src/mesa/swrast/s_copypix.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  7.1
   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/context.h"
  28 #include "main/colormac.h"
  29 #include "main/condrender.h"
  30 #include "main/image.h"
  31 #include "main/macros.h"
  32 #include "main/imports.h"
  33
  34 #include "s_context.h"
  35 #include "s_depth.h"
  36 #include "s_span.h"
  37 #include "s_stencil.h"
  38 #include "s_zoom.h"
  39
  40
  41
  42 /**
  43  * Determine if there's overlap in an image copy.
  44  * This test also compensates for the fact that copies are done from
  45  * bottom to top and overlaps can sometimes be handled correctly
  46  * without making a temporary image copy.
  47  * \return GL_TRUE if the regions overlap, GL_FALSE otherwise.
  48  */
  49 static GLboolean
  50 regions_overlap(GLint srcx, GLint srcy,
  51                 GLint dstx, GLint dsty,
  52                 GLint width, GLint height,
  53                 GLfloat zoomX, GLfloat zoomY)
  54 {
  55    if (zoomX == 1.0 && zoomY == 1.0) {
  56       /* no zoom */
  57       if (srcx >= dstx + width || (srcx + width <= dstx)) {
  58          return GL_FALSE;
  59       }
  60       else if (srcy < dsty) { /* this is OK */
  61          return GL_FALSE;
  62       }
  63       else if (srcy > dsty + height) {
  64          return GL_FALSE;
  65       }
  66       else {
  67          return GL_TRUE;
  68       }
  69    }
  70    else {
  71       /* add one pixel of slop when zooming, just to be safe */
  72       if (srcx > (dstx + ((zoomX > 0.0F) ? (width * zoomX + 1.0F) : 0.0F))) {
  73          /* src is completely right of dest */
  74          return GL_FALSE;
  75       }
  76       else if (srcx + width + 1.0F < dstx + ((zoomX > 0.0F) ? 0.0F : (width * zoomX))) {
  77          /* src is completely left of dest */
  78          return GL_FALSE;
  79       }
  80       else if ((srcy < dsty) && (srcy + height < dsty + (height * zoomY))) {
  81          /* src is completely below dest */
  82          return GL_FALSE;
  83       }
  84       else if ((srcy > dsty) && (srcy + height > dsty + (height * zoomY))) {
  85          /* src is completely above dest */
  86          return GL_FALSE;
  87       }
  88       else {
  89          return GL_TRUE;
  90       }
  91    }
  92 }
  93
  94
  95 /**
  96  * RGBA copypixels
  97  */
  98 static void
  99 copy_rgba_pixels(struct gl_context *ctx, GLint srcx, GLint srcy,
 100                  GLint width, GLint height, GLint destx, GLint desty)
 101 {
 102    GLfloat *tmpImage, *p;
 103    GLint sy, dy, stepy, row;
 104    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 105    GLint overlapping;
 106    GLuint transferOps = ctx->_ImageTransferState;
 107    SWspan span;
 108
 109    if (!ctx->ReadBuffer->_ColorReadBuffer) {
 110       /* no readbuffer - OK */
 111       return;
 112    }
 113
 114    if (ctx->DrawBuffer == ctx->ReadBuffer) {
 115       overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
 116                                     ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
 117    }
 118    else {
 119       overlapping = GL_FALSE;
 120    }
 121
 122    /* Determine if copy should be done bottom-to-top or top-to-bottom */
 123    if (!overlapping && srcy < desty) {
 124       /* top-down  max-to-min */
 125       sy = srcy + height - 1;
 126       dy = desty + height - 1;
 127       stepy = -1;
 128    }
 129    else {
 130       /* bottom-up  min-to-max */
 131       sy = srcy;
