src/mesa/main/framebuffer.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  22  * 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 "blend.h"
  36 #include "buffers.h"
  37 #include "context.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 #include "glformats.h"
  47
  48
  49
  50 /**
  51  * Compute/set the _DepthMax field for the given framebuffer.
  52  * This value depends on the Z buffer resolution.
  53  */
  54 static void
  55 compute_depth_max(struct gl_framebuffer *fb)
  56 {
  57    if (fb->Visual.depthBits == 0) {
  58       /* Special case.  Even if we don't have a depth buffer we need
  59        * good values for DepthMax for Z vertex transformation purposes
  60        * and for per-fragment fog computation.
  61        */
  62       fb->_DepthMax = (1 << 16) - 1;
  63    }
  64    else if (fb->Visual.depthBits < 32) {
  65       fb->_DepthMax = (1 << fb->Visual.depthBits) - 1;
  66    }
  67    else {
  68       /* Special case since shift values greater than or equal to the
  69        * number of bits in the left hand expression's type are undefined.
  70        */
  71       fb->_DepthMax = 0xffffffff;
  72    }
  73    fb->_DepthMaxF = (GLfloat) fb->_DepthMax;
  74
  75    /* Minimum resolvable depth value, for polygon offset */
  76    fb->_MRD = (GLfloat)1.0 / fb->_DepthMaxF;
  77 }
  78
  79 /**
  80  * Create and initialize a gl_framebuffer object.
  81  * This is intended for creating _window_system_ framebuffers, not generic
  82  * framebuffer objects ala GL_EXT_framebuffer_object.
  83  *
  84  * \sa _mesa_new_framebuffer
  85  */
  86 struct gl_framebuffer *
  87 _mesa_create_framebuffer(const struct gl_config *visual)
  88 {
  89    struct gl_framebuffer *fb = CALLOC_STRUCT(gl_framebuffer);
  90    assert(visual);
  91    if (fb) {
  92       _mesa_initialize_window_framebuffer(fb, visual);
  93    }
  94    return fb;
  95 }
  96
  97
  98 /**
  99  * Allocate a new gl_framebuffer object.
 100  * This is the default function for ctx->Driver.NewFramebuffer().
 101  * This is for allocating user-created framebuffers, not window-system
 102  * framebuffers!
 103  * \sa _mesa_create_framebuffer
 104  */
 105 struct gl_framebuffer *
 106 _mesa_new_framebuffer(struct gl_context *ctx, GLuint name)
 107 {
 108    struct gl_framebuffer *fb;
 109    (void) ctx;
 110    assert(name != 0);
 111    fb = CALLOC_STRUCT(gl_framebuffer);
 112    if (fb) {
 113       _mesa_initialize_user_framebuffer(fb, name);
 114    }
 115    return fb;
 116 }
 117
 118
 119 /**
 120  * Initialize a gl_framebuffer object.  Typically used to initialize
 121  * window system-created framebuffers, not user-created framebuffers.
 122  * \sa _mesa_initialize_user_framebuffer
 123  */
 124 void
 125 _mesa_initialize_window_framebuffer(struct gl_framebuffer *fb,
 126                                      const struct gl_config *visual)
 127 {
 128    assert(fb);
 129    assert(visual);
 130
 131    memset(fb, 0, sizeof(struct gl_framebuffer));
 132
 133    _glthread_INIT_MUTEX(fb->Mutex);
 134
 135    fb->RefCount = 1;
 136
 137    /* save the visual */
 138    fb->Visual = *visual;
 139
 140    /* Init read/draw renderbuffer state */
 141    if (visual->doubleBufferMode) {
 142       fb->_NumColorDrawBuffers = 1;
 143       fb->ColorDrawBuffer[0] = GL_BACK;
 144       fb->_ColorDrawBufferIndexes[0] = BUFFER_BACK_LEFT;
 145       fb->ColorReadBuffer = GL_BACK;
 146       fb->_ColorReadBufferIndex = BUFFER_BACK_LEFT;
 147    }
 148    else {
 149       fb->_NumColorDrawBuffers = 1;
 150       fb->ColorDrawBuffer[0] = GL_FRONT;
 151       fb->_ColorDrawBufferIndexes[0] = BUFFER_FRONT_LEFT;
 152       fb->ColorReadBuffer = GL_FRONT;
 153       fb->_ColorReadBufferIndex = BUFFER_FRONT_LEFT;
 154    }
 155
 156    fb->Delete = _mesa_destroy_framebuffer;
 157    fb->_Status = GL_FRAMEBUFFER_COMPLETE_EXT;
 158    fb->_AllColorBuffersFixedPoint = !visual->floatMode;
 159    fb->_HasSNormOrFloatColorBuffer = visual->floatMode;
 160
 161    compute_depth_max(fb);
 162 }
 163
 164
 165 /**
 166  * Initialize a user-created gl_framebuffer object.
