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 "macros.h"
  39 #include "mtypes.h"
  40 #include "fbobject.h"
  41 #include "framebuffer.h"
  42 #include "renderbuffer.h"
  43 #include "texobj.h"
  44
  45
  46
  47 /**
  48  * Compute/set the _DepthMax field for the given framebuffer.
  49  * This value depends on the Z buffer resolution.
  50  */
  51 static void
  52 compute_depth_max(struct gl_framebuffer *fb)
  53 {
  54    if (fb->Visual.depthBits == 0) {
  55       /* Special case.  Even if we don't have a depth buffer we need
  56        * good values for DepthMax for Z vertex transformation purposes
  57        * and for per-fragment fog computation.
  58        */
  59       fb->_DepthMax = (1 << 16) - 1;
  60    }
  61    else if (fb->Visual.depthBits < 32) {
  62       fb->_DepthMax = (1 << fb->Visual.depthBits) - 1;
  63    }
  64    else {
  65       /* Special case since shift values greater than or equal to the
  66        * number of bits in the left hand expression's type are undefined.
  67        */
  68       fb->_DepthMax = 0xffffffff;
  69    }
  70    fb->_DepthMaxF = (GLfloat) fb->_DepthMax;
  71
  72    /* Minimum resolvable depth value, for polygon offset */
  73    fb->_MRD = (GLfloat)1.0 / fb->_DepthMaxF;
  74 }
  75
  76
  77 /**
  78  * Create and initialize a gl_framebuffer object.
  79  * This is intended for creating _window_system_ framebuffers, not generic
  80  * framebuffer objects ala GL_EXT_framebuffer_object.
  81  *
  82  * \sa _mesa_new_framebuffer
  83  */
  84 struct gl_framebuffer *
  85 _mesa_create_framebuffer(const GLvisual *visual)
  86 {
  87    struct gl_framebuffer *fb = CALLOC_STRUCT(gl_framebuffer);
  88    assert(visual);
  89    if (fb) {
  90       _mesa_initialize_framebuffer(fb, visual);
  91    }
  92    return fb;
  93 }
  94
  95
  96 /**
  97  * Allocate a new gl_framebuffer object.
  98  * This is the default function for ctx->Driver.NewFramebuffer().
  99  * This is for allocating user-created framebuffers, not window-system
 100  * framebuffers!
 101  * \sa _mesa_create_framebuffer
 102  */
 103 struct gl_framebuffer *
 104 _mesa_new_framebuffer(GLcontext *ctx, GLuint name)
 105 {
 106    struct gl_framebuffer *fb;
 107    (void) ctx;
 108    assert(name != 0);
 109    fb = CALLOC_STRUCT(gl_framebuffer);
 110    if (fb) {
 111       fb->Name = name;
 112       fb->RefCount = 1;
 113       fb->_NumColorDrawBuffers = 1;
 114       fb->ColorDrawBuffer[0] = GL_COLOR_ATTACHMENT0_EXT;
 115       fb->_ColorDrawBufferIndexes[0] = BUFFER_COLOR0;
 116       fb->ColorReadBuffer = GL_COLOR_ATTACHMENT0_EXT;
 117       fb->_ColorReadBufferIndex = BUFFER_COLOR0;
 118       fb->Delete = _mesa_destroy_framebuffer;
 119       _glthread_INIT_MUTEX(fb->Mutex);
 120    }
 121    return fb;
 122 }
 123
 124
 125 /**
 126  * Initialize a gl_framebuffer object.  Typically used to initialize
 127  * window system-created framebuffers, not user-created framebuffers.
 128  * \sa _mesa_create_framebuffer
 129  */
 130 void
 131 _mesa_initialize_framebuffer(struct gl_framebuffer *fb, const GLvisual *visual)
 132 {
 133    assert(fb);
 134    assert(visual);
 135
 136    _mesa_bzero(fb, sizeof(struct gl_framebuffer));
 137
 138    _glthread_INIT_MUTEX(fb->Mutex);
 139
 140    fb->RefCount = 1;
 141
 142    /* save the visual */
 143    fb->Visual = *visual;
 144
 145    /* Init read/draw renderbuffer state */
 146    if (visual->doubleBufferMode) {
 147       fb->_NumColorDrawBuffers = 1;
 148       fb->ColorDrawBuffer[0] = GL_BACK;
 149       fb->_ColorDrawBufferIndexes[0] = BUFFER_BACK_LEFT;
 150       fb->ColorReadBuffer = GL_BACK;
 151       fb->_ColorReadBufferIndex = BUFFER_BACK_LEFT;
 152    }
 153    else {
 154       fb->_NumColorDrawBuffers = 1;
 155       fb->ColorDrawBuffer[0] = GL_FRONT;
 156       fb->_ColorDrawBufferIndexes[0] = BUFFER_FRONT_LEFT;
 157       fb->ColorReadBuffer = GL_FRONT;
 158       fb->_ColorReadBufferIndex = BUFFER_FRONT_LEFT;
 159    }
 160
 161    fb->Delete = _mesa_destroy_framebuffer;
 162    fb->_Status = GL_FRAMEBUFFER_COMPLETE_EXT;
 163
 164    compute_depth_max(fb);
 165 }
 166
 167
 168 /**
 169  * Deallocate buffer and everything attached to it.
