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 "mtypes.h"
  39 #include "fbobject.h"
  40 #include "framebuffer.h"
  41 #include "renderbuffer.h"
  42 #include "texobj.h"
  43
  44
  45
  46 /**
  47  * Compute/set the _DepthMax field for the given framebuffer.
  48  * This value depends on the Z buffer resolution.
  49  */
  50 static void
  51 compute_depth_max(struct gl_framebuffer *fb)
  52 {
  53    if (fb->Visual.depthBits == 0) {
  54       /* Special case.  Even if we don't have a depth buffer we need
  55        * good values for DepthMax for Z vertex transformation purposes
  56        * and for per-fragment fog computation.
  57        */
  58       fb->_DepthMax = (1 << 16) - 1;
  59    }
  60    else if (fb->Visual.depthBits < 32) {
  61       fb->_DepthMax = (1 << fb->Visual.depthBits) - 1;
  62    }
  63    else {
  64       /* Special case since shift values greater than or equal to the
  65        * number of bits in the left hand expression's type are undefined.
  66        */
  67       fb->_DepthMax = 0xffffffff;
  68    }
  69    fb->_DepthMaxF = (GLfloat) fb->_DepthMax;
  70
  71    /* Minimum resolvable depth value, for polygon offset */
  72    fb->_MRD = (GLfloat)1.0 / fb->_DepthMaxF;
  73 }
  74
  75
  76 /**
  77  * Create and initialize a gl_framebuffer object.
  78  * This is intended for creating _window_system_ framebuffers, not generic
  79  * framebuffer objects ala GL_EXT_framebuffer_object.
  80  *
  81  * \sa _mesa_new_framebuffer
  82  */
  83 struct gl_framebuffer *
  84 _mesa_create_framebuffer(const GLvisual *visual)
  85 {
  86    struct gl_framebuffer *fb = CALLOC_STRUCT(gl_framebuffer);
  87    assert(visual);
  88    if (fb) {
  89       _mesa_initialize_framebuffer(fb, visual);
  90    }
  91    return fb;
  92 }
  93
  94
  95 /**
  96  * Allocate a new gl_framebuffer object.
  97  * This is the default function for ctx->Driver.NewFramebuffer().
  98  * This is for allocating user-created framebuffers, not window-system
  99  * framebuffers!
 100  * \sa _mesa_create_framebuffer
 101  */
 102 struct gl_framebuffer *
 103 _mesa_new_framebuffer(GLcontext *ctx, GLuint name)
 104 {
 105    struct gl_framebuffer *fb;
 106    (void) ctx;
 107    assert(name != 0);
 108    fb = CALLOC_STRUCT(gl_framebuffer);
 109    if (fb) {
 110       fb->Name = name;
 111       fb->RefCount = 1;
 112       fb->_NumColorDrawBuffers = 1;
 113       fb->ColorDrawBuffer[0] = GL_COLOR_ATTACHMENT0_EXT;
 114       fb->_ColorDrawBufferIndexes[0] = BUFFER_COLOR0;
 115       fb->ColorReadBuffer = GL_COLOR_ATTACHMENT0_EXT;
 116       fb->_ColorReadBufferIndex = BUFFER_COLOR0;
 117       fb->Delete = _mesa_destroy_framebuffer;
 118    }
 119    return fb;
 120 }
 121
 122
 123 /**
 124  * Initialize a gl_framebuffer object.  Typically used to initialize
 125  * window system-created framebuffers, not user-created framebuffers.
 126  * \sa _mesa_create_framebuffer
 127  */
 128 void
 129 _mesa_initialize_framebuffer(struct gl_framebuffer *fb, const GLvisual *visual)
 130 {
 131    assert(fb);
 132    assert(visual);
 133
 134    _mesa_bzero(fb, sizeof(struct gl_framebuffer));
 135
 136    _glthread_INIT_MUTEX(fb->Mutex);
 137
 138    fb->RefCount = 1;
 139
 140    /* save the visual */
 141    fb->Visual = *visual;
 142
 143    /* Init read/draw renderbuffer state */
 144    if (visual->doubleBufferMode) {
 145       fb->_NumColorDrawBuffers = 1;
 146       fb->ColorDrawBuffer[0] = GL_BACK;
 147       fb->_ColorDrawBufferIndexes[0] = BUFFER_BACK_LEFT;
 148       fb->ColorReadBuffer = GL_BACK;
 149       fb->_ColorReadBufferIndex = BUFFER_BACK_LEFT;
 150    }
 151    else {
 152       fb->_NumColorDrawBuffers = 1;
 153       fb->ColorDrawBuffer[0] = GL_FRONT;
 154       fb->_ColorDrawBufferIndexes[0] = BUFFER_FRONT_LEFT;
 155       fb->ColorReadBuffer = GL_FRONT;
 156       fb->_ColorReadBufferIndex = BUFFER_FRONT_LEFT;
 157    }
 158
 159    fb->Delete = _mesa_destroy_framebuffer;
 160    fb->_Status = GL_FRAMEBUFFER_COMPLETE_EXT;
 161
 162    compute_depth_max(fb);
 163 }
 164
 165
 166 /**
 167  * Deallocate buffer and everything attached to it.
