src/mesa/main/framebuffer.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.5.1
   4  *
   5  * Copyright (C) 1999-2006  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 "context.h"
  36 #include "depthstencil.h"
  37 #include "mtypes.h"
  38 #include "fbobject.h"
  39 #include "framebuffer.h"
  40 #include "renderbuffer.h"
  41
  42
  43
  44 /**
  45  * Compute/set the _DepthMax field for the given framebuffer.
  46  * This value depends on the Z buffer resolution.
  47  */
  48 static void
  49 compute_depth_max(struct gl_framebuffer *fb)
  50 {
  51    if (fb->Visual.depthBits == 0) {
  52       /* Special case.  Even if we don't have a depth buffer we need
  53        * good values for DepthMax for Z vertex transformation purposes
  54        * and for per-fragment fog computation.
  55        */
  56       fb->_DepthMax = (1 << 16) - 1;
  57    }
  58    else if (fb->Visual.depthBits < 32) {
  59       fb->_DepthMax = (1 << fb->Visual.depthBits) - 1;
  60    }
  61    else {
  62       /* Special case since shift values greater than or equal to the
  63        * number of bits in the left hand expression's type are undefined.
  64        */
  65       fb->_DepthMax = 0xffffffff;
  66    }
  67    fb->_DepthMaxF = (GLfloat) fb->_DepthMax;
  68    fb->_MRD = 1.0;  /* Minimum resolvable depth value, for polygon offset */
  69 }
  70
  71
  72 /**
  73  * Set the framebuffer's _DepthBuffer field, taking care of
  74  * reference counts, etc.
  75  */
  76 static void
  77 set_depth_renderbuffer(struct gl_framebuffer *fb,
  78                        struct gl_renderbuffer *rb)
  79 {
  80    if (fb->_DepthBuffer) {
  81       _mesa_unreference_renderbuffer(&fb->_DepthBuffer);
  82    }
  83    fb->_DepthBuffer = rb;
  84    if (rb) {
  85       rb->RefCount++;
  86    }
  87 }
  88
  89
  90 /**
  91  * Set the framebuffer's _StencilBuffer field, taking care of
  92  * reference counts, etc.
  93  */
  94 static void
  95 set_stencil_renderbuffer(struct gl_framebuffer *fb,
  96                          struct gl_renderbuffer *rb)
  97 {
  98    if (fb->_StencilBuffer) {
  99       _mesa_unreference_renderbuffer(&fb->_StencilBuffer);
 100    }
 101    fb->_StencilBuffer = rb;
 102    if (rb) {
 103       rb->RefCount++;
 104    }
 105 }
 106
 107
 108 /**
 109  * Create and initialize a gl_framebuffer object.
 110  * This is intended for creating _window_system_ framebuffers, not generic
 111  * framebuffer objects ala GL_EXT_framebuffer_object.
 112  *
 113  * \sa _mesa_new_framebuffer
 114  */
 115 struct gl_framebuffer *
 116 _mesa_create_framebuffer(const GLvisual *visual)
 117 {
 118    struct gl_framebuffer *fb = CALLOC_STRUCT(gl_framebuffer);
 119    assert(visual);
 120    if (fb) {
 121       _mesa_initialize_framebuffer(fb, visual);
 122    }
 123    return fb;
 124 }
 125
 126
 127 /**
 128  * Allocate a new gl_framebuffer object.
 129  * This is the default function for ctx->Driver.NewFramebuffer().
 130  * This is for allocating user-created framebuffers, not window-system
 131  * framebuffers!