 167  * \sa _mesa_initialize_window_framebuffer
 168  */
 169 void
 170 _mesa_initialize_user_framebuffer(struct gl_framebuffer *fb, GLuint name)
 171 {
 172    assert(fb);
 173    assert(name);
 174
 175    memset(fb, 0, sizeof(struct gl_framebuffer));
 176
 177    fb->Name = name;
 178    fb->RefCount = 1;
 179    fb->_NumColorDrawBuffers = 1;
 180    fb->ColorDrawBuffer[0] = GL_COLOR_ATTACHMENT0_EXT;
 181    fb->_ColorDrawBufferIndexes[0] = BUFFER_COLOR0;
 182    fb->ColorReadBuffer = GL_COLOR_ATTACHMENT0_EXT;
 183    fb->_ColorReadBufferIndex = BUFFER_COLOR0;
 184    fb->Delete = _mesa_destroy_framebuffer;
 185    _glthread_INIT_MUTEX(fb->Mutex);
 186 }
 187
 188
 189 /**
 190  * Deallocate buffer and everything attached to it.
 191  * Typically called via the gl_framebuffer->Delete() method.
 192  */
 193 void
 194 _mesa_destroy_framebuffer(struct gl_framebuffer *fb)
 195 {
 196    if (fb) {
 197       _mesa_free_framebuffer_data(fb);
 198       free(fb);
 199    }
 200 }
 201
 202
 203 /**
 204  * Free all the data hanging off the given gl_framebuffer, but don't free
 205  * the gl_framebuffer object itself.
 206  */
 207 void
 208 _mesa_free_framebuffer_data(struct gl_framebuffer *fb)
 209 {
 210    GLuint i;
 211
 212    assert(fb);
 213    assert(fb->RefCount == 0);
 214
 215    _glthread_DESTROY_MUTEX(fb->Mutex);
 216
 217    for (i = 0; i < BUFFER_COUNT; i++) {
 218       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 219       if (att->Renderbuffer) {
 220          _mesa_reference_renderbuffer(&att->Renderbuffer, NULL);
 221       }
 222       if (att->Texture) {
 223          _mesa_reference_texobj(&att->Texture, NULL);
 224       }
 225       ASSERT(!att->Renderbuffer);
 226       ASSERT(!att->Texture);
 227       att->Type = GL_NONE;
 228    }
 229 }
 230
 231
 232 /**
 233  * Set *ptr to point to fb, with refcounting and locking.
 234  * This is normally only called from the _mesa_reference_framebuffer() macro
 235  * when there's a real pointer change.
 236  */
 237 void
 238 _mesa_reference_framebuffer_(struct gl_framebuffer **ptr,
 239                              struct gl_framebuffer *fb)
 240 {
 241    if (*ptr) {
 242       /* unreference old renderbuffer */
 243       GLboolean deleteFlag = GL_FALSE;
 244       struct gl_framebuffer *oldFb = *ptr;
 245
 246       _glthread_LOCK_MUTEX(oldFb->Mutex);
 247       ASSERT(oldFb->RefCount > 0);
 248       oldFb->RefCount--;
 249       deleteFlag = (oldFb->RefCount == 0);
 250       _glthread_UNLOCK_MUTEX(oldFb->Mutex);
 251
 252       if (deleteFlag)
 253          oldFb->Delete(oldFb);
 254
 255       *ptr = NULL;
 256    }
 257    assert(!*ptr);
 258
 259    if (fb) {
 260       _glthread_LOCK_MUTEX(fb->Mutex);
 261       fb->RefCount++;
 262       _glthread_UNLOCK_MUTEX(fb->Mutex);
 263       *ptr = fb;
 264    }
 265 }
 266
 267
 268 /**
 269  * Resize the given framebuffer's renderbuffers to the new width and height.