 132       dy = desty;
 133       stepy = 1;
 134    }
 135
 136    INIT_SPAN(span, GL_BITMAP);
 137    _swrast_span_default_attribs(ctx, &span);
 138    span.arrayMask = SPAN_RGBA;
 139    span.arrayAttribs = FRAG_BIT_COL0; /* we'll fill in COL0 attrib values */
 140
 141    if (overlapping) {
 142       tmpImage = (GLfloat *) malloc(width * height * sizeof(GLfloat) * 4);
 143       if (!tmpImage) {
 144          _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
 145          return;
 146       }
 147       /* read the source image as RGBA/float */
 148       p = tmpImage;
 149       for (row = 0; row < height; row++) {
 150          _swrast_read_rgba_span( ctx, ctx->ReadBuffer->_ColorReadBuffer,
 151                                  width, srcx, sy + row, GL_FLOAT, p );
 152          p += width * 4;
 153       }
 154       p = tmpImage;
 155    }
 156    else {
 157       tmpImage = NULL;  /* silence compiler warnings */
 158       p = NULL;
 159    }
 160
 161    ASSERT(width < MAX_WIDTH);
 162
 163    for (row = 0; row < height; row++, sy += stepy, dy += stepy) {
 164       GLvoid *rgba = span.array->attribs[FRAG_ATTRIB_COL0];
 165
 166       /* Get row/span of source pixels */
 167       if (overlapping) {
 168          /* get from buffered image */
 169          memcpy(rgba, p, width * sizeof(GLfloat) * 4);
 170          p += width * 4;
 171       }
 172       else {
 173          /* get from framebuffer */
 174          _swrast_read_rgba_span( ctx, ctx->ReadBuffer->_ColorReadBuffer,
 175                                  width, srcx, sy, GL_FLOAT, rgba );
 176       }
 177
 178       if (transferOps) {
 179          _mesa_apply_rgba_transfer_ops(ctx, transferOps, width,
 180                                        (GLfloat (*)[4]) rgba);
 181       }
 182
 183       /* Write color span */
 184       span.x = destx;
 185       span.y = dy;
 186       span.end = width;
 187       span.array->ChanType = GL_FLOAT;
 188       if (zoom) {
 189          _swrast_write_zoomed_rgba_span(ctx, destx, desty, &span, rgba);
 190       }
 191       else {
 192          _swrast_write_rgba_span(ctx, &span);
 193       }
 194    }
 195
 196    span.array->ChanType = CHAN_TYPE; /* restore */
 197
 198    if (overlapping)
 199       free(tmpImage);
 200 }
 201
 202
 203 /**
 204  * Convert floating point Z values to integer Z values with pixel transfer's
 205  * Z scale and bias.
 206  */
 207 static void
 208 scale_and_bias_z(struct gl_context *ctx, GLuint width,
 209                  const GLfloat depth[], GLuint z[])
 210 {
 211    const GLuint depthMax = ctx->DrawBuffer->_DepthMax;
 212    GLuint i;
 213
 214    if (depthMax <= 0xffffff &&
 215        ctx->Pixel.DepthScale == 1.0 &&
 216        ctx->Pixel.DepthBias == 0.0) {
 217       /* no scale or bias and no clamping and no worry of overflow */
 218       const GLfloat depthMaxF = ctx->DrawBuffer->_DepthMaxF;
 219       for (i = 0; i < width; i++) {
 220          z[i] = (GLuint) (depth[i] * depthMaxF);
 221       }
 222    }
 223    else {
 224       /* need to be careful with overflow */
 225       const GLdouble depthMaxF = ctx->DrawBuffer->_DepthMaxF;
 226       for (i = 0; i < width; i++) {
 227          GLdouble d = depth[i] * ctx->Pixel.DepthScale + ctx->Pixel.DepthBias;
 228          d = CLAMP(d, 0.0, 1.0) * depthMaxF;
 229          if (d >= depthMaxF)
 230             z[i] = depthMax;
 231          else
 232             z[i] = (GLuint) d;
 233       }
 234    }
 235 }
 236
 237
 238
 239 /*
 240  * TODO: Optimize!!!!
