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->_StencilBuffer;
 146    GLint j;
 147
 148    if (!rb)
 149       return;
 150
 151    /* width should never be > MAX_WIDTH since we did clipping earlier */
 152    ASSERT(width <= MAX_WIDTH);
 153
 154    /* process image row by row */
 155    for (j=0;j<height;j++,y++) {
 156       GLvoid *dest;
 157       GLstencil stencil[MAX_WIDTH];
 158
 159       _swrast_read_stencil_span(ctx, rb, width, x, y, stencil);
 160
 161       dest = _mesa_image_address2d(packing, pixels, width, height,
 162                                    GL_STENCIL_INDEX, type, j, 0);
 163
 164       _mesa_pack_stencil_span(ctx, width, type, dest, stencil, packing);
 165    }
 166 }
 167
 168
 169
 170 /**
 171  * Optimized glReadPixels for particular pixel formats when pixel
 172  * scaling, biasing, mapping, etc. are disabled.
 173  * \return GL_TRUE if success, GL_FALSE if unable to do the readpixels
 174  */
 175 static GLboolean
 176 fast_read_rgba_pixels( struct gl_context *ctx,
 177                        GLint x, GLint y,
 178                        GLsizei width, GLsizei height,
 179                        GLenum format, GLenum type,
 180                        GLvoid *pixels,
 181                        const struct gl_pixelstore_attrib *packing,
 182                        GLbitfield transferOps)
 183 {
 184    struct gl_renderbuffer *rb = ctx->ReadBuffer->_ColorReadBuffer;
 185
 186    if (!rb)
 187       return GL_FALSE;
 188
 189    ASSERT(rb->_BaseFormat == GL_RGBA ||
 190           rb->_BaseFormat == GL_RGB ||
 191           rb->_BaseFormat == GL_RG ||
 192           rb->_BaseFormat == GL_RED ||
 193           rb->_BaseFormat == GL_LUMINANCE ||
 194           rb->_BaseFormat == GL_INTENSITY ||
 195           rb->_BaseFormat == GL_LUMINANCE_ALPHA ||
 196           rb->_BaseFormat == GL_ALPHA);
 197
 198    /* clipping should have already been done */
 199    ASSERT(x + width <= (GLint) rb->Width);
 200    ASSERT(y + height <= (GLint) rb->Height);
 201
 202    /* check for things we can't handle here */
 203    if (transferOps ||
 204        packing->SwapBytes ||
 205        packing->LsbFirst) {
 206       return GL_FALSE;
 207    }
 208
 209    if (format == GL_RGBA && rb->DataType == type) {
 210       const GLint dstStride = _mesa_image_row_stride(packing, width,
 211                                                      format, type);
 212       GLubyte *dest
 213          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 214                                              format, type, 0, 0);
 215       GLint row;
 216       ASSERT(rb->GetRow);
 217       for (row = 0; row < height; row++) {
 218          rb->GetRow(ctx, rb, width, x, y + row, dest);
 219          dest += dstStride;
 220       }
 221       return GL_TRUE;
 222    }
 223
 224    if (format == GL_RGB &&
 225        rb->DataType == GL_UNSIGNED_BYTE &&
 226        type == GL_UNSIGNED_BYTE) {
 227       const GLint dstStride = _mesa_image_row_stride(packing, width,
 228                                                      format, type);
 229       GLubyte *dest
 230          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 231                                              format, type, 0, 0);
 232       GLint row;
 233       ASSERT(rb->GetRow);
 234       for (row = 0; row < height; row++) {
 235          GLubyte tempRow[MAX_WIDTH][4];
 236          GLint col;
 237          rb->GetRow(ctx, rb, width, x, y + row, tempRow);
 238          /* convert RGBA to RGB */
 239          for (col = 0; col < width; col++) {
 240             dest[col * 3 + 0] = tempRow[col][0];
 241             dest[col * 3 + 1] = tempRow[col][1];
 242             dest[col * 3 + 2] = tempRow[col][2];
 243          }
 244          dest += dstStride;
 245       }
 246       return GL_TRUE;
 247    }
 248
 249    /* not handled */
 250    return GL_FALSE;
 251 }
 252
 253
 254 /**
 255  * When we're using a low-precision color buffer (like 16-bit 5/6/5)
 256  * we have to adjust our color values a bit to pass conformance.