 132  * \sa _mesa_create_framebuffer
 133  */
 134 struct gl_framebuffer *
 135 _mesa_new_framebuffer(GLcontext *ctx, GLuint name)
 136 {
 137    struct gl_framebuffer *fb;
 138    (void) ctx;
 139    assert(name != 0);
 140    fb = CALLOC_STRUCT(gl_framebuffer);
 141    if (fb) {
 142       fb->Name = name;
 143       fb->RefCount = 1;
 144       fb->ColorDrawBuffer[0] = GL_COLOR_ATTACHMENT0_EXT;
 145       fb->_ColorDrawBufferMask[0] = BUFFER_BIT_COLOR0;
 146       fb->ColorReadBuffer = GL_COLOR_ATTACHMENT0_EXT;
 147       fb->_ColorReadBufferIndex = BUFFER_COLOR0;
 148       fb->Delete = _mesa_destroy_framebuffer;
 149    }
 150    return fb;
 151 }
 152
 153
 154 /**
 155  * Initialize a gl_framebuffer object.  Typically used to initialize
 156  * window system-created framebuffers, not user-created framebuffers.
 157  * \sa _mesa_create_framebuffer
 158  */
 159 void
 160 _mesa_initialize_framebuffer(struct gl_framebuffer *fb, const GLvisual *visual)
 161 {
 162    assert(fb);
 163    assert(visual);
 164
 165    _mesa_bzero(fb, sizeof(struct gl_framebuffer));
 166
 167    _glthread_INIT_MUTEX(fb->Mutex);
 168
 169    fb->RefCount = 1;
 170
 171    /* save the visual */
 172    fb->Visual = *visual;
 173
 174    /* Init glRead/DrawBuffer state */
 175    if (visual->doubleBufferMode) {
 176       fb->ColorDrawBuffer[0] = GL_BACK;
 177       fb->_ColorDrawBufferMask[0] = BUFFER_BIT_BACK_LEFT;
 178       fb->ColorReadBuffer = GL_BACK;
 179       fb->_ColorReadBufferIndex = BUFFER_BACK_LEFT;
 180    }
 181    else {
 182       fb->ColorDrawBuffer[0] = GL_FRONT;
 183       fb->_ColorDrawBufferMask[0] = BUFFER_BIT_FRONT_LEFT;
 184       fb->ColorReadBuffer = GL_FRONT;
 185       fb->_ColorReadBufferIndex = BUFFER_FRONT_LEFT;
 186    }
 187
 188    fb->Delete = _mesa_destroy_framebuffer;
 189    fb->_Status = GL_FRAMEBUFFER_COMPLETE_EXT;
 190
 191    compute_depth_max(fb);
 192 }
 193
 194
 195 /**
 196  * Deallocate buffer and everything attached to it.
 197  * Typically called via the gl_framebuffer->Delete() method.
 198  */
 199 void
 200 _mesa_destroy_framebuffer(struct gl_framebuffer *fb)
 201 {
 202    if (fb) {
 203       _mesa_free_framebuffer_data(fb);
 204       _mesa_free(fb);
 205    }
 206 }
 207
 208
 209 /**
 210  * Free all the data hanging off the given gl_framebuffer, but don't free
 211  * the gl_framebuffer object itself.
 212  */
 213 void
 214 _mesa_free_framebuffer_data(struct gl_framebuffer *fb)
 215 {
 216    GLuint i;
 217
 218    assert(fb);
 219    assert(fb->RefCount == 0);
 220
 221    _glthread_DESTROY_MUTEX(fb->Mutex);
 222
 223    for (i = 0; i < BUFFER_COUNT; i++) {
 224       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 225       if (att->Renderbuffer) {
 226          _mesa_unreference_renderbuffer(&att->Renderbuffer);
 227       }
 228       if (att->Texture) {
 229          /* render to texture */
 230          att->Texture->RefCount--;
 231          if (att->Texture->RefCount == 0) {
 232             GET_CURRENT_CONTEXT(ctx);
 233             if (ctx) {
 234                ctx->Driver.DeleteTexture(ctx, att->Texture);
 235             }
 236          }
 237       }
 238       att->Type = GL_NONE;
 239       att->Texture = NULL;
 240    }
 241
 242    /* unbind depth/stencil to decr ref counts */
 243    set_depth_renderbuffer(fb, NULL);
 244    set_stencil_renderbuffer(fb, NULL);
 245 }
 246
 247
 248 /**
 249  * Set *ptr to point to fb, with refcounting and locking.