 170  * Typically called via the gl_framebuffer->Delete() method.
 171  */
 172 void
 173 _mesa_destroy_framebuffer(struct gl_framebuffer *fb)
 174 {
 175    if (fb) {
 176       _mesa_free_framebuffer_data(fb);
 177       _mesa_free(fb);
 178    }
 179 }
 180
 181
 182 /**
 183  * Free all the data hanging off the given gl_framebuffer, but don't free
 184  * the gl_framebuffer object itself.
 185  */
 186 void
 187 _mesa_free_framebuffer_data(struct gl_framebuffer *fb)
 188 {
 189    GLuint i;
 190
 191    assert(fb);
 192    assert(fb->RefCount == 0);
 193
 194    _glthread_DESTROY_MUTEX(fb->Mutex);
 195
 196    for (i = 0; i < BUFFER_COUNT; i++) {
 197       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 198       if (att->Renderbuffer) {
 199          _mesa_reference_renderbuffer(&att->Renderbuffer, NULL);
 200       }
 201       if (att->Texture) {
 202          _mesa_reference_texobj(&att->Texture, NULL);
 203       }
 204       ASSERT(!att->Renderbuffer);
 205       ASSERT(!att->Texture);
 206       att->Type = GL_NONE;
 207    }
 208
 209    /* unbind _Depth/_StencilBuffer to decr ref counts */
 210    _mesa_reference_renderbuffer(&fb->_DepthBuffer, NULL);
 211    _mesa_reference_renderbuffer(&fb->_StencilBuffer, NULL);
 212 }
 213
 214
 215 /**
 216  * Set *ptr to point to fb, with refcounting and locking.
 217  */
 218 void
 219 _mesa_reference_framebuffer(struct gl_framebuffer **ptr,
 220                             struct gl_framebuffer *fb)
 221 {
 222    assert(ptr);
 223    if (*ptr == fb) {
 224       /* no change */
 225       return;
 226    }
 227
 228    if (*ptr) {
 229       /* unreference old renderbuffer */
 230       GLboolean deleteFlag = GL_FALSE;
 231       struct gl_framebuffer *oldFb = *ptr;
 232
 233       _glthread_LOCK_MUTEX(oldFb->Mutex);
 234       ASSERT(oldFb->RefCount > 0);
 235       oldFb->RefCount--;
 236       deleteFlag = (oldFb->RefCount == 0);
 237       _glthread_UNLOCK_MUTEX(oldFb->Mutex);
 238
 239       if (deleteFlag)
 240          oldFb->Delete(oldFb);
 241
 242       *ptr = NULL;
 243    }
 244    assert(!*ptr);
 245
 246    if (fb) {
 247       _glthread_LOCK_MUTEX(fb->Mutex);
 248       fb->RefCount++;
 249       _glthread_UNLOCK_MUTEX(fb->Mutex);
 250       *ptr = fb;
 251    }
 252 }
 253
 254
 255 /**
 256  * Resize the given framebuffer's renderbuffers to the new width and height.
 257  * This should only be used for window-system framebuffers, not
 258  * user-created renderbuffers (i.e. made with GL_EXT_framebuffer_object).
 259  * This will typically be called via ctx->Driver.ResizeBuffers() or directly
 260  * from a device driver.
 261  *
 262  * \note it's possible for ctx to be null since a window can be resized
 263  * without a currently bound rendering context.
 264  */
 265 void
 266 _mesa_resize_framebuffer(GLcontext *ctx, struct gl_framebuffer *fb,
 267                          GLuint width, GLuint height)
 268 {
 269    GLuint i;
 270
 271    /* XXX I think we could check if the size is not changing
 272     * and return early.
