src/mesa/main/framebuffer.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  7.2
   4  *
   5  * Copyright (C) 1999-2008  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 /**
  27  * Functions for allocating/managing framebuffers and renderbuffers.
  28  * Also, routines for reading/writing renderbuffer data as ubytes,
  29  * ushorts, uints, etc.
  30  */
  31
  32
  33 #include "glheader.h"
  34 #include "imports.h"
  35 #include "buffers.h"
  36 #include "context.h"
  37 #include "depthstencil.h"
  38 #include "formats.h"
  39 #include "macros.h"
  40 #include "mtypes.h"
  41 #include "fbobject.h"
  42 #include "framebuffer.h"
  43 #include "renderbuffer.h"
  44 #include "texobj.h"
  45
  46
  47
  48 /**
  49  * Compute/set the _DepthMax field for the given framebuffer.
  50  * This value depends on the Z buffer resolution.
  51  */
  52 static void
  53 compute_depth_max(struct gl_framebuffer *fb)
  54 {
  55    if (fb->Visual.depthBits == 0) {
  56       /* Special case.  Even if we don't have a depth buffer we need
  57        * good values for DepthMax for Z vertex transformation purposes
  58        * and for per-fragment fog computation.
  59        */
  60       fb->_DepthMax = (1 << 16) - 1;
  61    }
  62    else if (fb->Visual.depthBits < 32) {
  63       fb->_DepthMax = (1 << fb->Visual.depthBits) - 1;
  64    }
  65    else {
  66       /* Special case since shift values greater than or equal to the
  67        * number of bits in the left hand expression's type are undefined.
  68        */
  69       fb->_DepthMax = 0xffffffff;
  70    }
  71    fb->_DepthMaxF = (GLfloat) fb->_DepthMax;
  72
  73    /* Minimum resolvable depth value, for polygon offset */
  74    fb->_MRD = (GLfloat)1.0 / fb->_DepthMaxF;
  75 }
  76
  77
  78 /**
  79  * Create and initialize a gl_framebuffer object.
  80  * This is intended for creating _window_system_ framebuffers, not generic
  81  * framebuffer objects ala GL_EXT_framebuffer_object.
  82  *
  83  * \sa _mesa_new_framebuffer
  84  */
  85 struct gl_framebuffer *
  86 _mesa_create_framebuffer(const GLvisual *visual)
  87 {
  88    struct gl_framebuffer *fb = CALLOC_STRUCT(gl_framebuffer);
  89    assert(visual);
  90    if (fb) {
  91       _mesa_initialize_window_framebuffer(fb, visual);
  92    }
  93    return fb;
  94 }
  95
  96
  97 /**
  98  * Allocate a new gl_framebuffer object.
  99  * This is the default function for ctx->Driver.NewFramebuffer().
 100  * This is for allocating user-created framebuffers, not window-system
 101  * framebuffers!
 102  * \sa _mesa_create_framebuffer
 103  */
 104 struct gl_framebuffer *
 105 _mesa_new_framebuffer(GLcontext *ctx, GLuint name)
 106 {
 107    struct gl_framebuffer *fb;
 108    (void) ctx;
 109    assert(name != 0);
 110    fb = CALLOC_STRUCT(gl_framebuffer);
 111    if (fb) {
 112       _mesa_initialize_user_framebuffer(fb, name);
 113    }
 114    return fb;
 115 }
 116
 117
 118 /**
 119  * Initialize a gl_framebuffer object.  Typically used to initialize
 120  * window system-created framebuffers, not user-created framebuffers.
 121  * \sa _mesa_initialize_user_framebuffer
 122  */
 123 void
 124 _mesa_initialize_window_framebuffer(struct gl_framebuffer *fb,
 125                                      const GLvisual *visual)
 126 {
 127    assert(fb);
 128    assert(visual);
 129
 130    memset(fb, 0, sizeof(struct gl_framebuffer));
 131
 132    _glthread_INIT_MUTEX(fb->Mutex);
 133
 134    fb->RefCount = 1;
 135
 136    /* save the visual */
 137    fb->Visual = *visual;
 138
 139    /* Init read/draw renderbuffer state */
 140    if (visual->doubleBufferMode) {
 141       fb->_NumColorDrawBuffers = 1;
 142       fb->ColorDrawBuffer[0] = GL_BACK;
 143       fb->_ColorDrawBufferIndexes[0] = BUFFER_BACK_LEFT;
 144       fb->ColorReadBuffer = GL_BACK;
 145       fb->_ColorReadBufferIndex = BUFFER_BACK_LEFT;
 146    }
 147    else {
 148       fb->_NumColorDrawBuffers = 1;
 149       fb->ColorDrawBuffer[0] = GL_FRONT;
 150       fb->_ColorDrawBufferIndexes[0] = BUFFER_FRONT_LEFT;
 151       fb->ColorReadBuffer = GL_FRONT;
 152       fb->_ColorReadBufferIndex = BUFFER_FRONT_LEFT;
 153    }
 154
 155    fb->Delete = _mesa_destroy_framebuffer;
 156    fb->_Status = GL_FRAMEBUFFER_COMPLETE_EXT;
 157
 158    compute_depth_max(fb);
 159 }
 160
 161
 162 /**
 163  * Initialize a user-created gl_framebuffer object.
