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 "enums.h"
  39 #include "formats.h"
  40 #include "macros.h"
  41 #include "mtypes.h"
  42 #include "fbobject.h"
  43 #include "framebuffer.h"
  44 #include "renderbuffer.h"
  45 #include "texobj.h"
  46
  47
  48
  49 /**
  50  * Compute/set the _DepthMax field for the given framebuffer.
  51  * This value depends on the Z buffer resolution.
  52  */
  53 static void
  54 compute_depth_max(struct gl_framebuffer *fb)
  55 {
  56    if (fb->Visual.depthBits == 0) {
  57       /* Special case.  Even if we don't have a depth buffer we need
  58        * good values for DepthMax for Z vertex transformation purposes
  59        * and for per-fragment fog computation.
  60        */
  61       fb->_DepthMax = (1 << 16) - 1;
  62    }
  63    else if (fb->Visual.depthBits < 32) {
  64       fb->_DepthMax = (1 << fb->Visual.depthBits) - 1;
  65    }
  66    else {
  67       /* Special case since shift values greater than or equal to the
  68        * number of bits in the left hand expression's type are undefined.
  69        */
  70       fb->_DepthMax = 0xffffffff;
  71    }
  72    fb->_DepthMaxF = (GLfloat) fb->_DepthMax;
  73
  74    /* Minimum resolvable depth value, for polygon offset */
  75    fb->_MRD = (GLfloat)1.0 / fb->_DepthMaxF;
  76 }
  77
  78 /**
  79  * Create and initialize a gl_framebuffer object.
  80  * This is intended for creating _window_system_ framebuffers, not generic
  81  * framebuffer objects ala GL_EXT_framebuffer_object.
  82  *
  83  * \sa _mesa_new_framebuffer
  84  */
  85 struct gl_framebuffer *
  86 _mesa_create_framebuffer(const struct gl_config *visual)
  87 {
  88    struct gl_framebuffer *fb = CALLOC_STRUCT(gl_framebuffer);
  89    assert(visual);
  90    if (fb) {
  91       _mesa_initialize_window_framebuffer(fb, visual);
  92    }
  93    return fb;
  94 }
  95
  96
  97 /**
  98  * Allocate a new gl_framebuffer object.
  99  * This is the default function for ctx->Driver.NewFramebuffer().
 100  * This is for allocating user-created framebuffers, not window-system
 101  * framebuffers!
 102  * \sa _mesa_create_framebuffer
 103  */
 104 struct gl_framebuffer *
 105 _mesa_new_framebuffer(struct gl_context *ctx, GLuint name)
 106 {
 107    struct gl_framebuffer *fb;
 108    (void) ctx;
 109    assert(name != 0);
 110    fb = CALLOC_STRUCT(gl_framebuffer);
 111    if (fb) {
 112       _mesa_initialize_user_framebuffer(fb, name);
 113    }
 114    return fb;
 115 }
 116
 117
 118 /**
 119  * Initialize a gl_framebuffer object.  Typically used to initialize
 120  * window system-created framebuffers, not user-created framebuffers.
 121  * \sa _mesa_initialize_user_framebuffer
 122  */
 123 void
 124 _mesa_initialize_window_framebuffer(struct gl_framebuffer *fb,
 125                                      const struct gl_config *visual)
 126 {
 127    assert(fb);
 128    assert(visual);
 129
 130    memset(fb, 0, sizeof(struct gl_framebuffer));
 131
 132    _glthread_INIT_MUTEX(fb->Mutex);
 133
 134    fb->RefCount = 1;
 135
 136    /* save the visual */
 137    fb->Visual = *visual;
 138
 139    /* Init read/draw renderbuffer state */
 140    if (visual->doubleBufferMode) {
 141       fb->_NumColorDrawBuffers = 1;
 142       fb->ColorDrawBuffer[0] = GL_BACK;
 143       fb->_ColorDrawBufferIndexes[0] = BUFFER_BACK_LEFT;
 144       fb->ColorReadBuffer = GL_BACK;
 145       fb->_ColorReadBufferIndex = BUFFER_BACK_LEFT;
 146    }
 147    else {
 148       fb->_NumColorDrawBuffers = 1;
 149       fb->ColorDrawBuffer[0] = GL_FRONT;
 150       fb->_ColorDrawBufferIndexes[0] = BUFFER_FRONT_LEFT;
 151       fb->ColorReadBuffer = GL_FRONT;
 152       fb->_ColorReadBufferIndex = BUFFER_FRONT_LEFT;
 153    }
 154
 155    fb->Delete = _mesa_destroy_framebuffer;
 156    fb->_Status = GL_FRAMEBUFFER_COMPLETE_EXT;
 157
 158    compute_depth_max(fb);
 159 }
 160
 161
 162 /**
 163  * Initialize a user-created gl_framebuffer object.
