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