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/macros.h"
  33 #include "main/imports.h"
  34 #include "main/state.h"
  35
  36 #include "s_context.h"
  37 #include "s_depth.h"
  38 #include "s_span.h"
  39 #include "s_stencil.h"
  40
  41
  42 /**
  43  * Read pixels for format=GL_DEPTH_COMPONENT.
  44  */
  45 static void
  46 read_depth_pixels( struct gl_context *ctx,
  47                    GLint x, GLint y,
  48                    GLsizei width, GLsizei height,
  49                    GLenum type, GLvoid *pixels,
  50                    const struct gl_pixelstore_attrib *packing )
  51 {
  52    struct gl_framebuffer *fb = ctx->ReadBuffer;
  53    struct gl_renderbuffer *rb = fb->_DepthBuffer;
  54    const GLboolean biasOrScale
  55       = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
  56
  57    if (!rb)
  58       return;
  59
  60    /* clipping should have been done already */
  61    ASSERT(x >= 0);
  62    ASSERT(y >= 0);
  63    ASSERT(x + width <= (GLint) rb->Width);
  64    ASSERT(y + height <= (GLint) rb->Height);
  65    /* width should never be > MAX_WIDTH since we did clipping earlier */
  66    ASSERT(width <= MAX_WIDTH);
  67
  68    if (type == GL_UNSIGNED_SHORT && fb->Visual.depthBits == 16
  69        && !biasOrScale && !packing->SwapBytes) {
  70       /* Special case: directly read 16-bit unsigned depth values. */
  71       GLint j;
  72       ASSERT(rb->Format == MESA_FORMAT_Z16);
  73       ASSERT(rb->DataType == GL_UNSIGNED_SHORT);
  74       for (j = 0; j < height; j++, y++) {
  75          void *dest =_mesa_image_address2d(packing, pixels, width, height,
  76                                            GL_DEPTH_COMPONENT, type, j, 0);
  77          rb->GetRow(ctx, rb, width, x, y, dest);
  78       }
  79    }
  80    else if (type == GL_UNSIGNED_INT && fb->Visual.depthBits == 24
  81             && !biasOrScale && !packing->SwapBytes) {
  82       /* Special case: directly read 24-bit unsigned depth values. */
  83       GLint j;
  84       ASSERT(rb->Format == MESA_FORMAT_X8_Z24 ||
  85              rb->Format == MESA_FORMAT_S8_Z24 ||
  86              rb->Format == MESA_FORMAT_Z24_X8 ||
  87              rb->Format == MESA_FORMAT_Z24_S8);
  88       ASSERT(rb->DataType == GL_UNSIGNED_INT ||
  89              rb->DataType == GL_UNSIGNED_INT_24_8);
  90       for (j = 0; j < height; j++, y++) {
  91          GLuint *dest = (GLuint *)
  92             _mesa_image_address2d(packing, pixels, width, height,
  93                                   GL_DEPTH_COMPONENT, type, j, 0);
  94          GLint k;
  95          rb->GetRow(ctx, rb, width, x, y, dest);
  96          /* convert range from 24-bit to 32-bit */
  97          if (rb->Format == MESA_FORMAT_X8_Z24 ||
  98              rb->Format == MESA_FORMAT_S8_Z24) {
  99             for (k = 0; k < width; k++) {
 100                /* Note: put MSByte of 24-bit value into LSByte */
 101                dest[k] = (dest[k] << 8) | ((dest[k] >> 16) & 0xff);
 102             }
 103          }
 104          else {
 105             for (k = 0; k < width; k++) {
 106                /* Note: fill in LSByte by replication */
 107                dest[k] = dest[k] | ((dest[k] >> 8) & 0xff);
 108             }
 109          }
 110       }
 111    }
 112    else if (type == GL_UNSIGNED_INT && fb->Visual.depthBits == 32
 113             && !biasOrScale && !packing->SwapBytes) {
 114       /* Special case: directly read 32-bit unsigned depth values. */
 115       GLint j;
 116       ASSERT(rb->Format == MESA_FORMAT_Z32);
 117       ASSERT(rb->DataType == GL_UNSIGNED_INT);
 118       for (j = 0; j < height; j++, y++) {
 119          void *dest = _mesa_image_address2d(packing, pixels, width, height,
 120                                             GL_DEPTH_COMPONENT, type, j, 0);
 121          rb->GetRow(ctx, rb, width, x, y, dest);
 122       }
 123    }
 124    else {
 125       /* General case (slower) */
 126       GLint j;
 127       for (j = 0; j < height; j++, y++) {
 128          GLfloat depthValues[MAX_WIDTH];
 129          GLvoid *dest = _mesa_image_address2d(packing, pixels, width, height,
 130                                               GL_DEPTH_COMPONENT, type, j, 0);
 131          _swrast_read_depth_span_float(ctx, rb, width, x, y, depthValues);
 132          _mesa_pack_depth_span(ctx, width, dest, type, depthValues, packing);
 133       }
 134    }
 135 }
 136
 137
 138 /**
 139  * Read pixels for format=GL_STENCIL_INDEX.