 164  * \sa _mesa_initialize_window_framebuffer
 165  */
 166 void
 167 _mesa_initialize_user_framebuffer(struct gl_framebuffer *fb, GLuint name)
 168 {
 169    assert(fb);
 170    assert(name);
 171
 172    memset(fb, 0, sizeof(struct gl_framebuffer));
 173
 174    fb->Name = name;
 175    fb->RefCount = 1;
 176    fb->_NumColorDrawBuffers = 1;
 177    fb->ColorDrawBuffer[0] = GL_COLOR_ATTACHMENT0_EXT;
 178    fb->_ColorDrawBufferIndexes[0] = BUFFER_COLOR0;
 179    fb->ColorReadBuffer = GL_COLOR_ATTACHMENT0_EXT;
 180    fb->_ColorReadBufferIndex = BUFFER_COLOR0;
 181    fb->Delete = _mesa_destroy_framebuffer;
 182    _glthread_INIT_MUTEX(fb->Mutex);
 183 }
 184
 185
 186 /**
 187  * Deallocate buffer and everything attached to it.
 188  * Typically called via the gl_framebuffer->Delete() method.
 189  */
 190 void
 191 _mesa_destroy_framebuffer(struct gl_framebuffer *fb)
 192 {
 193    if (fb) {
 194       _mesa_free_framebuffer_data(fb);
 195       free(fb);
 196    }
 197 }
 198
 199
 200 /**
 201  * Free all the data hanging off the given gl_framebuffer, but don't free
 202  * the gl_framebuffer object itself.
 203  */
 204 void
 205 _mesa_free_framebuffer_data(struct gl_framebuffer *fb)
 206 {
 207    GLuint i;
 208
 209    assert(fb);
 210    assert(fb->RefCount == 0);
 211
 212    _glthread_DESTROY_MUTEX(fb->Mutex);
 213
 214    for (i = 0; i < BUFFER_COUNT; i++) {
 215       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 216       if (att->Renderbuffer) {
 217          _mesa_reference_renderbuffer(&att->Renderbuffer, NULL);
 218       }
 219       if (att->Texture) {
 220          _mesa_reference_texobj(&att->Texture, NULL);
 221       }
 222       ASSERT(!att->Renderbuffer);
 223       ASSERT(!att->Texture);
 224       att->Type = GL_NONE;
 225    }
 226
 227    /* unbind _Depth/_StencilBuffer to decr ref counts */
 228    _mesa_reference_renderbuffer(&fb->_DepthBuffer, NULL);
 229    _mesa_reference_renderbuffer(&fb->_StencilBuffer, NULL);
 230 }
 231
 232
 233 /**
 234  * Set *ptr to point to fb, with refcounting and locking.
 235  */
 236 void
 237 _mesa_reference_framebuffer(struct gl_framebuffer **ptr,
 238                             struct gl_framebuffer *fb)
 239 {
 240    assert(ptr);
 241    if (*ptr == fb) {
 242       /* no change */
 243       return;
 244    }
 245
 246    if (*ptr) {
 247       /* unreference old renderbuffer */
 248       GLboolean deleteFlag = GL_FALSE;
 249       struct gl_framebuffer *oldFb = *ptr;
 250
 251       _glthread_LOCK_MUTEX(oldFb->Mutex);
 252       ASSERT(oldFb->RefCount > 0);
 253       oldFb->RefCount--;
 254       deleteFlag = (oldFb->RefCount == 0);
 255       _glthread_UNLOCK_MUTEX(oldFb->Mutex);
 256
 257       if (deleteFlag)
 258          oldFb->Delete(oldFb);
 259
 260       *ptr = NULL;
 261    }
 262    assert(!*ptr);
 263
 264    if (fb) {
 265       _glthread_LOCK_MUTEX(fb->Mutex);
 266       fb->RefCount++;
 267       _glthread_UNLOCK_MUTEX(fb->Mutex);
 268       *ptr = fb;
 269    }
 270 }
 271
 272
 273 /**
 274  * Resize the given framebuffer's renderbuffers to the new width and height.
 275  * This should only be used for window-system framebuffers, not
 276  * user-created renderbuffers (i.e. made with GL_EXT_framebuffer_object).
 277  * This will typically be called via ctx->Driver.ResizeBuffers() or directly
 278  * from a device driver.
 279  *
 280  * \note it's possible for ctx to be null since a window can be resized
 281  * without a currently bound rendering context.
 282  */
 283 void
 284 _mesa_resize_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb,
 285                          GLuint width, GLuint height)
 286 {
 287    GLuint i;
 288
 289    /* XXX I think we could check if the size is not changing
 290     * and return early.
