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/image.h"
  31 #include "main/imports.h"
  32 #include "main/macros.h"
  33 #include "main/pack.h"
  34 #include "main/pbo.h"
  35 #include "main/state.h"
  36
  37 #include "s_context.h"
  38 #include "s_depth.h"
  39 #include "s_span.h"
  40 #include "s_stencil.h"
  41
  42
  43 /**
  44  * Read pixels for format=GL_DEPTH_COMPONENT.
  45  */
  46 static void
  47 read_depth_pixels( struct gl_context *ctx,
  48                    GLint x, GLint y,
  49                    GLsizei width, GLsizei height,
  50                    GLenum type, GLvoid *pixels,
  51                    const struct gl_pixelstore_attrib *packing )
  52 {
  53    struct gl_framebuffer *fb = ctx->ReadBuffer;
  54    struct gl_renderbuffer *rb = fb->_DepthBuffer;
  55    const GLboolean biasOrScale
  56       = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
  57
  58    if (!rb)
  59       return;
  60
  61    /* clipping should have been done already */
  62    ASSERT(x >= 0);
  63    ASSERT(y >= 0);
  64    ASSERT(x + width <= (GLint) rb->Width);
  65    ASSERT(y + height <= (GLint) rb->Height);
  66    /* width should never be > MAX_WIDTH since we did clipping earlier */
  67    ASSERT(width <= MAX_WIDTH);
  68
  69    if (type == GL_UNSIGNED_SHORT && fb->Visual.depthBits == 16
  70        && !biasOrScale && !packing->SwapBytes) {
  71       /* Special case: directly read 16-bit unsigned depth values. */
  72       GLint j;
  73       ASSERT(rb->Format == MESA_FORMAT_Z16);
  74       ASSERT(rb->DataType == GL_UNSIGNED_SHORT);
  75       for (j = 0; j < height; j++, y++) {
  76          void *dest =_mesa_image_address2d(packing, pixels, width, height,
  77                                            GL_DEPTH_COMPONENT, type, j, 0);
  78          rb->GetRow(ctx, rb, width, x, y, dest);
  79       }
  80    }
  81    else if (type == GL_UNSIGNED_INT && fb->Visual.depthBits == 24
  82             && !biasOrScale && !packing->SwapBytes) {
  83       /* Special case: directly read 24-bit unsigned depth values. */
  84       GLint j;
  85       ASSERT(rb->Format == MESA_FORMAT_X8_Z24 ||
  86              rb->Format == MESA_FORMAT_S8_Z24 ||
  87              rb->Format == MESA_FORMAT_Z24_X8 ||
  88              rb->Format == MESA_FORMAT_Z24_S8);
  89       ASSERT(rb->DataType == GL_UNSIGNED_INT ||
  90              rb->DataType == GL_UNSIGNED_INT_24_8);
  91       for (j = 0; j < height; j++, y++) {
  92          GLuint *dest = (GLuint *)
  93             _mesa_image_address2d(packing, pixels, width, height,
  94                                   GL_DEPTH_COMPONENT, type, j, 0);
  95          GLint k;
  96          rb->GetRow(ctx, rb, width, x, y, dest);
  97          /* convert range from 24-bit to 32-bit */
  98          if (rb->Format == MESA_FORMAT_X8_Z24 ||
  99              rb->Format == MESA_FORMAT_S8_Z24) {
 100             for (k = 0; k < width; k++) {
 101                /* Note: put MSByte of 24-bit value into LSByte */
 102                dest[k] = (dest[k] << 8) | ((dest[k] >> 16) & 0xff);
 103             }
 104          }
 105          else {
 106             for (k = 0; k < width; k++) {
 107                /* Note: fill in LSByte by replication */
 108                dest[k] = dest[k] | ((dest[k] >> 8) & 0xff);
 109             }
 110          }
 111       }
 112    }
 113    else if (type == GL_UNSIGNED_INT && fb->Visual.depthBits == 32
 114             && !biasOrScale && !packing->SwapBytes) {
 115       /* Special case: directly read 32-bit unsigned depth values. */
 116       GLint j;
 117       ASSERT(rb->Format == MESA_FORMAT_Z32);
 118       ASSERT(rb->DataType == GL_UNSIGNED_INT);
 119       for (j = 0; j < height; j++, y++) {
 120          void *dest = _mesa_image_address2d(packing, pixels, width, height,
 121                                             GL_DEPTH_COMPONENT, type, j, 0);
 122          rb->GetRow(ctx, rb, width, x, y, dest);
 123       }
 124    }
 125    else {
 126       /* General case (slower) */
 127       GLint j;
 128       for (j = 0; j < height; j++, y++) {
 129          GLfloat depthValues[MAX_WIDTH];
 130          GLvoid *dest = _mesa_image_address2d(packing, pixels, width, height,
 131                                               GL_DEPTH_COMPONENT, type, j, 0);
 132          _swrast_read_depth_span_float(ctx, rb, width, x, y, depthValues);
 133          _mesa_pack_depth_span(ctx, width, dest, type, depthValues, packing);
 134       }
 135    }
 136 }
 137
 138
 139 /**
 140  * Read pixels for format=GL_STENCIL_INDEX.