 140  */
 141 static void
 142 read_stencil_pixels( struct gl_context *ctx,
 143                      GLint x, GLint y,
 144                      GLsizei width, GLsizei height,
 145                      GLenum type, GLvoid *pixels,
 146                      const struct gl_pixelstore_attrib *packing )
 147 {
 148    struct gl_framebuffer *fb = ctx->ReadBuffer;
 149    struct gl_renderbuffer *rb = fb->_StencilBuffer;
 150    GLint j;
 151
 152    if (!rb)
 153       return;
 154
 155    /* width should never be > MAX_WIDTH since we did clipping earlier */
 156    ASSERT(width <= MAX_WIDTH);
 157
 158    /* process image row by row */
 159    for (j=0;j<height;j++,y++) {
 160       GLvoid *dest;
 161       GLstencil stencil[MAX_WIDTH];
 162
 163       _swrast_read_stencil_span(ctx, rb, width, x, y, stencil);
 164
 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 }
 171
 172
 173
 174 /**
 175  * Optimized glReadPixels for particular pixel formats when pixel
 176  * scaling, biasing, mapping, etc. are disabled.
 177  * \return GL_TRUE if success, GL_FALSE if unable to do the readpixels
 178  */
 179 static GLboolean
 180 fast_read_rgba_pixels( struct gl_context *ctx,
 181                        GLint x, GLint y,
 182                        GLsizei width, GLsizei height,
 183                        GLenum format, GLenum type,
 184                        GLvoid *pixels,
 185                        const struct gl_pixelstore_attrib *packing,
 186                        GLbitfield transferOps)
 187 {
 188    struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
 189
 190    if (!rb)
 191       return GL_FALSE;
 192
 193    ASSERT(rb->_BaseFormat == GL_RGBA || rb->_BaseFormat == GL_RGB ||
 194           rb->_BaseFormat == GL_ALPHA);
 195
 196    /* clipping should have already been done */
 197    ASSERT(x + width <= (GLint) rb->Width);
 198    ASSERT(y + height <= (GLint) rb->Height);
 199
 200    /* check for things we can't handle here */
 201    if (transferOps ||
 202        packing->SwapBytes ||
 203        packing->LsbFirst) {
 204       return GL_FALSE;
 205    }
 206
 207    if (format == GL_RGBA && rb->DataType == type) {
 208       const GLint dstStride = _mesa_image_row_stride(packing, width,
 209                                                      format, type);
 210       GLubyte *dest
 211          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 212                                              format, type, 0, 0);
 213       GLint row;
 214       ASSERT(rb->GetRow);
 215       for (row = 0; row < height; row++) {
 216          rb->GetRow(ctx, rb, width, x, y + row, dest);
 217          dest += dstStride;
 218       }
 219       return GL_TRUE;
 220    }
 221
 222    if (format == GL_RGB &&
 223        rb->DataType == GL_UNSIGNED_BYTE &&
 224        type == GL_UNSIGNED_BYTE) {
 225       const GLint dstStride = _mesa_image_row_stride(packing, width,
 226                                                      format, type);
 227       GLubyte *dest
 228          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 229                                              format, type, 0, 0);
 230       GLint row;
 231       ASSERT(rb->GetRow);
 232       for (row = 0; row < height; row++) {
 233          GLubyte tempRow[MAX_WIDTH][4];
 234          GLint col;
 235          rb->GetRow(ctx, rb, width, x, y + row, tempRow);
 236          /* convert RGBA to RGB */
 237          for (col = 0; col < width; col++) {
 238             dest[col * 3 + 0] = tempRow[col][0];
 239             dest[col * 3 + 1] = tempRow[col][1];
 240             dest[col * 3 + 2] = tempRow[col][2];
 241          }
 242          dest += dstStride;
 243       }
 244       return GL_TRUE;
 245    }
 246
 247    /* not handled */
 248    return GL_FALSE;
 249 }
 250
 251
 252 /**
 253  * When we're using a low-precision color buffer (like 16-bit 5/6/5)
 254  * we have to adjust our color values a bit to pass conformance.