 241  */
 242 static void
 243 copy_depth_pixels( struct gl_context *ctx, GLint srcx, GLint srcy,
 244                    GLint width, GLint height,
 245                    GLint destx, GLint desty )
 246 {
 247    struct gl_framebuffer *fb = ctx->ReadBuffer;
 248    struct gl_renderbuffer *readRb = fb->_DepthBuffer;
 249    GLfloat *p, *tmpImage;
 250    GLint sy, dy, stepy;
 251    GLint j;
 252    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 253    GLint overlapping;
 254    SWspan span;
 255
 256    if (!readRb) {
 257       /* no readbuffer - OK */
 258       return;
 259    }
 260
 261    INIT_SPAN(span, GL_BITMAP);
 262    _swrast_span_default_attribs(ctx, &span);
 263    span.arrayMask = SPAN_Z;
 264
 265    if (ctx->DrawBuffer == ctx->ReadBuffer) {
 266       overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
 267                                     ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
 268    }
 269    else {
 270       overlapping = GL_FALSE;
 271    }
 272
 273    /* Determine if copy should be bottom-to-top or top-to-bottom */
 274    if (!overlapping && srcy < desty) {
 275       /* top-down  max-to-min */
 276       sy = srcy + height - 1;
 277       dy = desty + height - 1;
 278       stepy = -1;
 279    }
 280    else {
 281       /* bottom-up  min-to-max */
 282       sy = srcy;
 283       dy = desty;
 284       stepy = 1;
 285    }
 286
 287    if (overlapping) {
 288       GLint ssy = sy;
 289       tmpImage = (GLfloat *) malloc(width * height * sizeof(GLfloat));
 290       if (!tmpImage) {
 291          _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
 292          return;
 293       }
 294       p = tmpImage;
 295       for (j = 0; j < height; j++, ssy += stepy) {
 296          _swrast_read_depth_span_float(ctx, readRb, width, srcx, ssy, p);
 297          p += width;
 298       }
 299       p = tmpImage;
 300    }
 301    else {
 302       tmpImage = NULL;  /* silence compiler warning */
 303       p = NULL;
 304    }
 305
 306    for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
 307       GLfloat depth[MAX_WIDTH];
 308       /* get depth values */
 309       if (overlapping) {
 310          memcpy(depth, p, width * sizeof(GLfloat));
 311          p += width;
 312       }
 313       else {
 314          _swrast_read_depth_span_float(ctx, readRb, width, srcx, sy, depth);
 315       }
 316
 317       /* apply scale and bias */
 318       scale_and_bias_z(ctx, width, depth, span.array->z);
 319
 320       /* write depth values */
 321       span.x = destx;
 322       span.y = dy;
 323       span.end = width;
 324       if (zoom)
 325          _swrast_write_zoomed_depth_span(ctx, destx, desty, &span);
 326       else
 327          _swrast_write_rgba_span(ctx, &span);
 328    }
 329
 330    if (overlapping)
 331       free(tmpImage);
 332 }
 333
 334
 335
 336 static void
 337 copy_stencil_pixels( struct gl_context *ctx, GLint srcx, GLint srcy,
 338                      GLint width, GLint height,
 339                      GLint destx, GLint desty )
 340 {
 341    struct gl_framebuffer *fb = ctx->ReadBuffer;
 342    struct gl_renderbuffer *rb = fb->_StencilBuffer;
 343    GLint sy, dy, stepy;
 344    GLint j;
 345    GLstencil *p, *tmpImage;
 346    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 347    GLint overlapping;
 348
 349    if (!rb) {
 350       /* no readbuffer - OK */
 351       return;
 352    }
 353
 354    if (ctx->DrawBuffer == ctx->ReadBuffer) {
 355       overlapping = regions_overlap(srcx, srcy, destx, desty, width, height,
 356                                     ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
 357    }
 358    else {
 359       overlapping = GL_FALSE;
 360    }
 361
 362    /* Determine if copy should be bottom-to-top or top-to-bottom */
 363    if (!overlapping && srcy < desty) {
 364       /* top-down  max-to-min */
 365       sy = srcy + height - 1;
 366       dy = desty + height - 1;
 367       stepy = -1;
 368    }
 369    else {
 370       /* bottom-up  min-to-max */
 371       sy = srcy;
 372       dy = desty;
 373       stepy = 1;
 374    }
 375
 376    if (overlapping) {
 377       GLint ssy = sy;
 378       tmpImage = (GLstencil *) malloc(width * height * sizeof(GLstencil));
 379       if (!tmpImage) {
 380          _mesa_error( ctx, GL_OUT_OF_MEMORY, "glCopyPixels" );
 381          return;
 382       }
 383       p = tmpImage;
 384       for (j = 0; j < height; j++, ssy += stepy) {
 385          _swrast_read_stencil_span( ctx, rb, width, srcx, ssy, p );
 386          p += width;
 387       }
 388       p = tmpImage;
 389    }
 390    else {
 391       tmpImage = NULL;  /* silence compiler warning */
 392       p = NULL;
 393    }
 394
 395    for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
 396       GLstencil stencil[MAX_WIDTH];
 397
 398       /* Get stencil values */
 399       if (overlapping) {
 400          memcpy(stencil, p, width * sizeof(GLstencil));
 401          p += width;
 402       }
 403       else {
 404          _swrast_read_stencil_span( ctx, rb, width, srcx, sy, stencil );
 405       }
 406
 407       _mesa_apply_stencil_transfer_ops(ctx, width, stencil);
 408
 409       /* Write stencil values */
 410       if (zoom) {
 411          _swrast_write_zoomed_stencil_span(ctx, destx, desty, width,
 412                                            destx, dy, stencil);
 413       }
 414       else {
 415          _swrast_write_stencil_span( ctx, width, destx, dy, stencil );
 416       }
 417    }
 418
 419    if (overlapping)
 420       free(tmpImage);
 421 }
 422
 423
 424 /**
 425  * This isn't terribly efficient.  If a driver really has combined
 426  * depth/stencil buffers the driver should implement an optimized
 427  * CopyPixels function.