 257  * The problem is when a 5 or 6-bit color value is converted to an 8-bit
 258  * value and then a floating point value, the floating point values don't
 259  * increment uniformly as the 5 or 6-bit value is incremented.
 260  *
 261  * This function adjusts floating point values to compensate.
 262  */
 263 static void
 264 adjust_colors(const struct gl_framebuffer *fb, GLuint n, GLfloat rgba[][4])
 265 {
 266    const GLuint rShift = 8 - fb->Visual.redBits;
 267    const GLuint gShift = 8 - fb->Visual.greenBits;
 268    const GLuint bShift = 8 - fb->Visual.blueBits;
 269    GLfloat rScale = 1.0F / (GLfloat) ((1 << fb->Visual.redBits  ) - 1);
 270    GLfloat gScale = 1.0F / (GLfloat) ((1 << fb->Visual.greenBits) - 1);
 271    GLfloat bScale = 1.0F / (GLfloat) ((1 << fb->Visual.blueBits ) - 1);
 272    GLuint i;
 273
 274    if (fb->Visual.redBits == 0)
 275       rScale = 0;
 276    if (fb->Visual.greenBits == 0)
 277       gScale = 0;
 278    if (fb->Visual.blueBits == 0)
 279       bScale = 0;
 280
 281    for (i = 0; i < n; i++) {
 282       GLint r, g, b;
 283       /* convert float back to ubyte */
 284       CLAMPED_FLOAT_TO_UBYTE(r, rgba[i][RCOMP]);
 285       CLAMPED_FLOAT_TO_UBYTE(g, rgba[i][GCOMP]);
 286       CLAMPED_FLOAT_TO_UBYTE(b, rgba[i][BCOMP]);
 287       /* using only the N most significant bits of the ubyte value, convert to
 288        * float in [0,1].
 289        */
 290       rgba[i][RCOMP] = (GLfloat) (r >> rShift) * rScale;
 291       rgba[i][GCOMP] = (GLfloat) (g >> gShift) * gScale;
 292       rgba[i][BCOMP] = (GLfloat) (b >> bShift) * bScale;
 293    }
 294 }
 295
 296
 297
 298 /*
 299  * Read R, G, B, A, RGB, L, or LA pixels.
 300  */
 301 static void
 302 read_rgba_pixels( struct gl_context *ctx,
 303                   GLint x, GLint y,
 304                   GLsizei width, GLsizei height,
 305                   GLenum format, GLenum type, GLvoid *pixels,
 306                   const struct gl_pixelstore_attrib *packing )
 307 {
 308    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 309    GLbitfield transferOps = ctx->_ImageTransferState;
 310    struct gl_framebuffer *fb = ctx->ReadBuffer;
 311    struct gl_renderbuffer *rb = fb->_ColorReadBuffer;
 312
 313    if (!rb)
 314       return;
 315
 316    if ((ctx->Color._ClampReadColor == GL_TRUE || type != GL_FLOAT) &&
 317        !_mesa_is_integer_format(format)) {
 318       transferOps |= IMAGE_CLAMP_BIT;
 319    }
 320
 321    /* Try the optimized path first. */
 322    if (fast_read_rgba_pixels(ctx, x, y, width, height,
 323                              format, type, pixels, packing, transferOps)) {
 324       return; /* done! */
 325    }
 326
 327    /* width should never be > MAX_WIDTH since we did clipping earlier */
 328    ASSERT(width <= MAX_WIDTH);
 329
 330    {
 331       const GLint dstStride
 332          = _mesa_image_row_stride(packing, width, format, type);
 333       GLfloat (*rgba)[4] = swrast->SpanArrays->attribs[FRAG_ATTRIB_COL0];
 334       GLint row;
 335       GLubyte *dst
 336          = (GLubyte *) _mesa_image_address2d(packing, pixels, width, height,
 337                                              format, type, 0, 0);
 338
 339       for (row = 0; row < height; row++, y++) {
 340