 164  * \sa _mesa_initialize_window_framebuffer
 165  */
 166 void
 167 _mesa_initialize_user_framebuffer(struct gl_framebuffer *fb, GLuint name)
 168 {
 169    assert(fb);
 170    assert(name);
 171
 172    memset(fb, 0, sizeof(struct gl_framebuffer));
 173
 174    fb->Name = name;
 175    fb->RefCount = 1;
 176    fb->_NumColorDrawBuffers = 1;
 177    fb->ColorDrawBuffer[0] = GL_COLOR_ATTACHMENT0_EXT;
 178    fb->_ColorDrawBufferIndexes[0] = BUFFER_COLOR0;
 179    fb->ColorReadBuffer = GL_COLOR_ATTACHMENT0_EXT;
 180    fb->_ColorReadBufferIndex = BUFFER_COLOR0;
 181    fb->Delete = _mesa_destroy_framebuffer;
 182    _glthread_INIT_MUTEX(fb->Mutex);
 183 }
 184
 185
 186 /**
 187  * Deallocate buffer and everything attached to it.
 188  * Typically called via the gl_framebuffer->Delete() method.
 189  */
 190 void
 191 _mesa_destroy_framebuffer(struct gl_framebuffer *fb)
 192 {
 193    if (fb) {
 194       _mesa_free_framebuffer_data(fb);
 195       free(fb);
 196    }
 197 }
 198
 199
 200 /**
 201  * Free all the data hanging off the given gl_framebuffer, but don't free
 202  * the gl_framebuffer object itself.
 203  */
 204 void
 205 _mesa_free_framebuffer_data(struct gl_framebuffer *fb)
 206 {
 207    GLuint i;
 208
 209    assert(fb);
 210    assert(fb->RefCount == 0);
 211
 212    _glthread_DESTROY_MUTEX(fb->Mutex);
 213
 214    for (i = 0; i < BUFFER_COUNT; i++) {
 215       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 216       if (att->Renderbuffer) {
 217          _mesa_reference_renderbuffer(&att->Renderbuffer, NULL);
 218       }
 219       if (att->Texture) {
 220          _mesa_reference_texobj(&att->Texture, NULL);
 221       }
 222       ASSERT(!att->Renderbuffer);
 223       ASSERT(!att->Texture);
 224       att->Type = GL_NONE;
 225    }
 226
 227    /* unbind _Depth/_StencilBuffer to decr ref counts */
 228    _mesa_reference_renderbuffer(&fb->_DepthBuffer, NULL);
 229    _mesa_reference_renderbuffer(&fb->_StencilBuffer, NULL);
 230 }
 231
 232
 233 /**
 234  * Set *ptr to point to fb, with refcounting and locking.
 235  */
 236 void
 237 _mesa_reference_framebuffer(struct gl_framebuffer **ptr,
 238                             struct gl_framebuffer *fb)
 239 {
 240    assert(ptr);
 241    if (*ptr == fb) {
 242       /* no change */
 243       return;
 244    }
 245
 246    if (*ptr) {
 247       /* unreference old renderbuffer */
 248       GLboolean deleteFlag = GL_FALSE;
 249       struct gl_framebuffer *oldFb = *ptr;
 250
 251       _glthread_LOCK_MUTEX(oldFb->Mutex);
 252       ASSERT(oldFb->RefCount > 0);
 253       oldFb->RefCount--;
 254       deleteFlag = (oldFb->RefCount == 0);
 255       _glthread_UNLOCK_MUTEX(oldFb->Mutex);
 256
 257       if (deleteFlag)
 258          oldFb->Delete(oldFb);
 259
 260       *ptr = NULL;
 261    }
 262    assert(!*ptr);
 263
 264    if (fb) {
 265       _glthread_LOCK_MUTEX(fb->Mutex);
 266       fb->RefCount++;
 267       _glthread_UNLOCK_MUTEX(fb->Mutex);
 268       *ptr = fb;
 269    }
 270 }
 271
 272
 273 /**
 274  * Resize the given framebuffer's renderbuffers to the new width and height.
 275  * This should only be used for window-system framebuffers, not
 276  * user-created renderbuffers (i.e. made with GL_EXT_framebuffer_object).