 291     */
 292
 293    /* For window system framebuffers, Name is zero */
 294    assert(fb->Name == 0);
 295
 296    for (i = 0; i < BUFFER_COUNT; i++) {
 297       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 298       if (att->Type == GL_RENDERBUFFER_EXT && att->Renderbuffer) {
 299          struct gl_renderbuffer *rb = att->Renderbuffer;
 300          /* only resize if size is changing */
 301          if (rb->Width != width || rb->Height != height) {
 302             if (rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 303                ASSERT(rb->Width == width);
 304                ASSERT(rb->Height == height);
 305             }
 306             else {
 307                _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 308                /* no return */
 309             }
 310          }
 311       }
 312    }
 313
 314    if (fb->_DepthBuffer) {
 315       struct gl_renderbuffer *rb = fb->_DepthBuffer;
 316       if (rb->Width != width || rb->Height != height) {
 317          if (!rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 318             _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 319          }
 320       }
 321    }
 322
 323    if (fb->_StencilBuffer) {
 324       struct gl_renderbuffer *rb = fb->_StencilBuffer;
 325       if (rb->Width != width || rb->Height != height) {
 326          if (!rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 327             _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 328          }
 329       }
 330    }
 331
 332    fb->Width = width;
 333    fb->Height = height;
 334
 335    if (ctx) {
 336       /* update scissor / window bounds */
 337       _mesa_update_draw_buffer_bounds(ctx);
 338       /* Signal new buffer state so that swrast will update its clipping
 339        * info (the CLIP_BIT flag).
 340        */
 341       ctx->NewState |= _NEW_BUFFERS;
 342    }
 343 }
 344
 345
 346
 347 /**
 348  * XXX THIS IS OBSOLETE - drivers should take care of detecting window
 349  * size changes and act accordingly, likely calling _mesa_resize_framebuffer().
 350  *
 351  * GL_MESA_resize_buffers extension.
 352  *
 353  * When this function is called, we'll ask the window system how large
 354  * the current window is.  If it's a new size, we'll call the driver's
 355  * ResizeBuffers function.  The driver will then resize its color buffers
 356  * as needed, and maybe call the swrast's routine for reallocating
 357  * swrast-managed depth/stencil/accum/etc buffers.
 358  * \note This function should only be called through the GL API, not
 359  * from device drivers (as was done in the past).
 360  */
 361 void
 362 _mesa_resizebuffers( struct gl_context *ctx )
 363 {
 364    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 365
 366    if (MESA_VERBOSE & VERBOSE_API)
 367       _mesa_debug(ctx, "glResizeBuffersMESA\n");
 368
 369    if (!ctx->Driver.GetBufferSize) {
 370       return;
 371    }
 372
 373    if (ctx->WinSysDrawBuffer) {
 374       GLuint newWidth, newHeight;
 375       struct gl_framebuffer *buffer = ctx->WinSysDrawBuffer;
 376
 377       assert(buffer->Name == 0);
 378
 379       /* ask device driver for size of output buffer */
 380       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 381
 382       /* see if size of device driver's color buffer (window) has changed */
 383       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 384          if (ctx->Driver.ResizeBuffers)
 385             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 386       }
 387    }
 388
 389    if (ctx->WinSysReadBuffer
 390        && ctx->WinSysReadBuffer != ctx->WinSysDrawBuffer) {
 391       GLuint newWidth, newHeight;
 392       struct gl_framebuffer *buffer = ctx->WinSysReadBuffer;
 393
 394       assert(buffer->Name == 0);
 395
 396       /* ask device driver for size of read buffer */
 397       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 398
 399       /* see if size of device driver's color buffer (window) has changed */
 400       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 401          if (ctx->Driver.ResizeBuffers)
 402             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 403       }
 404    }
 405
 406    ctx->NewState |= _NEW_BUFFERS;  /* to update scissor / window bounds */
 407 }
 408
 409
 410 /*
 411  * XXX THIS IS OBSOLETE
 412  */
 413 void GLAPIENTRY
 414 _mesa_ResizeBuffersMESA( void )
 415 {
 416    GET_CURRENT_CONTEXT(ctx);
 417
 418    if (ctx->Extensions.MESA_resize_buffers)
 419       _mesa_resizebuffers( ctx );
 420 }
 421
 422
 423
 424 /**
 425  * Examine all the framebuffer's renderbuffers to update the Width/Height
 426  * fields of the framebuffer.  If we have renderbuffers with different
 427  * sizes, set the framebuffer's width and height to the min size.
 428  * Note: this is only intended for user-created framebuffers, not
 429  * window-system framebuffes.
 430  */
 431 static void
 432 update_framebuffer_size(struct gl_context *ctx, struct gl_framebuffer *fb)
 433 {
 434    GLuint minWidth = ~0, minHeight = ~0;
 435    GLuint i;
 436
 437    /* user-created framebuffers only */
 438    assert(fb->Name);
 439
 440    for (i = 0; i < BUFFER_COUNT; i++) {
 441       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 442       const struct gl_renderbuffer *rb = att->Renderbuffer;
 443       if (rb) {
 444          minWidth = MIN2(minWidth, rb->Width);
 445          minHeight = MIN2(minHeight, rb->Height);
 446       }
 447    }
 448
 449    if (minWidth != ~0) {
 450       fb->Width = minWidth;
 451       fb->Height = minHeight;
 452    }
 453    else {
 454       fb->Width = 0;
 455       fb->Height = 0;
 456    }
 457 }
 458
 459
 460 /**
 461  * Update the context's current drawing buffer's Xmin, Xmax, Ymin, Ymax fields.
 462  * These values are computed from the buffer's width and height and
 463  * the scissor box, if it's enabled.
 464  * \param ctx  the GL context.