 273     */
 274
 275    /* For window system framebuffers, Name is zero */
 276    assert(fb->Name == 0);
 277
 278    for (i = 0; i < BUFFER_COUNT; i++) {
 279       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 280       if (att->Type == GL_RENDERBUFFER_EXT && att->Renderbuffer) {
 281          struct gl_renderbuffer *rb = att->Renderbuffer;
 282          /* only resize if size is changing */
 283          if (rb->Width != width || rb->Height != height) {
 284             /* could just as well pass rb->_ActualFormat here */
 285             if (rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 286                ASSERT(rb->Width == width);
 287                ASSERT(rb->Height == height);
 288             }
 289             else {
 290                _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 291                /* no return */
 292             }
 293          }
 294       }
 295    }
 296
 297    if (fb->_DepthBuffer) {
 298       struct gl_renderbuffer *rb = fb->_DepthBuffer;
 299       if (rb->Width != width || rb->Height != height) {
 300          if (!rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 301             _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 302          }
 303       }
 304    }
 305
 306    if (fb->_StencilBuffer) {
 307       struct gl_renderbuffer *rb = fb->_StencilBuffer;
 308       if (rb->Width != width || rb->Height != height) {
 309          if (!rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 310             _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 311          }
 312       }
 313    }
 314
 315    fb->Width = width;
 316    fb->Height = height;
 317
 318    if (ctx) {
 319       /* update scissor / window bounds */
 320       _mesa_update_draw_buffer_bounds(ctx);
 321       /* Signal new buffer state so that swrast will update its clipping
 322        * info (the CLIP_BIT flag).
 323        */
 324       ctx->NewState |= _NEW_BUFFERS;
 325    }
 326 }
 327
 328
 329
 330 /**
 331  * XXX THIS IS OBSOLETE - drivers should take care of detecting window
 332  * size changes and act accordingly, likely calling _mesa_resize_framebuffer().
 333  *
 334  * GL_MESA_resize_buffers extension.
 335  *
 336  * When this function is called, we'll ask the window system how large
 337  * the current window is.  If it's a new size, we'll call the driver's
 338  * ResizeBuffers function.  The driver will then resize its color buffers
 339  * as needed, and maybe call the swrast's routine for reallocating
 340  * swrast-managed depth/stencil/accum/etc buffers.
 341  * \note This function should only be called through the GL API, not
 342  * from device drivers (as was done in the past).
 343  */
 344 void
 345 _mesa_resizebuffers( GLcontext *ctx )
 346 {
 347    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 348
 349    if (MESA_VERBOSE & VERBOSE_API)
 350       _mesa_debug(ctx, "glResizeBuffersMESA\n");
 351
 352    if (!ctx->Driver.GetBufferSize) {
 353       return;
 354    }
 355
 356    if (ctx->WinSysDrawBuffer) {
 357       GLuint newWidth, newHeight;
 358       GLframebuffer *buffer = ctx->WinSysDrawBuffer;
 359
 360       assert(buffer->Name == 0);
 361
 362       /* ask device driver for size of output buffer */
 363       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 364
 365       /* see if size of device driver's color buffer (window) has changed */
 366       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 367          if (ctx->Driver.ResizeBuffers)
 368             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 369       }
 370    }
 371
 372    if (ctx->WinSysReadBuffer
 373        && ctx->WinSysReadBuffer != ctx->WinSysDrawBuffer) {
 374       GLuint newWidth, newHeight;
 375       GLframebuffer *buffer = ctx->WinSysReadBuffer;
 376
 377       assert(buffer->Name == 0);
 378
 379       /* ask device driver for size of read 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    ctx->NewState |= _NEW_BUFFERS;  /* to update scissor / window bounds */
 390 }
 391
 392
 393 /*
 394  * XXX THIS IS OBSOLETE
 395  */
 396 void GLAPIENTRY
 397 _mesa_ResizeBuffersMESA( void )
 398 {
 399    GET_CURRENT_CONTEXT(ctx);
 400
 401    if (ctx->Extensions.MESA_resize_buffers)
 402       _mesa_resizebuffers( ctx );
 403 }
 404
 405
 406
 407 /**
 408  * Examine all the framebuffer's renderbuffers to update the Width/Height
 409  * fields of the framebuffer.  If we have renderbuffers with different
 410  * sizes, set the framebuffer's width and height to the min size.
 411  * Note: this is only intended for user-created framebuffers, not
 412  * window-system framebuffes.