 277  * This will typically be called via ctx->Driver.ResizeBuffers() or directly
 278  * from a device driver.
 279  *
 280  * \note it's possible for ctx to be null since a window can be resized
 281  * without a currently bound rendering context.
 282  */
 283 void
 284 _mesa_resize_framebuffer(GLcontext *ctx, struct gl_framebuffer *fb,
 285                          GLuint width, GLuint height)
 286 {
 287    GLuint i;
 288
 289    /* XXX I think we could check if the size is not changing
 290     * and return early.
 291     */
 292
 293    /* For window system framebuffers, Name is zero */
 294    assert(fb->Name == 0);
 295
 296    for (i = 0; i < BUFFER_COUNT; i++) {
 297       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 298       if (att->Type == GL_RENDERBUFFER_EXT && att->Renderbuffer) {
 299          struct gl_renderbuffer *rb = att->Renderbuffer;
 300          /* only resize if size is changing */
 301          if (rb->Width != width || rb->Height != height) {
 302             if (rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 303                ASSERT(rb->Width == width);
 304                ASSERT(rb->Height == height);
 305             }
 306             else {
 307                _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 308                /* no return */
 309             }
 310          }
 311       }
 312    }
 313
 314    if (fb->_DepthBuffer) {
 315       struct gl_renderbuffer *rb = fb->_DepthBuffer;
 316       if (rb->Width != width || rb->Height != height) {
 317          if (!rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 318             _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 319          }
 320       }
 321    }
 322
 323    if (fb->_StencilBuffer) {
 324       struct gl_renderbuffer *rb = fb->_StencilBuffer;
 325       if (rb->Width != width || rb->Height != height) {
 326          if (!rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 327             _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 328          }
 329       }
 330    }
 331
 332    fb->Width = width;
 333    fb->Height = height;
 334
 335    if (ctx) {
 336       /* update scissor / window bounds */
 337       _mesa_update_draw_buffer_bounds(ctx);
 338       /* Signal new buffer state so that swrast will update its clipping
 339        * info (the CLIP_BIT flag).
 340        */
 341       ctx->NewState |= _NEW_BUFFERS;
 342    }
 343 }
 344
 345
 346
 347 /**
 348  * XXX THIS IS OBSOLETE - drivers should take care of detecting window
 349  * size changes and act accordingly, likely calling _mesa_resize_framebuffer().
 350  *
 351  * GL_MESA_resize_buffers extension.
 352  *
 353  * When this function is called, we'll ask the window system how large
 354  * the current window is.  If it's a new size, we'll call the driver's
 355  * ResizeBuffers function.  The driver will then resize its color buffers
 356  * as needed, and maybe call the swrast's routine for reallocating
 357  * swrast-managed depth/stencil/accum/etc buffers.
 358  * \note This function should only be called through the GL API, not
 359  * from device drivers (as was done in the past).
 360  */
 361 void
 362 _mesa_resizebuffers( GLcontext *ctx )
 363 {
 364    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 365
 366    if (MESA_VERBOSE & VERBOSE_API)
 367       _mesa_debug(ctx, "glResizeBuffersMESA\n");
 368
 369    if (!ctx->Driver.GetBufferSize) {
 370       return;
 371    }
 372
 373    if (ctx->WinSysDrawBuffer) {
 374       GLuint newWidth, newHeight;
 375       GLframebuffer *buffer = ctx->WinSysDrawBuffer;
 376
 377       assert(buffer->Name == 0);
 378
 379       /* ask device driver for size of output buffer */
 380       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 381
 382       /* see if size of device driver's color buffer (window) has changed */
 383       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 384          if (ctx->Driver.ResizeBuffers)
 385             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 386       }
 387    }
 388
 389    if (ctx->WinSysReadBuffer
 390        && ctx->WinSysReadBuffer != ctx->WinSysDrawBuffer) {
 391       GLuint newWidth, newHeight;
 392       GLframebuffer *buffer = ctx->WinSysReadBuffer;
 393
 394       assert(buffer->Name == 0);
 395
 396       /* ask device driver for size of read buffer */
 397       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 398
 399       /* see if size of device driver's color buffer (window) has changed */
 400       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 401          if (ctx->Driver.ResizeBuffers)
 402             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 403       }
 404    }
 405
 406    ctx->NewState |= _NEW_BUFFERS;  /* to update scissor / window bounds */
 407 }
 408
 409
 410 /*
 411  * XXX THIS IS OBSOLETE
 412  */
 413 void GLAPIENTRY
 414 _mesa_ResizeBuffersMESA( void )
 415 {
 416    GET_CURRENT_CONTEXT(ctx);
 417
 418    if (ctx->Extensions.MESA_resize_buffers)
 419       _mesa_resizebuffers( ctx );
 420 }
 421
 422
 423
 424 /**
 425  * Examine all the framebuffer's renderbuffers to update the Width/Height
 426  * fields of the framebuffer.  If we have renderbuffers with different
 427  * sizes, set the framebuffer's width and height to the min size.