 465  */
 466 void
 467 _mesa_update_draw_buffer_bounds(struct gl_context *ctx)
 468 {
 469    struct gl_framebuffer *buffer = ctx->DrawBuffer;
 470
 471    if (!buffer)
 472       return;
 473
 474    if (buffer->Name) {
 475       /* user-created framebuffer size depends on the renderbuffers */
 476       update_framebuffer_size(ctx, buffer);
 477    }
 478
 479    buffer->_Xmin = 0;
 480    buffer->_Ymin = 0;
 481    buffer->_Xmax = buffer->Width;
 482    buffer->_Ymax = buffer->Height;
 483
 484    if (ctx->Scissor.Enabled) {
 485       if (ctx->Scissor.X > buffer->_Xmin) {
 486          buffer->_Xmin = ctx->Scissor.X;
 487       }
 488       if (ctx->Scissor.Y > buffer->_Ymin) {
 489          buffer->_Ymin = ctx->Scissor.Y;
 490       }
 491       if (ctx->Scissor.X + ctx->Scissor.Width < buffer->_Xmax) {
 492          buffer->_Xmax = ctx->Scissor.X + ctx->Scissor.Width;
 493       }
 494       if (ctx->Scissor.Y + ctx->Scissor.Height < buffer->_Ymax) {
 495          buffer->_Ymax = ctx->Scissor.Y + ctx->Scissor.Height;
 496       }
 497       /* finally, check for empty region */
 498       if (buffer->_Xmin > buffer->_Xmax) {
 499          buffer->_Xmin = buffer->_Xmax;
 500       }
 501       if (buffer->_Ymin > buffer->_Ymax) {
 502          buffer->_Ymin = buffer->_Ymax;
 503       }
 504    }
 505
 506    ASSERT(buffer->_Xmin <= buffer->_Xmax);
 507    ASSERT(buffer->_Ymin <= buffer->_Ymax);
 508 }
 509
 510
 511 /**
 512  * The glGet queries of the framebuffer red/green/blue size, stencil size,
 513  * etc. are satisfied by the fields of ctx->DrawBuffer->Visual.  These can
 514  * change depending on the renderbuffer bindings.  This function updates
 515  * the given framebuffer's Visual from the current renderbuffer bindings.
 516  *
 517  * This may apply to user-created framebuffers or window system framebuffers.
 518  *
 519  * Also note: ctx->DrawBuffer->Visual.depthBits might not equal
 520  * ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer.DepthBits.
 521  * The former one is used to convert floating point depth values into
 522  * integer Z values.
 523  */
 524 void
 525 _mesa_update_framebuffer_visual(struct gl_context *ctx,
 526                                 struct gl_framebuffer *fb)
 527 {
 528    GLuint i;
 529
 530    memset(&fb->Visual, 0, sizeof(fb->Visual));
 531    fb->Visual.rgbMode = GL_TRUE; /* assume this */
 532
 533 #if 0 /* this _might_ be needed */
 534    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 535       /* leave visual fields zero'd */
 536       return;
 537    }
 538 #endif
 539
 540    /* find first RGB renderbuffer */
 541    for (i = 0; i < BUFFER_COUNT; i++) {
 542       if (fb->Attachment[i].Renderbuffer) {
 543          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 544          const GLenum baseFormat = _mesa_get_format_base_format(rb->Format);
 545          const gl_format fmt = rb->Format;
 546
 547          if (_mesa_is_legal_color_format(ctx, baseFormat)) {
 548             fb->Visual.redBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 549             fb->Visual.greenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 550             fb->Visual.blueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 551             fb->Visual.alphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 552             fb->Visual.rgbBits = fb->Visual.redBits
 553                + fb->Visual.greenBits + fb->Visual.blueBits;
 554             fb->Visual.floatMode = GL_FALSE;
 555             fb->Visual.samples = rb->NumSamples;
 556             if (_mesa_get_format_color_encoding(fmt) == GL_SRGB)
 557                 fb->Visual.sRGBCapable = ctx->Const.sRGBCapable;
 558             break;
 559          }
 560       }
 561    }
 562
 563    if (fb->Attachment[BUFFER_DEPTH].Renderbuffer) {
 564       const struct gl_renderbuffer *rb =
 565          fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 566       const gl_format fmt = rb->Format;
 567       fb->Visual.haveDepthBuffer = GL_TRUE;
 568       fb->Visual.depthBits = _mesa_get_format_bits(fmt, GL_DEPTH_BITS);
 569    }
 570
 571    if (fb->Attachment[BUFFER_STENCIL].Renderbuffer) {
 572       const struct gl_renderbuffer *rb =
 573          fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 574       const gl_format fmt = rb->Format;
 575       fb->Visual.haveStencilBuffer = GL_TRUE;
 576       fb->Visual.stencilBits = _mesa_get_format_bits(fmt, GL_STENCIL_BITS);
 577    }
 578
 579    if (fb->Attachment[BUFFER_ACCUM].Renderbuffer) {
 580       const struct gl_renderbuffer *rb =
 581          fb->Attachment[BUFFER_ACCUM].Renderbuffer;
 582       const gl_format fmt = rb->Format;
 583       fb->Visual.haveAccumBuffer = GL_TRUE;
 584       fb->Visual.accumRedBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 585       fb->Visual.accumGreenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 586       fb->Visual.accumBlueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 587       fb->Visual.accumAlphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 588    }
 589
 590    compute_depth_max(fb);
 591 }
 592
 593
 594 /**
 595  * Update the framebuffer's _DepthBuffer field using the renderbuffer
 596  * found at the given attachment index.