 428  */
 429 static void
 430 copy_depth_stencil_pixels(struct gl_context *ctx,
 431                           const GLint srcX, const GLint srcY,
 432                           const GLint width, const GLint height,
 433                           const GLint destX, const GLint destY)
 434 {
 435    struct gl_renderbuffer *stencilReadRb, *depthReadRb, *depthDrawRb;
 436    GLint sy, dy, stepy;
 437    GLint j;
 438    GLstencil *tempStencilImage = NULL, *stencilPtr = NULL;
 439    GLfloat *tempDepthImage = NULL, *depthPtr = NULL;
 440    const GLfloat depthScale = ctx->DrawBuffer->_DepthMaxF;
 441    const GLuint stencilMask = ctx->Stencil.WriteMask[0];
 442    const GLboolean zoom = ctx->Pixel.ZoomX != 1.0F || ctx->Pixel.ZoomY != 1.0F;
 443    const GLboolean scaleOrBias
 444       = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
 445    GLint overlapping;
 446
 447    depthDrawRb = ctx->DrawBuffer->_DepthBuffer;
 448    depthReadRb = ctx->ReadBuffer->_DepthBuffer;
 449    stencilReadRb = ctx->ReadBuffer->_StencilBuffer;
 450
 451    ASSERT(depthDrawRb);
 452    ASSERT(depthReadRb);
 453    ASSERT(stencilReadRb);
 454
 455    if (ctx->DrawBuffer == ctx->ReadBuffer) {
 456       overlapping = regions_overlap(srcX, srcY, destX, destY, width, height,
 457                                     ctx->Pixel.ZoomX, ctx->Pixel.ZoomY);
 458    }
 459    else {
 460       overlapping = GL_FALSE;
 461    }
 462
 463    /* Determine if copy should be bottom-to-top or top-to-bottom */
 464    if (!overlapping && srcY < destY) {
 465       /* top-down  max-to-min */
 466       sy = srcY + height - 1;
 467       dy = destY + height - 1;
 468       stepy = -1;
 469    }
 470    else {
 471       /* bottom-up  min-to-max */
 472       sy = srcY;
 473       dy = destY;
 474       stepy = 1;
 475    }
 476
 477    if (overlapping) {
 478       GLint ssy = sy;
 479
 480       if (stencilMask != 0x0) {
 481          tempStencilImage
 482             = (GLstencil *) malloc(width * height * sizeof(GLstencil));
 483          if (!tempStencilImage) {
 484             _mesa_error(ctx, GL_OUT_OF_MEMORY, "glCopyPixels");
 485             return;
 486          }
 487
 488          /* get copy of stencil pixels */
 489          stencilPtr = tempStencilImage;
 490          for (j = 0; j < height; j++, ssy += stepy) {
 491             _swrast_read_stencil_span(ctx, stencilReadRb,
 492                                       width, srcX, ssy, stencilPtr);
 493             stencilPtr += width;
 494          }
 495          stencilPtr = tempStencilImage;
 496       }
 497
 498       if (ctx->Depth.Mask) {
 499          tempDepthImage
 500             = (GLfloat *) malloc(width * height * sizeof(GLfloat));
 501          if (!tempDepthImage) {
 502             _mesa_error(ctx, GL_OUT_OF_MEMORY, "glCopyPixels");
 503             free(tempStencilImage);
 504             return;
 505          }
 506
 507          /* get copy of depth pixels */
 508          depthPtr = tempDepthImage;
 509          for (j = 0; j < height; j++, ssy += stepy) {