 428  * Note: this is only intended for user-created framebuffers, not
 429  * window-system framebuffes.
 430  */
 431 static void
 432 update_framebuffer_size(GLcontext *ctx, struct gl_framebuffer *fb)
 433 {
 434    GLuint minWidth = ~0, minHeight = ~0;
 435    GLuint i;
 436
 437    /* user-created framebuffers only */
 438    assert(fb->Name);
 439
 440    for (i = 0; i < BUFFER_COUNT; i++) {
 441       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 442       const struct gl_renderbuffer *rb = att->Renderbuffer;
 443       if (rb) {
 444          minWidth = MIN2(minWidth, rb->Width);
 445          minHeight = MIN2(minHeight, rb->Height);
 446       }
 447    }
 448
 449    if (minWidth != ~0) {
 450       fb->Width = minWidth;
 451       fb->Height = minHeight;
 452    }
 453    else {
 454       fb->Width = 0;
 455       fb->Height = 0;
 456    }
 457 }
 458
 459
 460 /**
 461  * Update the context's current drawing buffer's Xmin, Xmax, Ymin, Ymax fields.
 462  * These values are computed from the buffer's width and height and
 463  * the scissor box, if it's enabled.
 464  * \param ctx  the GL context.
 465  */
 466 void
 467 _mesa_update_draw_buffer_bounds(GLcontext *ctx)
 468 {
 469    struct gl_framebuffer *buffer = ctx->DrawBuffer;
 470
 471    if (!buffer)
 472       return;
 473
 474    if (buffer->Name) {
 475       /* user-created framebuffer size depends on the renderbuffers */
 476       update_framebuffer_size(ctx, buffer);
 477    }
 478
 479    buffer->_Xmin = 0;
 480    buffer->_Ymin = 0;
 481    buffer->_Xmax = buffer->Width;
 482    buffer->_Ymax = buffer->Height;
 483
 484    if (ctx->Scissor.Enabled) {
 485       if (ctx->Scissor.X > buffer->_Xmin) {
 486          buffer->_Xmin = ctx->Scissor.X;
 487       }
 488       if (ctx->Scissor.Y > buffer->_Ymin) {
 489          buffer->_Ymin = ctx->Scissor.Y;
 490       }
 491       if (ctx->Scissor.X + ctx->Scissor.Width < buffer->_Xmax) {
 492          buffer->_Xmax = ctx->Scissor.X + ctx->Scissor.Width;
 493       }
 494       if (ctx->Scissor.Y + ctx->Scissor.Height < buffer->_Ymax) {
 495          buffer->_Ymax = ctx->Scissor.Y + ctx->Scissor.Height;
 496       }
 497       /* finally, check for empty region */
 498       if (buffer->_Xmin > buffer->_Xmax) {
 499          buffer->_Xmin = buffer->_Xmax;
 500       }
 501       if (buffer->_Ymin > buffer->_Ymax) {
 502          buffer->_Ymin = buffer->_Ymax;
 503       }
 504    }
 505
 506    ASSERT(buffer->_Xmin <= buffer->_Xmax);
 507    ASSERT(buffer->_Ymin <= buffer->_Ymax);
 508 }
 509
 510
 511 /**
 512  * The glGet queries of the framebuffer red/green/blue size, stencil size,
 513  * etc. are satisfied by the fields of ctx->DrawBuffer->Visual.  These can
 514  * change depending on the renderbuffer bindings.  This function updates
 515  * the given framebuffer's Visual from the current renderbuffer bindings.
 516  *
 517  * This may apply to user-created framebuffers or window system framebuffers.
 518  *
 519  * Also note: ctx->DrawBuffer->Visual.depthBits might not equal
 520  * ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer.DepthBits.
 521  * The former one is used to convert floating point depth values into
 522  * integer Z values.