 413  */
 414 static void
 415 update_framebuffer_size(GLcontext *ctx, struct gl_framebuffer *fb)
 416 {
 417    GLuint minWidth = ~0, minHeight = ~0;
 418    GLuint i;
 419
 420    /* user-created framebuffers only */
 421    assert(fb->Name);
 422
 423    for (i = 0; i < BUFFER_COUNT; i++) {
 424       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 425       const struct gl_renderbuffer *rb = att->Renderbuffer;
 426       if (rb) {
 427          minWidth = MIN2(minWidth, rb->Width);
 428          minHeight = MIN2(minHeight, rb->Height);
 429       }
 430    }
 431
 432    if (minWidth != ~0) {
 433       fb->Width = minWidth;
 434       fb->Height = minHeight;
 435    }
 436    else {
 437       fb->Width = 0;
 438       fb->Height = 0;
 439    }
 440 }
 441
 442
 443 /**
 444  * Update the context's current drawing buffer's Xmin, Xmax, Ymin, Ymax fields.
 445  * These values are computed from the buffer's width and height and
 446  * the scissor box, if it's enabled.
 447  * \param ctx  the GL context.
 448  */
 449 void
 450 _mesa_update_draw_buffer_bounds(GLcontext *ctx)
 451 {
 452    struct gl_framebuffer *buffer = ctx->DrawBuffer;
 453
 454    if (!buffer)
 455       return;
 456
 457    if (buffer->Name) {
 458       /* user-created framebuffer size depends on the renderbuffers */
 459       update_framebuffer_size(ctx, buffer);
 460    }
 461
 462    buffer->_Xmin = 0;
 463    buffer->_Ymin = 0;
 464    buffer->_Xmax = buffer->Width;
 465    buffer->_Ymax = buffer->Height;
 466
 467    if (ctx->Scissor.Enabled) {
 468       if (ctx->Scissor.X > buffer->_Xmin) {
 469          buffer->_Xmin = ctx->Scissor.X;
 470       }
 471       if (ctx->Scissor.Y > buffer->_Ymin) {
 472          buffer->_Ymin = ctx->Scissor.Y;
 473       }
 474       if (ctx->Scissor.X + ctx->Scissor.Width < buffer->_Xmax) {
 475          buffer->_Xmax = ctx->Scissor.X + ctx->Scissor.Width;
 476       }
 477       if (ctx->Scissor.Y + ctx->Scissor.Height < buffer->_Ymax) {
 478          buffer->_Ymax = ctx->Scissor.Y + ctx->Scissor.Height;
 479       }
 480       /* finally, check for empty region */
 481       if (buffer->_Xmin > buffer->_Xmax) {
 482          buffer->_Xmin = buffer->_Xmax;
 483       }
 484       if (buffer->_Ymin > buffer->_Ymax) {
 485          buffer->_Ymin = buffer->_Ymax;
 486       }
 487    }
 488
 489    ASSERT(buffer->_Xmin <= buffer->_Xmax);
 490    ASSERT(buffer->_Ymin <= buffer->_Ymax);
 491 }
 492
 493
 494 /**
 495  * The glGet queries of the framebuffer red/green/blue size, stencil size,
 496  * etc. are satisfied by the fields of ctx->DrawBuffer->Visual.  These can
 497  * change depending on the renderbuffer bindings.  This function updates
 498  * the given framebuffer's Visual from the current renderbuffer bindings.
 499  *
 500  * This may apply to user-created framebuffers or window system framebuffers.
 501  *
 502  * Also note: ctx->DrawBuffer->Visual.depthBits might not equal
 503  * ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer.DepthBits.
 504  * The former one is used to convert floating point depth values into
 505  * integer Z values.
