src/mesa/swrast/s_readpix.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  7.0.3
   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/colormac.h"
  28 #include "main/feedback.h"
  29 #include "main/formats.h"
  30 #include "main/format_unpack.h"
  31 #include "main/image.h"
  32 #include "main/imports.h"
  33 #include "main/macros.h"
  34 #include "main/pack.h"
  35 #include "main/pbo.h"
  36 #include "main/state.h"
  37
  38 #include "s_context.h"
  39 #include "s_depth.h"
  40 #include "s_span.h"
  41 #include "s_stencil.h"
  42
  43 /**
  44  * Tries to implement glReadPixels() of GL_DEPTH_COMPONENT using memcpy of the
  45  * mapping.
  46  */
  47 static GLboolean
  48 fast_read_depth_pixels( struct gl_context *ctx,
  49                         GLint x, GLint y,
  50                         GLsizei width, GLsizei height,
  51                         GLenum type, GLvoid *pixels,
  52                         const struct gl_pixelstore_attrib *packing )
  53 {
  54    struct gl_framebuffer *fb = ctx->ReadBuffer;
  55    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_DEPTH].Renderbuffer;
  56    GLubyte *map, *dst;
  57    int stride, dstStride, j;
  58
  59    if (ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0)
  60       return GL_FALSE;
  61
  62    if (packing->SwapBytes)
  63       return GL_FALSE;
  64
  65    if (_mesa_get_format_datatype(rb->Format) != GL_UNSIGNED_INT)
  66       return GL_FALSE;
  67
  68    if (!((type == GL_UNSIGNED_SHORT && rb->Format == MESA_FORMAT_Z16) ||
  69          type == GL_UNSIGNED_INT))
  70       return GL_FALSE;
  71
  72    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
  73                                &map, &stride);
  74
  75    dstStride = _mesa_image_row_stride(packing, width, GL_DEPTH_COMPONENT, type);
  76    dst = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
  77                                            GL_DEPTH_COMPONENT, type, 0, 0);
  78
  79    for (j = 0; j < height; j++) {
  80       if (type == GL_UNSIGNED_INT) {
  81          _mesa_unpack_uint_z_row(rb->Format, width, map, (GLuint *)dst);
  82       } else {
  83          ASSERT(type == GL_UNSIGNED_SHORT && rb->Format == MESA_FORMAT_Z16);
  84          memcpy(dst, map, width * 2);
  85       }
  86
  87       map += stride;
  88       dst += dstStride;
  89    }
  90    ctx->Driver.UnmapRenderbuffer(ctx, rb);
  91
  92    return GL_TRUE;
  93 }
  94
  95 /**
  96  * Read pixels for format=GL_DEPTH_COMPONENT.
  97  */
  98 static void
  99 read_depth_pixels( struct gl_context *ctx,
 100                    GLint x, GLint y,
 101                    GLsizei width, GLsizei height,
 102                    GLenum type, GLvoid *pixels,
 103                    const struct gl_pixelstore_attrib *packing )
 104 {
 105    struct gl_framebuffer *fb = ctx->ReadBuffer;
 106    struct gl_renderbuffer *rb = fb->_DepthBuffer;
 107    GLint j;
 108
 109    if (!rb)
 110       return;
 111
 112    /* clipping should have been done already */
 113    ASSERT(x >= 0);
 114    ASSERT(y >= 0);
 115    ASSERT(x + width <= (GLint) rb->Width);
 116    ASSERT(y + height <= (GLint) rb->Height);
 117    /* width should never be > MAX_WIDTH since we did clipping earlier */
 118    ASSERT(width <= MAX_WIDTH);
 119
 120    if (fast_read_depth_pixels(ctx, x, y, width, height, type, pixels, packing))
 121       return;
 122
 123    /* General case (slower) */
 124    for (j = 0; j < height; j++, y++) {
 125       GLfloat depthValues[MAX_WIDTH];
 126       GLvoid *dest = _mesa_image_address2d(packing, pixels, width, height,
 127                                            GL_DEPTH_COMPONENT, type, j, 0);
 128       _swrast_read_depth_span_float(ctx, rb, width, x, y, depthValues);
 129       _mesa_pack_depth_span(ctx, width, dest, type, depthValues, packing);
 130    }
 131 }
 132
 133
 134 /**
 135  * Read pixels for format=GL_STENCIL_INDEX.