 523  */
 524 void
 525 _mesa_update_framebuffer_visual(struct gl_framebuffer *fb)
 526 {
 527    GLuint i;
 528
 529    memset(&fb->Visual, 0, sizeof(fb->Visual));
 530    fb->Visual.rgbMode = GL_TRUE; /* assume this */
 531
 532 #if 0 /* this _might_ be needed */
 533    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 534       /* leave visual fields zero'd */
 535       return;
 536    }
 537 #endif
 538
 539    /* find first RGB renderbuffer */
 540    for (i = 0; i < BUFFER_COUNT; i++) {
 541       if (fb->Attachment[i].Renderbuffer) {
 542          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 543          const GLenum baseFormat = _mesa_get_format_base_format(rb->Format);
 544          const gl_format fmt = rb->Format;
 545
 546          if (baseFormat == GL_RGBA || baseFormat == GL_RGB) {
 547             fb->Visual.redBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 548             fb->Visual.greenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 549             fb->Visual.blueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 550             fb->Visual.alphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 551             fb->Visual.rgbBits = fb->Visual.redBits
 552                + fb->Visual.greenBits + fb->Visual.blueBits;
 553             fb->Visual.floatMode = GL_FALSE;
 554             fb->Visual.samples = rb->NumSamples;
 555             break;
 556          }
 557       }
 558    }
 559
 560    if (fb->Attachment[BUFFER_DEPTH].Renderbuffer) {
 561       const struct gl_renderbuffer *rb =
 562          fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 563       const gl_format fmt = rb->Format;
 564       fb->Visual.haveDepthBuffer = GL_TRUE;
 565       fb->Visual.depthBits = _mesa_get_format_bits(fmt, GL_DEPTH_BITS);
 566    }
 567
 568    if (fb->Attachment[BUFFER_STENCIL].Renderbuffer) {
 569       const struct gl_renderbuffer *rb =
 570          fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 571       const gl_format fmt = rb->Format;
 572       fb->Visual.haveStencilBuffer = GL_TRUE;
 573       fb->Visual.stencilBits = _mesa_get_format_bits(fmt, GL_STENCIL_BITS);
 574    }
 575
 576    if (fb->Attachment[BUFFER_ACCUM].Renderbuffer) {
 577       const struct gl_renderbuffer *rb =
 578          fb->Attachment[BUFFER_ACCUM].Renderbuffer;
 579       const gl_format fmt = rb->Format;
 580       fb->Visual.haveAccumBuffer = GL_TRUE;
 581       fb->Visual.accumRedBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 582       fb->Visual.accumGreenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 583       fb->Visual.accumBlueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 584       fb->Visual.accumAlphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 585    }
 586
 587    compute_depth_max(fb);
 588 }
 589
 590
 591 /**
 592  * Update the framebuffer's _DepthBuffer field using the renderbuffer
 593  * found at the given attachment index.
 594  *
 595  * If that attachment points to a combined GL_DEPTH_STENCIL renderbuffer,
 596  * create and install a depth wrapper/adaptor.
 597  *
 598  * \param fb  the framebuffer whose _DepthBuffer field to update
 599  * \param attIndex  indicates the renderbuffer to possibly wrap
 600  */
 601 void
 602 _mesa_update_depth_buffer(GLcontext *ctx,
 603                           struct gl_framebuffer *fb,
 604                           GLuint attIndex)
 605 {
 606    struct gl_renderbuffer *depthRb;
 607
 608    /* only one possiblity for now */
 609    ASSERT(attIndex == BUFFER_DEPTH);
 610
 611    depthRb = fb->Attachment[attIndex].Renderbuffer;
 612
 613    if (depthRb && depthRb->_BaseFormat == GL_DEPTH_STENCIL) {
 614       /* The attached depth buffer is a GL_DEPTH_STENCIL renderbuffer */
 615       if (!fb->_DepthBuffer
 616           || fb->_DepthBuffer->Wrapped != depthRb
 617           || _mesa_get_format_base_format(fb->_DepthBuffer->Format) != GL_DEPTH_COMPONENT) {
 618          /* need to update wrapper */
 619          struct gl_renderbuffer *wrapper
 620             = _mesa_new_z24_renderbuffer_wrapper(ctx, depthRb);
 621          _mesa_reference_renderbuffer(&fb->_DepthBuffer, wrapper);
 622          ASSERT(fb->_DepthBuffer->Wrapped == depthRb);
 623       }
 624    }
 625    else {
 626       /* depthRb may be null */
 627       _mesa_reference_renderbuffer(&fb->_DepthBuffer, depthRb);
 628    }
 629 }
 630
 631
 632 /**
 633  * Update the framebuffer's _StencilBuffer field using the renderbuffer
 634  * found at the given attachment index.
 635  *
 636  * If that attachment points to a combined GL_DEPTH_STENCIL renderbuffer,
 637  * create and install a stencil wrapper/adaptor.