 506  */
 507 void
 508 _mesa_update_framebuffer_visual(struct gl_framebuffer *fb)
 509 {
 510    GLuint i;
 511
 512    _mesa_bzero(&fb->Visual, sizeof(fb->Visual));
 513    fb->Visual.rgbMode = GL_TRUE; /* assume this */
 514
 515 #if 0 /* this _might_ be needed */
 516    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 517       /* leave visual fields zero'd */
 518       return;
 519    }
 520 #endif
 521
 522    /* find first RGB or CI renderbuffer */
 523    for (i = 0; i < BUFFER_COUNT; i++) {
 524       if (fb->Attachment[i].Renderbuffer) {
 525          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 526          if (rb->_BaseFormat == GL_RGBA || rb->_BaseFormat == GL_RGB) {
 527             fb->Visual.redBits = rb->RedBits;
 528             fb->Visual.greenBits = rb->GreenBits;
 529             fb->Visual.blueBits = rb->BlueBits;
 530             fb->Visual.alphaBits = rb->AlphaBits;
 531             fb->Visual.rgbBits = fb->Visual.redBits
 532                + fb->Visual.greenBits + fb->Visual.blueBits;
 533             fb->Visual.floatMode = GL_FALSE;
 534             fb->Visual.samples = rb->NumSamples;
 535             break;
 536          }
 537          else if (rb->_BaseFormat == GL_COLOR_INDEX) {
 538             fb->Visual.indexBits = rb->IndexBits;
 539             fb->Visual.rgbMode = GL_FALSE;
 540             break;
 541          }
 542       }
 543    }
 544
 545    if (fb->Attachment[BUFFER_DEPTH].Renderbuffer) {
 546       fb->Visual.haveDepthBuffer = GL_TRUE;
 547       fb->Visual.depthBits
 548          = fb->Attachment[BUFFER_DEPTH].Renderbuffer->DepthBits;
 549    }
 550
 551    if (fb->Attachment[BUFFER_STENCIL].Renderbuffer) {
 552       fb->Visual.haveStencilBuffer = GL_TRUE;
 553       fb->Visual.stencilBits
 554          = fb->Attachment[BUFFER_STENCIL].Renderbuffer->StencilBits;
 555    }
 556
 557    if (fb->Attachment[BUFFER_ACCUM].Renderbuffer) {
 558       fb->Visual.haveAccumBuffer = GL_TRUE;
 559       fb->Visual.accumRedBits
 560          = fb->Attachment[BUFFER_ACCUM].Renderbuffer->RedBits;
 561       fb->Visual.accumGreenBits
 562          = fb->Attachment[BUFFER_ACCUM].Renderbuffer->GreenBits;
 563       fb->Visual.accumBlueBits
 564          = fb->Attachment[BUFFER_ACCUM].Renderbuffer->BlueBits;
 565       fb->Visual.accumAlphaBits
 566          = fb->Attachment[BUFFER_ACCUM].Renderbuffer->AlphaBits;
 567    }
 568
 569    compute_depth_max(fb);
 570 }
 571
 572
 573 /**
 574  * Update the framebuffer's _DepthBuffer field using the renderbuffer
 575  * found at the given attachment index.
 576  *
 577  * If that attachment points to a combined GL_DEPTH_STENCIL renderbuffer,
 578  * create and install a depth wrapper/adaptor.
 579  *
 580  * \param fb  the framebuffer whose _DepthBuffer field to update
 581  * \param attIndex  indicates the renderbuffer to possibly wrap
 582  */
 583 void
 584 _mesa_update_depth_buffer(GLcontext *ctx,
 585                           struct gl_framebuffer *fb,
 586                           GLuint attIndex)
 587 {
 588    struct gl_renderbuffer *depthRb;
 589
 590    /* only one possiblity for now */
 591    ASSERT(attIndex == BUFFER_DEPTH);
 592
 593    depthRb = fb->Attachment[attIndex].Renderbuffer;
 594
 595    if (depthRb && depthRb->_ActualFormat == GL_DEPTH24_STENCIL8_EXT) {
 596       /* The attached depth buffer is a GL_DEPTH_STENCIL renderbuffer */
 597       if (!fb->_DepthBuffer
 598           || fb->_DepthBuffer->Wrapped != depthRb
 599           || fb->_DepthBuffer->_BaseFormat != GL_DEPTH_COMPONENT) {
 600          /* need to update wrapper */
 601          struct gl_renderbuffer *wrapper
 602             = _mesa_new_z24_renderbuffer_wrapper(ctx, depthRb);
 603          _mesa_reference_renderbuffer(&fb->_DepthBuffer, wrapper);
 604          ASSERT(fb->_DepthBuffer->Wrapped == depthRb);
 605       }
 606    }
 607    else {
 608       /* depthRb may be null */
 609       _mesa_reference_renderbuffer(&fb->_DepthBuffer, depthRb);
 610    }
 611 }
 612
 613
 614 /**
 615  * Update the framebuffer's _StencilBuffer field using the renderbuffer
 616  * found at the given attachment index.
 617  *
 618  * If that attachment points to a combined GL_DEPTH_STENCIL renderbuffer,
 619  * create and install a stencil wrapper/adaptor.