 510             _swrast_read_depth_span_float(ctx, depthReadRb,
 511                                           width, srcX, ssy, depthPtr);
 512             depthPtr += width;
 513          }
 514          depthPtr = tempDepthImage;
 515       }
 516    }
 517
 518    for (j = 0; j < height; j++, sy += stepy, dy += stepy) {
 519       if (stencilMask != 0x0) {
 520          GLstencil stencil[MAX_WIDTH];
 521
 522          /* Get stencil values */
 523          if (overlapping) {
 524             memcpy(stencil, stencilPtr, width * sizeof(GLstencil));
 525             stencilPtr += width;
 526          }
 527          else {
 528             _swrast_read_stencil_span(ctx, stencilReadRb,
 529                                       width, srcX, sy, stencil);
 530          }
 531
 532          _mesa_apply_stencil_transfer_ops(ctx, width, stencil);
 533
 534          /* Write values */
 535          if (zoom) {
 536             _swrast_write_zoomed_stencil_span(ctx, destX, destY, width,
 537                                               destX, dy, stencil);
 538          }
 539          else {
 540             _swrast_write_stencil_span( ctx, width, destX, dy, stencil );
 541          }
 542       }
 543
 544       if (ctx->Depth.Mask) {
 545          GLfloat depth[MAX_WIDTH];
 546          GLuint zVals32[MAX_WIDTH];
 547          GLushort zVals16[MAX_WIDTH];
 548          GLvoid *zVals;
 549          GLuint zBytes;
 550
 551          /* get depth values */
 552          if (overlapping) {
 553             memcpy(depth, depthPtr, width * sizeof(GLfloat));
 554             depthPtr += width;
 555          }
 556          else {
 557             _swrast_read_depth_span_float(ctx, depthReadRb,
 558                                           width, srcX, sy, depth);
 559          }
 560
 561          /* scale & bias */
 562          if (scaleOrBias) {
 563             _mesa_scale_and_bias_depth(ctx, width, depth);
 564          }
 565          /* convert to integer Z values */
 566          if (depthDrawRb->DataType == GL_UNSIGNED_SHORT) {
 567             GLint k;
 568             for (k = 0; k < width; k++)
 569                zVals16[k] = (GLushort) (depth[k] * depthScale);
 570             zVals = zVals16;
 571             zBytes = 2;
 572          }
 573          else {
 574             GLint k;
 575             for (k = 0; k < width; k++)
 576                zVals32[k] = (GLuint) (depth[k] * depthScale);
 577             zVals = zVals32;
 578             zBytes = 4;
 579          }
 580
 581          /* Write values */
 582          if (zoom) {
 583             _swrast_write_zoomed_z_span(ctx, destX, destY, width,
 584                                         destX, dy, zVals);
 585          }
 586          else {
 587             _swrast_put_row(ctx, depthDrawRb, width, destX, dy, zVals, zBytes);
 588          }
 589       }
 590    }
 591
 592    if (tempStencilImage)
 593       free(tempStencilImage);
 594
 595    if (tempDepthImage)
 596       free(tempDepthImage);
 597 }
 598
 599
 600
 601 /**
 602  * Try to do a fast copy pixels.