 270  * This should only be used for window-system framebuffers, not
 271  * user-created renderbuffers (i.e. made with GL_EXT_framebuffer_object).
 272  * This will typically be called via ctx->Driver.ResizeBuffers() or directly
 273  * from a device driver.
 274  *
 275  * \note it's possible for ctx to be null since a window can be resized
 276  * without a currently bound rendering context.
 277  */
 278 void
 279 _mesa_resize_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb,
 280                          GLuint width, GLuint height)
 281 {
 282    GLuint i;
 283
 284    /* XXX I think we could check if the size is not changing
 285     * and return early.
 286     */
 287
 288    /* Can only resize win-sys framebuffer objects */
 289    assert(_mesa_is_winsys_fbo(fb));
 290
 291    for (i = 0; i < BUFFER_COUNT; i++) {
 292       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 293       if (att->Type == GL_RENDERBUFFER_EXT && att->Renderbuffer) {
 294          struct gl_renderbuffer *rb = att->Renderbuffer;
 295          /* only resize if size is changing */
 296          if (rb->Width != width || rb->Height != height) {
 297             if (rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 298                ASSERT(rb->Width == width);
 299                ASSERT(rb->Height == height);
 300             }
 301             else {
 302                _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 303                /* no return */
 304             }
 305          }
 306       }
 307    }
 308
 309    fb->Width = width;
 310    fb->Height = height;
 311
 312    if (ctx) {
 313       /* update scissor / window bounds */
 314       _mesa_update_draw_buffer_bounds(ctx);
 315       /* Signal new buffer state so that swrast will update its clipping
 316        * info (the CLIP_BIT flag).
 317        */
 318       ctx->NewState |= _NEW_BUFFERS;
 319    }
 320 }
 321
 322 /*
 323  * XXX THIS IS OBSOLETE
 324  */
 325 void GLAPIENTRY
 326 _mesa_ResizeBuffersMESA( void )
 327 {
 328 }
 329
 330
 331
 332 /**
 333  * Examine all the framebuffer's renderbuffers to update the Width/Height
 334  * fields of the framebuffer.  If we have renderbuffers with different
 335  * sizes, set the framebuffer's width and height to the min size.
 336  * Note: this is only intended for user-created framebuffers, not
 337  * window-system framebuffes.
 338  */
 339 static void
 340 update_framebuffer_size(struct gl_context *ctx, struct gl_framebuffer *fb)
 341 {
 342    GLuint minWidth = ~0, minHeight = ~0;
 343    GLuint i;
 344
 345    /* user-created framebuffers only */
 346    assert(_mesa_is_user_fbo(fb));
 347
 348    for (i = 0; i < BUFFER_COUNT; i++) {
 349       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 350       const struct gl_renderbuffer *rb = att->Renderbuffer;
 351       if (rb) {
 352          minWidth = MIN2(minWidth, rb->Width);
 353          minHeight = MIN2(minHeight, rb->Height);
 354       }
 355    }
 356
 357    if (minWidth != ~0) {
 358       fb->Width = minWidth;
 359       fb->Height = minHeight;
 360    }
 361    else {
 362       fb->Width = 0;
 363       fb->Height = 0;
 364    }
 365 }
 366
 367
 368 /**
 369  * Update the context's current drawing buffer's Xmin, Xmax, Ymin, Ymax fields.
 370  * These values are computed from the buffer's width and height and
 371  * the scissor box, if it's enabled.
 372  * \param ctx  the GL context.