 141  */
 142 static void
 143 read_stencil_pixels( struct gl_context *ctx,
 144                      GLint x, GLint y,
 145                      GLsizei width, GLsizei height,
 146                      GLenum type, GLvoid *pixels,
 147                      const struct gl_pixelstore_attrib *packing )
 148 {
 149    struct gl_framebuffer *fb = ctx->ReadBuffer;
 150    struct gl_renderbuffer *rb = fb->_StencilBuffer;
 151    GLint j;
 152
 153    if (!rb)
 154       return;
 155
 156    /* width should never be > MAX_WIDTH since we did clipping earlier */
 157    ASSERT(width <= MAX_WIDTH);
 158
 159    /* process image row by row */
 160    for (j=0;j<height;j++,y++) {
 161       GLvoid *dest;
 162       GLstencil stencil[MAX_WIDTH];
 163
 164       _swrast_read_stencil_span(ctx, rb, width, x, y, stencil);
 165
 166       dest = _mesa_image_address2d(packing, pixels, width, height,
 167                                    GL_STENCIL_INDEX, type, j, 0);
 168
 169       _mesa_pack_stencil_span(ctx, width, type, dest, stencil, packing);
 170    }
 171 }
 172
 173
 174
 175 /**
 176  * Optimized glReadPixels for particular pixel formats when pixel
 177  * scaling, biasing, mapping, etc. are disabled.
 178  * \return GL_TRUE if success, GL_FALSE if unable to do the readpixels
 179  */
 180 static GLboolean
 181 fast_read_rgba_pixels( struct gl_context *ctx,
 182                        GLint x, GLint y,
 183                        GLsizei width, GLsizei height,
 184                        GLenum format, GLenum type,
 185                        GLvoid *pixels,
 186                        const struct gl_pixelstore_attrib *packing,
 187                        GLbitfield transferOps)
 188 {
 189    struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
 190
 191    if (!rb)
 192       return GL_FALSE;
 193
 194    ASSERT(rb->_BaseFormat == GL_RGBA ||
 195           rb->_BaseFormat == GL_RGB ||
 196           rb->_BaseFormat == GL_RG ||
 197           rb->_BaseFormat == GL_RED ||
 198           rb->_BaseFormat == GL_ALPHA);
 199
 200    /* clipping should have already been done */
 201    ASSERT(x + width <= (GLint) rb->Width);
 202    ASSERT(y + height <= (GLint) rb->Height);
 203
 204    /* check for things we can't handle here */
 205    if (transferOps ||
 206        packing->SwapBytes ||
 207        packing->LsbFirst) {
 208       return GL_FALSE;
 209    }
 210
 211    if (format == GL_RGBA && rb->DataType == type) {
 212       const GLint dstStride = _mesa_image_row_stride(packing, width,
 213                                                      format, type);
 214       GLubyte *dest
 215          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 216                                              format, type, 0, 0);
 217       GLint row;
 218       ASSERT(rb->GetRow);
 219       for (row = 0; row < height; row++) {
 220          rb->GetRow(ctx, rb, width, x, y + row, dest);
 221          dest += dstStride;
 222       }
