src/mesa/swrast/s_blit.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.5
   4  *
   5  * Copyright (C) 1999-2006  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/condrender.h"
  28 #include "main/image.h"
  29 #include "main/macros.h"
  30 #include "main/format_unpack.h"
  31 #include "main/format_pack.h"
  32 #include "s_context.h"
  33
  34
  35 #define ABS(X)   ((X) < 0 ? -(X) : (X))
  36
  37
  38 /**
  39  * Generate a row resampler function for GL_NEAREST mode.
  40  */
  41 #define RESAMPLE(NAME, PIXELTYPE, SIZE)                 \
  42 static void                                             \
  43 NAME(GLint srcWidth, GLint dstWidth,                    \
  44      const GLvoid *srcBuffer, GLvoid *dstBuffer,        \
  45      GLboolean flip)                                    \
  46 {                                                       \
  47    const PIXELTYPE *src = (const PIXELTYPE *) srcBuffer;\
  48    PIXELTYPE *dst = (PIXELTYPE *) dstBuffer;            \
  49    GLint dstCol;                                        \
  50                                                         \
  51    if (flip) {                                          \
  52       for (dstCol = 0; dstCol < dstWidth; dstCol++) {   \
  53          GLint srcCol = (dstCol * srcWidth) / dstWidth; \
  54          ASSERT(srcCol >= 0);                           \
  55          ASSERT(srcCol < srcWidth);                     \
  56          srcCol = srcWidth - 1 - srcCol; /* flip */     \
  57          if (SIZE == 1) {                               \
  58             dst[dstCol] = src[srcCol];                  \
  59          }                                              \
  60          else if (SIZE == 2) {                          \
  61             dst[dstCol*2+0] = src[srcCol*2+0];          \
  62             dst[dstCol*2+1] = src[srcCol*2+1];          \
  63          }                                              \
  64          else if (SIZE == 4) {                          \
  65             dst[dstCol*4+0] = src[srcCol*4+0];          \
  66             dst[dstCol*4+1] = src[srcCol*4+1];          \
  67             dst[dstCol*4+2] = src[srcCol*4+2];          \
  68             dst[dstCol*4+3] = src[srcCol*4+3];          \
  69          }                                              \
  70       }                                                 \
  71    }                                                    \
  72    else {                                               \
  73       for (dstCol = 0; dstCol < dstWidth; dstCol++) {   \
  74          GLint srcCol = (dstCol * srcWidth) / dstWidth; \
  75          ASSERT(srcCol >= 0);                           \
  76          ASSERT(srcCol < srcWidth);                     \
  77          if (SIZE == 1) {                               \
  78             dst[dstCol] = src[srcCol];                  \
  79          }                                              \
  80          else if (SIZE == 2) {                          \
  81             dst[dstCol*2+0] = src[srcCol*2+0];          \
  82             dst[dstCol*2+1] = src[srcCol*2+1];          \
  83          }                                              \
  84          else if (SIZE == 4) {                          \
  85             dst[dstCol*4+0] = src[srcCol*4+0];          \
  86             dst[dstCol*4+1] = src[srcCol*4+1];          \
  87             dst[dstCol*4+2] = src[srcCol*4+2];          \
  88             dst[dstCol*4+3] = src[srcCol*4+3];          \
  89          }                                              \
  90       }                                                 \
  91    }                                                    \
  92 }
  93
  94 /**
  95  * Resamplers for 1, 2, 4, 8 and 16-byte pixels.
  96  */
  97 RESAMPLE(resample_row_1, GLubyte, 1)
  98 RESAMPLE(resample_row_2, GLushort, 1)
  99 RESAMPLE(resample_row_4, GLuint, 1)
 100 RESAMPLE(resample_row_8, GLuint, 2)
 101 RESAMPLE(resample_row_16, GLuint, 4)
 102
 103
 104 /**
 105  * Blit color, depth or stencil with GL_NEAREST filtering.