 373  */
 374 void
 375 _mesa_update_draw_buffer_bounds(struct gl_context *ctx)
 376 {
 377    struct gl_framebuffer *buffer = ctx->DrawBuffer;
 378
 379    if (!buffer)
 380       return;
 381
 382    if (_mesa_is_user_fbo(buffer)) {
 383       /* user-created framebuffer size depends on the renderbuffers */
 384       update_framebuffer_size(ctx, buffer);
 385    }
 386
 387    buffer->_Xmin = 0;
 388    buffer->_Ymin = 0;
 389    buffer->_Xmax = buffer->Width;
 390    buffer->_Ymax = buffer->Height;
 391
 392    if (ctx->Scissor.Enabled) {
 393       if (ctx->Scissor.X > buffer->_Xmin) {
 394          buffer->_Xmin = ctx->Scissor.X;
 395       }
 396       if (ctx->Scissor.Y > buffer->_Ymin) {
 397          buffer->_Ymin = ctx->Scissor.Y;
 398       }
 399       if (ctx->Scissor.X + ctx->Scissor.Width < buffer->_Xmax) {
 400          buffer->_Xmax = ctx->Scissor.X + ctx->Scissor.Width;
 401       }
 402       if (ctx->Scissor.Y + ctx->Scissor.Height < buffer->_Ymax) {
 403          buffer->_Ymax = ctx->Scissor.Y + ctx->Scissor.Height;
 404       }
 405       /* finally, check for empty region */
 406       if (buffer->_Xmin > buffer->_Xmax) {
 407          buffer->_Xmin = buffer->_Xmax;
 408       }
 409       if (buffer->_Ymin > buffer->_Ymax) {
 410          buffer->_Ymin = buffer->_Ymax;
 411       }
 412    }
 413
 414    ASSERT(buffer->_Xmin <= buffer->_Xmax);
 415    ASSERT(buffer->_Ymin <= buffer->_Ymax);
 416 }
 417
 418
 419 /**
 420  * The glGet queries of the framebuffer red/green/blue size, stencil size,
 421  * etc. are satisfied by the fields of ctx->DrawBuffer->Visual.  These can
 422  * change depending on the renderbuffer bindings.  This function updates
 423  * the given framebuffer's Visual from the current renderbuffer bindings.
 424  *
 425  * This may apply to user-created framebuffers or window system framebuffers.
 426  *
 427  * Also note: ctx->DrawBuffer->Visual.depthBits might not equal
 428  * ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer.DepthBits.
 429  * The former one is used to convert floating point depth values into
 430  * integer Z values.
 431  */
 432 void
 433 _mesa_update_framebuffer_visual(struct gl_context *ctx,
 434                                 struct gl_framebuffer *fb)
 435 {
 436    GLuint i;
 437
 438    memset(&fb->Visual, 0, sizeof(fb->Visual));
 439    fb->Visual.rgbMode = GL_TRUE; /* assume this */
 440
 441 #if 0 /* this _might_ be needed */
 442    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 443       /* leave visual fields zero'd */
 444       return;
 445    }
 446 #endif
 447
 448    /* find first RGB renderbuffer */
 449    for (i = 0; i < BUFFER_COUNT; i++) {
 450       if (fb->Attachment[i].Renderbuffer) {
 451          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 452          const GLenum baseFormat = _mesa_get_format_base_format(rb->Format);
 453          const gl_format fmt = rb->Format;
 454
 455          /* Grab samples and sampleBuffers from any attachment point (assuming
 456           * the framebuffer is complete, we'll get the same answer from all
 457           * attachments).