 136  */
 137 static void
 138 read_stencil_pixels( struct gl_context *ctx,
 139                      GLint x, GLint y,
 140                      GLsizei width, GLsizei height,
 141                      GLenum type, GLvoid *pixels,
 142                      const struct gl_pixelstore_attrib *packing )
 143 {
 144    struct gl_framebuffer *fb = ctx->ReadBuffer;
 145    struct gl_renderbuffer *rb = fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 146    GLint j;
 147    GLubyte *map;
 148    GLint stride;
 149
 150    if (!rb)
 151       return;
 152
 153    /* width should never be > MAX_WIDTH since we did clipping earlier */
 154    ASSERT(width <= MAX_WIDTH);
 155
 156    ctx->Driver.MapRenderbuffer(ctx, rb, x, y, width, height, GL_MAP_READ_BIT,
 157                                &map, &stride);
 158
 159    /* process image row by row */
 160    for (j = 0; j < height; j++) {
 161       GLvoid *dest;
 162       GLstencil stencil[MAX_WIDTH];
 163
 164       _mesa_unpack_ubyte_stencil_row(rb->Format, width, map, stencil);
 165       dest = _mesa_image_address2d(packing, pixels, width, height,
 166                                    GL_STENCIL_INDEX, type, j, 0);
 167
 168       _mesa_pack_stencil_span(ctx, width, type, dest, stencil, packing);
 169
 170       map += stride;
 171    }
 172
 173    ctx->Driver.UnmapRenderbuffer(ctx, rb);
 174 }
 175
 176
 177
 178 /**
 179  * Optimized glReadPixels for particular pixel formats when pixel
 180  * scaling, biasing, mapping, etc. are disabled.
 181  * \return GL_TRUE if success, GL_FALSE if unable to do the readpixels
 182  */
 183 static GLboolean
 184 fast_read_rgba_pixels( struct gl_context *ctx,
 185                        GLint x, GLint y,
 186                        GLsizei width, GLsizei height,
 187                        GLenum format, GLenum type,
 188                        GLvoid *pixels,
 189                        const struct gl_pixelstore_attrib *packing,
 190                        GLbitfield transferOps)
 191 {
 192    struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
 193
 194    if (!rb)
 195       return GL_FALSE;
 196
 197    ASSERT(rb->_BaseFormat == GL_RGBA ||
 198           rb->_BaseFormat == GL_RGB ||
 199           rb->_BaseFormat == GL_RG ||
 200           rb->_BaseFormat == GL_RED ||
 201           rb->_BaseFormat == GL_LUMINANCE ||
 202           rb->_BaseFormat == GL_INTENSITY ||
 203           rb->_BaseFormat == GL_LUMINANCE_ALPHA ||
 204           rb->_BaseFormat == GL_ALPHA);
 205
 206    /* clipping should have already been done */
 207    ASSERT(x + width <= (GLint) rb->Width);
 208    ASSERT(y + height <= (GLint) rb->Height);
 209
 210    /* check for things we can't handle here */
 211    if (transferOps ||
 212        packing->SwapBytes ||
 213        packing->LsbFirst) {
 214       return GL_FALSE;
 215    }
 216
 217    if (format == GL_RGBA && rb->DataType == type) {
 218       const GLint dstStride = _mesa_image_row_stride(packing, width,
 219                                                      format, type);
 220       GLubyte *dest
 221          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 222                                              format, type, 0, 0);
 223       GLint row;
 224       ASSERT(rb->GetRow);
 225       for (row = 0; row < height; row++) {
 226          rb->GetRow(ctx, rb, width, x, y + row, dest);
 227          dest += dstStride;
 228       }
 229       return GL_TRUE;
 230    }
 231
 232    if (format == GL_RGB &&
 233        rb->DataType == GL_UNSIGNED_BYTE &&
 234        type == GL_UNSIGNED_BYTE) {
 235       const GLint dstStride = _mesa_image_row_stride(packing, width,
 236                                                      format, type);
 237       GLubyte *dest
 238          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 239                                              format, type, 0, 0);
 240       GLint row;
 241       ASSERT(rb->GetRow);
 242       for (row = 0; row < height; row++) {
 243          GLubyte tempRow[MAX_WIDTH][4];
 244          GLint col;
 245          rb->GetRow(ctx, rb, width, x, y + row, tempRow);
 246          /* convert RGBA to RGB */
 247          for (col = 0; col < width; col++) {
 248             dest[col * 3 + 0] = tempRow[col][0];
 249             dest[col * 3 + 1] = tempRow[col][1];
 250             dest[col * 3 + 2] = tempRow[col][2];
 251          }
 252          dest += dstStride;
 253       }
 254       return GL_TRUE;
 255    }
 256
 257    /* not handled */
 258    return GL_FALSE;
 259 }
 260
 261
 262 /**
 263  * When we're using a low-precision color buffer (like 16-bit 5/6/5)
 264  * we have to adjust our color values a bit to pass conformance.