 250  */
 251 void
 252 _mesa_reference_framebuffer(struct gl_framebuffer **ptr,
 253                             struct gl_framebuffer *fb)
 254 {
 255    assert(ptr);
 256    if (*ptr == fb) {
 257       /* no change */
 258       return;
 259    }
 260    if (*ptr) {
 261       _mesa_unreference_framebuffer(ptr);
 262    }
 263    assert(!*ptr);
 264    assert(fb);
 265    _glthread_LOCK_MUTEX(fb->Mutex);
 266    fb->RefCount++;
 267    _glthread_UNLOCK_MUTEX(fb->Mutex);
 268    *ptr = fb;
 269 }
 270
 271
 272 /**
 273  * Undo/remove a reference to a framebuffer object.
 274  * Decrement the framebuffer object's reference count and delete it when
 275  * the refcount hits zero.
 276  * Note: we pass the address of a pointer and set it to NULL.
 277  */
 278 void
 279 _mesa_unreference_framebuffer(struct gl_framebuffer **fb)
 280 {
 281    assert(fb);
 282    if (*fb) {
 283       GLboolean deleteFlag = GL_FALSE;
 284
 285       _glthread_LOCK_MUTEX((*fb)->Mutex);
 286       ASSERT((*fb)->RefCount > 0);
 287       (*fb)->RefCount--;
 288       deleteFlag = ((*fb)->RefCount == 0);
 289       _glthread_UNLOCK_MUTEX((*fb)->Mutex);
 290
 291       if (deleteFlag)
 292          (*fb)->Delete(*fb);
 293
 294       *fb = NULL;
 295    }
 296 }
 297
 298
 299
 300
 301 /**
 302  * Resize the given framebuffer's renderbuffers to the new width and height.
 303  * This should only be used for window-system framebuffers, not
 304  * user-created renderbuffers (i.e. made with GL_EXT_framebuffer_object).
 305  * This will typically be called via ctx->Driver.ResizeBuffers() or directly
 306  * from a device driver.
 307  *
 308  * \note it's possible for ctx to be null since a window can be resized
 309  * without a currently bound rendering context.
 310  */
 311 void
 312 _mesa_resize_framebuffer(GLcontext *ctx, struct gl_framebuffer *fb,
 313                          GLuint width, GLuint height)
 314 {
 315    GLuint i;
 316
 317    /* XXX I think we could check if the size is not changing
 318     * and return early.
 319     */
 320
 321    /* For window system framebuffers, Name is zero */
 322    assert(fb->Name == 0);
 323
 324    for (i = 0; i < BUFFER_COUNT; i++) {
 325       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 326       if (att->Type == GL_RENDERBUFFER_EXT && att->Renderbuffer) {
 327          struct gl_renderbuffer *rb = att->Renderbuffer;
 328          /* only resize if size is changing */
 329          if (rb->Width != width || rb->Height != height) {
 330             /* could just as well pass rb->_ActualFormat here */
 331             if (rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 332                ASSERT(rb->Width == width);
 333                ASSERT(rb->Height == height);
 334             }
 335             else {
 336                _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 337                /* no return */
 338             }
 339          }
 340       }
 341    }
 342
 343    if (fb->_DepthBuffer) {
 344       struct gl_renderbuffer *rb = fb->_DepthBuffer;
 345       if (rb->Width != width || rb->Height != height) {
 346          if (!rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 347             _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 348          }
 349       }
 350    }
 351
 352    if (fb->_StencilBuffer) {
 353       struct gl_renderbuffer *rb = fb->_StencilBuffer;
 354       if (rb->Width != width || rb->Height != height) {
 355          if (!rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 356             _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 357          }
 358       }
 359    }
 360
 361    fb->Width = width;
 362    fb->Height = height;
 363
 364    if (ctx) {
 365       /* update scissor / window bounds */
 366       _mesa_update_draw_buffer_bounds(ctx);
 367       /* Signal new buffer state so that swrast will update its clipping
 368        * info (the CLIP_BIT flag).