 223       return GL_TRUE;
 224    }
 225
 226    if (format == GL_RGB &&
 227        rb->DataType == GL_UNSIGNED_BYTE &&
 228        type == GL_UNSIGNED_BYTE) {
 229       const GLint dstStride = _mesa_image_row_stride(packing, width,
 230                                                      format, type);
 231       GLubyte *dest
 232          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 233                                              format, type, 0, 0);
 234       GLint row;
 235       ASSERT(rb->GetRow);
 236       for (row = 0; row < height; row++) {
 237          GLubyte tempRow[MAX_WIDTH][4];
 238          GLint col;
 239          rb->GetRow(ctx, rb, width, x, y + row, tempRow);
 240          /* convert RGBA to RGB */
 241          for (col = 0; col < width; col++) {
 242             dest[col * 3 + 0] = tempRow[col][0];
 243             dest[col * 3 + 1] = tempRow[col][1];
 244             dest[col * 3 + 2] = tempRow[col][2];
 245          }
 246          dest += dstStride;
 247       }
 248       return GL_TRUE;
 249    }
 250
 251    /* not handled */
 252    return GL_FALSE;
 253 }
 254
 255
 256 /**
 257  * When we're using a low-precision color buffer (like 16-bit 5/6/5)
 258  * we have to adjust our color values a bit to pass conformance.
 259  * The problem is when a 5 or 6-bit color value is converted to an 8-bit
 260  * value and then a floating point value, the floating point values don't
 261  * increment uniformly as the 5 or 6-bit value is incremented.
 262  *
 263  * This function adjusts floating point values to compensate.
 264  */
 265 static void
 266 adjust_colors(const struct gl_framebuffer *fb, GLuint n, GLfloat rgba[][4])
 267 {
 268    const GLuint rShift = 8 - fb->Visual.redBits;
 269    const GLuint gShift = 8 - fb->Visual.greenBits;
 270    const GLuint bShift = 8 - fb->Visual.blueBits;
 271    GLfloat rScale = 1.0F / (GLfloat) ((1 << fb->Visual.redBits  ) - 1);
 272    GLfloat gScale = 1.0F / (GLfloat) ((1 << fb->Visual.greenBits) - 1);
 273    GLfloat bScale = 1.0F / (GLfloat) ((1 << fb->Visual.blueBits ) - 1);
 274    GLuint i;
 275
 276    if (fb->Visual.redBits == 0)
 277       rScale = 0;
 278    if (fb->Visual.greenBits == 0)
 279       gScale = 0;
 280    if (fb->Visual.blueBits == 0)
 281       bScale = 0;
 282
 283    for (i = 0; i < n; i++) {
 284       GLint r, g, b;
 285       /* convert float back to ubyte */
 286       CLAMPED_FLOAT_TO_UBYTE(r, rgba[i][RCOMP]);
 287       CLAMPED_FLOAT_TO_UBYTE(g, rgba[i][GCOMP]);
 288       CLAMPED_FLOAT_TO_UBYTE(b, rgba[i][BCOMP]);
 289       /* using only the N most significant bits of the ubyte value, convert to
 290        * float in [0,1].
 291        */
 292       rgba[i][RCOMP] = (GLfloat) (r >> rShift) * rScale;
 293       rgba[i][GCOMP] = (GLfloat) (g >> gShift) * gScale;
 294       rgba[i][BCOMP] = (GLfloat) (b >> bShift) * bScale;
 295    }
 296 }
 297
 298
 299
 300 /*
 301  * Read R, G, B, A, RGB, L, or LA pixels.