 265  * The problem is when a 5 or 6-bit color value is converted to an 8-bit
 266  * value and then a floating point value, the floating point values don't
 267  * increment uniformly as the 5 or 6-bit value is incremented.
 268  *
 269  * This function adjusts floating point values to compensate.
 270  */
 271 static void
 272 adjust_colors(const struct gl_framebuffer *fb, GLuint n, GLfloat rgba[][4])
 273 {
 274    const GLuint rShift = 8 - fb->Visual.redBits;
 275    const GLuint gShift = 8 - fb->Visual.greenBits;
 276    const GLuint bShift = 8 - fb->Visual.blueBits;
 277    GLfloat rScale = 1.0F / (GLfloat) ((1 << fb->Visual.redBits  ) - 1);
 278    GLfloat gScale = 1.0F / (GLfloat) ((1 << fb->Visual.greenBits) - 1);
 279    GLfloat bScale = 1.0F / (GLfloat) ((1 << fb->Visual.blueBits ) - 1);
 280    GLuint i;
 281
 282    if (fb->Visual.redBits == 0)
 283       rScale = 0;
 284    if (fb->Visual.greenBits == 0)
 285       gScale = 0;
 286    if (fb->Visual.blueBits == 0)
 287       bScale = 0;
 288
 289    for (i = 0; i < n; i++) {
 290       GLint r, g, b;
 291       /* convert float back to ubyte */
 292       CLAMPED_FLOAT_TO_UBYTE(r, rgba[i][RCOMP]);
 293       CLAMPED_FLOAT_TO_UBYTE(g, rgba[i][GCOMP]);
 294       CLAMPED_FLOAT_TO_UBYTE(b, rgba[i][BCOMP]);
 295       /* using only the N most significant bits of the ubyte value, convert to
 296        * float in [0,1].
 297        */
 298       rgba[i][RCOMP] = (GLfloat) (r >> rShift) * rScale;
 299       rgba[i][GCOMP] = (GLfloat) (g >> gShift) * gScale;
 300       rgba[i][BCOMP] = (GLfloat) (b >> bShift) * bScale;
 301    }
 302 }
 303
 304
 305
 306 /*
 307  * Read R, G, B, A, RGB, L, or LA pixels.