 458           */
 459          fb->Visual.samples = rb->NumSamples;
 460          fb->Visual.sampleBuffers = rb->NumSamples > 0 ? 1 : 0;
 461
 462          if (_mesa_is_legal_color_format(ctx, baseFormat)) {
 463             fb->Visual.redBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 464             fb->Visual.greenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 465             fb->Visual.blueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 466             fb->Visual.alphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 467             fb->Visual.rgbBits = fb->Visual.redBits
 468                + fb->Visual.greenBits + fb->Visual.blueBits;
 469             if (_mesa_get_format_color_encoding(fmt) == GL_SRGB)
 470                 fb->Visual.sRGBCapable = ctx->Extensions.EXT_framebuffer_sRGB;
 471             break;
 472          }
 473       }
 474    }
 475
 476    fb->Visual.floatMode = GL_FALSE;
 477    for (i = 0; i < BUFFER_COUNT; i++) {
 478       if (fb->Attachment[i].Renderbuffer) {
 479          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 480          const gl_format fmt = rb->Format;
 481
 482          if (_mesa_get_format_datatype(fmt) == GL_FLOAT) {
 483             fb->Visual.floatMode = GL_TRUE;
 484             break;
 485          }
 486       }
 487    }
 488
 489    if (fb->Attachment[BUFFER_DEPTH].Renderbuffer) {
 490       const struct gl_renderbuffer *rb =
 491          fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 492       const gl_format fmt = rb->Format;
 493       fb->Visual.haveDepthBuffer = GL_TRUE;
 494       fb->Visual.depthBits = _mesa_get_format_bits(fmt, GL_DEPTH_BITS);
 495    }
 496
 497    if (fb->Attachment[BUFFER_STENCIL].Renderbuffer) {
 498       const struct gl_renderbuffer *rb =
 499          fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 500       const gl_format fmt = rb->Format;
 501       fb->Visual.haveStencilBuffer = GL_TRUE;
 502       fb->Visual.stencilBits = _mesa_get_format_bits(fmt, GL_STENCIL_BITS);
 503    }
 504
 505    if (fb->Attachment[BUFFER_ACCUM].Renderbuffer) {
 506       const struct gl_renderbuffer *rb =
 507          fb->Attachment[BUFFER_ACCUM].Renderbuffer;
 508       const gl_format fmt = rb->Format;
 509       fb->Visual.haveAccumBuffer = GL_TRUE;
 510       fb->Visual.accumRedBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 511       fb->Visual.accumGreenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 512       fb->Visual.accumBlueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 513       fb->Visual.accumAlphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 514    }
 515
 516    compute_depth_max(fb);
 517 }
 518
 519
 520 /*
 521  * Example DrawBuffers scenarios:
 522  *
 523  * 1. glDrawBuffer(GL_FRONT_AND_BACK), fixed-func or shader writes to
 524  * "gl_FragColor" or program writes to the "result.color" register:
 525  *
 526  *   fragment color output   renderbuffer
 527  *   ---------------------   ---------------
 528  *   color[0]                Front, Back
 529  *
 530  *
 531  * 2. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]), shader writes to
 532  * gl_FragData[i] or program writes to result.color[i] registers:
 533  *
 534  *   fragment color output   renderbuffer
 535  *   ---------------------   ---------------
 536  *   color[0]                Front
 537  *   color[1]                Aux0
 538  *   color[3]                Aux1
 539  *
 540  *
 541  * 3. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]) and shader writes to
 542  * gl_FragColor, or fixed function:
 543  *
 544  *   fragment color output   renderbuffer
 545  *   ---------------------   ---------------
 546  *   color[0]                Front, Aux0, Aux1
 547  *
 548  *
 549  * In either case, the list of renderbuffers is stored in the
 550  * framebuffer->_ColorDrawBuffers[] array and
 551  * framebuffer->_NumColorDrawBuffers indicates the number of buffers.
 552  * The renderer (like swrast) has to look at the current fragment shader
 553  * to see if it writes to gl_FragColor vs. gl_FragData[i] to determine
 554  * how to map color outputs to renderbuffers.
 555  *
 556  * Note that these two calls are equivalent (for fixed function fragment
 557  * shading anyway):
 558  *   a)  glDrawBuffer(GL_FRONT_AND_BACK);  (assuming non-stereo framebuffer)
 559  *   b)  glDrawBuffers(2, [GL_FRONT_LEFT, GL_BACK_LEFT]);
 560  */
 561
 562
 563
 564
 565 /**
 566  * Update the (derived) list of color drawing renderbuffer pointers.
 567  * Later, when we're rendering we'll loop from 0 to _NumColorDrawBuffers
 568  * writing colors.
 569  */
 570 static void
 571 update_color_draw_buffers(struct gl_context *ctx, struct gl_framebuffer *fb)
 572 {
 573    GLuint output;
 574
 575    /* set 0th buffer to NULL now in case _NumColorDrawBuffers is zero */
 576    fb->_ColorDrawBuffers[0] = NULL;
 577
 578    for (output = 0; output < fb->_NumColorDrawBuffers; output++) {
 579       GLint buf = fb->_ColorDrawBufferIndexes[output];
 580       if (buf >= 0) {
 581          fb->_ColorDrawBuffers[output] = fb->Attachment[buf].Renderbuffer;
 582       }
 583       else {
 584          fb->_ColorDrawBuffers[output] = NULL;
 585       }
 586    }
 587 }
 588
 589
 590 /**
 591  * Update the (derived) color read renderbuffer pointer.