 341          /* Get float rgba pixels */
 342          _swrast_read_rgba_span(ctx, rb, width, x, y, GL_FLOAT, rgba);
 343
 344          /* apply fudge factor for shallow color buffers */
 345          if ((fb->Visual.redBits < 8 && fb->Visual.redBits != 0) ||
 346              (fb->Visual.greenBits < 8 && fb->Visual.greenBits != 0) ||
 347              (fb->Visual.blueBits < 8 && fb->Visual.blueBits != 0)) {
 348             adjust_colors(fb, width, rgba);
 349          }
 350
 351          /* pack the row of RGBA pixels into user's buffer */
 352          _mesa_pack_rgba_span_float(ctx, width, rgba, format, type, dst,
 353                                     packing, transferOps);
 354
 355          dst += dstStride;
 356       }
 357    }
 358 }
 359
 360
 361 /**
 362  * Read combined depth/stencil values.
 363  * We'll have already done error checking to be sure the expected
 364  * depth and stencil buffers really exist.
 365  */
 366 static void
 367 read_depth_stencil_pixels(struct gl_context *ctx,
 368                           GLint x, GLint y,
 369                           GLsizei width, GLsizei height,
 370                           GLenum type, GLvoid *pixels,
 371                           const struct gl_pixelstore_attrib *packing )
 372 {
 373    const GLboolean scaleOrBias
 374       = ctx->Pixel.DepthScale != 1.0 || ctx->Pixel.DepthBias != 0.0;
 375    const GLboolean stencilTransfer = ctx->Pixel.IndexShift
 376       || ctx->Pixel.IndexOffset || ctx->Pixel.MapStencilFlag;
 377    struct gl_renderbuffer *depthRb, *stencilRb;
 378
 379    depthRb = ctx->ReadBuffer->_DepthBuffer;
 380    stencilRb = ctx->ReadBuffer->_StencilBuffer;
 381
 382    if (!depthRb || !stencilRb)
 383       return;
 384
 385    depthRb = ctx->ReadBuffer->Attachment[BUFFER_DEPTH].Renderbuffer;
 386    stencilRb = ctx->ReadBuffer->Attachment[BUFFER_STENCIL].Renderbuffer;
 387
 388    if (depthRb->_BaseFormat == GL_DEPTH_STENCIL_EXT &&
 389        depthRb->Format == MESA_FORMAT_Z24_S8 &&
 390        type == GL_UNSIGNED_INT_24_8 &&
 391        depthRb == stencilRb &&
 392        depthRb->GetRow &&  /* May be null if depthRb is a wrapper around
 393                             * separate depth and stencil buffers. */
 394        !scaleOrBias &&
 395        !stencilTransfer) {
 396       /* This is the ideal case.
 397        * Reading GL_DEPTH_STENCIL pixels from combined depth/stencil buffer.
 398        * Plus, no pixel transfer ops to worry about!
 399        */
 400       GLint i;
 401       GLint dstStride = _mesa_image_row_stride(packing, width,
 402                                                GL_DEPTH_STENCIL_EXT, type);
 403       GLubyte *dst = (GLubyte *) _mesa_image_address2d(packing, pixels,
 404                                                        width, height,
 405                                                        GL_DEPTH_STENCIL_EXT,
 406                                                        type, 0, 0);
 407       for (i = 0; i < height; i++) {
 408          depthRb->GetRow(ctx, depthRb, width, x, y + i, dst);
 409          dst += dstStride;
 410       }
 411    }
 412    else {
 413       /* Reading GL_DEPTH_STENCIL pixels from separate depth/stencil buffers,
 414        * or we need pixel transfer.