 106  */
 107 static void
 108 blit_nearest(struct gl_context *ctx,
 109              GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1,
 110              GLint dstX0, GLint dstY0, GLint dstX1, GLint dstY1,
 111              GLbitfield buffer)
 112 {
 113    struct gl_renderbuffer *readRb, *drawRb;
 114
 115    const GLint srcWidth = ABS(srcX1 - srcX0);
 116    const GLint dstWidth = ABS(dstX1 - dstX0);
 117    const GLint srcHeight = ABS(srcY1 - srcY0);
 118    const GLint dstHeight = ABS(dstY1 - dstY0);
 119
 120    const GLint srcXpos = MIN2(srcX0, srcX1);
 121    const GLint srcYpos = MIN2(srcY0, srcY1);
 122    const GLint dstXpos = MIN2(dstX0, dstX1);
 123    const GLint dstYpos = MIN2(dstY0, dstY1);
 124
 125    const GLboolean invertX = (srcX1 < srcX0) ^ (dstX1 < dstX0);
 126    const GLboolean invertY = (srcY1 < srcY0) ^ (dstY1 < dstY0);
 127    enum mode {
 128       DIRECT,
 129       UNPACK_RGBA_FLOAT,
 130       UNPACK_Z_FLOAT,
 131       UNPACK_Z_INT,
 132       UNPACK_S,
 133    } mode;
 134    GLubyte *srcMap, *dstMap;
 135    GLint srcRowStride, dstRowStride;
 136    GLint dstRow;
 137
 138    GLint pixelSize;
 139    GLvoid *srcBuffer, *dstBuffer;
 140    GLint prevY = -1;
 141
 142    typedef void (*resample_func)(GLint srcWidth, GLint dstWidth,
 143                                  const GLvoid *srcBuffer, GLvoid *dstBuffer,
 144                                  GLboolean flip);
 145    resample_func resampleRow;
 146
 147    switch (buffer) {
 148    case GL_COLOR_BUFFER_BIT:
 149       readRb = ctx->ReadBuffer->_ColorReadBuffer;
 150       drawRb = ctx->DrawBuffer->_ColorDrawBuffers[0];
 151
 152       if (readRb->Format == drawRb->Format) {
 153          mode = DIRECT;
 154          pixelSize = _mesa_get_format_bytes(readRb->Format);
 155       } else {
 156          mode = UNPACK_RGBA_FLOAT;
 157          pixelSize = 16;
 158       }
 159
 160       break;
 161    case GL_DEPTH_BUFFER_BIT:
 162       readRb = ctx->ReadBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
 163       drawRb = ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
 164
 165       /* Note that for depth/stencil, the formats of src/dst must match.  By
 166        * using the core helpers for pack/unpack, we avoid needing to handle
 167        * masking for things like DEPTH copies of Z24S8.
 168        */
 169       if (readRb->Format == MESA_FORMAT_Z32_FLOAT ||
 170           readRb->Format == MESA_FORMAT_Z32_FLOAT_X24S8) {
 171          mode = UNPACK_Z_FLOAT;
 172       } else {
 173          mode = UNPACK_Z_INT;
 174       }
 175       pixelSize = 4;
 176       break;
 177    case GL_STENCIL_BUFFER_BIT:
 178       readRb = ctx->ReadBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
 179       drawRb = ctx->DrawBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
 180       mode = UNPACK_S;
 181       pixelSize = 1;
 182       break;
 183    default:
 184       _mesa_problem(ctx, "unexpected buffer in blit_nearest()");
 185       return;
 186    }
 187
 188    /* choose row resampler */
 189    switch (pixelSize) {
 190    case 1:
 191       resampleRow = resample_row_1;
 192       break;
 193    case 2:
 194       resampleRow = resample_row_2;
 195       break;
 196    case 4:
 197       resampleRow = resample_row_4;
 198       break;
 199    case 8:
 200       resampleRow = resample_row_8;
 201       break;
 202    case 16:
 203       resampleRow = resample_row_16;
 204       break;
 205    default:
 206       _mesa_problem(ctx, "unexpected pixel size (%d) in blit_nearest",
 207                     pixelSize);
 208       return;
 209    }
 210
 211    if (readRb == drawRb) {
 212       /* map whole buffer for read/write */
 213       /* XXX we could be clever and just map the union region of the
 214        * source and dest rects.