 638  *
 639  * \param fb  the framebuffer whose _StencilBuffer field to update
 640  * \param attIndex  indicates the renderbuffer to possibly wrap
 641  */
 642 void
 643 _mesa_update_stencil_buffer(GLcontext *ctx,
 644                             struct gl_framebuffer *fb,
 645                             GLuint attIndex)
 646 {
 647    struct gl_renderbuffer *stencilRb;
 648
 649    ASSERT(attIndex == BUFFER_DEPTH ||
 650           attIndex == BUFFER_STENCIL);
 651
 652    stencilRb = fb->Attachment[attIndex].Renderbuffer;
 653
 654    if (stencilRb && stencilRb->_BaseFormat == GL_DEPTH_STENCIL) {
 655       /* The attached stencil buffer is a GL_DEPTH_STENCIL renderbuffer */
 656       if (!fb->_StencilBuffer
 657           || fb->_StencilBuffer->Wrapped != stencilRb
 658           || _mesa_get_format_base_format(fb->_StencilBuffer->Format) != GL_STENCIL_INDEX) {
 659          /* need to update wrapper */
 660          struct gl_renderbuffer *wrapper
 661             = _mesa_new_s8_renderbuffer_wrapper(ctx, stencilRb);
 662          _mesa_reference_renderbuffer(&fb->_StencilBuffer, wrapper);
 663          ASSERT(fb->_StencilBuffer->Wrapped == stencilRb);
 664       }
 665    }
 666    else {
 667       /* stencilRb may be null */
 668       _mesa_reference_renderbuffer(&fb->_StencilBuffer, stencilRb);
 669    }
 670 }
 671
 672
 673 /*
 674  * Example DrawBuffers scenarios:
 675  *
 676  * 1. glDrawBuffer(GL_FRONT_AND_BACK), fixed-func or shader writes to
 677  * "gl_FragColor" or program writes to the "result.color" register:
 678  *
 679  *   fragment color output   renderbuffer
 680  *   ---------------------   ---------------
 681  *   color[0]                Front, Back
 682  *
 683  *
 684  * 2. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]), shader writes to
 685  * gl_FragData[i] or program writes to result.color[i] registers:
 686  *
 687  *   fragment color output   renderbuffer
 688  *   ---------------------   ---------------
 689  *   color[0]                Front
 690  *   color[1]                Aux0
 691  *   color[3]                Aux1
 692  *
 693  *
 694  * 3. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]) and shader writes to
 695  * gl_FragColor, or fixed function:
 696  *
 697  *   fragment color output   renderbuffer
 698  *   ---------------------   ---------------
 699  *   color[0]                Front, Aux0, Aux1
 700  *
 701  *
 702  * In either case, the list of renderbuffers is stored in the
 703  * framebuffer->_ColorDrawBuffers[] array and
 704  * framebuffer->_NumColorDrawBuffers indicates the number of buffers.
 705  * The renderer (like swrast) has to look at the current fragment shader
 706  * to see if it writes to gl_FragColor vs. gl_FragData[i] to determine
 707  * how to map color outputs to renderbuffers.
 708  *
 709  * Note that these two calls are equivalent (for fixed function fragment
 710  * shading anyway):
 711  *   a)  glDrawBuffer(GL_FRONT_AND_BACK);  (assuming non-stereo framebuffer)
 712  *   b)  glDrawBuffers(2, [GL_FRONT_LEFT, GL_BACK_LEFT]);
 713  */
 714
 715
 716
 717
 718 /**
 719  * Update the (derived) list of color drawing renderbuffer pointers.
 720  * Later, when we're rendering we'll loop from 0 to _NumColorDrawBuffers
 721  * writing colors.
 722  */
 723 static void
 724 update_color_draw_buffers(GLcontext *ctx, struct gl_framebuffer *fb)
 725 {
 726    GLuint output;
 727
 728    /* set 0th buffer to NULL now in case _NumColorDrawBuffers is zero */
 729    fb->_ColorDrawBuffers[0] = NULL;
 730
 731    for (output = 0; output < fb->_NumColorDrawBuffers; output++) {
 732       GLint buf = fb->_ColorDrawBufferIndexes[output];
 733       if (buf >= 0) {
 734          fb->_ColorDrawBuffers[output] = fb->Attachment[buf].Renderbuffer;
 735       }
 736       else {
 737          fb->_ColorDrawBuffers[output] = NULL;
 738       }
 739    }
 740 }
 741
 742
 743 /**
 744  * Update the (derived) color read renderbuffer pointer.
 745  * Unlike the DrawBuffer, we can only read from one (or zero) color buffers.
 746  */
 747 static void
 748 update_color_read_buffer(GLcontext *ctx, struct gl_framebuffer *fb)
 749 {
 750    (void) ctx;
 751    if (fb->_ColorReadBufferIndex == -1 ||
 752        fb->DeletePending ||
 753        fb->Width == 0 ||
 754        fb->Height == 0) {
 755       fb->_ColorReadBuffer = NULL; /* legal! */
 756    }
 757    else {
 758       ASSERT(fb->_ColorReadBufferIndex >= 0);
 759       ASSERT(fb->_ColorReadBufferIndex < BUFFER_COUNT);
 760       fb->_ColorReadBuffer
 761          = fb->Attachment[fb->_ColorReadBufferIndex].Renderbuffer;
 762    }
 763 }
 764
 765
 766 /**
 767  * Update a gl_framebuffer's derived state.