 369        */
 370       ctx->NewState |= _NEW_BUFFERS;
 371    }
 372 }
 373
 374
 375 /**
 376  * Examine all the framebuffer's renderbuffers to update the Width/Height
 377  * fields of the framebuffer.  If we have renderbuffers with different
 378  * sizes, set the framebuffer's width and height to zero.
 379  * Note: this is only intended for user-created framebuffers, not
 380  * window-system framebuffes.
 381  */
 382 static void
 383 update_framebuffer_size(struct gl_framebuffer *fb)
 384 {
 385    GLboolean haveSize = GL_FALSE;
 386    GLuint i;
 387
 388    /* user-created framebuffers only */
 389    assert(fb->Name);
 390
 391    for (i = 0; i < BUFFER_COUNT; i++) {
 392       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 393       const struct gl_renderbuffer *rb = att->Renderbuffer;
 394       if (rb) {
 395          if (haveSize) {
 396             if (rb->Width != fb->Width && rb->Height != fb->Height) {
 397                /* size mismatch! */
 398                fb->Width = 0;
 399                fb->Height = 0;
 400                return;
 401             }
 402          }
 403          else {
 404             fb->Width = rb->Width;
 405             fb->Height = rb->Height;
 406             haveSize = GL_TRUE;
 407          }
 408       }
 409    }
 410 }
 411
 412
 413 /**
 414  * Update the context's current drawing buffer's Xmin, Xmax, Ymin, Ymax fields.
 415  * These values are computed from the buffer's width and height and
 416  * the scissor box, if it's enabled.
 417  * \param ctx  the GL context.
 418  */
 419 void
 420 _mesa_update_draw_buffer_bounds(GLcontext *ctx)
 421 {
 422    struct gl_framebuffer *buffer = ctx->DrawBuffer;
 423
 424    if (!buffer)
 425       return;
 426
 427    if (buffer->Name) {
 428       /* user-created framebuffer size depends on the renderbuffers */
 429       update_framebuffer_size(buffer);
 430    }
 431
 432    buffer->_Xmin = 0;
 433    buffer->_Ymin = 0;
 434    buffer->_Xmax = buffer->Width;
 435    buffer->_Ymax = buffer->Height;
 436
 437    if (ctx->Scissor.Enabled) {
 438       if (ctx->Scissor.X > buffer->_Xmin) {
 439          buffer->_Xmin = ctx->Scissor.X;
 440       }
 441       if (ctx->Scissor.Y > buffer->_Ymin) {
 442          buffer->_Ymin = ctx->Scissor.Y;
 443       }
 444       if (ctx->Scissor.X + ctx->Scissor.Width < buffer->_Xmax) {
 445          buffer->_Xmax = ctx->Scissor.X + ctx->Scissor.Width;
 446       }
 447       if (ctx->Scissor.Y + ctx->Scissor.Height < buffer->_Ymax) {
 448          buffer->_Ymax = ctx->Scissor.Y + ctx->Scissor.Height;
 449       }
 450       /* finally, check for empty region */
 451       if (buffer->_Xmin > buffer->_Xmax) {
 452          buffer->_Xmin = buffer->_Xmax;
 453       }
 454       if (buffer->_Ymin > buffer->_Ymax) {
 455          buffer->_Ymin = buffer->_Ymax;
 456       }
 457    }
 458
 459    ASSERT(buffer->_Xmin <= buffer->_Xmax);
 460    ASSERT(buffer->_Ymin <= buffer->_Ymax);
 461 }
 462
 463
 464 /**
 465  * The glGet queries of the framebuffer red/green/blue size, stencil size,
 466  * etc. are satisfied by the fields of ctx->DrawBuffer->Visual.  These can
 467  * change depending on the renderbuffer bindings.  This function updates
 468  * the given framebuffer's Visual from the current renderbuffer bindings.