 215        */
 216       GLubyte *map;
 217       GLint rowStride;
 218       GLint formatSize = _mesa_get_format_bytes(readRb->Format);
 219
 220       ctx->Driver.MapRenderbuffer(ctx, readRb, 0, 0,
 221                                   readRb->Width, readRb->Height,
 222                                   GL_MAP_READ_BIT | GL_MAP_WRITE_BIT,
 223                                   &map, &rowStride);
 224       if (!map) {
 225          _mesa_error(ctx, GL_OUT_OF_MEMORY, "glBlitFramebuffer");
 226          return;
 227       }
 228
 229       srcMap = map + srcYpos * rowStride + srcXpos * formatSize;
 230       dstMap = map + dstYpos * rowStride + dstXpos * formatSize;
 231
 232       /* this handles overlapping copies */
 233       if (srcY0 < dstY0) {
 234          /* copy in reverse (top->down) order */
 235          srcMap += rowStride * (readRb->Height - 1);
 236          dstMap += rowStride * (readRb->Height - 1);
 237          srcRowStride = -rowStride;
 238          dstRowStride = -rowStride;
 239       }
 240       else {
 241          /* copy in normal (bottom->up) order */
 242          srcRowStride = rowStride;
 243          dstRowStride = rowStride;
 244       }
 245    }
 246    else {
 247       /* different src/dst buffers */
 248       ctx->Driver.MapRenderbuffer(ctx, readRb,
 249                                   srcXpos, srcYpos,
 250                                   srcWidth, srcHeight,
 251                                   GL_MAP_READ_BIT, &srcMap, &srcRowStride);
 252       if (!srcMap) {
 253          _mesa_error(ctx, GL_OUT_OF_MEMORY, "glBlitFramebuffer");
 254          return;
 255       }
 256       ctx->Driver.MapRenderbuffer(ctx, drawRb,
 257                                   dstXpos, dstYpos,
 258                                   dstWidth, dstHeight,
 259                                   GL_MAP_WRITE_BIT, &dstMap, &dstRowStride);
 260       if (!dstMap) {
 261          ctx->Driver.UnmapRenderbuffer(ctx, readRb);
 262          _mesa_error(ctx, GL_OUT_OF_MEMORY, "glBlitFramebuffer");
 263          return;
 264       }
 265    }
 266
 267    /* allocate the src/dst row buffers */
 268    srcBuffer = malloc(pixelSize * srcWidth);
 269    if (!srcBuffer) {
 270       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glBlitFrameBufferEXT");
 271       return;
 272    }
 273    dstBuffer = malloc(pixelSize * dstWidth);
 274    if (!dstBuffer) {
 275       free(srcBuffer);
 276       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glBlitFrameBufferEXT");
 277       return;
 278    }
 279
 280    for (dstRow = 0; dstRow < dstHeight; dstRow++) {
 281       GLint srcRow = (dstRow * srcHeight) / dstHeight;
 282       GLubyte *dstRowStart = dstMap + dstRowStride * dstRow;
 283
 284       ASSERT(srcRow >= 0);
 285       ASSERT(srcRow < srcHeight);
 286
 287       if (invertY) {
 288          srcRow = srcHeight - 1 - srcRow;
 289       }
 290
 291       /* get pixel row from source and resample to match dest width */
 292       if (prevY != srcRow) {
 293          GLubyte *srcRowStart = srcMap + srcRowStride * srcRow;
 294
 295          switch (mode) {
 296          case DIRECT:
 297             memcpy(srcBuffer, srcRowStart, pixelSize * srcWidth);
 298             break;
 299          case UNPACK_RGBA_FLOAT:
 300             _mesa_unpack_rgba_row(readRb->Format, srcWidth, srcRowStart,
 301                                   srcBuffer);
 302             break;
 303          case UNPACK_Z_FLOAT:
 304             _mesa_unpack_float_z_row(readRb->Format, srcWidth, srcRowStart,
 305                                      srcBuffer);
 306             break;
 307          case UNPACK_Z_INT:
 308             _mesa_unpack_uint_z_row(readRb->Format, srcWidth, srcRowStart,
 309                                     srcBuffer);
 310             break;
 311          case UNPACK_S:
 312             _mesa_unpack_ubyte_stencil_row(readRb->Format, srcWidth,
 313                                            srcRowStart, srcBuffer);
 314             break;
 315          }
 316
 317          (*resampleRow)(srcWidth, dstWidth, srcBuffer, dstBuffer, invertX);
 318          prevY = srcRow;
 319       }
 320
 321       /* store pixel row in destination */
 322       switch (mode) {
 323       case DIRECT:
 324          memcpy(dstRowStart, dstBuffer, pixelSize * srcWidth);
 325          break;
 326       case UNPACK_RGBA_FLOAT:
 327          _mesa_pack_float_rgba_row(drawRb->Format, dstWidth, dstBuffer,
 328                                    dstRowStart);
 329          break;
 330       case UNPACK_Z_FLOAT:
 331          _mesa_pack_float_z_row(drawRb->Format, dstWidth, dstBuffer,
 332                                 dstRowStart);
 333          break;
 334       case UNPACK_Z_INT:
 335          _mesa_pack_uint_z_row(drawRb->Format, dstWidth, dstBuffer,
 336                                dstRowStart);
 337          break;
 338       case UNPACK_S:
 339          _mesa_pack_ubyte_stencil_row(drawRb->Format, dstWidth, dstBuffer,
 340                                       dstRowStart);
 341          break;
 342       }
 343    }
 344
 345    free(srcBuffer);
 346    free(dstBuffer);
 347
 348    ctx->Driver.UnmapRenderbuffer(ctx, readRb);
 349    if (drawRb != readRb) {
 350       ctx->Driver.UnmapRenderbuffer(ctx, drawRb);
 351    }
 352 }
 353
 354
 355
 356 #define LERP(T, A, B)  ( (A) + (T) * ((B) - (A)) )
 357
 358 static inline GLfloat
 359 lerp_2d(GLfloat a, GLfloat b,
 360         GLfloat v00, GLfloat v10, GLfloat v01, GLfloat v11)
 361 {
 362    const GLfloat temp0 = LERP(a, v00, v10);
 363    const GLfloat temp1 = LERP(a, v01, v11);
 364    return LERP(b, temp0, temp1);
 365 }
 366
 367
 368 /**
 369  * Bilinear interpolation of two source rows.