 168  * Typically called via the gl_framebuffer->Delete() method.
 169  */
 170 void
 171 _mesa_destroy_framebuffer(struct gl_framebuffer *fb)
 172 {
 173    if (fb) {
 174       _mesa_free_framebuffer_data(fb);
 175       _mesa_free(fb);
 176    }
 177 }
 178
 179
 180 /**
 181  * Free all the data hanging off the given gl_framebuffer, but don't free
 182  * the gl_framebuffer object itself.
 183  */
 184 void
 185 _mesa_free_framebuffer_data(struct gl_framebuffer *fb)
 186 {
 187    GLuint i;
 188
 189    assert(fb);
 190    assert(fb->RefCount == 0);
 191
 192    _glthread_DESTROY_MUTEX(fb->Mutex);
 193
 194    for (i = 0; i < BUFFER_COUNT; i++) {
 195       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 196       if (att->Renderbuffer) {
 197          _mesa_reference_renderbuffer(&att->Renderbuffer, NULL);
 198       }
 199       if (att->Texture) {
 200          _mesa_reference_texobj(&att->Texture, NULL);
 201       }
 202       ASSERT(!att->Renderbuffer);
 203       ASSERT(!att->Texture);
 204       att->Type = GL_NONE;
 205    }
 206
 207    /* unbind _Depth/_StencilBuffer to decr ref counts */
 208    _mesa_reference_renderbuffer(&fb->_DepthBuffer, NULL);
 209    _mesa_reference_renderbuffer(&fb->_StencilBuffer, NULL);
 210 }
 211
 212
 213 /**
 214  * Set *ptr to point to fb, with refcounting and locking.
 215  */
 216 void
 217 _mesa_reference_framebuffer(struct gl_framebuffer **ptr,
 218                             struct gl_framebuffer *fb)
 219 {
 220    assert(ptr);
 221    if (*ptr == fb) {
 222       /* no change */
 223       return;
 224    }
 225    if (*ptr) {
 226       _mesa_unreference_framebuffer(ptr);
 227    }
 228    assert(!*ptr);
 229    assert(fb);
 230    _glthread_LOCK_MUTEX(fb->Mutex);
 231    fb->RefCount++;
 232    _glthread_UNLOCK_MUTEX(fb->Mutex);
 233    *ptr = fb;
 234 }
 235
 236
 237 /**
 238  * Undo/remove a reference to a framebuffer object.
 239  * Decrement the framebuffer object's reference count and delete it when
 240  * the refcount hits zero.
 241  * Note: we pass the address of a pointer and set it to NULL.
 242  */
 243 void
 244 _mesa_unreference_framebuffer(struct gl_framebuffer **fb)
 245 {
 246    assert(fb);
 247    if (*fb) {
 248       GLboolean deleteFlag = GL_FALSE;
 249
 250       _glthread_LOCK_MUTEX((*fb)->Mutex);
 251       ASSERT((*fb)->RefCount > 0);
 252       (*fb)->RefCount--;
 253       deleteFlag = ((*fb)->RefCount == 0);
 254       _glthread_UNLOCK_MUTEX((*fb)->Mutex);
 255
 256       if (deleteFlag)
 257          (*fb)->Delete(*fb);
 258
 259       *fb = NULL;
 260    }
 261 }
 262
 263
 264
 265
 266 /**
 267  * Resize the given framebuffer's renderbuffers to the new width and height.
 268  * This should only be used for window-system framebuffers, not
 269  * user-created renderbuffers (i.e. made with GL_EXT_framebuffer_object).
 270  * This will typically be called via ctx->Driver.ResizeBuffers() or directly
 271  * from a device driver.