 597  *
 598  * If that attachment points to a combined GL_DEPTH_STENCIL renderbuffer,
 599  * create and install a depth wrapper/adaptor.
 600  *
 601  * \param fb  the framebuffer whose _DepthBuffer field to update
 602  * \param attIndex  indicates the renderbuffer to possibly wrap
 603  */
 604 void
 605 _mesa_update_depth_buffer(struct gl_context *ctx,
 606                           struct gl_framebuffer *fb,
 607                           GLuint attIndex)
 608 {
 609    struct gl_renderbuffer *depthRb;
 610
 611    /* only one possiblity for now */
 612    ASSERT(attIndex == BUFFER_DEPTH);
 613
 614    depthRb = fb->Attachment[attIndex].Renderbuffer;
 615
 616    if (depthRb && _mesa_is_format_packed_depth_stencil(depthRb->Format)) {
 617       /* The attached depth buffer is a GL_DEPTH_STENCIL renderbuffer */
 618       if (!fb->_DepthBuffer
 619           || fb->_DepthBuffer->Wrapped != depthRb
 620           || _mesa_get_format_base_format(fb->_DepthBuffer->Format) != GL_DEPTH_COMPONENT) {
 621          /* need to update wrapper */
 622          struct gl_renderbuffer *wrapper
 623             = _mesa_new_z24_renderbuffer_wrapper(ctx, depthRb);
 624          _mesa_reference_renderbuffer(&fb->_DepthBuffer, wrapper);
 625          ASSERT(fb->_DepthBuffer->Wrapped == depthRb);
 626       }
 627    }
 628    else {
 629       /* depthRb may be null */
 630       _mesa_reference_renderbuffer(&fb->_DepthBuffer, depthRb);
 631    }
 632 }
 633
 634
 635 /**
 636  * Update the framebuffer's _StencilBuffer field using the renderbuffer
 637  * found at the given attachment index.
 638  *
 639  * If that attachment points to a combined GL_DEPTH_STENCIL renderbuffer,
 640  * create and install a stencil wrapper/adaptor.
 641  *
 642  * \param fb  the framebuffer whose _StencilBuffer field to update
 643  * \param attIndex  indicates the renderbuffer to possibly wrap
 644  */
 645 void
 646 _mesa_update_stencil_buffer(struct gl_context *ctx,
 647                             struct gl_framebuffer *fb,
 648                             GLuint attIndex)
 649 {
 650    struct gl_renderbuffer *stencilRb;
 651
 652    ASSERT(attIndex == BUFFER_DEPTH ||
 653           attIndex == BUFFER_STENCIL);
 654
 655    stencilRb = fb->Attachment[attIndex].Renderbuffer;
 656
 657    if (stencilRb && _mesa_is_format_packed_depth_stencil(stencilRb->Format)) {
 658       /* The attached stencil buffer is a GL_DEPTH_STENCIL renderbuffer */
 659       if (!fb->_StencilBuffer
 660           || fb->_StencilBuffer->Wrapped != stencilRb
 661           || _mesa_get_format_base_format(fb->_StencilBuffer->Format) != GL_STENCIL_INDEX) {
 662          /* need to update wrapper */
 663          struct gl_renderbuffer *wrapper
 664             = _mesa_new_s8_renderbuffer_wrapper(ctx, stencilRb);
 665          _mesa_reference_renderbuffer(&fb->_StencilBuffer, wrapper);
 666          ASSERT(fb->_StencilBuffer->Wrapped == stencilRb);
 667       }
 668    }
 669    else {
 670       /* stencilRb may be null */
 671       _mesa_reference_renderbuffer(&fb->_StencilBuffer, stencilRb);
 672    }
 673 }
 674
 675
 676 /*
 677  * Example DrawBuffers scenarios:
 678  *
 679  * 1. glDrawBuffer(GL_FRONT_AND_BACK), fixed-func or shader writes to
 680  * "gl_FragColor" or program writes to the "result.color" register:
 681  *
 682  *   fragment color output   renderbuffer
 683  *   ---------------------   ---------------
 684  *   color[0]                Front, Back
 685  *
 686  *
 687  * 2. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]), shader writes to
 688  * gl_FragData[i] or program writes to result.color[i] registers:
 689  *
 690  *   fragment color output   renderbuffer
 691  *   ---------------------   ---------------
 692  *   color[0]                Front
 693  *   color[1]                Aux0
 694  *   color[3]                Aux1
 695  *
 696  *
 697  * 3. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]) and shader writes to
 698  * gl_FragColor, or fixed function:
 699  *
 700  *   fragment color output   renderbuffer
 701  *   ---------------------   ---------------
 702  *   color[0]                Front, Aux0, Aux1
 703  *
 704  *
 705  * In either case, the list of renderbuffers is stored in the
 706  * framebuffer->_ColorDrawBuffers[] array and
 707  * framebuffer->_NumColorDrawBuffers indicates the number of buffers.