 603  */
 604 static GLboolean
 605 fast_copy_pixels(struct gl_context *ctx,
 606                  GLint srcX, GLint srcY, GLsizei width, GLsizei height,
 607                  GLint dstX, GLint dstY, GLenum type)
 608 {
 609    struct gl_framebuffer *srcFb = ctx->ReadBuffer;
 610    struct gl_framebuffer *dstFb = ctx->DrawBuffer;
 611    struct gl_renderbuffer *srcRb, *dstRb;
 612    GLint row, yStep;
 613
 614    if (SWRAST_CONTEXT(ctx)->_RasterMask != 0x0 ||
 615        ctx->Pixel.ZoomX != 1.0F ||
 616        ctx->Pixel.ZoomY != 1.0F ||
 617        ctx->_ImageTransferState) {
 618       /* can't handle these */
 619       return GL_FALSE;
 620    }
 621
 622    if (type == GL_COLOR) {
 623       if (dstFb->_NumColorDrawBuffers != 1)
 624          return GL_FALSE;
 625       srcRb = srcFb->_ColorReadBuffer;
 626       dstRb = dstFb->_ColorDrawBuffers[0];
 627    }
 628    else if (type == GL_STENCIL) {
 629       srcRb = srcFb->_StencilBuffer;
 630       dstRb = dstFb->_StencilBuffer;
 631    }
 632    else if (type == GL_DEPTH) {
 633       srcRb = srcFb->_DepthBuffer;
 634       dstRb = dstFb->_DepthBuffer;
 635    }
 636    else {
 637       ASSERT(type == GL_DEPTH_STENCIL_EXT);
 638       /* XXX correct? */
 639       srcRb = srcFb->Attachment[BUFFER_DEPTH].Renderbuffer;
 640       dstRb = dstFb->Attachment[BUFFER_DEPTH].Renderbuffer;
 641    }
 642
 643    /* src and dst renderbuffers must be same format and type */
 644    if (!srcRb || !dstRb ||
 645        srcRb->DataType != dstRb->DataType ||
 646        srcRb->_BaseFormat != dstRb->_BaseFormat) {
 647       return GL_FALSE;
 648    }
 649
 650    /* clipping not supported */
 651    if (srcX < 0 || srcX + width > (GLint) srcFb->Width ||
 652        srcY < 0 || srcY + height > (GLint) srcFb->Height ||
 653        dstX < dstFb->_Xmin || dstX + width > dstFb->_Xmax ||
 654        dstY < dstFb->_Ymin || dstY + height > dstFb->_Ymax) {
 655       return GL_FALSE;
 656    }
 657
 658    /* overlapping src/dst doesn't matter, just determine Y direction */
 659    if (srcY < dstY) {
 660       /* top-down  max-to-min */
 661       srcY = srcY + height - 1;
 662       dstY = dstY + height - 1;
 663       yStep = -1;
 664    }
 665    else {
 666       /* bottom-up  min-to-max */
 667       yStep = 1;
 668    }
 669
 670    for (row = 0; row < height; row++) {
 671       GLuint temp[MAX_WIDTH][4];
 672       srcRb->GetRow(ctx, srcRb, width, srcX, srcY, temp);
 673       dstRb->PutRow(ctx, dstRb, width, dstX, dstY, temp, NULL);
 674       srcY += yStep;
 675       dstY += yStep;
 676    }
 677
 678    return GL_TRUE;
 679 }
 680
 681
 682 /**
 683  * Do software-based glCopyPixels.
 684  * By time we get here, all parameters will have been error-checked.
 685  */
 686 void
 687 _swrast_CopyPixels( struct gl_context *ctx,
 688                     GLint srcx, GLint srcy, GLsizei width, GLsizei height,
 689                     GLint destx, GLint desty, GLenum type )
 690 {
 691    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 692    swrast_render_start(ctx);
 693
 694    if (!_mesa_check_conditional_render(ctx))
 695       return; /* don't copy */
 696
 697    if (swrast->NewState)
 698       _swrast_validate_derived( ctx );
 699
 700    if (!fast_copy_pixels(ctx, srcx, srcy, width, height, destx, desty, type)) {
 701       switch (type) {
 702       case GL_COLOR:
 703          copy_rgba_pixels( ctx, srcx, srcy, width, height, destx, desty );
 704          break;
 705       case GL_DEPTH:
 706          copy_depth_pixels( ctx, srcx, srcy, width, height, destx, desty );
 707          break;
 708       case GL_STENCIL:
 709          copy_stencil_pixels( ctx, srcx, srcy, width, height, destx, desty );
 710          break;
 711       case GL_DEPTH_STENCIL_EXT:
 712          copy_depth_stencil_pixels(ctx, srcx, srcy, width, height, destx, desty);
 713          break;
 714       default:
 715          _mesa_problem(ctx, "unexpected type in _swrast_CopyPixels");
 716       }
 717    }
 718
 719    swrast_render_finish(ctx);
 720 }