 592  * Unlike the DrawBuffer, we can only read from one (or zero) color buffers.
 593  */
 594 static void
 595 update_color_read_buffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 596 {
 597    (void) ctx;
 598    if (fb->_ColorReadBufferIndex == -1 ||
 599        fb->DeletePending ||
 600        fb->Width == 0 ||
 601        fb->Height == 0) {
 602       fb->_ColorReadBuffer = NULL; /* legal! */
 603    }
 604    else {
 605       ASSERT(fb->_ColorReadBufferIndex >= 0);
 606       ASSERT(fb->_ColorReadBufferIndex < BUFFER_COUNT);
 607       fb->_ColorReadBuffer
 608          = fb->Attachment[fb->_ColorReadBufferIndex].Renderbuffer;
 609    }
 610 }
 611
 612
 613 /**
 614  * Update a gl_framebuffer's derived state.
 615  *
 616  * Specifically, update these framebuffer fields:
 617  *    _ColorDrawBuffers
 618  *    _NumColorDrawBuffers
 619  *    _ColorReadBuffer
 620  *
 621  * If the framebuffer is user-created, make sure it's complete.
 622  *
 623  * The following functions (at least) can effect framebuffer state:
 624  * glReadBuffer, glDrawBuffer, glDrawBuffersARB, glFramebufferRenderbufferEXT,
 625  * glRenderbufferStorageEXT.
 626  */
 627 static void
 628 update_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 629 {
 630    if (_mesa_is_winsys_fbo(fb)) {
 631       /* This is a window-system framebuffer */
 632       /* Need to update the FB's GL_DRAW_BUFFER state to match the
 633        * context state (GL_READ_BUFFER too).
 634        */
 635       if (fb->ColorDrawBuffer[0] != ctx->Color.DrawBuffer[0]) {
 636          _mesa_drawbuffers(ctx, ctx->Const.MaxDrawBuffers,
 637                            ctx->Color.DrawBuffer, NULL);
 638       }
 639    }
 640    else {
 641       /* This is a user-created framebuffer.
 642        * Completeness only matters for user-created framebuffers.
 643        */
 644       if (fb->_Status != GL_FRAMEBUFFER_COMPLETE) {
 645          _mesa_test_framebuffer_completeness(ctx, fb);
 646       }
 647    }
 648
 649    /* Strictly speaking, we don't need to update the draw-state
 650     * if this FB is bound as ctx->ReadBuffer (and conversely, the
 651     * read-state if this FB is bound as ctx->DrawBuffer), but no
 652     * harm.
 653     */
 654    update_color_draw_buffers(ctx, fb);
 655    update_color_read_buffer(ctx, fb);
 656
 657    compute_depth_max(fb);
 658 }
 659
 660
 661 /**
 662  * Update state related to the current draw/read framebuffers.
 663  */
 664 void
 665 _mesa_update_framebuffer(struct gl_context *ctx)
 666 {
 667    struct gl_framebuffer *drawFb;
 668    struct gl_framebuffer *readFb;
 669
 670    assert(ctx);
 671    drawFb = ctx->DrawBuffer;
 672    readFb = ctx->ReadBuffer;
 673
 674    update_framebuffer(ctx, drawFb);
 675    if (readFb != drawFb)
 676       update_framebuffer(ctx, readFb);
 677
 678    _mesa_update_clamp_vertex_color(ctx);
 679    _mesa_update_clamp_fragment_color(ctx);
 680 }
 681
 682
 683 /**
 684  * Check if the renderbuffer for a read/draw operation exists.
 685  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 686  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 687  * \param reading  if TRUE, we're going to read from the buffer,
 688                    if FALSE, we're going to write to the buffer.