 308  */
 309 static void
 310 read_rgba_pixels( struct gl_context *ctx,
 311                   GLint x, GLint y,
 312                   GLsizei width, GLsizei height,
 313                   GLenum format, GLenum type, GLvoid *pixels,
 314                   const struct gl_pixelstore_attrib *packing )
 315 {
 316    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 317    GLbitfield transferOps = ctx->_ImageTransferState;
 318    struct gl_framebuffer *fb = ctx->ReadBuffer;
 319    struct gl_renderbuffer *rb = fb->_ColorReadBuffer;
 320
 321    if (!rb)
 322       return;
 323
 324    if ((ctx->Color._ClampReadColor == GL_TRUE || type != GL_FLOAT) &&
 325        !_mesa_is_integer_format(format)) {
 326       transferOps |= IMAGE_CLAMP_BIT;
 327    }
 328
 329    /* Try the optimized path first. */
 330    if (fast_read_rgba_pixels(ctx, x, y, width, height,
 331                              format, type, pixels, packing, transferOps)) {
 332       return; /* done! */
 333    }
 334
 335    /* width should never be > MAX_WIDTH since we did clipping earlier */
 336    ASSERT(width <= MAX_WIDTH);
 337
 338    {
 339       const GLint dstStride
 340          = _mesa_image_row_stride(packing, width, format, type);
 341       GLfloat (*rgba)[4] = swrast->SpanArrays->attribs[FRAG_ATTRIB_COL0];
 342       GLint row;
 343       GLubyte *dst
 344          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 345                                              format, type, 0, 0);
 346
 347       for (row = 0; row < height; row++, y++) {
 348
 349          /* Get float rgba pixels */
 350          _swrast_read_rgba_span(ctx, rb, width, x, y, GL_FLOAT, rgba);
 351
 352          /* apply fudge factor for shallow color buffers */
 353          if ((fb->Visual.redBits < 8 && fb->Visual.redBits != 0) ||
 354              (fb->Visual.greenBits < 8 && fb->Visual.greenBits != 0) ||
 355              (fb->Visual.blueBits < 8 && fb->Visual.blueBits != 0)) {
 356             adjust_colors(fb, width, rgba);
 357          }
 358
 359          /* pack the row of RGBA pixels into user's buffer */
 360          _mesa_pack_rgba_span_float(ctx, width, rgba, format, type, dst,
 361                                     packing, transferOps);
 362
 363          dst += dstStride;
 364       }
 365    }
 366 }
 367
 368
 369 /**
 370  * Read combined depth/stencil values.
 371  * We'll have already done error checking to be sure the expected
 372  * depth and stencil buffers really exist.
 373  */
 374 static void
 375 read_depth_stencil_pixels(struct gl_context *ctx,
 376                           GLint x, GLint y,
 377                           GLsizei width, GLsizei height,
 378                           GLenum type, GLvoid *pixels,
 379                           const struct gl_pixelstore_attrib *packing )
 380 {
 381    const GLboolean scaleOrBias
 382       = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
 383    const GLboolean stencilTransfer = ctx->Pixel.IndexShift
 384       || ctx->Pixel.IndexOffset || ctx->Pixel.MapStencilFlag;
 385    struct gl_renderbuffer *depthRb, *stencilRb;
 386
 387    depthRb = ctx->ReadBuffer->_DepthBuffer;
 388    stencilRb = ctx->ReadBuffer->_StencilBuffer;
 389
 390    if (!depthRb || !stencilRb)
 391       return;
 392
 393    depthRb = ctx->ReadBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
 394    stencilRb = ctx->ReadBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
 395
 396    if (depthRb->_BaseFormat == GL_DEPTH_STENCIL_EXT &&
 397        depthRb->Format == MESA_FORMAT_Z24_S8 &&
 398        type == GL_UNSIGNED_INT_24_8 &&
 399        depthRb == stencilRb &&
 400        depthRb->GetRow &&  /* May be null if depthRb is a wrapper around
 401                             * separate depth and stencil buffers. */
 402        !scaleOrBias &&
 403        !stencilTransfer) {
 404       /* This is the ideal case.
 405        * Reading GL_DEPTH_STENCIL pixels from combined depth/stencil buffer.
 406        * Plus, no pixel transfer ops to worry about!
 407        */
 408       GLint i;
 409       GLint dstStride = _mesa_image_row_stride(packing, width,
 410                                                GL_DEPTH_STENCIL_EXT, type);
 411       GLubyte *dst = (GLubyte *) _mesa_image_address2d(packing, pixels,
 412                                                        width, height,
 413                                                        GL_DEPTH_STENCIL_EXT,
 414                                                        type, 0, 0);
 415       for (i = 0; i < height; i++) {
 416          depthRb->GetRow(ctx, depthRb, width, x, y + i, dst);
 417          dst += dstStride;
 418       }
 419    }
 420    else {
 421       /* Reading GL_DEPTH_STENCIL pixels from separate depth/stencil buffers,
 422        * or we need pixel transfer.