 708  * The renderer (like swrast) has to look at the current fragment shader
 709  * to see if it writes to gl_FragColor vs. gl_FragData[i] to determine
 710  * how to map color outputs to renderbuffers.
 711  *
 712  * Note that these two calls are equivalent (for fixed function fragment
 713  * shading anyway):
 714  *   a)  glDrawBuffer(GL_FRONT_AND_BACK);  (assuming non-stereo framebuffer)
 715  *   b)  glDrawBuffers(2, [GL_FRONT_LEFT, GL_BACK_LEFT]);
 716  */
 717
 718
 719
 720
 721 /**
 722  * Update the (derived) list of color drawing renderbuffer pointers.
 723  * Later, when we're rendering we'll loop from 0 to _NumColorDrawBuffers
 724  * writing colors.
 725  */
 726 static void
 727 update_color_draw_buffers(struct gl_context *ctx, struct gl_framebuffer *fb)
 728 {
 729    GLuint output;
 730
 731    /* set 0th buffer to NULL now in case _NumColorDrawBuffers is zero */
 732    fb->_ColorDrawBuffers[0] = NULL;
 733
 734    for (output = 0; output < fb->_NumColorDrawBuffers; output++) {
 735       GLint buf = fb->_ColorDrawBufferIndexes[output];
 736       if (buf >= 0) {
 737          fb->_ColorDrawBuffers[output] = fb->Attachment[buf].Renderbuffer;
 738       }
 739       else {
 740          fb->_ColorDrawBuffers[output] = NULL;
 741       }
 742    }
 743 }
 744
 745
 746 /**
 747  * Update the (derived) color read renderbuffer pointer.
 748  * Unlike the DrawBuffer, we can only read from one (or zero) color buffers.
 749  */
 750 static void
 751 update_color_read_buffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 752 {
 753    (void) ctx;
 754    if (fb->_ColorReadBufferIndex == -1 ||
 755        fb->DeletePending ||
 756        fb->Width == 0 ||
 757        fb->Height == 0) {
 758       fb->_ColorReadBuffer = NULL; /* legal! */
 759    }
 760    else {
 761       ASSERT(fb->_ColorReadBufferIndex >= 0);
 762       ASSERT(fb->_ColorReadBufferIndex < BUFFER_COUNT);
 763       fb->_ColorReadBuffer
 764          = fb->Attachment[fb->_ColorReadBufferIndex].Renderbuffer;
 765    }
 766 }
 767
 768
 769 /**
 770  * Update a gl_framebuffer's derived state.
 771  *
 772  * Specifically, update these framebuffer fields:
 773  *    _ColorDrawBuffers
 774  *    _NumColorDrawBuffers
 775  *    _ColorReadBuffer
 776  *    _DepthBuffer
 777  *    _StencilBuffer
 778  *
 779  * If the framebuffer is user-created, make sure it's complete.
 780  *
 781  * The following functions (at least) can effect framebuffer state:
 782  * glReadBuffer, glDrawBuffer, glDrawBuffersARB, glFramebufferRenderbufferEXT,
 783  * glRenderbufferStorageEXT.
 784  */
 785 static void
 786 update_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 787 {
 788    if (fb->Name == 0) {
 789       /* This is a window-system framebuffer */
 790       /* Need to update the FB's GL_DRAW_BUFFER state to match the
 791        * context state (GL_READ_BUFFER too).
 792        */
 793       if (fb->ColorDrawBuffer[0] != ctx->Color.DrawBuffer[0]) {
 794          _mesa_drawbuffers(ctx, ctx->Const.MaxDrawBuffers,
 795                            ctx->Color.DrawBuffer, NULL);
 796       }
 797    }
 798    else {
 799       /* This is a user-created framebuffer.
 800        * Completeness only matters for user-created framebuffers.
 801        */
 802       if (fb->_Status == 0) {
 803          _mesa_test_framebuffer_completeness(ctx, fb);
 804       }
 805    }
 806
 807    /* Strictly speaking, we don't need to update the draw-state
 808     * if this FB is bound as ctx->ReadBuffer (and conversely, the
 809     * read-state if this FB is bound as ctx->DrawBuffer), but no
 810     * harm.
 811     */
 812    update_color_draw_buffers(ctx, fb);
 813    update_color_read_buffer(ctx, fb);
 814    _mesa_update_depth_buffer(ctx, fb, BUFFER_DEPTH);
 815    _mesa_update_stencil_buffer(ctx, fb, BUFFER_STENCIL);
 816
 817    compute_depth_max(fb);
 818 }
 819
 820
 821 /**
 822  * Update state related to the current draw/read framebuffers.