 469  *
 470  * This may apply to user-created framebuffers or window system framebuffers.
 471  *
 472  * Also note: ctx->DrawBuffer->Visual.depthBits might not equal
 473  * ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer.DepthBits.
 474  * The former one is used to convert floating point depth values into
 475  * integer Z values.
 476  */
 477 void
 478 _mesa_update_framebuffer_visual(struct gl_framebuffer *fb)
 479 {
 480    GLuint i;
 481
 482    _mesa_bzero(&fb->Visual, sizeof(fb->Visual));
 483    fb->Visual.rgbMode = GL_TRUE; /* assume this */
 484
 485 #if 0 /* this _might_ be needed */
 486    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 487       /* leave visual fields zero'd */
 488       return;
 489    }
 490 #endif
 491
 492    /* find first RGB or CI renderbuffer */
 493    for (i = 0; i < BUFFER_COUNT; i++) {
 494       if (fb->Attachment[i].Renderbuffer) {
 495          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 496          if (rb->_BaseFormat == GL_RGBA || rb->_BaseFormat == GL_RGB) {
 497             fb->Visual.redBits = rb->RedBits;
 498             fb->Visual.greenBits = rb->GreenBits;
 499             fb->Visual.blueBits = rb->BlueBits;
 500             fb->Visual.alphaBits = rb->AlphaBits;
 501             fb->Visual.rgbBits = fb->Visual.redBits
 502                + fb->Visual.greenBits + fb->Visual.blueBits;
 503             fb->Visual.floatMode = GL_FALSE;
 504             break;
 505          }
 506          else if (rb->_BaseFormat == GL_COLOR_INDEX) {
 507             fb->Visual.indexBits = rb->IndexBits;
 508             fb->Visual.rgbMode = GL_FALSE;
 509             break;
 510          }
 511       }
 512    }
 513
 514    if (fb->Attachment[BUFFER_DEPTH].Renderbuffer) {
 515       fb->Visual.haveDepthBuffer = GL_TRUE;
 516       fb->Visual.depthBits
 517          = fb->Attachment[BUFFER_DEPTH].Renderbuffer->DepthBits;
 518    }
 519
 520    if (fb->Attachment[BUFFER_STENCIL].Renderbuffer) {
 521       fb->Visual.haveStencilBuffer = GL_TRUE;
 522       fb->Visual.stencilBits
 523          = fb->Attachment[BUFFER_STENCIL].Renderbuffer->StencilBits;
 524    }
 525
 526    if (fb->Attachment[BUFFER_ACCUM].Renderbuffer) {
 527       fb->Visual.haveAccumBuffer = GL_TRUE;
 528       fb->Visual.accumRedBits
 529          = fb->Attachment[BUFFER_DEPTH].Renderbuffer->RedBits;
 530       fb->Visual.accumGreenBits
 531          = fb->Attachment[BUFFER_DEPTH].Renderbuffer->GreenBits;
 532       fb->Visual.accumBlueBits
 533          = fb->Attachment[BUFFER_DEPTH].Renderbuffer->BlueBits;
 534       fb->Visual.accumAlphaBits
 535          = fb->Attachment[BUFFER_DEPTH].Renderbuffer->AlphaBits;
 536    }
 537
 538    compute_depth_max(fb);
 539 }
 540
 541
 542 /**
 543  * Update the framebuffer's _DepthBuffer field using the renderbuffer
 544  * found at the given attachment index.
 545  *
 546  * If that attachment points to a combined GL_DEPTH_STENCIL renderbuffer,
 547  * create and install a depth wrapper/adaptor.
