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