 823  */
 824 void
 825 _mesa_update_framebuffer(struct gl_context *ctx)
 826 {
 827    struct gl_framebuffer *drawFb;
 828    struct gl_framebuffer *readFb;
 829
 830    assert(ctx);
 831    drawFb = ctx->DrawBuffer;
 832    readFb = ctx->ReadBuffer;
 833
 834    update_framebuffer(ctx, drawFb);
 835    if (readFb != drawFb)
 836       update_framebuffer(ctx, readFb);
 837 }
 838
 839
 840 /**
 841  * Check if the renderbuffer for a read operation (glReadPixels, glCopyPixels,
 842  * glCopyTex[Sub]Image, etc) exists.
 843  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 844  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 845  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 846  */
 847 GLboolean
 848 _mesa_source_buffer_exists(struct gl_context *ctx, GLenum format)
 849 {
 850    const struct gl_renderbuffer_attachment *att = ctx->ReadBuffer->Attachment;
 851
 852    /* If we don't know the framebuffer status, update it now */
 853    if (ctx->ReadBuffer->_Status == 0) {
 854       _mesa_test_framebuffer_completeness(ctx, ctx->ReadBuffer);
 855    }
 856
 857    if (ctx->ReadBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 858       return GL_FALSE;
 859    }
 860
 861    switch (format) {
 862    case GL_COLOR:
 863    case GL_RED:
 864    case GL_GREEN:
 865    case GL_BLUE:
 866    case GL_ALPHA:
 867    case GL_LUMINANCE:
 868    case GL_LUMINANCE_ALPHA:
 869    case GL_INTENSITY:
 870    case GL_RG:
 871    case GL_RGB:
 872    case GL_BGR:
 873    case GL_RGBA:
 874    case GL_BGRA:
 875    case GL_ABGR_EXT:
 876    case GL_COLOR_INDEX:
 877    case GL_RED_INTEGER_EXT:
 878    case GL_GREEN_INTEGER_EXT:
 879    case GL_BLUE_INTEGER_EXT:
 880    case GL_ALPHA_INTEGER_EXT:
 881    case GL_RGB_INTEGER_EXT:
 882    case GL_RGBA_INTEGER_EXT:
 883    case GL_BGR_INTEGER_EXT:
 884    case GL_BGRA_INTEGER_EXT:
 885    case GL_LUMINANCE_INTEGER_EXT:
 886    case GL_LUMINANCE_ALPHA_INTEGER_EXT:
 887       if (ctx->ReadBuffer->_ColorReadBuffer == NULL) {
 888          return GL_FALSE;
 889       }
 890       ASSERT(_mesa_get_format_bits(ctx->ReadBuffer->_ColorReadBuffer->Format, GL_RED_BITS) > 0 ||
 891              _mesa_get_format_bits(ctx->ReadBuffer->_ColorReadBuffer->Format, GL_ALPHA_BITS) > 0 ||
 892              _mesa_get_format_bits(ctx->ReadBuffer->_ColorReadBuffer->Format, GL_INDEX_BITS) > 0);
 893       break;
 894    case GL_DEPTH:
 895    case GL_DEPTH_COMPONENT:
 896       if (!att[BUFFER_DEPTH].Renderbuffer) {
 897          return GL_FALSE;
 898       }
 899       /*ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);*/
 900       break;
 901    case GL_STENCIL:
 902    case GL_STENCIL_INDEX:
 903       if (!att[BUFFER_STENCIL].Renderbuffer) {
 904          return GL_FALSE;
 905       }
 906       /*ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);*/
 907       break;
 908    case GL_DEPTH_STENCIL_EXT:
 909       if (!att[BUFFER_DEPTH].Renderbuffer ||
 910           !att[BUFFER_STENCIL].Renderbuffer) {
 911          return GL_FALSE;
 912       }
 913       /*
 914       ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);
 915       ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);
 916       */
 917       break;
 918    default:
 919       _mesa_problem(ctx,
 920                     "Unexpected format 0x%x in _mesa_source_buffer_exists",
 921                     format);
 922       return GL_FALSE;
 923    }
 924
 925    /* OK */
 926    return GL_TRUE;
 927 }
 928
 929
 930 /**
 931  * As above, but for drawing operations.
 932  * XXX could do some code merging w/ above function.
