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/bufferobj.h"
  28 #include "main/colormac.h"
  29 #include "main/feedback.h"
  30 #include "main/formats.h"
  31 #include "main/image.h"
  32 #include "main/imports.h"
  33 #include "main/macros.h"
  34 #include "main/pack.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 || rb->_BaseFormat == GL_RGB ||
 195           rb->_BaseFormat == GL_ALPHA);
 196
 197    /* clipping should have already been done */
 198    ASSERT(x + width <= (GLint) rb->Width);
 199    ASSERT(y + height <= (GLint) rb->Height);
 200
 201    /* check for things we can't handle here */
 202    if (transferOps ||
 203        packing->SwapBytes ||
 204        packing->LsbFirst) {
 205       return GL_FALSE;
 206    }
 207
 208    if (format == GL_RGBA && rb->DataType == type) {
 209       const GLint dstStride = _mesa_image_row_stride(packing, width,
 210                                                      format, type);
 211       GLubyte *dest
 212          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 213                                              format, type, 0, 0);
 214       GLint row;
 215       ASSERT(rb->GetRow);
 216       for (row = 0; row < height; row++) {
 217          rb->GetRow(ctx, rb, width, x, y + row, dest);
 218          dest += dstStride;
 219       }
 220       return GL_TRUE;
 221    }
 222
 223    if (format == GL_RGB &&
 224        rb->DataType == GL_UNSIGNED_BYTE &&
 225        type == GL_UNSIGNED_BYTE) {
 226       const GLint dstStride = _mesa_image_row_stride(packing, width,
 227                                                      format, type);
 228       GLubyte *dest
 229          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 230                                              format, type, 0, 0);
 231       GLint row;
 232       ASSERT(rb->GetRow);
 233       for (row = 0; row < height; row++) {
 234          GLubyte tempRow[MAX_WIDTH][4];
 235          GLint col;
 236          rb->GetRow(ctx, rb, width, x, y + row, tempRow);
 237          /* convert RGBA to RGB */
 238          for (col = 0; col < width; col++) {
 239             dest[col * 3 + 0] = tempRow[col][0];
 240             dest[col * 3 + 1] = tempRow[col][1];
 241             dest[col * 3 + 2] = tempRow[col][2];
 242          }
 243          dest += dstStride;
 244       }
 245       return GL_TRUE;
 246    }
 247
 248    /* not handled */
 249    return GL_FALSE;
 250 }
 251
 252
 253 /**
 254  * When we're using a low-precision color buffer (like 16-bit 5/6/5)
 255  * we have to adjust our color values a bit to pass conformance.
 256  * The problem is when a 5 or 6-bit color value is converted to an 8-bit
 257  * value and then a floating point value, the floating point values don't
 258  * increment uniformly as the 5 or 6-bit value is incremented.
 259  *
 260  * This function adjusts floating point values to compensate.
 261  */
 262 static void
 263 adjust_colors(const struct gl_framebuffer *fb, GLuint n, GLfloat rgba[][4])
 264 {
 265    const GLuint rShift = 8 - fb->Visual.redBits;
 266    const GLuint gShift = 8 - fb->Visual.greenBits;
 267    const GLuint bShift = 8 - fb->Visual.blueBits;
 268    GLfloat rScale = 1.0F / (GLfloat) ((1 << fb->Visual.redBits  ) - 1);
 269    GLfloat gScale = 1.0F / (GLfloat) ((1 << fb->Visual.greenBits) - 1);
 270    GLfloat bScale = 1.0F / (GLfloat) ((1 << fb->Visual.blueBits ) - 1);
 271    GLuint i;
 272
 273    if (fb->Visual.redBits == 0)
 274       rScale = 0;
 275    if (fb->Visual.greenBits == 0)
 276       gScale = 0;
 277    if (fb->Visual.blueBits == 0)
 278       bScale = 0;
 279
 280    for (i = 0; i < n; i++) {
 281       GLint r, g, b;
 282       /* convert float back to ubyte */
 283       CLAMPED_FLOAT_TO_UBYTE(r, rgba[i][RCOMP]);
 284       CLAMPED_FLOAT_TO_UBYTE(g, rgba[i][GCOMP]);
 285       CLAMPED_FLOAT_TO_UBYTE(b, rgba[i][BCOMP]);
 286       /* using only the N most significant bits of the ubyte value, convert to
 287        * float in [0,1].
 288        */
 289       rgba[i][RCOMP] = (GLfloat) (r >> rShift) * rScale;
 290       rgba[i][GCOMP] = (GLfloat) (g >> gShift) * gScale;
 291       rgba[i][BCOMP] = (GLfloat) (b >> bShift) * bScale;
 292    }
 293 }
 294
 295
 296
 297 /*
 298  * Read R, G, B, A, RGB, L, or LA pixels.