 423        */
 424       GLint i;
 425       depthRb = ctx->ReadBuffer->_DepthBuffer;
 426       stencilRb = ctx->ReadBuffer->_StencilBuffer;
 427
 428       for (i = 0; i < height; i++) {
 429          GLstencil stencilVals[MAX_WIDTH];
 430
 431          GLuint *depthStencilDst = (GLuint *)
 432             _mesa_image_address2d(packing, pixels, width, height,
 433                                   GL_DEPTH_STENCIL_EXT, type, i, 0);
 434
 435          _swrast_read_stencil_span(ctx, stencilRb, width,
 436                                    x, y + i, stencilVals);
 437
 438          if (!scaleOrBias && !stencilTransfer
 439              && ctx->ReadBuffer->Visual.depthBits == 24) {
 440             /* ideal case */
 441             GLuint zVals[MAX_WIDTH]; /* 24-bit values! */
 442             GLint j;
 443             ASSERT(depthRb->DataType == GL_UNSIGNED_INT);
 444             /* note, we've already been clipped */
 445             depthRb->GetRow(ctx, depthRb, width, x, y + i, zVals);
 446             for (j = 0; j < width; j++) {
 447                depthStencilDst[j] = (zVals[j] << 8) | (stencilVals[j] & 0xff);
 448             }
 449          }
 450          else {
 451             /* general case */
 452             GLfloat depthVals[MAX_WIDTH];
 453             _swrast_read_depth_span_float(ctx, depthRb, width, x, y + i,
 454                                           depthVals);
 455             _mesa_pack_depth_stencil_span(ctx, width, type, depthStencilDst,
 456                                           depthVals, stencilVals, packing);
 457          }
 458       }
 459    }
 460 }
 461
 462
 463
 464 /**
 465  * Software fallback routine for ctx->Driver.ReadPixels().
 466  * By time we get here, all error checking will have been done.
 467  */
 468 void
 469 _swrast_ReadPixels( struct gl_context *ctx,
 470                     GLint x, GLint y, GLsizei width, GLsizei height,
 471                     GLenum format, GLenum type,
 472                     const struct gl_pixelstore_attrib *packing,
 473                     GLvoid *pixels )
 474 {
 475    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 476    struct gl_pixelstore_attrib clippedPacking = *packing;
 477
 478    if (ctx->NewState)
 479       _mesa_update_state(ctx);
 480
 481    /* Need to do swrast_render_start() before clipping or anything else
 482     * since this is where a driver may grab the hw lock and get an updated
 483     * window size.
 484     */
 485    swrast_render_start(ctx);
 486
 487    if (swrast->NewState)
 488       _swrast_validate_derived( ctx );
 489
 490    /* Do all needed clipping here, so that we can forget about it later */
 491    if (_mesa_clip_readpixels(ctx, &x, &y, &width, &height, &clippedPacking)) {
 492
 493       pixels = _mesa_map_pbo_dest(ctx, &clippedPacking, pixels);
 494
 495       if (pixels) {
 496          switch (format) {
 497          case GL_STENCIL_INDEX:
 498             read_stencil_pixels(ctx, x, y, width, height, type, pixels,
 499                                 &clippedPacking);
 500             break;
 501          case GL_DEPTH_COMPONENT:
 502             read_depth_pixels(ctx, x, y, width, height, type, pixels,
 503                               &clippedPacking);
 504             break;
 505          case GL_DEPTH_STENCIL_EXT:
 506             read_depth_stencil_pixels(ctx, x, y, width, height, type, pixels,
 507                                       &clippedPacking);
 508             break;
 509          default:
 510             /* all other formats should be color formats */
 511             read_rgba_pixels(ctx, x, y, width, height, format, type, pixels,
 512                              &clippedPacking);
 513          }
 514
 515          _mesa_unmap_pbo_dest(ctx, &clippedPacking);
 516       }
 517    }
 518
 519    swrast_render_finish(ctx);
 520 }