 933  */
 934 GLboolean
 935 _mesa_dest_buffer_exists(struct gl_context *ctx, GLenum format)
 936 {
 937    const struct gl_renderbuffer_attachment *att = ctx->DrawBuffer->Attachment;
 938
 939    /* If we don't know the framebuffer status, update it now */
 940    if (ctx->DrawBuffer->_Status == 0) {
 941       _mesa_test_framebuffer_completeness(ctx, ctx->DrawBuffer);
 942    }
 943
 944    if (ctx->DrawBuffer->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 945       return GL_FALSE;
 946    }
 947
 948    switch (format) {
 949    case GL_COLOR:
 950    case GL_RED:
 951    case GL_GREEN:
 952    case GL_BLUE:
 953    case GL_ALPHA:
 954    case GL_LUMINANCE:
 955    case GL_LUMINANCE_ALPHA:
 956    case GL_INTENSITY:
 957    case GL_RGB:
 958    case GL_BGR:
 959    case GL_RGBA:
 960    case GL_BGRA:
 961    case GL_ABGR_EXT:
 962    case GL_COLOR_INDEX:
 963    case GL_RED_INTEGER_EXT:
 964    case GL_GREEN_INTEGER_EXT:
 965    case GL_BLUE_INTEGER_EXT:
 966    case GL_ALPHA_INTEGER_EXT:
 967    case GL_RGB_INTEGER_EXT:
 968    case GL_RGBA_INTEGER_EXT:
 969    case GL_BGR_INTEGER_EXT:
 970    case GL_BGRA_INTEGER_EXT:
 971    case GL_LUMINANCE_INTEGER_EXT:
 972    case GL_LUMINANCE_ALPHA_INTEGER_EXT:
 973       /* Nothing special since GL_DRAW_BUFFER could be GL_NONE. */
 974       /* Could assert that colorbuffer has RedBits > 0 */
 975       break;
 976    case GL_DEPTH:
 977    case GL_DEPTH_COMPONENT:
 978       if (!att[BUFFER_DEPTH].Renderbuffer) {
 979          return GL_FALSE;
 980       }
 981       /*ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);*/
 982       break;
 983    case GL_STENCIL:
 984    case GL_STENCIL_INDEX:
 985       if (!att[BUFFER_STENCIL].Renderbuffer) {
 986          return GL_FALSE;
 987       }
 988       /*ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);*/
 989       break;
 990    case GL_DEPTH_STENCIL_EXT:
 991       if (!att[BUFFER_DEPTH].Renderbuffer ||
 992           !att[BUFFER_STENCIL].Renderbuffer) {
 993          return GL_FALSE;
 994       }
 995       /*
 996       ASSERT(att[BUFFER_DEPTH].Renderbuffer->DepthBits > 0);
 997       ASSERT(att[BUFFER_STENCIL].Renderbuffer->StencilBits > 0);
 998       */
 999       break;
1000    default:
1001       _mesa_problem(ctx,
1002                     "Unexpected format 0x%x in _mesa_dest_buffer_exists",
1003                     format);
1004       return GL_FALSE;
1005    }
1006
1007    /* OK */
1008    return GL_TRUE;
1009 }
1010
1011
1012 /**
1013  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_FORMAT_OES query.
1014  */
1015 GLenum
1016 _mesa_get_color_read_format(struct gl_context *ctx)
1017 {
1018    switch (ctx->ReadBuffer->_ColorReadBuffer->Format) {
1019    case MESA_FORMAT_ARGB8888:
1020       return GL_BGRA;
1021    case MESA_FORMAT_RGB565:
1022       return GL_BGR;
1023    default:
1024       return GL_RGBA;
1025    }
1026 }
1027
1028
1029 /**
1030  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_TYPE_OES query.
1031  */
1032 GLenum
1033 _mesa_get_color_read_type(struct gl_context *ctx)
1034 {
1035    switch (ctx->ReadBuffer->_ColorReadBuffer->Format) {
1036    case MESA_FORMAT_ARGB8888:
1037       return GL_UNSIGNED_BYTE;
1038    case MESA_FORMAT_RGB565:
1039       return GL_UNSIGNED_SHORT_5_6_5_REV;
1040    default:
1041       return GL_UNSIGNED_BYTE;
1042    }
1043 }
1044
1045
1046 /**
1047  * Print framebuffer info to stderr, for debugging.
1048  */
1049 void
1050 _mesa_print_framebuffer(const struct gl_framebuffer *fb)
1051 {
1052    GLuint i;
1053
1054    fprintf(stderr, "Mesa Framebuffer %u at %p\n", fb->Name, (void *) fb);
1055    fprintf(stderr, "  Size: %u x %u  Status: %s\n", fb->Width, fb->Height,
1056            _mesa_lookup_enum_by_nr(fb->_Status));
1057    fprintf(stderr, "  Attachments:\n");
1058
1059    for (i = 0; i < BUFFER_COUNT; i++) {
1060       const struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
1061       if (att->Type == GL_TEXTURE) {
1062          const struct gl_texture_image *texImage;
1063          fprintf(stderr,
1064                  "  %2d: Texture %u, level %u, face %u, slice %u, complete %d\n",
1065                  i, att->Texture->Name, att->TextureLevel, att->CubeMapFace,
1066                  att->Zoffset, att->Complete);
1067          texImage = att->Texture->Image[att->CubeMapFace][att->TextureLevel];
1068          fprintf(stderr, "       Size: %u x %u x %u  Format %s\n",
1069                  texImage->Width, texImage->Height, texImage->Depth,
1070                  _mesa_get_format_name(texImage->TexFormat));
1071       }
1072       else if (att->Type == GL_RENDERBUFFER) {
1073          fprintf(stderr, "  %2d: Renderbuffer %u, complete %d\n",
1074                  i, att->Renderbuffer->Name, att->Complete);
1075          fprintf(stderr, "       Size: %u x %u  Format %s\n",
1076                  att->Renderbuffer->Width, att->Renderbuffer->Height,
1077                  _mesa_get_format_name(att->Renderbuffer->Format));
1078       }
1079       else {
1080          fprintf(stderr, "  %2d: none\n", i);
1081       }
1082    }
1083 }