 272  *
 273  * \note it's possible for ctx to be null since a window can be resized
 274  * without a currently bound rendering context.
 275  */
 276 void
 277 _mesa_resize_framebuffer(GLcontext *ctx, struct gl_framebuffer *fb,
 278                          GLuint width, GLuint height)
 279 {
 280    GLuint i;
 281
 282    /* XXX I think we could check if the size is not changing
 283     * and return early.
 284     */
 285
 286    /* For window system framebuffers, Name is zero */
 287    assert(fb->Name == 0);
 288
 289    for (i = 0; i < BUFFER_COUNT; i++) {
 290       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 291       if (att->Type == GL_RENDERBUFFER_EXT && att->Renderbuffer) {
 292          struct gl_renderbuffer *rb = att->Renderbuffer;
 293          /* only resize if size is changing */
 294          if (rb->Width != width || rb->Height != height) {
 295             /* could just as well pass rb->_ActualFormat here */
 296             if (rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 297                ASSERT(rb->Width == width);
 298                ASSERT(rb->Height == height);
 299             }
 300             else {
 301                _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 302                /* no return */
 303             }
 304          }
 305       }
 306    }
 307
 308    if (fb->_DepthBuffer) {
 309       struct gl_renderbuffer *rb = fb->_DepthBuffer;
 310       if (rb->Width != width || rb->Height != height) {
 311          if (!rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 312             _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 313          }
 314       }
 315    }
 316
 317    if (fb->_StencilBuffer) {
 318       struct gl_renderbuffer *rb = fb->_StencilBuffer;
 319       if (rb->Width != width || rb->Height != height) {
 320          if (!rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 321             _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 322          }
 323       }
 324    }
 325
 326    fb->Width = width;
 327    fb->Height = height;
 328
 329    if (ctx) {
 330       /* update scissor / window bounds */
 331       _mesa_update_draw_buffer_bounds(ctx);
 332       /* Signal new buffer state so that swrast will update its clipping
 333        * info (the CLIP_BIT flag).
 334        */
 335       ctx->NewState |= _NEW_BUFFERS;
 336    }
 337 }
 338
 339
 340
 341 /**
 342  * XXX THIS IS OBSOLETE - drivers should take care of detecting window
 343  * size changes and act accordingly, likely calling _mesa_resize_framebuffer().
 344  *
 345  * GL_MESA_resize_buffers extension.
 346  *
 347  * When this function is called, we'll ask the window system how large
 348  * the current window is.  If it's a new size, we'll call the driver's
 349  * ResizeBuffers function.  The driver will then resize its color buffers
 350  * as needed, and maybe call the swrast's routine for reallocating
 351  * swrast-managed depth/stencil/accum/etc buffers.
 352  * \note This function should only be called through the GL API, not
 353  * from device drivers (as was done in the past).
 354  */
 355 void
 356 _mesa_resizebuffers( GLcontext *ctx )
 357 {
 358    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 359
 360    if (MESA_VERBOSE & VERBOSE_API)
 361       _mesa_debug(ctx, "glResizeBuffersMESA\n");
 362
 363    if (!ctx->Driver.GetBufferSize) {
 364       return;
 365    }
 366
 367    if (ctx->WinSysDrawBuffer) {
 368       GLuint newWidth, newHeight;
 369       GLframebuffer *buffer = ctx->WinSysDrawBuffer;
 370
 371       assert(buffer->Name == 0);
 372
 373       /* ask device driver for size of output buffer */
 374       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 375
 376       /* see if size of device driver's color buffer (window) has changed */
 377       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 378          if (ctx->Driver.ResizeBuffers)
 379             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 380       }
 381    }
 382
 383    if (ctx->WinSysReadBuffer
 384        && ctx->WinSysReadBuffer != ctx->WinSysDrawBuffer) {
 385       GLuint newWidth, newHeight;
 386       GLframebuffer *buffer = ctx->WinSysReadBuffer;
 387
 388       assert(buffer->Name == 0);
 389
 390       /* ask device driver for size of read buffer */
 391       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 392
 393       /* see if size of device driver's color buffer (window) has changed */
 394       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 395          if (ctx->Driver.ResizeBuffers)
 396             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 397       }
 398    }
 399
 400    ctx->NewState |= _NEW_BUFFERS;  /* to update scissor / window bounds */
 401 }
 402
 403
 404 /*
 405  * XXX THIS IS OBSOLETE
 406  */
 407 void GLAPIENTRY
 408 _mesa_ResizeBuffersMESA( void )
 409 {
 410    GET_CURRENT_CONTEXT(ctx);
 411
 412    if (ctx->Extensions.MESA_resize_buffers)
 413       _mesa_resizebuffers( ctx );
 414 }
 415
 416
 417
 418 /**
 419  * Examine all the framebuffer's renderbuffers to update the Width/Height
 420  * fields of the framebuffer.  If we have renderbuffers with different
 421  * sizes, set the framebuffer's width and height to zero.