 620  *
 621  * \param fb  the framebuffer whose _StencilBuffer field to update
 622  * \param attIndex  indicates the renderbuffer to possibly wrap
 623  */
 624 void
 625 _mesa_update_stencil_buffer(GLcontext *ctx,
 626                             struct gl_framebuffer *fb,
 627                             GLuint attIndex)
 628 {
 629    struct gl_renderbuffer *stencilRb;
 630
 631    ASSERT(attIndex == BUFFER_DEPTH ||
 632           attIndex == BUFFER_STENCIL);
 633
 634    stencilRb = fb->Attachment[attIndex].Renderbuffer;
 635
 636    if (stencilRb && stencilRb->_ActualFormat == GL_DEPTH24_STENCIL8_EXT) {
 637       /* The attached stencil buffer is a GL_DEPTH_STENCIL renderbuffer */
 638       if (!fb->_StencilBuffer
 639           || fb->_StencilBuffer->Wrapped != stencilRb
 640           || fb->_StencilBuffer->_BaseFormat != GL_STENCIL_INDEX) {
 641          /* need to update wrapper */
 642          struct gl_renderbuffer *wrapper
 643             = _mesa_new_s8_renderbuffer_wrapper(ctx, stencilRb);
 644          _mesa_reference_renderbuffer(&fb->_StencilBuffer, wrapper);
 645          ASSERT(fb->_StencilBuffer->Wrapped == stencilRb);
 646       }
 647    }
 648    else {
 649       /* stencilRb may be null */
 650       _mesa_reference_renderbuffer(&fb->_StencilBuffer, stencilRb);
 651    }
 652 }
 653
 654
 655 /*
 656  * Example DrawBuffers scenarios:
 657  *
 658  * 1. glDrawBuffer(GL_FRONT_AND_BACK), fixed-func or shader writes to
 659  * "gl_FragColor" or program writes to the "result.color" register:
 660  *
 661  *   fragment color output   renderbuffer
 662  *   ---------------------   ---------------
 663  *   color[0]                Front, Back
 664  *
 665  *
 666  * 2. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]), shader writes to
 667  * gl_FragData[i] or program writes to result.color[i] registers:
 668  *
 669  *   fragment color output   renderbuffer
 670  *   ---------------------   ---------------
 671  *   color[0]                Front
 672  *   color[1]                Aux0
 673  *   color[3]                Aux1
 674  *
 675  *
 676  * 3. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]) and shader writes to
 677  * gl_FragColor, or fixed function:
 678  *
 679  *   fragment color output   renderbuffer
 680  *   ---------------------   ---------------
 681  *   color[0]                Front, Aux0, Aux1
 682  *
 683  *
 684  * In either case, the list of renderbuffers is stored in the
 685  * framebuffer->_ColorDrawBuffers[] array and
 686  * framebuffer->_NumColorDrawBuffers indicates the number of buffers.
 687  * The renderer (like swrast) has to look at the current fragment shader
 688  * to see if it writes to gl_FragColor vs. gl_FragData[i] to determine
 689  * how to map color outputs to renderbuffers.
 690  *
 691  * Note that these two calls are equivalent (for fixed function fragment
 692  * shading anyway):
 693  *   a)  glDrawBuffer(GL_FRONT_AND_BACK);  (assuming non-stereo framebuffer)
 694  *   b)  glDrawBuffers(2, [GL_FRONT_LEFT, GL_BACK_LEFT]);
 695  */
 696
 697
 698
 699
 700 /**
 701  * Update the (derived) list of color drawing renderbuffer pointers.
 702  * Later, when we're rendering we'll loop from 0 to _NumColorDrawBuffers
 703  * writing colors.
 704  */
 705 static void
 706 update_color_draw_buffers(GLcontext *ctx, struct gl_framebuffer *fb)
 707 {
 708    GLuint output;
 709
 710    /* set 0th buffer to NULL now in case _NumColorDrawBuffers is zero */
 711    fb->_ColorDrawBuffers[0] = NULL;
 712
 713    for (output = 0; output < fb->_NumColorDrawBuffers; output++) {
 714       GLint buf = fb->_ColorDrawBufferIndexes[output];
 715       if (buf >= 0) {
 716          fb->_ColorDrawBuffers[output] = fb->Attachment[buf].Renderbuffer;
 717       }
 718       else {
 719          fb->_ColorDrawBuffers[output] = NULL;
 720       }
 721    }
 722 }
 723
 724
 725 /**
 726  * Update the (derived) color read renderbuffer pointer.