 548  *
 549  * \param fb  the framebuffer whose _DepthBuffer field to update
 550  * \param attIndex  indicates the renderbuffer to possibly wrap
 551  */
 552 void
 553 _mesa_update_depth_buffer(GLcontext *ctx,
 554                           struct gl_framebuffer *fb,
 555                           GLuint attIndex)
 556 {
 557    struct gl_renderbuffer *depthRb;
 558
 559    /* only one possiblity for now */
 560    ASSERT(attIndex == BUFFER_DEPTH);
 561
 562    depthRb = fb->Attachment[attIndex].Renderbuffer;
 563
 564    if (depthRb && depthRb->_ActualFormat == GL_DEPTH24_STENCIL8_EXT) {
 565       /* The attached depth buffer is a GL_DEPTH_STENCIL renderbuffer */
 566       if (!fb->_DepthBuffer
 567           || fb->_DepthBuffer->Wrapped != depthRb
 568           || fb->_DepthBuffer->_BaseFormat != GL_DEPTH_COMPONENT) {
 569          /* need to update wrapper */
 570          struct gl_renderbuffer *wrapper
 571             = _mesa_new_z24_renderbuffer_wrapper(ctx, depthRb);
 572          set_depth_renderbuffer(fb, wrapper);
 573          ASSERT(fb->_DepthBuffer->Wrapped == depthRb);
 574       }
 575    }
 576    else {
 577       /* depthRb may be null */
 578       set_depth_renderbuffer(fb, depthRb);
 579    }
 580 }
 581
 582
 583 /**
 584  * Update the framebuffer's _StencilBuffer field using the renderbuffer
 585  * found at the given attachment index.
 586  *
 587  * If that attachment points to a combined GL_DEPTH_STENCIL renderbuffer,
 588  * create and install a stencil wrapper/adaptor.
 589  *
 590  * \param fb  the framebuffer whose _StencilBuffer field to update
 591  * \param attIndex  indicates the renderbuffer to possibly wrap
 592  */
 593 void
 594 _mesa_update_stencil_buffer(GLcontext *ctx,
 595                             struct gl_framebuffer *fb,
 596                             GLuint attIndex)
 597 {
 598    struct gl_renderbuffer *stencilRb;
 599
 600    ASSERT(attIndex == BUFFER_DEPTH ||
 601           attIndex == BUFFER_STENCIL);
 602
 603    stencilRb = fb->Attachment[attIndex].Renderbuffer;
 604
 605    if (stencilRb && stencilRb->_ActualFormat == GL_DEPTH24_STENCIL8_EXT) {
 606       /* The attached stencil buffer is a GL_DEPTH_STENCIL renderbuffer */
 607       if (!fb->_StencilBuffer
 608           || fb->_StencilBuffer->Wrapped != stencilRb
 609           || fb->_StencilBuffer->_BaseFormat != GL_STENCIL_INDEX) {
 610          /* need to update wrapper */
 611          struct gl_renderbuffer *wrapper
 612             = _mesa_new_s8_renderbuffer_wrapper(ctx, stencilRb);
 613          set_stencil_renderbuffer(fb, wrapper);
 614          ASSERT(fb->_StencilBuffer->Wrapped == stencilRb);
 615       }
 616    }
 617    else {
 618       /* stencilRb may be null */
 619       set_stencil_renderbuffer(fb, stencilRb);
 620    }
 621 }
 622
 623
 624 /**
 625  * Update the list of color drawing renderbuffer pointers.
 626  * Later, when we're rendering we'll loop from 0 to _NumColorDrawBuffers
 627  * writing colors.
 628  */
 629 static void
 630 update_color_draw_buffers(GLcontext *ctx, struct gl_framebuffer *fb)
 631 {
 632    GLuint output;
 633
 634    /*
 635     * Fragment programs can write to multiple colorbuffers with
 636     * the GL_ARB_draw_buffers extension.
 637     */
 638    for (output = 0; output < ctx->Const.MaxDrawBuffers; output++) {
 639       GLbitfield bufferMask = fb->_ColorDrawBufferMask[output];
 640       GLuint count = 0;
 641       GLuint i;
 642       if (!fb->DeletePending) {
 643          /* We need the inner loop here because glDrawBuffer(GL_FRONT_AND_BACK)
 644           * can specify writing to two or four color buffers (for example).