 422  * Note: this is only intended for user-created framebuffers, not
 423  * window-system framebuffes.
 424  */
 425 static void
 426 update_framebuffer_size(struct gl_framebuffer *fb)
 427 {
 428    GLboolean haveSize = GL_FALSE;
 429    GLuint i;
 430
 431    /* user-created framebuffers only */
 432    assert(fb->Name);
 433
 434    for (i = 0; i < BUFFER_COUNT; i++) {
 435       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 436       const struct gl_renderbuffer *rb = att->Renderbuffer;
 437       if (rb) {
 438          if (haveSize) {
 439             if (rb->Width != fb->Width && rb->Height != fb->Height) {
 440                /* size mismatch! */
 441                fb->Width = 0;
 442                fb->Height = 0;
 443                return;
 444             }
 445          }
 446          else {
 447             fb->Width = rb->Width;
 448             fb->Height = rb->Height;
 449             haveSize = GL_TRUE;
 450          }
 451       }
 452    }
 453 }
 454
 455
 456 /**
 457  * Update the context's current drawing buffer's Xmin, Xmax, Ymin, Ymax fields.
 458  * These values are computed from the buffer's width and height and
 459  * the scissor box, if it's enabled.
 460  * \param ctx  the GL context.
 461  */
 462 void
 463 _mesa_update_draw_buffer_bounds(GLcontext *ctx)
 464 {
 465    struct gl_framebuffer *buffer = ctx->DrawBuffer;
 466
 467    if (!buffer)
 468       return;
 469
 470    if (buffer->Name) {
 471       /* user-created framebuffer size depends on the renderbuffers */
 472       update_framebuffer_size(buffer);
 473    }
 474
 475    buffer->_Xmin = 0;
 476    buffer->_Ymin = 0;
 477    buffer->_Xmax = buffer->Width;
 478    buffer->_Ymax = buffer->Height;
 479
 480    if (ctx->Scissor.Enabled) {
 481       if (ctx->Scissor.X > buffer->_Xmin) {
 482          buffer->_Xmin = ctx->Scissor.X;
 483       }
 484       if (ctx->Scissor.Y > buffer->_Ymin) {
 485          buffer->_Ymin = ctx->Scissor.Y;
 486       }
 487       if (ctx->Scissor.X + ctx->Scissor.Width < buffer->_Xmax) {
 488          buffer->_Xmax = ctx->Scissor.X + ctx->Scissor.Width;
 489       }
 490       if (ctx->Scissor.Y + ctx->Scissor.Height < buffer->_Ymax) {
 491          buffer->_Ymax = ctx->Scissor.Y + ctx->Scissor.Height;
 492       }
 493       /* finally, check for empty region */
 494       if (buffer->_Xmin > buffer->_Xmax) {
 495          buffer->_Xmin = buffer->_Xmax;
 496       }
 497       if (buffer->_Ymin > buffer->_Ymax) {
 498          buffer->_Ymin = buffer->_Ymax;
 499       }
 500    }
 501
 502    ASSERT(buffer->_Xmin <= buffer->_Xmax);
 503    ASSERT(buffer->_Ymin <= buffer->_Ymax);
 504 }
 505
 506
 507 /**
 508  * The glGet queries of the framebuffer red/green/blue size, stencil size,
 509  * etc. are satisfied by the fields of ctx->DrawBuffer->Visual.  These can
 510  * change depending on the renderbuffer bindings.  This function updates
 511  * the given framebuffer's Visual from the current renderbuffer bindings.
 512  *
 513  * This may apply to user-created framebuffers or window system framebuffers.
 514  *
 515  * Also note: ctx->DrawBuffer->Visual.depthBits might not equal
 516  * ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer.DepthBits.
 517  * The former one is used to convert floating point depth values into
 518  * integer Z values.