 727  * Unlike the DrawBuffer, we can only read from one (or zero) color buffers.
 728  */
 729 static void
 730 update_color_read_buffer(GLcontext *ctx, struct gl_framebuffer *fb)
 731 {
 732    (void) ctx;
 733    if (fb->_ColorReadBufferIndex == -1 ||
 734        fb->DeletePending ||
 735        fb->Width == 0 ||
 736        fb->Height == 0) {
 737       fb->_ColorReadBuffer = NULL; /* legal! */
 738    }
 739    else {
 740       ASSERT(fb->_ColorReadBufferIndex >= 0);
 741       ASSERT(fb->_ColorReadBufferIndex < BUFFER_COUNT);
 742       fb->_ColorReadBuffer
 743          = fb->Attachment[fb->_ColorReadBufferIndex].Renderbuffer;
 744    }
 745 }
 746
 747
 748 /**
 749  * Update a gl_framebuffer's derived state.
 750  *
 751  * Specifically, update these framebuffer fields:
 752  *    _ColorDrawBuffers
 753  *    _NumColorDrawBuffers
 754  *    _ColorReadBuffer
 755  *    _DepthBuffer
 756  *    _StencilBuffer
 757  *
 758  * If the framebuffer is user-created, make sure it's complete.
 759  *
 760  * The following functions (at least) can effect framebuffer state:
 761  * glReadBuffer, glDrawBuffer, glDrawBuffersARB, glFramebufferRenderbufferEXT,
 762  * glRenderbufferStorageEXT.
 763  */
 764 static void
 765 update_framebuffer(GLcontext *ctx, struct gl_framebuffer *fb)
 766 {
 767    if (fb->Name == 0) {
 768       /* This is a window-system framebuffer */
 769       /* Need to update the FB's GL_DRAW_BUFFER state to match the
 770        * context state (GL_READ_BUFFER too).
 771        */
 772       if (fb->ColorDrawBuffer[0] != ctx->Color.DrawBuffer[0]) {
 773          _mesa_drawbuffers(ctx, ctx->Const.MaxDrawBuffers,
 774                            ctx->Color.DrawBuffer, NULL);
 775       }
 776       if (fb->ColorReadBuffer != ctx->Pixel.ReadBuffer) {
 777
 778       }
 779    }
 780    else {
 781       /* This is a user-created framebuffer.
 782        * Completeness only matters for user-created framebuffers.
 783        */
 784       if (fb->_Status != GL_FRAMEBUFFER_COMPLETE) {
 785          _mesa_test_framebuffer_completeness(ctx, fb);
 786       }
 787    }
 788
 789    /* Strictly speaking, we don't need to update the draw-state
 790     * if this FB is bound as ctx->ReadBuffer (and conversely, the
 791     * read-state if this FB is bound as ctx->DrawBuffer), but no
 792     * harm.
 793     */
 794    update_color_draw_buffers(ctx, fb);
 795    update_color_read_buffer(ctx, fb);
 796    _mesa_update_depth_buffer(ctx, fb, BUFFER_DEPTH);
 797    _mesa_update_stencil_buffer(ctx, fb, BUFFER_STENCIL);
 798
 799    compute_depth_max(fb);
 800 }
 801
 802
 803 /**
 804  * Update state related to the current draw/read framebuffers.
 805  */
 806 void
 807 _mesa_update_framebuffer(GLcontext *ctx)
 808 {
 809    struct gl_framebuffer *drawFb = ctx->DrawBuffer;
 810    struct gl_framebuffer *readFb = ctx->ReadBuffer;
 811
 812    update_framebuffer(ctx, drawFb);
 813    if (readFb != drawFb)
 814       update_framebuffer(ctx, readFb);
 815 }
 816
 817
 818 /**
 819  * Check if the renderbuffer for a read operation (glReadPixels, glCopyPixels,
 820  * glCopyTex[Sub]Image, etc) exists.