 645           */
 646          for (i = 0; bufferMask && i < BUFFER_COUNT; i++) {
 647             const GLuint bufferBit = 1 << i;
 648             if (bufferBit & bufferMask) {
 649                struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 650                if (rb && rb->Width > 0 && rb->Height > 0) {
 651                   fb->_ColorDrawBuffers[output][count] = rb;
 652                   count++;
 653                }
 654                else {
 655                   /*
 656                   _mesa_warning(ctx, "DrawBuffer names a missing buffer!\n");
 657                   */
 658                }
 659                bufferMask &= ~bufferBit;
 660             }
 661          }
 662       }
 663       fb->_NumColorDrawBuffers[output] = count;
 664    }
 665 }
 666
 667
 668 /**
 669  * Update the color read renderbuffer pointer.
 670  * Unlike the DrawBuffer, we can only read from one (or zero) color buffers.
 671  */
 672 static void
 673 update_color_read_buffer(GLcontext *ctx, struct gl_framebuffer *fb)
 674 {
 675    (void) ctx;
 676    if (fb->_ColorReadBufferIndex == -1 ||
 677        fb->DeletePending ||
 678        fb->Width == 0 ||
 679        fb->Height == 0) {
 680       fb->_ColorReadBuffer = NULL; /* legal! */
 681    }
 682    else {
 683       ASSERT(fb->_ColorReadBufferIndex >= 0);
 684       ASSERT(fb->_ColorReadBufferIndex < BUFFER_COUNT);
 685       fb->_ColorReadBuffer
 686          = fb->Attachment[fb->_ColorReadBufferIndex].Renderbuffer;
 687    }
 688 }
 689
 690
 691 /**
 692  * Update state related to the current draw/read framebuffers.
 693  * Specifically, update these framebuffer fields:
 694  *    _ColorDrawBuffers
 695  *    _NumColorDrawBuffers
 696  *    _ColorReadBuffer
 697  *    _DepthBuffer
 698  *    _StencilBuffer
 699  * If the current framebuffer is user-created, make sure it's complete.
 700  * The following functions can effect this state:  glReadBuffer,
 701  * glDrawBuffer, glDrawBuffersARB, glFramebufferRenderbufferEXT,
 702  * glRenderbufferStorageEXT.
 703  */
 704 void
 705 _mesa_update_framebuffer(GLcontext *ctx)
 706 {
 707    struct gl_framebuffer *fb = ctx->DrawBuffer;
 708
 709    /* Completeness only matters for user-created framebuffers */
 710    if (fb->Name != 0) {
 711       _mesa_test_framebuffer_completeness(ctx, fb);
 712       _mesa_update_framebuffer_visual(fb);
 713    }
 714
 715    update_color_draw_buffers(ctx, fb);
 716    update_color_read_buffer(ctx, fb);
 717    _mesa_update_depth_buffer(ctx, fb, BUFFER_DEPTH);
 718    _mesa_update_stencil_buffer(ctx, fb, BUFFER_STENCIL);
 719
 720    compute_depth_max(fb);
 721 }
 722
 723
 724 /**
 725  * Check if the renderbuffer for a read operation (glReadPixels, glCopyPixels,
 726  * glCopyTex[Sub]Image, etc. exists.