 519  */
 520 void
 521 _mesa_update_framebuffer_visual(struct gl_framebuffer *fb)
 522 {
 523    GLuint i;
 524
 525    _mesa_bzero(&fb->Visual, sizeof(fb->Visual));
 526    fb->Visual.rgbMode = GL_TRUE; /* assume this */
 527
 528 #if 0 /* this _might_ be needed */
 529    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 530       /* leave visual fields zero'd */
 531       return;
 532    }
 533 #endif
 534
 535    /* find first RGB or CI renderbuffer */
 536    for (i = 0; i < BUFFER_COUNT; i++) {
 537       if (fb->Attachment[i].Renderbuffer) {
 538          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 539          if (rb->_BaseFormat == GL_RGBA || rb->_BaseFormat == GL_RGB) {
 540             fb->Visual.redBits = rb->RedBits;
 541             fb->Visual.greenBits = rb->GreenBits;
 542             fb->Visual.blueBits = rb->BlueBits;
 543             fb->Visual.alphaBits = rb->AlphaBits;
 544             fb->Visual.rgbBits = fb->Visual.redBits
 545                + fb->Visual.greenBits + fb->Visual.blueBits;
 546             fb->Visual.floatMode = GL_FALSE;
 547             break;
 548          }
 549          else if (rb->_BaseFormat == GL_COLOR_INDEX) {
 550             fb->Visual.indexBits = rb->IndexBits;
 551             fb->Visual.rgbMode = GL_FALSE;
 552             break;
 553          }
 554       }
 555    }
 556
 557    if (fb->Attachment[BUFFER_DEPTH].Renderbuffer) {
 558       fb->Visual.haveDepthBuffer = GL_TRUE;
 559       fb->Visual.depthBits
 560          = fb->Attachment[BUFFER_DEPTH].Renderbuffer->DepthBits;
 561    }
 562
 563    if (fb->Attachment[BUFFER_STENCIL].Renderbuffer) {
 564       fb->Visual.haveStencilBuffer = GL_TRUE;
 565       fb->Visual.stencilBits
 566          = fb->Attachment[BUFFER_STENCIL].Renderbuffer->StencilBits;
 567    }
 568
 569    if (fb->Attachment[BUFFER_ACCUM].Renderbuffer) {
 570       fb->Visual.haveAccumBuffer = GL_TRUE;
 571       fb->Visual.accumRedBits
 572          = fb->Attachment[BUFFER_ACCUM].Renderbuffer->RedBits;
 573       fb->Visual.accumGreenBits
 574          = fb->Attachment[BUFFER_ACCUM].Renderbuffer->GreenBits;
 575       fb->Visual.accumBlueBits
 576          = fb->Attachment[BUFFER_ACCUM].Renderbuffer->BlueBits;
 577       fb->Visual.accumAlphaBits
 578          = fb->Attachment[BUFFER_ACCUM].Renderbuffer->AlphaBits;
 579    }
 580
 581    compute_depth_max(fb);
 582 }
 583
 584
 585 /**
 586  * Update the framebuffer's _DepthBuffer field using the renderbuffer
 587  * found at the given attachment index.
 588  *
 589  * If that attachment points to a combined GL_DEPTH_STENCIL renderbuffer,
 590  * create and install a depth wrapper/adaptor.
 591  *
 592  * \param fb  the framebuffer whose _DepthBuffer field to update
 593  * \param attIndex  indicates the renderbuffer to possibly wrap
 594  */
 595 void
 596 _mesa_update_depth_buffer(GLcontext *ctx,
 597                           struct gl_framebuffer *fb,
 598                           GLuint attIndex)
 599 {
 600    struct gl_renderbuffer *depthRb;
 601
 602    /* only one possiblity for now */
 603    ASSERT(attIndex == BUFFER_DEPTH);
 604
 605    depthRb = fb->Attachment[attIndex].Renderbuffer;
 606
 607    if (depthRb && depthRb->_ActualFormat == GL_DEPTH24_STENCIL8_EXT) {
 608       /* The attached depth buffer is a GL_DEPTH_STENCIL renderbuffer */
 609       if (!fb->_DepthBuffer
 610           || fb->_DepthBuffer->Wrapped != depthRb
 611           || fb->_DepthBuffer->_BaseFormat != GL_DEPTH_COMPONENT) {
 612          /* need to update wrapper */
 613          struct gl_renderbuffer *wrapper
 614             = _mesa_new_z24_renderbuffer_wrapper(ctx, depthRb);
 615          _mesa_reference_renderbuffer(&fb->_DepthBuffer, wrapper);
 616          ASSERT(fb->_DepthBuffer->Wrapped == depthRb);
 617       }
 618    }
 619    else {
 620       /* depthRb may be null */
 621       _mesa_reference_renderbuffer(&fb->_DepthBuffer, depthRb);
 622    }
 623 }
 624
 625
 626 /**
 627  * Update the framebuffer's _StencilBuffer field using the renderbuffer
 628  * found at the given attachment index.