 768  *
 769  * Specifically, update these framebuffer fields:
 770  *    _ColorDrawBuffers
 771  *    _NumColorDrawBuffers
 772  *    _ColorReadBuffer
 773  *    _DepthBuffer
 774  *    _StencilBuffer
 775  *
 776  * If the framebuffer is user-created, make sure it's complete.
 777  *
 778  * The following functions (at least) can effect framebuffer state:
 779  * glReadBuffer, glDrawBuffer, glDrawBuffersARB, glFramebufferRenderbufferEXT,
 780  * glRenderbufferStorageEXT.
 781  */
 782 static void
 783 update_framebuffer(GLcontext *ctx, struct gl_framebuffer *fb)
 784 {
 785    if (fb->Name == 0) {
 786       /* This is a window-system framebuffer */
 787       /* Need to update the FB's GL_DRAW_BUFFER state to match the
 788        * context state (GL_READ_BUFFER too).
 789        */
 790       if (fb->ColorDrawBuffer[0] != ctx->Color.DrawBuffer[0]) {
 791          _mesa_drawbuffers(ctx, ctx->Const.MaxDrawBuffers,
 792                            ctx->Color.DrawBuffer, NULL);
 793       }
 794       if (fb->ColorReadBuffer != ctx->Pixel.ReadBuffer) {
 795
 796       }
 797    }
 798    else {
 799       /* This is a user-created framebuffer.
 800        * Completeness only matters for user-created framebuffers.
 801        */
 802       if (fb->_Status != GL_FRAMEBUFFER_COMPLETE) {
 803          _mesa_test_framebuffer_completeness(ctx, fb);
 804       }
 805    }
 806
 807    /* Strictly speaking, we don't need to update the draw-state
 808     * if this FB is bound as ctx->ReadBuffer (and conversely, the
 809     * read-state if this FB is bound as ctx->DrawBuffer), but no
 810     * harm.
 811     */
 812    update_color_draw_buffers(ctx, fb);
 813    update_color_read_buffer(ctx, fb);
 814    _mesa_update_depth_buffer(ctx, fb, BUFFER_DEPTH);
 815    _mesa_update_stencil_buffer(ctx, fb, BUFFER_STENCIL);
 816
 817    compute_depth_max(fb);
 818 }
 819
 820
 821 /**
 822  * Update state related to the current draw/read framebuffers.
 823  */
 824 void
 825 _mesa_update_framebuffer(GLcontext *ctx)
 826 {
 827    struct gl_framebuffer *drawFb;
 828    struct gl_framebuffer *readFb;
 829
 830    assert(ctx);
 831    drawFb = ctx->DrawBuffer;
 832    readFb = ctx->ReadBuffer;
 833
 834    update_framebuffer(ctx, drawFb);
 835    if (readFb != drawFb)
 836       update_framebuffer(ctx, readFb);
 837 }
 838
 839
 840 /**
 841  * Check if the renderbuffer for a read operation (glReadPixels, glCopyPixels,
 842  * glCopyTex[Sub]Image, etc) exists.
 843  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 844  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 845  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 846  */
 847 GLboolean
 848 _mesa_source_buffer_exists(GLcontext *ctx, GLenum format)
 849 {
 850    const struct gl_renderbuffer_attachment *att = ctx->ReadBuffer->Attachment;
 851
 852    /* If we don't know the framebuffer status, update it now */
 853    if (ctx->ReadBuffer->_Status == 0) {
 854       _mesa_test_framebuffer_completeness(ctx, ctx->ReadBuffer);
 855    }
 856
 857    if (ctx->ReadBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 858       return GL_FALSE;
 859    }
 860
 861    switch (format) {
 862    case GL_COLOR:
 863    case GL_RED:
 864    case GL_GREEN:
 865    case GL_BLUE:
 866    case GL_ALPHA:
 867    case GL_LUMINANCE:
 868    case GL_LUMINANCE_ALPHA:
 869    case GL_INTENSITY:
 870    case GL_RGB:
 871    case GL_BGR:
 872    case GL_RGBA:
 873    case GL_BGRA:
 874    case GL_ABGR_EXT:
 875    case GL_COLOR_INDEX:
 876       if (ctx->ReadBuffer->_ColorReadBuffer == NULL) {
 877          return GL_FALSE;
 878       }
 879       ASSERT(_mesa_get_format_bits(ctx->ReadBuffer->_ColorReadBuffer->Format, GL_RED_BITS) > 0 ||
 880              _mesa_get_format_bits(ctx->ReadBuffer->_ColorReadBuffer->Format, GL_INDEX_BITS) > 0);
 881       break;
 882    case GL_DEPTH:
 883    case GL_DEPTH_COMPONENT:
 884       if (!att[BUFFER_DEPTH].Renderbuffer) {
 885          return GL_FALSE;
 886       }
 887       /*ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);*/
 888       break;
 889    case GL_STENCIL:
 890    case GL_STENCIL_INDEX:
 891       if (!att[BUFFER_STENCIL].Renderbuffer) {
 892          return GL_FALSE;
 893       }
 894       /*ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);*/
 895       break;
 896    case GL_DEPTH_STENCIL_EXT:
 897       if (!att[BUFFER_DEPTH].Renderbuffer ||
 898           !att[BUFFER_STENCIL].Renderbuffer) {
 899          return GL_FALSE;
 900       }
 901       /*
 902       ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);
 903       ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);
 904       */
 905       break;
 906    default:
 907       _mesa_problem(ctx,
 908                     "Unexpected format 0x%x in _mesa_source_buffer_exists",
 909                     format);
 910       return GL_FALSE;
 911    }
 912
 913    /* OK */
 914    return GL_TRUE;
 915 }
 916
 917
 918 /**
 919  * As above, but for drawing operations.