 255  * The problem is when a 5 or 6-bit color value is converted to an 8-bit
 256  * value and then a floating point value, the floating point values don't
 257  * increment uniformly as the 5 or 6-bit value is incremented.
 258  *
 259  * This function adjusts floating point values to compensate.
 260  */
 261 static void
 262 adjust_colors(const struct gl_framebuffer *fb, GLuint n, GLfloat rgba[][4])
 263 {
 264    const GLuint rShift = 8 - fb->Visual.redBits;
 265    const GLuint gShift = 8 - fb->Visual.greenBits;
 266    const GLuint bShift = 8 - fb->Visual.blueBits;
 267    GLfloat rScale = 1.0F / (GLfloat) ((1 << fb->Visual.redBits  ) - 1);
 268    GLfloat gScale = 1.0F / (GLfloat) ((1 << fb->Visual.greenBits) - 1);
 269    GLfloat bScale = 1.0F / (GLfloat) ((1 << fb->Visual.blueBits ) - 1);
 270    GLuint i;
 271
 272    if (fb->Visual.redBits == 0)
 273       rScale = 0;
 274    if (fb->Visual.greenBits == 0)
 275       gScale = 0;
 276    if (fb->Visual.blueBits == 0)
 277       bScale = 0;
 278
 279    for (i = 0; i < n; i++) {
 280       GLint r, g, b;
 281       /* convert float back to ubyte */
 282       CLAMPED_FLOAT_TO_UBYTE(r, rgba[i][RCOMP]);
 283       CLAMPED_FLOAT_TO_UBYTE(g, rgba[i][GCOMP]);
 284       CLAMPED_FLOAT_TO_UBYTE(b, rgba[i][BCOMP]);
 285       /* using only the N most significant bits of the ubyte value, convert to
 286        * float in [0,1].
 287        */
 288       rgba[i][RCOMP] = (GLfloat) (r >> rShift) * rScale;
 289       rgba[i][GCOMP] = (GLfloat) (g >> gShift) * gScale;
 290       rgba[i][BCOMP] = (GLfloat) (b >> bShift) * bScale;
 291    }
 292 }
 293
 294
 295
 296 /*
 297  * Read R, G, B, A, RGB, L, or LA pixels.