 689  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 690  */
 691 static GLboolean
 692 renderbuffer_exists(struct gl_context *ctx,
 693                     struct gl_framebuffer *fb,
 694                     GLenum format,
 695                     GLboolean reading)
 696 {
 697    const struct gl_renderbuffer_attachment *att = fb->Attachment;
 698
 699    /* If we don't know the framebuffer status, update it now */
 700    if (fb->_Status == 0) {
 701       _mesa_test_framebuffer_completeness(ctx, fb);
 702    }
 703
 704    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 705       return GL_FALSE;
 706    }
 707
 708    switch (format) {
 709    case GL_COLOR:
 710    case GL_RED:
 711    case GL_GREEN:
 712    case GL_BLUE:
 713    case GL_ALPHA:
 714    case GL_LUMINANCE:
 715    case GL_LUMINANCE_ALPHA:
 716    case GL_INTENSITY:
 717    case GL_RG:
 718    case GL_RGB:
 719    case GL_BGR:
 720    case GL_RGBA:
 721    case GL_BGRA:
 722    case GL_ABGR_EXT:
 723    case GL_RED_INTEGER_EXT:
 724    case GL_RG_INTEGER:
 725    case GL_GREEN_INTEGER_EXT:
 726    case GL_BLUE_INTEGER_EXT:
 727    case GL_ALPHA_INTEGER_EXT:
 728    case GL_RGB_INTEGER_EXT:
 729    case GL_RGBA_INTEGER_EXT:
 730    case GL_BGR_INTEGER_EXT:
 731    case GL_BGRA_INTEGER_EXT:
 732    case GL_LUMINANCE_INTEGER_EXT:
 733    case GL_LUMINANCE_ALPHA_INTEGER_EXT:
 734       if (reading) {
 735          /* about to read from a color buffer */
 736          const struct gl_renderbuffer *readBuf = fb->_ColorReadBuffer;
 737          if (!readBuf) {
 738             return GL_FALSE;
 739          }
 740          ASSERT(_mesa_get_format_bits(readBuf->Format, GL_RED_BITS) > 0 ||
 741                 _mesa_get_format_bits(readBuf->Format, GL_ALPHA_BITS) > 0 ||
 742                 _mesa_get_format_bits(readBuf->Format, GL_TEXTURE_LUMINANCE_SIZE) > 0 ||
 743                 _mesa_get_format_bits(readBuf->Format, GL_TEXTURE_INTENSITY_SIZE) > 0 ||
 744                 _mesa_get_format_bits(readBuf->Format, GL_INDEX_BITS) > 0);
 745       }
 746       else {
 747          /* about to draw to zero or more color buffers (none is OK) */
 748          return GL_TRUE;
 749       }
 750       break;
 751    case GL_DEPTH:
 752    case GL_DEPTH_COMPONENT:
 753       if (att[BUFFER_DEPTH].Type == GL_NONE) {
 754          return GL_FALSE;
 755       }
 756       break;
 757    case GL_STENCIL:
 758    case GL_STENCIL_INDEX:
 759       if (att[BUFFER_STENCIL].Type == GL_NONE) {
 760          return GL_FALSE;
 761       }
 762       break;
 763    case GL_DEPTH_STENCIL_EXT:
 764       if (att[BUFFER_DEPTH].Type == GL_NONE ||
 765           att[BUFFER_STENCIL].Type == GL_NONE) {
 766          return GL_FALSE;
 767       }
 768       break;
 769    default:
 770       _mesa_problem(ctx,
 771                     "Unexpected format 0x%x in renderbuffer_exists",
 772                     format);
 773       return GL_FALSE;
 774    }
 775
 776    /* OK */
 777    return GL_TRUE;
 778 }
 779
 780
 781 /**
 782  * Check if the renderbuffer for a read operation (glReadPixels, glCopyPixels,
 783  * glCopyTex[Sub]Image, etc) exists.
 784  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 785  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 786  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 787  */
 788 GLboolean
 789 _mesa_source_buffer_exists(struct gl_context *ctx, GLenum format)
 790 {
 791    return renderbuffer_exists(ctx, ctx->ReadBuffer, format, GL_TRUE);
 792 }
 793
 794
 795 /**
 796  * As above, but for drawing operations.