 629  *
 630  * If that attachment points to a combined GL_DEPTH_STENCIL renderbuffer,
 631  * create and install a stencil wrapper/adaptor.
 632  *
 633  * \param fb  the framebuffer whose _StencilBuffer field to update
 634  * \param attIndex  indicates the renderbuffer to possibly wrap
 635  */
 636 void
 637 _mesa_update_stencil_buffer(GLcontext *ctx,
 638                             struct gl_framebuffer *fb,
 639                             GLuint attIndex)
 640 {
 641    struct gl_renderbuffer *stencilRb;
 642
 643    ASSERT(attIndex == BUFFER_DEPTH ||
 644           attIndex == BUFFER_STENCIL);
 645
 646    stencilRb = fb->Attachment[attIndex].Renderbuffer;
 647
 648    if (stencilRb && stencilRb->_ActualFormat == GL_DEPTH24_STENCIL8_EXT) {
 649       /* The attached stencil buffer is a GL_DEPTH_STENCIL renderbuffer */
 650       if (!fb->_StencilBuffer
 651           || fb->_StencilBuffer->Wrapped != stencilRb
 652           || fb->_StencilBuffer->_BaseFormat != GL_STENCIL_INDEX) {
 653          /* need to update wrapper */
 654          struct gl_renderbuffer *wrapper
 655             = _mesa_new_s8_renderbuffer_wrapper(ctx, stencilRb);
 656          _mesa_reference_renderbuffer(&fb->_StencilBuffer, wrapper);
 657          ASSERT(fb->_StencilBuffer->Wrapped == stencilRb);
 658       }
 659    }
 660    else {
 661       /* stencilRb may be null */
 662       _mesa_reference_renderbuffer(&fb->_StencilBuffer, stencilRb);
 663    }
 664 }
 665
 666
 667 /*
 668  * Example DrawBuffers scenarios:
 669  *
 670  * 1. glDrawBuffer(GL_FRONT_AND_BACK), fixed-func or shader writes to
 671  * "gl_FragColor" or program writes to the "result.color" register:
 672  *
 673  *   fragment color output   renderbuffer
 674  *   ---------------------   ---------------
 675  *   color[0]                Front, Back
 676  *
 677  *
 678  * 2. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]), shader writes to
 679  * gl_FragData[i] or program writes to result.color[i] registers:
 680  *
 681  *   fragment color output   renderbuffer
 682  *   ---------------------   ---------------
 683  *   color[0]                Front
 684  *   color[1]                Aux0
 685  *   color[3]                Aux1
 686  *
 687  *
 688  * 3. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]) and shader writes to
 689  * gl_FragColor, or fixed function:
 690  *
 691  *   fragment color output   renderbuffer
 692  *   ---------------------   ---------------
 693  *   color[0]                Front, Aux0, Aux1
 694  *
 695  *
 696  * In either case, the list of renderbuffers is stored in the
 697  * framebuffer->_ColorDrawBuffers[] array and
 698  * framebuffer->_NumColorDrawBuffers indicates the number of buffers.
 699  * The renderer (like swrast) has to look at the current fragment shader
 700  * to see if it writes to gl_FragColor vs. gl_FragData[i] to determine
 701  * how to map color outputs to renderbuffers.
 702  *
 703  * Note that these two calls are equivalent (for fixed function fragment
 704  * shading anyway):
 705  *   a)  glDrawBuffer(GL_FRONT_AND_BACK);  (assuming non-stereo framebuffer)
 706  *   b)  glDrawBuffers(2, [GL_FRONT_LEFT, GL_BACK_LEFT]);
 707  */
 708
 709
 710
 711
 712 /**
 713  * Update the (derived) list of color drawing renderbuffer pointers.
 714  * Later, when we're rendering we'll loop from 0 to _NumColorDrawBuffers
 715  * writing colors.