 298  */
 299 static void
 300 read_rgba_pixels( struct gl_context *ctx,
 301                   GLint x, GLint y,
 302                   GLsizei width, GLsizei height,
 303                   GLenum format, GLenum type, GLvoid *pixels,
 304                   const struct gl_pixelstore_attrib *packing )
 305 {
 306    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 307    GLbitfield transferOps = ctx->_ImageTransferState;
 308    struct gl_framebuffer *fb = ctx->ReadBuffer;
 309    struct gl_renderbuffer *rb = fb->_ColorReadBuffer;
 310
 311    if (!rb)
 312       return;
 313
 314    if (type == GL_FLOAT && ((ctx->Color.ClampReadColor == GL_TRUE) ||
 315                             (ctx->Color.ClampReadColor == GL_FIXED_ONLY_ARB &&
 316                              rb->DataType != GL_FLOAT)))
 317       transferOps |= IMAGE_CLAMP_BIT;
 318
 319    /* Try optimized path first */
 320    if (fast_read_rgba_pixels(ctx, x, y, width, height,
 321                              format, type, pixels, packing, transferOps)) {
 322       return; /* done! */
 323    }
 324
 325    /* width should never be > MAX_WIDTH since we did clipping earlier */
 326    ASSERT(width <= MAX_WIDTH);
 327
 328    do {
 329       const GLint dstStride
 330          = _mesa_image_row_stride(packing, width, format, type);
 331       GLfloat (*rgba)[4] = swrast->SpanArrays->attribs[FRAG_ATTRIB_COL0];
 332       GLint row;
 333       GLubyte *dst
 334          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 335                                              format, type, 0, 0);
 336
 337       for (row = 0; row < height; row++, y++) {
 338
 339          /* Get float rgba pixels */
 340          _swrast_read_rgba_span(ctx, rb, width, x, y, GL_FLOAT, rgba);
 341
 342          /* apply fudge factor for shallow color buffers */
 343          if (fb->Visual.redBits < 8 ||
 344              fb->Visual.greenBits < 8 ||
 345              fb->Visual.blueBits < 8) {
 346             adjust_colors(fb, width, rgba);
 347          }
 348
 349          /* pack the row of RGBA pixels into user's buffer */
 350          _mesa_pack_rgba_span_float(ctx, width, rgba, format, type, dst,
 351                                     packing, transferOps);
 352
 353          dst += dstStride;
 354       }
 355    } while (0);
 356 }
 357
 358
 359 /**
 360  * Read combined depth/stencil values.
 361  * We'll have already done error checking to be sure the expected
 362  * depth and stencil buffers really exist.
 363  */
 364 static void
 365 read_depth_stencil_pixels(struct gl_context *ctx,
 366                           GLint x, GLint y,
 367                           GLsizei width, GLsizei height,
 368                           GLenum type, GLvoid *pixels,
 369                           const struct gl_pixelstore_attrib *packing )
 370 {
 371    const GLboolean scaleOrBias
 372       = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
 373    const GLboolean stencilTransfer = ctx->Pixel.IndexShift
 374       || ctx->Pixel.IndexOffset || ctx->Pixel.MapStencilFlag;
 375    struct gl_renderbuffer *depthRb, *stencilRb;
 376
 377    depthRb = ctx->ReadBuffer->_DepthBuffer;
 378    stencilRb = ctx->ReadBuffer->_StencilBuffer;
 379
 380    if (!depthRb || !stencilRb)
 381       return;
 382
 383    depthRb = ctx->ReadBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
 384    stencilRb = ctx->ReadBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
 385
 386    if (depthRb->_BaseFormat == GL_DEPTH_STENCIL_EXT &&
 387        stencilRb->_BaseFormat == GL_DEPTH_STENCIL_EXT &&
 388        depthRb == stencilRb &&
 389        !scaleOrBias &&
 390        !stencilTransfer) {
 391       /* This is the ideal case.
 392        * Reading GL_DEPTH_STENCIL pixels from combined depth/stencil buffer.
 393        * Plus, no pixel transfer ops to worry about!
 394        */
 395       GLint i;
 396       GLint dstStride = _mesa_image_row_stride(packing, width,
 397                                                GL_DEPTH_STENCIL_EXT, type);
 398       GLubyte *dst = (GLubyte *) _mesa_image_address2d(packing, pixels,
 399                                                        width, height,
 400                                                        GL_DEPTH_STENCIL_EXT,
 401                                                        type, 0, 0);
 402       for (i = 0; i < height; i++) {
 403          depthRb->GetRow(ctx, depthRb, width, x, y + i, dst);
 404          dst += dstStride;
 405       }
 406    }
 407    else {
 408       /* Reading GL_DEPTH_STENCIL pixels from separate depth/stencil buffers,
 409        * or we need pixel transfer.