 302  */
 303 static void
 304 read_rgba_pixels( struct gl_context *ctx,
 305                   GLint x, GLint y,
 306                   GLsizei width, GLsizei height,
 307                   GLenum format, GLenum type, GLvoid *pixels,
 308                   const struct gl_pixelstore_attrib *packing )
 309 {
 310    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 311    GLbitfield transferOps = ctx->_ImageTransferState;
 312    struct gl_framebuffer *fb = ctx->ReadBuffer;
 313    struct gl_renderbuffer *rb = fb->_ColorReadBuffer;
 314
 315    if (!rb)
 316       return;
 317
 318    if (type == GL_FLOAT && ((ctx->Color.ClampReadColor == GL_TRUE) ||
 319                             (ctx->Color.ClampReadColor == GL_FIXED_ONLY_ARB &&
 320                              rb->DataType != GL_FLOAT)))
 321       transferOps |= IMAGE_CLAMP_BIT;
 322
 323    /* Try optimized path first */
 324    if (fast_read_rgba_pixels(ctx, x, y, width, height,
 325                              format, type, pixels, packing, transferOps)) {
 326       return; /* done! */
 327    }
 328
 329    /* width should never be > MAX_WIDTH since we did clipping earlier */
 330    ASSERT(width <= MAX_WIDTH);
 331
 332    do {
 333       const GLint dstStride
 334          = _mesa_image_row_stride(packing, width, format, type);
 335       GLfloat (*rgba)[4] = swrast->SpanArrays->attribs[FRAG_ATTRIB_COL0];
 336       GLint row;
 337       GLubyte *dst
 338          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 339                                              format, type, 0, 0);
 340
 341       for (row = 0; row < height; row++, y++) {
 342
 343          /* Get float rgba pixels */
 344          _swrast_read_rgba_span(ctx, rb, width, x, y, GL_FLOAT, rgba);
 345
 346          /* apply fudge factor for shallow color buffers */
 347          if (fb->Visual.redBits < 8 ||
 348              fb->Visual.greenBits < 8 ||
 349              fb->Visual.blueBits < 8) {
 350             adjust_colors(fb, width, rgba);
 351          }
 352
 353          /* pack the row of RGBA pixels into user's buffer */
 354          _mesa_pack_rgba_span_float(ctx, width, rgba, format, type, dst,
 355                                     packing, transferOps);
 356
 357          dst += dstStride;
 358       }
 359    } while (0);
 360 }
 361
 362
 363 /**
 364  * Read combined depth/stencil values.
 365  * We'll have already done error checking to be sure the expected
 366  * depth and stencil buffers really exist.
 367  */
 368 static void
 369 read_depth_stencil_pixels(struct gl_context *ctx,
 370                           GLint x, GLint y,
 371                           GLsizei width, GLsizei height,
 372                           GLenum type, GLvoid *pixels,
 373                           const struct gl_pixelstore_attrib *packing )
 374 {
 375    const GLboolean scaleOrBias
 376       = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
 377    const GLboolean stencilTransfer = ctx->Pixel.IndexShift
 378       || ctx->Pixel.IndexOffset || ctx->Pixel.MapStencilFlag;
 379    struct gl_renderbuffer *depthRb, *stencilRb;
 380
 381    depthRb = ctx->ReadBuffer->_DepthBuffer;
 382    stencilRb = ctx->ReadBuffer->_StencilBuffer;
 383
 384    if (!depthRb || !stencilRb)
 385       return;
 386
 387    depthRb = ctx->ReadBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
 388    stencilRb = ctx->ReadBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
 389
 390    if (depthRb->_BaseFormat == GL_DEPTH_STENCIL_EXT &&
 391        stencilRb->_BaseFormat == GL_DEPTH_STENCIL_EXT &&
 392        depthRb == stencilRb &&
 393        !scaleOrBias &&
 394        !stencilTransfer) {
 395       /* This is the ideal case.
 396        * Reading GL_DEPTH_STENCIL pixels from combined depth/stencil buffer.
 397        * Plus, no pixel transfer ops to worry about!
 398        */
 399       GLint i;
 400       GLint dstStride = _mesa_image_row_stride(packing, width,
 401                                                GL_DEPTH_STENCIL_EXT, type);
 402       GLubyte *dst = (GLubyte *) _mesa_image_address2d(packing, pixels,
 403                                                        width, height,
 404                                                        GL_DEPTH_STENCIL_EXT,
 405                                                        type, 0, 0);
 406       for (i = 0; i < height; i++) {
 407          depthRb->GetRow(ctx, depthRb, width, x, y + i, dst);
 408          dst += dstStride;
 409       }
 410    }
 411    else {
 412       /* Reading GL_DEPTH_STENCIL pixels from separate depth/stencil buffers,
 413        * or we need pixel transfer.