 415        */
 416       GLint i;
 417       depthRb = ctx->ReadBuffer->_DepthBuffer;
 418       stencilRb = ctx->ReadBuffer->_StencilBuffer;
 419
 420       for (i = 0; i < height; i++) {
 421          GLstencil stencilVals[MAX_WIDTH];
 422
 423          GLuint *depthStencilDst = (GLuint *)
 424             _mesa_image_address2d(packing, pixels, width, height,
 425                                   GL_DEPTH_STENCIL_EXT, type, i, 0);
 426
 427          _swrast_read_stencil_span(ctx, stencilRb, width,
 428                                    x, y + i, stencilVals);
 429
 430          if (!scaleOrBias && !stencilTransfer
 431              && ctx->ReadBuffer->Visual.depthBits == 24) {
 432             /* ideal case */
 433             GLuint zVals[MAX_WIDTH]; /* 24-bit values! */
 434             GLint j;
 435             ASSERT(depthRb->DataType == GL_UNSIGNED_INT);
 436             /* note, we've already been clipped */
 437             depthRb->GetRow(ctx, depthRb, width, x, y + i, zVals);
 438             for (j = 0; j < width; j++) {
 439                depthStencilDst[j] = (zVals[j] << 8) | (stencilVals[j] & 0xff);
 440             }
 441          }
 442          else {
 443             /* general case */
 444             GLfloat depthVals[MAX_WIDTH];
 445             _swrast_read_depth_span_float(ctx, depthRb, width, x, y + i,
 446                                           depthVals);
 447             _mesa_pack_depth_stencil_span(ctx, width, type, depthStencilDst,
 448                                           depthVals, stencilVals, packing);
 449          }
 450       }
 451    }
 452 }
 453
 454
 455
 456 /**
 457  * Software fallback routine for ctx->Driver.ReadPixels().
 458  * By time we get here, all error checking will have been done.
 459  */
 460 void
 461 _swrast_ReadPixels( struct gl_context *ctx,
 462                     GLint x, GLint y, GLsizei width, GLsizei height,
 463                     GLenum format, GLenum type,
 464                     const struct gl_pixelstore_attrib *packing,
 465                     GLvoid *pixels )
 466 {
 467    SWcontext *swrast = SWRAST_CONTEXT(ctx);
 468    struct gl_pixelstore_attrib clippedPacking = *packing;
 469
 470    if (ctx->NewState)
 471       _mesa_update_state(ctx);
 472
 473    /* Need to do swrast_render_start() before clipping or anything else
 474     * since this is where a driver may grab the hw lock and get an updated
 475     * window size.
 476     */
 477    swrast_render_start(ctx);
 478
 479    if (swrast->NewState)
 480       _swrast_validate_derived( ctx );
 481
 482    /* Do all needed clipping here, so that we can forget about it later */
 483    if (_mesa_clip_readpixels(ctx, &x, &y, &width, &height, &clippedPacking)) {
 484
 485       pixels = _mesa_map_pbo_dest(ctx, &clippedPacking, pixels);
 486
 487       if (pixels) {
 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_DEPTH_STENCIL_EXT:
 498             read_depth_stencil_pixels(ctx, x, y, width, height, type, pixels,
 499                                       &clippedPacking);
 500             break;
 501          default:
 502             /* all other formats should be color formats */
 503             read_rgba_pixels(ctx, x, y, width, height, format, type, pixels,
 504                              &clippedPacking);
 505          }
 506
 507          _mesa_unmap_pbo_dest(ctx, &clippedPacking);
 508       }
 509    }
 510
 511    swrast_render_finish(ctx);
 512 }