 410        */
 411       GLint i;
 412       depthRb = ctx->ReadBuffer->_DepthBuffer;
 413       stencilRb = ctx->ReadBuffer->_StencilBuffer;
 414
 415       for (i = 0; i < height; i++) {
 416          GLstencil stencilVals[MAX_WIDTH];
 417
 418          GLuint *depthStencilDst = (GLuint *)
 419             _mesa_image_address2d(packing, pixels, width, height,
 420                                   GL_DEPTH_STENCIL_EXT, type, i, 0);
 421
 422          _swrast_read_stencil_span(ctx, stencilRb, width,
 423                                    x, y + i, stencilVals);
 424
 425          if (!scaleOrBias && !stencilTransfer
 426              && ctx->ReadBuffer->Visual.depthBits == 24) {
 427             /* ideal case */
 428             GLuint zVals[MAX_WIDTH]; /* 24-bit values! */
 429             GLint j;
 430             ASSERT(depthRb->DataType == GL_UNSIGNED_INT);
 431             /* note, we've already been clipped */
 432             depthRb->GetRow(ctx, depthRb, width, x, y + i, zVals);
 433             for (j = 0; j < width; j++) {
 434                depthStencilDst[j] = (zVals[j] << 8) | (stencilVals[j] & 0xff);
 435             }
 436          }
 437          else {
 438             /* general case */
 439             GLfloat depthVals[MAX_WIDTH];
 440             _swrast_read_depth_span_float(ctx, depthRb, width, x, y + i,
 441                                           depthVals);
 442             _mesa_pack_depth_stencil_span(ctx, width, depthStencilDst,
 443                                           depthVals, stencilVals, packing);
 444          }
 445       }
 446    }
 447 }
 448
 449
 450
 451 /**
 452  * Software fallback routine for ctx->Driver.ReadPixels().
 453  * By time we get here, all error checking will have been done.
 454  */
 455 void
 456 _swrast_ReadPixels( struct gl_context *ctx,
 457                     GLint x, GLint y, GLsizei width, GLsizei height,
 458                     GLenum format, GLenum type,
 459                     const struct gl_pixelstore_attrib *packing,
 460                     GLvoid *pixels )
 461 {
 462    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 463    struct gl_pixelstore_attrib clippedPacking = *packing;
 464
 465    if (ctx->NewState)
 466       _mesa_update_state(ctx);
 467
 468    /* Need to do swrast_render_start() before clipping or anything else
 469     * since this is where a driver may grab the hw lock and get an updated
 470     * window size.
 471     */
 472    swrast_render_start(ctx);
 473
 474    if (swrast->NewState)
 475       _swrast_validate_derived( ctx );
 476
 477    /* Do all needed clipping here, so that we can forget about it later */
 478    if (!_mesa_clip_readpixels(ctx, &x, &y, &width, &height, &clippedPacking)) {
 479       /* The ReadPixels region is totally outside the window bounds */
 480       swrast_render_finish(ctx);
 481       return;
 482    }
 483
 484    pixels = _mesa_map_pbo_dest(ctx, &clippedPacking, pixels);
 485    if (!pixels)
 486       return;
 487
 488    switch (format) {
 489       case GL_STENCIL_INDEX:
 490          read_stencil_pixels(ctx, x, y, width, height, type, pixels,
 491                              &clippedPacking);
 492          break;
 493       case GL_DEPTH_COMPONENT:
 494          read_depth_pixels(ctx, x, y, width, height, type, pixels,
 495                            &clippedPacking);
 496          break;
 497       case GL_RED:
 498       case GL_GREEN:
 499       case GL_BLUE:
 500       case GL_ALPHA:
 501       case GL_RGB:
 502       case GL_LUMINANCE:
 503       case GL_LUMINANCE_ALPHA:
 504       case GL_RGBA:
 505       case GL_BGR:
 506       case GL_BGRA:
 507       case GL_ABGR_EXT:
 508          read_rgba_pixels(ctx, x, y, width, height,
 509                           format, type, pixels, &clippedPacking);
 510          break;
 511       case GL_DEPTH_STENCIL_EXT:
 512          read_depth_stencil_pixels(ctx, x, y, width, height,
 513                                    type, pixels, &clippedPacking);
 514          break;
 515       default:
 516          _mesa_problem(ctx, "unexpected format in _swrast_ReadPixels");
 517          /* don't return yet, clean-up */
 518    }
 519
 520    swrast_render_finish(ctx);
 521
 522    _mesa_unmap_pbo_dest(ctx, &clippedPacking);
 523 }