 716  */
 717 static void
 718 update_color_draw_buffers(GLcontext *ctx, struct gl_framebuffer *fb)
 719 {
 720    GLuint output;
 721
 722    /* set 0th buffer to NULL now in case _NumColorDrawBuffers is zero */
 723    fb->_ColorDrawBuffers[0] = NULL;
 724
 725    for (output = 0; output < fb->_NumColorDrawBuffers; output++) {
 726       GLint buf = fb->_ColorDrawBufferIndexes[output];
 727       if (buf >= 0) {
 728          fb->_ColorDrawBuffers[output] = fb->Attachment[buf].Renderbuffer;
 729       }
 730       else {
 731          fb->_ColorDrawBuffers[output] = NULL;
 732       }
 733    }
 734 }
 735
 736
 737 /**
 738  * Update the (derived) color read renderbuffer pointer.
 739  * Unlike the DrawBuffer, we can only read from one (or zero) color buffers.
 740  */
 741 static void
 742 update_color_read_buffer(GLcontext *ctx, struct gl_framebuffer *fb)
 743 {
 744    (void) ctx;
 745    if (fb->_ColorReadBufferIndex == -1 ||
 746        fb->DeletePending ||
 747        fb->Width == 0 ||
 748        fb->Height == 0) {
 749       fb->_ColorReadBuffer = NULL; /* legal! */
 750    }
 751    else {
 752       ASSERT(fb->_ColorReadBufferIndex >= 0);
 753       ASSERT(fb->_ColorReadBufferIndex < BUFFER_COUNT);
 754       fb->_ColorReadBuffer
 755          = fb->Attachment[fb->_ColorReadBufferIndex].Renderbuffer;
 756    }
 757 }
 758
 759
 760 /**
 761  * Update a gl_framebuffer's derived state.
 762  *
 763  * Specifically, update these framebuffer fields:
 764  *    _ColorDrawBuffers
 765  *    _NumColorDrawBuffers
 766  *    _ColorReadBuffer
 767  *    _DepthBuffer
 768  *    _StencilBuffer
 769  *
 770  * If the framebuffer is user-created, make sure it's complete.
 771  *
 772  * The following functions (at least) can effect framebuffer state:
 773  * glReadBuffer, glDrawBuffer, glDrawBuffersARB, glFramebufferRenderbufferEXT,
 774  * glRenderbufferStorageEXT.
 775  */
 776 static void
 777 update_framebuffer(GLcontext *ctx, struct gl_framebuffer *fb)
 778 {
 779    if (fb->Name == 0) {
 780       /* This is a window-system framebuffer */
 781       /* Need to update the FB's GL_DRAW_BUFFER state to match the
 782        * context state (GL_READ_BUFFER too).
 783        */
 784       if (fb->ColorDrawBuffer[0] != ctx->Color.DrawBuffer[0]) {
 785          _mesa_drawbuffers(ctx, ctx->Const.MaxDrawBuffers,
 786                            ctx->Color.DrawBuffer, NULL);
 787       }
 788       if (fb->ColorReadBuffer != ctx->Pixel.ReadBuffer) {
 789
 790       }
 791    }
 792    else {
 793       /* This is a user-created framebuffer.
 794        * Completeness only matters for user-created framebuffers.
 795        */
 796       _mesa_test_framebuffer_completeness(ctx, fb);
 797       _mesa_update_framebuffer_visual(fb);
 798    }
 799
 800    /* Strictly speaking, we don't need to update the draw-state
 801     * if this FB is bound as ctx->ReadBuffer (and conversely, the
 802     * read-state if this FB is bound as ctx->DrawBuffer), but no
 803     * harm.
 804     */
 805    update_color_draw_buffers(ctx, fb);
 806    update_color_read_buffer(ctx, fb);
 807    _mesa_update_depth_buffer(ctx, fb, BUFFER_DEPTH);
 808    _mesa_update_stencil_buffer(ctx, fb, BUFFER_STENCIL);
 809
 810    compute_depth_max(fb);
 811 }
 812
 813
 814 /**
 815  * Update state related to the current draw/read framebuffers.
 816  */
 817 void
 818 _mesa_update_framebuffer(GLcontext *ctx)
 819 {
 820    struct gl_framebuffer *drawFb = ctx->DrawBuffer;
 821    struct gl_framebuffer *readFb = ctx->ReadBuffer;
 822
 823    update_framebuffer(ctx, drawFb);
 824    if (readFb != drawFb)
 825       update_framebuffer(ctx, readFb);
 826 }
 827
 828
 829 /**
 830  * Check if the renderbuffer for a read operation (glReadPixels, glCopyPixels,
 831  * glCopyTex[Sub]Image, etc. exists.