 727  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 728  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 729  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 730  */
 731 GLboolean
 732 _mesa_source_buffer_exists(GLcontext *ctx, GLenum format)
 733 {
 734    const struct gl_renderbuffer_attachment *att
 735       = ctx->ReadBuffer->Attachment;
 736
 737    if (ctx->ReadBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 738       return GL_FALSE;
 739    }
 740
 741    switch (format) {
 742    case GL_COLOR:
 743    case GL_RED:
 744    case GL_GREEN:
 745    case GL_BLUE:
 746    case GL_ALPHA:
 747    case GL_LUMINANCE:
 748    case GL_LUMINANCE_ALPHA:
 749    case GL_INTENSITY:
 750    case GL_RGB:
 751    case GL_BGR:
 752    case GL_RGBA:
 753    case GL_BGRA:
 754    case GL_ABGR_EXT:
 755    case GL_COLOR_INDEX:
 756       if (ctx->ReadBuffer->_ColorReadBuffer == NULL) {
 757          return GL_FALSE;
 758       }
 759       /* XXX enable this post 6.5 release:
 760       ASSERT(ctx->ReadBuffer->_ColorReadBuffer->RedBits > 0 ||
 761              ctx->ReadBuffer->_ColorReadBuffer->IndexBits > 0);
 762       */
 763       break;
 764    case GL_DEPTH:
 765    case GL_DEPTH_COMPONENT:
 766       if (!att[BUFFER_DEPTH].Renderbuffer) {
 767          return GL_FALSE;
 768       }
 769       ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);
 770       break;
 771    case GL_STENCIL:
 772    case GL_STENCIL_INDEX:
 773       if (!att[BUFFER_STENCIL].Renderbuffer) {
 774          return GL_FALSE;
 775       }
 776       ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);
 777       break;
 778    case GL_DEPTH_STENCIL_EXT:
 779       if (!att[BUFFER_DEPTH].Renderbuffer ||
 780           !att[BUFFER_STENCIL].Renderbuffer) {
 781          return GL_FALSE;
 782       }
 783       ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);
 784       ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);
 785       break;
 786    default:
 787       _mesa_problem(ctx,
 788                     "Unexpected format 0x%x in _mesa_source_buffer_exists",
 789                     format);
 790       return GL_FALSE;
 791    }
 792
 793    /* OK */
 794    return GL_TRUE;
 795 }
 796
 797
 798 /**
 799  * As above, but for drawing operations.
 800  * XXX code do some code merging w/ above function.
 801  */
 802 GLboolean
 803 _mesa_dest_buffer_exists(GLcontext *ctx, GLenum format)
 804 {
 805    const struct gl_renderbuffer_attachment *att
 806       = ctx->ReadBuffer->Attachment;
 807
 808    if (ctx->DrawBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 809       return GL_FALSE;
 810    }
 811
 812    switch (format) {
 813    case GL_COLOR:
 814    case GL_RED:
 815    case GL_GREEN:
 816    case GL_BLUE:
 817    case GL_ALPHA:
 818    case GL_LUMINANCE:
 819    case GL_LUMINANCE_ALPHA:
 820    case GL_INTENSITY:
 821    case GL_RGB:
 822    case GL_BGR:
 823    case GL_RGBA:
 824    case GL_BGRA:
 825    case GL_ABGR_EXT:
 826    case GL_COLOR_INDEX:
 827       /* nothing special */
 828       /* Could assert that colorbuffer has RedBits > 0 */
 829       break;
 830    case GL_DEPTH:
 831    case GL_DEPTH_COMPONENT:
 832       if (!att[BUFFER_DEPTH].Renderbuffer) {
 833          return GL_FALSE;
 834       }
 835       ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);
 836       break;
 837    case GL_STENCIL:
 838    case GL_STENCIL_INDEX:
 839       if (!att[BUFFER_STENCIL].Renderbuffer) {
 840          return GL_FALSE;
 841       }
 842       ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);
 843       break;
 844    case GL_DEPTH_STENCIL_EXT:
 845       if (!att[BUFFER_DEPTH].Renderbuffer ||
 846           !att[BUFFER_STENCIL].Renderbuffer) {
 847          return GL_FALSE;
 848       }
 849       ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);
 850       ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);
 851       break;
 852    default:
 853       _mesa_problem(ctx,
 854                     "Unexpected format 0x%x in _mesa_source_buffer_exists",
 855                     format);
 856       return GL_FALSE;
 857    }
 858
 859    /* OK */
 860    return GL_TRUE;
 861 }