 370  * GLubyte pixels.
 371  */
 372 static void
 373 resample_linear_row_ub(GLint srcWidth, GLint dstWidth,
 374                        const GLvoid *srcBuffer0, const GLvoid *srcBuffer1,
 375                        GLvoid *dstBuffer, GLboolean flip, GLfloat rowWeight)
 376 {
 377    const GLubyte (*srcColor0)[4] = (const GLubyte (*)[4]) srcBuffer0;
 378    const GLubyte (*srcColor1)[4] = (const GLubyte (*)[4]) srcBuffer1;
 379    GLubyte (*dstColor)[4] = (GLubyte (*)[4]) dstBuffer;
 380    const GLfloat dstWidthF = (GLfloat) dstWidth;
 381    GLint dstCol;
 382
 383    for (dstCol = 0; dstCol < dstWidth; dstCol++) {
 384       const GLfloat srcCol = (dstCol * srcWidth) / dstWidthF;
 385       GLint srcCol0 = IFLOOR(srcCol);
 386       GLint srcCol1 = srcCol0 + 1;
 387       GLfloat colWeight = srcCol - srcCol0; /* fractional part of srcCol */
 388       GLfloat red, green, blue, alpha;
 389
 390       ASSERT(srcCol0 >= 0);
 391       ASSERT(srcCol0 < srcWidth);
 392       ASSERT(srcCol1 <= srcWidth);
 393
 394       if (srcCol1 == srcWidth) {
 395          /* last column fudge */
 396          srcCol1--;
 397          colWeight = 0.0;
 398       }
 399
 400       if (flip) {
 401          srcCol0 = srcWidth - 1 - srcCol0;
 402          srcCol1 = srcWidth - 1 - srcCol1;
 403       }
 404
 405       red = lerp_2d(colWeight, rowWeight,
 406                     srcColor0[srcCol0][RCOMP], srcColor0[srcCol1][RCOMP],
 407                     srcColor1[srcCol0][RCOMP], srcColor1[srcCol1][RCOMP]);
 408       green = lerp_2d(colWeight, rowWeight,
 409                     srcColor0[srcCol0][GCOMP], srcColor0[srcCol1][GCOMP],
 410                     srcColor1[srcCol0][GCOMP], srcColor1[srcCol1][GCOMP]);
 411       blue = lerp_2d(colWeight, rowWeight,
 412                     srcColor0[srcCol0][BCOMP], srcColor0[srcCol1][BCOMP],
 413                     srcColor1[srcCol0][BCOMP], srcColor1[srcCol1][BCOMP]);
 414       alpha = lerp_2d(colWeight, rowWeight,
 415                     srcColor0[srcCol0][ACOMP], srcColor0[srcCol1][ACOMP],
 416                     srcColor1[srcCol0][ACOMP], srcColor1[srcCol1][ACOMP]);
 417
 418       dstColor[dstCol][RCOMP] = IFLOOR(red);
 419       dstColor[dstCol][GCOMP] = IFLOOR(green);
 420       dstColor[dstCol][BCOMP] = IFLOOR(blue);
 421       dstColor[dstCol][ACOMP] = IFLOOR(alpha);
 422    }
 423 }
 424
 425
 426
 427 /**
 428  * Bilinear filtered blit (color only).