 832  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 833  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 834  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 835  */
 836 GLboolean
 837 _mesa_source_buffer_exists(GLcontext *ctx, GLenum format)
 838 {
 839    const struct gl_renderbuffer_attachment *att
 840       = ctx->ReadBuffer->Attachment;
 841
 842    if (ctx->ReadBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 843       return GL_FALSE;
 844    }
 845
 846    switch (format) {
 847    case GL_COLOR:
 848    case GL_RED:
 849    case GL_GREEN:
 850    case GL_BLUE:
 851    case GL_ALPHA:
 852    case GL_LUMINANCE:
 853    case GL_LUMINANCE_ALPHA:
 854    case GL_INTENSITY:
 855    case GL_RGB:
 856    case GL_BGR:
 857    case GL_RGBA:
 858    case GL_BGRA:
 859    case GL_ABGR_EXT:
 860    case GL_COLOR_INDEX:
 861       if (ctx->ReadBuffer->_ColorReadBuffer == NULL) {
 862          return GL_FALSE;
 863       }
 864       /* XXX enable this post 6.5 release:
 865       ASSERT(ctx->ReadBuffer->_ColorReadBuffer->RedBits > 0 ||
 866              ctx->ReadBuffer->_ColorReadBuffer->IndexBits > 0);
 867       */
 868       break;
 869    case GL_DEPTH:
 870    case GL_DEPTH_COMPONENT:
 871       if (!att[BUFFER_DEPTH].Renderbuffer) {
 872          return GL_FALSE;
 873       }
 874       ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);
 875       break;
 876    case GL_STENCIL:
 877    case GL_STENCIL_INDEX:
 878       if (!att[BUFFER_STENCIL].Renderbuffer) {
 879          return GL_FALSE;
 880       }
 881       ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);
 882       break;
 883    case GL_DEPTH_STENCIL_EXT:
 884       if (!att[BUFFER_DEPTH].Renderbuffer ||
 885           !att[BUFFER_STENCIL].Renderbuffer) {
 886          return GL_FALSE;
 887       }
 888       ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);
 889       ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);
 890       break;
 891    default:
 892       _mesa_problem(ctx,
 893                     "Unexpected format 0x%x in _mesa_source_buffer_exists",
 894                     format);
 895       return GL_FALSE;
 896    }
 897
 898    /* OK */
 899    return GL_TRUE;
 900 }
 901
 902
 903 /**
 904  * As above, but for drawing operations.
 905  * XXX code do some code merging w/ above function.
 906  */
 907 GLboolean
 908 _mesa_dest_buffer_exists(GLcontext *ctx, GLenum format)
 909 {
 910    const struct gl_renderbuffer_attachment *att
 911       = ctx->ReadBuffer->Attachment;
 912
 913    if (ctx->DrawBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 914       return GL_FALSE;
 915    }
 916
 917    switch (format) {
 918    case GL_COLOR:
 919    case GL_RED:
 920    case GL_GREEN:
 921    case GL_BLUE:
 922    case GL_ALPHA:
 923    case GL_LUMINANCE:
 924    case GL_LUMINANCE_ALPHA:
 925    case GL_INTENSITY:
 926    case GL_RGB:
 927    case GL_BGR:
 928    case GL_RGBA:
 929    case GL_BGRA:
 930    case GL_ABGR_EXT:
 931    case GL_COLOR_INDEX:
 932       /* nothing special */
 933       /* Could assert that colorbuffer has RedBits > 0 */
 934       break;
 935    case GL_DEPTH:
 936    case GL_DEPTH_COMPONENT:
 937       if (!att[BUFFER_DEPTH].Renderbuffer) {
 938          return GL_FALSE;
 939       }
 940       ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);
 941       break;
 942    case GL_STENCIL:
 943    case GL_STENCIL_INDEX:
 944       if (!att[BUFFER_STENCIL].Renderbuffer) {
 945          return GL_FALSE;
 946       }
 947       ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);
 948       break;
 949    case GL_DEPTH_STENCIL_EXT:
 950       if (!att[BUFFER_DEPTH].Renderbuffer ||
 951           !att[BUFFER_STENCIL].Renderbuffer) {
 952          return GL_FALSE;
 953       }
 954       ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);
 955       ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);
 956       break;
 957    default:
 958       _mesa_problem(ctx,
 959                     "Unexpected format 0x%x in _mesa_source_buffer_exists",
 960                     format);
 961       return GL_FALSE;
 962    }
 963
 964    /* OK */
 965    return GL_TRUE;
 966 }