 299  */
 300 static void
 301 read_rgba_pixels( struct gl_context *ctx,
 302                   GLint x, GLint y,
 303                   GLsizei width, GLsizei height,
 304                   GLenum format, GLenum type, GLvoid *pixels,
 305                   const struct gl_pixelstore_attrib *packing )
 306 {
 307    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 308    GLbitfield transferOps = ctx->_ImageTransferState;
 309    struct gl_framebuffer *fb = ctx->ReadBuffer;
 310    struct gl_renderbuffer *rb = fb->_ColorReadBuffer;
 311
 312    if (!rb)
 313       return;
 314
 315    if (type == GL_FLOAT && ((ctx->Color.ClampReadColor == GL_TRUE) ||
 316                             (ctx->Color.ClampReadColor == GL_FIXED_ONLY_ARB &&
 317                              rb->DataType != GL_FLOAT)))
 318       transferOps |= IMAGE_CLAMP_BIT;
 319
 320    /* Try optimized path first */
 321    if (fast_read_rgba_pixels(ctx, x, y, width, height,
 322                              format, type, pixels, packing, transferOps)) {
 323       return; /* done! */
 324    }
 325
 326    /* width should never be > MAX_WIDTH since we did clipping earlier */
 327    ASSERT(width <= MAX_WIDTH);
 328
 329    do {
 330       const GLint dstStride
 331          = _mesa_image_row_stride(packing, width, format, type);
 332       GLfloat (*rgba)[4] = swrast->SpanArrays->attribs[FRAG_ATTRIB_COL0];
 333       GLint row;
 334       GLubyte *dst
 335          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 336                                              format, type, 0, 0);
 337
 338       for (row = 0; row < height; row++, y++) {
 339
 340          /* Get float rgba pixels */
 341          _swrast_read_rgba_span(ctx, rb, width, x, y, GL_FLOAT, rgba);
 342
 343          /* apply fudge factor for shallow color buffers */
 344          if (fb->Visual.redBits < 8 ||
 345              fb->Visual.greenBits < 8 ||
 346              fb->Visual.blueBits < 8) {
 347             adjust_colors(fb, width, rgba);
 348          }
 349
 350          /* pack the row of RGBA pixels into user's buffer */
 351          _mesa_pack_rgba_span_float(ctx, width, rgba, format, type, dst,
 352                                     packing, transferOps);
 353
 354          dst += dstStride;
 355       }
 356    } while (0);
 357 }
 358
 359
 360 /**
 361  * Read combined depth/stencil values.
 362  * We'll have already done error checking to be sure the expected
 363  * depth and stencil buffers really exist.
 364  */
 365 static void
 366 read_depth_stencil_pixels(struct gl_context *ctx,
 367                           GLint x, GLint y,
 368                           GLsizei width, GLsizei height,
 369                           GLenum type, GLvoid *pixels,
 370                           const struct gl_pixelstore_attrib *packing )
 371 {
 372    const GLboolean scaleOrBias
 373       = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
 374    const GLboolean stencilTransfer = ctx->Pixel.IndexShift
 375       || ctx->Pixel.IndexOffset || ctx->Pixel.MapStencilFlag;
 376    struct gl_renderbuffer *depthRb, *stencilRb;
 377
 378    depthRb = ctx->ReadBuffer->_DepthBuffer;
 379    stencilRb = ctx->ReadBuffer->_StencilBuffer;
 380
 381    if (!depthRb || !stencilRb)
 382       return;
 383
 384    depthRb = ctx->ReadBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
 385    stencilRb = ctx->ReadBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
 386
 387    if (depthRb->_BaseFormat == GL_DEPTH_STENCIL_EXT &&
 388        stencilRb->_BaseFormat == GL_DEPTH_STENCIL_EXT &&
 389        depthRb == stencilRb &&
 390        !scaleOrBias &&
 391        !stencilTransfer) {
 392       /* This is the ideal case.
 393        * Reading GL_DEPTH_STENCIL pixels from combined depth/stencil buffer.
 394        * Plus, no pixel transfer ops to worry about!
 395        */
 396       GLint i;
 397       GLint dstStride = _mesa_image_row_stride(packing, width,
 398                                                GL_DEPTH_STENCIL_EXT, type);
 399       GLubyte *dst = (GLubyte *) _mesa_image_address2d(packing, pixels,
 400                                                        width, height,
 401                                                        GL_DEPTH_STENCIL_EXT,
 402                                                        type, 0, 0);
 403       for (i = 0; i < height; i++) {
 404          depthRb->GetRow(ctx, depthRb, width, x, y + i, dst);
 405          dst += dstStride;
 406       }
 407    }
 408    else {
 409       /* Reading GL_DEPTH_STENCIL pixels from separate depth/stencil buffers,
 410        * or we need pixel transfer.
