730       tmpImage = NULL;  /* silence compiler warning */
 731       p = NULL;
 732    }
 733
 734    for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
 735       GLstencil stencil[MAX_WIDTH];
 736
 737       /* Get stencil values */
 738       if (overlapping) {
 739          MEMCPY(stencil, p, width * sizeof(GLstencil));
 740          p += width;
 741       }
 742       else {
 743          _swrast_read_stencil_span( ctx, rb, width, srcx, sy, stencil );
 744       }
 745
 746       /* Apply shift, offset, look-up table */
 747       if (shift_or_offset) {
 748          _mesa_shift_and_offset_stencil( ctx, width, stencil );
 749       }
 750       if (ctx->Pixel.MapStencilFlag) {
 751          _mesa_map_stencil( ctx, width, stencil );
 752       }
 753
 754       /* Write stencil values */
 755       if (zoom) {
 756          _swrast_write_zoomed_stencil_span( ctx, width, destx, dy,
 757                                           stencil, desty, 0 );
 758       }
 759       else {
 760          _swrast_write_stencil_span( ctx, width, destx, dy, stencil );
 761       }
 762    }
 763
 764    if (overlapping)
 765       FREE(tmpImage);
 766 }
 767
 768
 769
 770 void
 771 _swrast_CopyPixels( GLcontext *ctx,
 772                     GLint srcx, GLint srcy, GLsizei width, GLsizei height,
 773                     GLint destx, GLint desty,
 774                     GLenum type )
 775 {
 776    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 777    RENDER_START(swrast,ctx);
 778
 779    if (swrast->NewState)
 780       _swrast_validate_derived( ctx );
 781
 782    if (type == GL_COLOR && ctx->Visual.rgbMode) {
 783       copy_rgba_pixels( ctx, srcx, srcy, width, height, destx, desty );
 784    }
 785    else if (type == GL_COLOR && !ctx->Visual.rgbMode) {
 786       copy_ci_pixels( ctx, srcx, srcy, width, height, destx, desty );
 787    }
 788    else if (type == GL_DEPTH) {
 789       copy_depth_pixels( ctx, srcx, srcy, width, height, destx, desty );
 790    }
 791    else if (type == GL_STENCIL) {
 792       copy_stencil_pixels( ctx, srcx, srcy, width, height, destx, desty );
 793    }
 794    else {
 795       _mesa_error( ctx, GL_INVALID_ENUM, "glCopyPixels" );
 796    }
 797
 798    RENDER_FINISH(swrast,ctx);
 799 }