 920  * XXX could do some code merging w/ above function.
 921  */
 922 GLboolean
 923 _mesa_dest_buffer_exists(GLcontext *ctx, GLenum format)
 924 {
 925    const struct gl_renderbuffer_attachment *att = ctx->DrawBuffer->Attachment;
 926
 927    /* If we don't know the framebuffer status, update it now */
 928    if (ctx->DrawBuffer->_Status == 0) {
 929       _mesa_test_framebuffer_completeness(ctx, ctx->DrawBuffer);
 930    }
 931
 932    if (ctx->DrawBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 933       return GL_FALSE;
 934    }
 935
 936    switch (format) {
 937    case GL_COLOR:
 938    case GL_RED:
 939    case GL_GREEN:
 940    case GL_BLUE:
 941    case GL_ALPHA:
 942    case GL_LUMINANCE:
 943    case GL_LUMINANCE_ALPHA:
 944    case GL_INTENSITY:
 945    case GL_RGB:
 946    case GL_BGR:
 947    case GL_RGBA:
 948    case GL_BGRA:
 949    case GL_ABGR_EXT:
 950    case GL_COLOR_INDEX:
 951       /* Nothing special since GL_DRAW_BUFFER could be GL_NONE. */
 952       /* Could assert that colorbuffer has RedBits > 0 */
 953       break;
 954    case GL_DEPTH:
 955    case GL_DEPTH_COMPONENT:
 956       if (!att[BUFFER_DEPTH].Renderbuffer) {
 957          return GL_FALSE;
 958       }
 959       /*ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);*/
 960       break;
 961    case GL_STENCIL:
 962    case GL_STENCIL_INDEX:
 963       if (!att[BUFFER_STENCIL].Renderbuffer) {
 964          return GL_FALSE;
 965       }
 966       /*ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);*/
 967       break;
 968    case GL_DEPTH_STENCIL_EXT:
 969       if (!att[BUFFER_DEPTH].Renderbuffer ||
 970           !att[BUFFER_STENCIL].Renderbuffer) {
 971          return GL_FALSE;
 972       }
 973       /*
 974       ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);
 975       ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);
 976       */
 977       break;
 978    default:
 979       _mesa_problem(ctx,
 980                     "Unexpected format 0x%x in _mesa_dest_buffer_exists",
 981                     format);
 982       return GL_FALSE;
 983    }
 984
 985    /* OK */
 986    return GL_TRUE;
 987 }
 988
 989
 990 /**
 991  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_FORMAT_OES query.
 992  */
 993 GLenum
 994 _mesa_get_color_read_format(GLcontext *ctx)
 995 {
 996    switch (ctx->ReadBuffer->_ColorReadBuffer->Format) {
 997    case MESA_FORMAT_ARGB8888:
 998       return GL_BGRA;
 999    case MESA_FORMAT_RGB565:
1000       return GL_BGR;
1001    default:
1002       return GL_RGBA;
1003    }
1004 }
1005
1006
1007 /**
1008  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_TYPE_OES query.
1009  */
1010 GLenum
1011 _mesa_get_color_read_type(GLcontext *ctx)
1012 {
1013    switch (ctx->ReadBuffer->_ColorReadBuffer->Format) {
1014    case MESA_FORMAT_ARGB8888:
1015       return GL_UNSIGNED_BYTE;
1016    case MESA_FORMAT_RGB565:
1017       return GL_UNSIGNED_SHORT_5_6_5_REV;
1018    default:
1019       return GL_UNSIGNED_BYTE;
1020    }
1021 }