 411        */
 412       GLint i;
 413       depthRb = ctx->ReadBuffer->_DepthBuffer;
 414       stencilRb = ctx->ReadBuffer->_StencilBuffer;
 415
 416       for (i = 0; i < height; i++) {
 417          GLstencil stencilVals[MAX_WIDTH];
 418
 419          GLuint *depthStencilDst = (GLuint *)
 420             _mesa_image_address2d(packing, pixels, width, height,
 421                                   GL_DEPTH_STENCIL_EXT, type, i, 0);
 422
 423          _swrast_read_stencil_span(ctx, stencilRb, width,
 424                                    x, y + i, stencilVals);
 425
 426          if (!scaleOrBias && !stencilTransfer
 427              && ctx->ReadBuffer->Visual.depthBits == 24) {
 428             /* ideal case */
 429             GLuint zVals[MAX_WIDTH]; /* 24-bit values! */
 430             GLint j;
 431             ASSERT(depthRb->DataType == GL_UNSIGNED_INT);
 432             /* note, we've already been clipped */
 433             depthRb->GetRow(ctx, depthRb, width, x, y + i, zVals);
 434             for (j = 0; j < width; j++) {
 435                depthStencilDst[j] = (zVals[j] << 8) | (stencilVals[j] & 0xff);
 436             }
 437          }
 438          else {
 439             /* general case */
 440             GLfloat depthVals[MAX_WIDTH];
 441             _swrast_read_depth_span_float(ctx, depthRb, width, x, y + i,
 442                                           depthVals);
 443             _mesa_pack_depth_stencil_span(ctx, width, depthStencilDst,
 444                                           depthVals, stencilVals, packing);
 445          }
 446       }
 447    }
 448 }
 449
 450
 451
 452 /**
 453  * Software fallback routine for ctx->Driver.ReadPixels().
 454  * By time we get here, all error checking will have been done.
 455  */
 456 void
 457 _swrast_ReadPixels( struct gl_context *ctx,
 458                     GLint x, GLint y, GLsizei width, GLsizei height,
 459                     GLenum format, GLenum type,
 460                     const struct gl_pixelstore_attrib *packing,
 461                     GLvoid *pixels )
 462 {
 463    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 464    struct gl_pixelstore_attrib clippedPacking = *packing;
 465
 466    if (ctx->NewState)
 467       _mesa_update_state(ctx);
 468
 469    /* Need to do swrast_render_start() before clipping or anything else
 470     * since this is where a driver may grab the hw lock and get an updated
 471     * window size.
 472     */
 473    swrast_render_start(ctx);
 474
 475    if (swrast->NewState)
 476       _swrast_validate_derived( ctx );
 477
 478    /* Do all needed clipping here, so that we can forget about it later */
 479    if (!_mesa_clip_readpixels(ctx, &x, &y, &width, &height, &clippedPacking)) {
 480       /* The ReadPixels region is totally outside the window bounds */
 481       swrast_render_finish(ctx);
 482       return;
 483    }
 484
 485    pixels = _mesa_map_pbo_dest(ctx, &clippedPacking, pixels);
 486    if (!pixels)
 487       return;
 488
 489    switch (format) {
 490       case GL_STENCIL_INDEX:
 491          read_stencil_pixels(ctx, x, y, width, height, type, pixels,
 492                              &clippedPacking);
 493          break;
 494       case GL_DEPTH_COMPONENT:
 495          read_depth_pixels(ctx, x, y, width, height, type, pixels,
 496                            &clippedPacking);
 497          break;
 498       case GL_RED:
 499       case GL_GREEN:
 500       case GL_BLUE:
 501       case GL_ALPHA:
 502       case GL_RGB:
 503       case GL_LUMINANCE:
 504       case GL_LUMINANCE_ALPHA:
 505       case GL_RGBA:
 506       case GL_BGR:
 507       case GL_BGRA:
 508       case GL_ABGR_EXT:
 509          read_rgba_pixels(ctx, x, y, width, height,
 510                           format, type, pixels, &clippedPacking);
 511          break;
 512       case GL_DEPTH_STENCIL_EXT:
 513          read_depth_stencil_pixels(ctx, x, y, width, height,
 514                                    type, pixels, &clippedPacking);
 515          break;
 516       default:
 517          _mesa_problem(ctx, "unexpected format 0x%x in _swrast_ReadPixels", format);
 518          /* don't return yet, clean-up */
 519    }
 520
 521    swrast_render_finish(ctx);
 522
 523    _mesa_unmap_pbo_dest(ctx, &clippedPacking);
 524 }