 821  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 822  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 823  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 824  */
 825 GLboolean
 826 _mesa_source_buffer_exists(GLcontext *ctx, GLenum format)
 827 {
 828    const struct gl_renderbuffer_attachment *att = ctx->ReadBuffer->Attachment;
 829
 830    /* If we don't know the framebuffer status, update it now */
 831    if (ctx->ReadBuffer->_Status == 0) {
 832       _mesa_test_framebuffer_completeness(ctx, ctx->ReadBuffer);
 833    }
 834
 835    if (ctx->ReadBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 836       return GL_FALSE;
 837    }
 838
 839    switch (format) {
 840    case GL_COLOR:
 841    case GL_RED:
 842    case GL_GREEN:
 843    case GL_BLUE:
 844    case GL_ALPHA:
 845    case GL_LUMINANCE:
 846    case GL_LUMINANCE_ALPHA:
 847    case GL_INTENSITY:
 848    case GL_RGB:
 849    case GL_BGR:
 850    case GL_RGBA:
 851    case GL_BGRA:
 852    case GL_ABGR_EXT:
 853    case GL_COLOR_INDEX:
 854       if (ctx->ReadBuffer->_ColorReadBuffer == NULL) {
 855          return GL_FALSE;
 856       }
 857       ASSERT(ctx->ReadBuffer->_ColorReadBuffer->RedBits > 0 ||
 858              ctx->ReadBuffer->_ColorReadBuffer->IndexBits > 0);
 859       break;
 860    case GL_DEPTH:
 861    case GL_DEPTH_COMPONENT:
 862       if (!att[BUFFER_DEPTH].Renderbuffer) {
 863          return GL_FALSE;
 864       }
 865       ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);
 866       break;
 867    case GL_STENCIL:
 868    case GL_STENCIL_INDEX:
 869       if (!att[BUFFER_STENCIL].Renderbuffer) {
 870          return GL_FALSE;
 871       }
 872       ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);
 873       break;
 874    case GL_DEPTH_STENCIL_EXT:
 875       if (!att[BUFFER_DEPTH].Renderbuffer ||
 876           !att[BUFFER_STENCIL].Renderbuffer) {
 877          return GL_FALSE;
 878       }
 879       ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);
 880       ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);
 881       break;
 882    default:
 883       _mesa_problem(ctx,
 884                     "Unexpected format 0x%x in _mesa_source_buffer_exists",
 885                     format);
 886       return GL_FALSE;
 887    }
 888
 889    /* OK */
 890    return GL_TRUE;
 891 }
 892
 893
 894 /**
 895  * As above, but for drawing operations.
 896  * XXX could do some code merging w/ above function.
 897  */
 898 GLboolean
 899 _mesa_dest_buffer_exists(GLcontext *ctx, GLenum format)
 900 {
 901    const struct gl_renderbuffer_attachment *att = ctx->DrawBuffer->Attachment;
 902
 903    /* If we don't know the framebuffer status, update it now */
 904    if (ctx->DrawBuffer->_Status == 0) {
 905       _mesa_test_framebuffer_completeness(ctx, ctx->DrawBuffer);
 906    }
 907
 908    if (ctx->DrawBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 909       return GL_FALSE;
 910    }
 911
 912    switch (format) {
 913    case GL_COLOR:
 914    case GL_RED:
 915    case GL_GREEN:
 916    case GL_BLUE:
 917    case GL_ALPHA:
 918    case GL_LUMINANCE:
 919    case GL_LUMINANCE_ALPHA:
 920    case GL_INTENSITY:
 921    case GL_RGB:
 922    case GL_BGR:
 923    case GL_RGBA:
 924    case GL_BGRA:
 925    case GL_ABGR_EXT:
 926    case GL_COLOR_INDEX:
 927       /* Nothing special since GL_DRAW_BUFFER could be GL_NONE. */
 928       /* Could assert that colorbuffer has RedBits > 0 */
 929       break;
 930    case GL_DEPTH:
 931    case GL_DEPTH_COMPONENT:
 932       if (!att[BUFFER_DEPTH].Renderbuffer) {
 933          return GL_FALSE;
 934       }
 935       ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);
 936       break;
 937    case GL_STENCIL:
 938    case GL_STENCIL_INDEX:
 939       if (!att[BUFFER_STENCIL].Renderbuffer) {
 940          return GL_FALSE;
 941       }
 942       ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);
 943       break;
 944    case GL_DEPTH_STENCIL_EXT:
 945       if (!att[BUFFER_DEPTH].Renderbuffer ||
 946           !att[BUFFER_STENCIL].Renderbuffer) {
 947          return GL_FALSE;
 948       }
 949       ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);
 950       ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);
 951       break;
 952    default:
 953       _mesa_problem(ctx,
 954                     "Unexpected format 0x%x in _mesa_dest_buffer_exists",
 955                     format);
 956       return GL_FALSE;
 957    }
 958
 959    /* OK */
 960    return GL_TRUE;
 961 }