 414        */
 415       GLint i;
 416       depthRb = ctx->ReadBuffer->_DepthBuffer;
 417       stencilRb = ctx->ReadBuffer->_StencilBuffer;
 418
 419       for (i = 0; i < height; i++) {
 420          GLstencil stencilVals[MAX_WIDTH];
 421
 422          GLuint *depthStencilDst = (GLuint *)
 423             _mesa_image_address2d(packing, pixels, width, height,
 424                                   GL_DEPTH_STENCIL_EXT, type, i, 0);
 425
 426          _swrast_read_stencil_span(ctx, stencilRb, width,
 427                                    x, y + i, stencilVals);
 428
 429          if (!scaleOrBias && !stencilTransfer
 430              && ctx->ReadBuffer->Visual.depthBits == 24) {
 431             /* ideal case */
 432             GLuint zVals[MAX_WIDTH]; /* 24-bit values! */
 433             GLint j;
 434             ASSERT(depthRb->DataType == GL_UNSIGNED_INT);
 435             /* note, we've already been clipped */
 436             depthRb->GetRow(ctx, depthRb, width, x, y + i, zVals);
 437             for (j = 0; j < width; j++) {
 438                depthStencilDst[j] = (zVals[j] << 8) | (stencilVals[j] & 0xff);
 439             }
 440          }
 441          else {
 442             /* general case */
 443             GLfloat depthVals[MAX_WIDTH];
 444             _swrast_read_depth_span_float(ctx, depthRb, width, x, y + i,
 445                                           depthVals);
 446             _mesa_pack_depth_stencil_span(ctx, width, depthStencilDst,
 447                                           depthVals, stencilVals, packing);
 448          }
 449       }
 450    }
 451 }
 452
 453
 454
 455 /**
 456  * Software fallback routine for ctx->Driver.ReadPixels().
 457  * By time we get here, all error checking will have been done.
 458  */
 459 void
 460 _swrast_ReadPixels( struct gl_context *ctx,
 461                     GLint x, GLint y, GLsizei width, GLsizei height,
 462                     GLenum format, GLenum type,
 463                     const struct gl_pixelstore_attrib *packing,
 464                     GLvoid *pixels )
 465 {
 466    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 467    struct gl_pixelstore_attrib clippedPacking = *packing;
 468
 469    if (ctx->NewState)
 470       _mesa_update_state(ctx);
 471
 472    /* Need to do swrast_render_start() before clipping or anything else
 473     * since this is where a driver may grab the hw lock and get an updated
 474     * window size.
 475     */
 476    swrast_render_start(ctx);
 477
 478    if (swrast->NewState)
 479       _swrast_validate_derived( ctx );
 480
 481    /* Do all needed clipping here, so that we can forget about it later */
 482    if (_mesa_clip_readpixels(ctx, &x, &y, &width, &height, &clippedPacking)) {
 483
 484       pixels = _mesa_map_pbo_dest(ctx, &clippedPacking, pixels);
 485
 486       if (pixels) {
 487          switch (format) {
 488          case GL_STENCIL_INDEX:
 489             read_stencil_pixels(ctx, x, y, width, height, type, pixels,
 490                                 &clippedPacking);
 491             break;
 492          case GL_DEPTH_COMPONENT:
 493             read_depth_pixels(ctx, x, y, width, height, type, pixels,
 494                               &clippedPacking);
 495             break;
 496          case GL_DEPTH_STENCIL_EXT:
 497             read_depth_stencil_pixels(ctx, x, y, width, height, type, pixels,
 498                                       &clippedPacking);
 499             break;
 500          default:
 501             /* all other formats should be color formats */
 502             read_rgba_pixels(ctx, x, y, width, height, format, type, pixels,
 503                              &clippedPacking);
 504          }
 505
 506          _mesa_unmap_pbo_dest(ctx, &clippedPacking);
 507       }
 508    }
 509
 510    swrast_render_finish(ctx);
 511 }