 429  */
 430 static void
 431 blit_linear(struct gl_context *ctx,
 432             GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1,
 433             GLint dstX0, GLint dstY0, GLint dstX1, GLint dstY1)
 434 {
 435    struct gl_renderbuffer *readRb = ctx->ReadBuffer->_ColorReadBuffer;
 436    struct gl_renderbuffer *drawRb = ctx->DrawBuffer->_ColorDrawBuffers[0];
 437
 438    const GLint srcWidth = ABS(srcX1 - srcX0);
 439    const GLint dstWidth = ABS(dstX1 - dstX0);
 440    const GLint srcHeight = ABS(srcY1 - srcY0);
 441    const GLint dstHeight = ABS(dstY1 - dstY0);
 442    const GLfloat dstHeightF = (GLfloat) dstHeight;
 443
 444    const GLint srcXpos = MIN2(srcX0, srcX1);
 445    const GLint srcYpos = MIN2(srcY0, srcY1);
 446    const GLint dstXpos = MIN2(dstX0, dstX1);
 447    const GLint dstYpos = MIN2(dstY0, dstY1);
 448
 449    const GLboolean invertX = (srcX1 < srcX0) ^ (dstX1 < dstX0);
 450    const GLboolean invertY = (srcY1 < srcY0) ^ (dstY1 < dstY0);
 451
 452    GLint dstRow;
 453
 454    GLint pixelSize;
 455    GLvoid *srcBuffer0, *srcBuffer1;
 456    GLint srcBufferY0 = -1, srcBufferY1 = -1;
 457    GLvoid *dstBuffer;
 458
 459    switch (readRb->DataType) {
 460    case GL_UNSIGNED_BYTE:
 461       pixelSize = 4 * sizeof(GLubyte);
 462       break;
 463    case GL_UNSIGNED_SHORT:
 464       pixelSize = 4 * sizeof(GLushort);
 465       break;
 466    case GL_UNSIGNED_INT:
 467       pixelSize = 4 * sizeof(GLuint);
 468       break;
 469    case GL_FLOAT:
 470       pixelSize = 4 * sizeof(GLfloat);
 471       break;
 472    default:
 473       _mesa_problem(ctx, "unexpected buffer type (0x%x) in blit_nearest",
 474                     readRb->DataType);
 475       return;
 476    }
 477
 478    /* Allocate the src/dst row buffers.
 479     * Keep two adjacent src rows around for bilinear sampling.
 480     */
 481    srcBuffer0 = malloc(pixelSize * srcWidth);
 482    if (!srcBuffer0) {
 483       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glBlitFrameBufferEXT");
 484       return;
 485    }
 486    srcBuffer1 = malloc(pixelSize * srcWidth);
 487    if (!srcBuffer1) {
 488       free(srcBuffer0);
 489       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glBlitFrameBufferEXT");
 490       return;
 491    }
 492    dstBuffer = malloc(pixelSize * dstWidth);
 493    if (!dstBuffer) {
 494       free(srcBuffer0);
 495       free(srcBuffer1);
 496       _mesa_error(ctx, GL_OUT_OF_MEMORY, "glBlitFrameBufferEXT");
 497       return;
 498    }
 499
 500    for (dstRow = 0; dstRow < dstHeight; dstRow++) {
 501       const GLint dstY = dstYpos + dstRow;
 502       const GLfloat srcRow = (dstRow * srcHeight) / dstHeightF;
 503       GLint srcRow0 = IFLOOR(srcRow);
 504       GLint srcRow1 = srcRow0 + 1;
 505       GLfloat rowWeight = srcRow - srcRow0; /* fractional part of srcRow */
 506
 507       ASSERT(srcRow >= 0);
 508       ASSERT(srcRow < srcHeight);
 509
 510       if (srcRow1 == srcHeight) {
 511          /* last row fudge */
 512          srcRow1 = srcRow0;
 513          rowWeight = 0.0;
 514       }
 515
 516       if (invertY) {
 517          srcRow0 = srcHeight - 1 - srcRow0;
 518          srcRow1 = srcHeight - 1 - srcRow1;
 519       }
 520
 521       srcY0 = srcYpos + srcRow0;
 522       srcY1 = srcYpos + srcRow1;
 523
 524       /* get the two source rows */
 525       if (srcY0 == srcBufferY0 && srcY1 == srcBufferY1) {
 526          /* use same source row buffers again */
 527       }
 528       else if (srcY0 == srcBufferY1) {
 529          /* move buffer1 into buffer0 by swapping pointers */
 530          GLvoid *tmp = srcBuffer0;
 531          srcBuffer0 = srcBuffer1;
 532          srcBuffer1 = tmp;
 533          /* get y1 row */
 534          readRb->GetRow(ctx, readRb, srcWidth, srcXpos, srcY1, srcBuffer1);
 535          srcBufferY0 = srcY0;
 536          srcBufferY1 = srcY1;
 537       }
 538       else {
 539          /* get both new rows */
 540          readRb->GetRow(ctx, readRb, srcWidth, srcXpos, srcY0, srcBuffer0);
 541          readRb->GetRow(ctx, readRb, srcWidth, srcXpos, srcY1, srcBuffer1);
 542          srcBufferY0 = srcY0;
 543          srcBufferY1 = srcY1;
 544       }
 545
 546       if (readRb->DataType == GL_UNSIGNED_BYTE) {
 547          resample_linear_row_ub(srcWidth, dstWidth, srcBuffer0, srcBuffer1,
 548                                 dstBuffer, invertX, rowWeight);
 549       }
 550       else {
 551          _mesa_problem(ctx, "Unsupported color channel type in sw blit");
 552          break;
 553       }
 554
 555       /* store pixel row in destination */
 556       drawRb->PutRow(ctx, drawRb, dstWidth, dstXpos, dstY, dstBuffer, NULL);
 557    }
 558
 559    free(srcBuffer0);
 560    free(srcBuffer1);
 561    free(dstBuffer);
 562 }
 563
 564 /**
 565  * Software fallback for glBlitFramebufferEXT().
 566  */
 567 void
 568 _swrast_BlitFramebuffer(struct gl_context *ctx,
 569                         GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1,
 570                         GLint dstX0, GLint dstY0, GLint dstX1, GLint dstY1,
 571                         GLbitfield mask, GLenum filter)
 572 {
 573    static const GLbitfield buffers[3] = {
 574       GL_COLOR_BUFFER_BIT,
 575       GL_DEPTH_BUFFER_BIT,
 576       GL_STENCIL_BUFFER_BIT
 577    };
 578    static const GLenum buffer_enums[3] = {
 579       GL_COLOR,
 580       GL_DEPTH,
 581       GL_STENCIL,
 582    };
 583    GLint i;
 584
 585    if (!_mesa_clip_blit(ctx, &srcX0, &srcY0, &srcX1, &srcY1,
 586                         &dstX0, &dstY0, &dstX1, &dstY1)) {
 587       return;
 588    }
 589
 590    if (SWRAST_CONTEXT(ctx)->NewState)
 591       _swrast_validate_derived(ctx);
 592
 593    /* First, try covering whatever buffers possible using the fast 1:1 copy
 594     * path.
 595     */
 596    if (srcX1 - srcX0 == dstX1 - dstX0 &&
 597        srcY1 - srcY0 == dstY1 - dstY0 &&
 598        srcX0 < srcX1 &&
 599        srcY0 < srcY1 &&
 600        dstX0 < dstX1 &&
 601        dstY0 < dstY1) {
 602       for (i = 0; i < 3; i++) {
 603          if (mask & buffers[i]) {
 604             if (swrast_fast_copy_pixels(ctx,
 605                                         srcX0, srcY0,
 606                                         srcX1 - srcX0, srcY1 - srcY0,
 607                                         dstX0, dstY0,
 608                                         buffer_enums[i])) {
 609                mask &= ~buffers[i];
 610             }
 611          }
 612       }
 613
 614       if (!mask)
 615          return;
 616    }
 617
 618    if (filter == GL_NEAREST) {
 619       for (i = 0; i < 3; i++) {
 620          if (mask & buffers[i]) {
 621             blit_nearest(ctx,  srcX0, srcY0, srcX1, srcY1,
 622                          dstX0, dstY0, dstX1, dstY1, buffers[i]);
 623          }
 624       }
 625    }
 626    else {
 627       ASSERT(filter == GL_LINEAR);
 628       if (mask & GL_COLOR_BUFFER_BIT) {  /* depth/stencil not allowed */
 629          swrast_render_start(ctx);
 630          blit_linear(ctx,  srcX0, srcY0, srcX1, srcY1,
 631                      dstX0, dstY0, dstX1, dstY1);
 632          swrast_render_finish(ctx);
 633       }
 634    }
 635
 636 }