 797  */
 798 GLboolean
 799 _mesa_dest_buffer_exists(struct gl_context *ctx, GLenum format)
 800 {
 801    return renderbuffer_exists(ctx, ctx->DrawBuffer, format, GL_FALSE);
 802 }
 803
 804
 805 /**
 806  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_FORMAT_OES query.
 807  */
 808 GLenum
 809 _mesa_get_color_read_format(struct gl_context *ctx)
 810 {
 811    if (!ctx->ReadBuffer || !ctx->ReadBuffer->_ColorReadBuffer) {
 812       /* The spec is unclear how to handle this case, but NVIDIA's
 813        * driver generates GL_INVALID_OPERATION.
 814        */
 815       _mesa_error(ctx, GL_INVALID_OPERATION,
 816                   "glGetIntegerv(GL_IMPLEMENTATION_COLOR_READ_FORMAT: "
 817                   "no GL_READ_BUFFER)");
 818       return GL_NONE;
 819    }
 820    else {
 821       const GLenum format = ctx->ReadBuffer->_ColorReadBuffer->Format;
 822       const GLenum data_type = _mesa_get_format_datatype(format);
 823
 824       if (format == MESA_FORMAT_ARGB8888)
 825          return GL_BGRA;
 826       else if (format == MESA_FORMAT_RGB565)
 827          return GL_BGR;
 828
 829       switch (data_type) {
 830       case GL_UNSIGNED_INT:
 831       case GL_INT:
 832          return GL_RGBA_INTEGER;
 833       default:
 834          return GL_RGBA;
 835       }
 836    }
 837 }
 838
 839
 840 /**
 841  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_TYPE_OES query.
 842  */
 843 GLenum
 844 _mesa_get_color_read_type(struct gl_context *ctx)
 845 {
 846    if (!ctx->ReadBuffer || !ctx->ReadBuffer->_ColorReadBuffer) {
 847       /* The spec is unclear how to handle this case, but NVIDIA's
 848        * driver generates GL_INVALID_OPERATION.
 849        */
 850       _mesa_error(ctx, GL_INVALID_OPERATION,
 851                   "glGetIntegerv(GL_IMPLEMENTATION_COLOR_READ_TYPE: "
 852                   "no GL_READ_BUFFER)");
 853       return GL_NONE;
 854    }
 855    else {
 856       const GLenum format = ctx->ReadBuffer->_ColorReadBuffer->Format;
 857       const GLenum data_type = _mesa_get_format_datatype(format);
 858
 859       if (format == MESA_FORMAT_RGB565)
 860          return GL_UNSIGNED_SHORT_5_6_5_REV;
 861
 862       switch (data_type) {
 863       case GL_SIGNED_NORMALIZED:
 864          return GL_BYTE;
 865       case GL_UNSIGNED_INT:
 866       case GL_INT:
 867       case GL_FLOAT:
 868          return data_type;
 869       case GL_UNSIGNED_NORMALIZED:
 870       default:
 871          return GL_UNSIGNED_BYTE;
 872       }
 873    }
 874 }
 875
 876
 877 /**
 878  * Returns the read renderbuffer for the specified format.
 879  */
 880 struct gl_renderbuffer *
 881 _mesa_get_read_renderbuffer_for_format(const struct gl_context *ctx,
 882                                        GLenum format)
 883 {
 884    const struct gl_framebuffer *rfb = ctx->ReadBuffer;
 885
 886    if (_mesa_is_color_format(format)) {
 887       return rfb->Attachment[rfb->_ColorReadBufferIndex].Renderbuffer;
 888    } else if (_mesa_is_depth_format(format) ||
 889               _mesa_is_depthstencil_format(format)) {
 890       return rfb->Attachment[BUFFER_DEPTH].Renderbuffer;
 891    } else {
 892       return rfb->Attachment[BUFFER_STENCIL].Renderbuffer;
 893    }
 894 }
 895
 896
 897 /**
 898  * Print framebuffer info to stderr, for debugging.
 899  */
 900 void
 901 _mesa_print_framebuffer(const struct gl_framebuffer *fb)
 902 {
 903    GLuint i;
 904
 905    fprintf(stderr, "Mesa Framebuffer %u at %p\n", fb->Name, (void *) fb);
 906    fprintf(stderr, "  Size: %u x %u  Status: %s\n", fb->Width, fb->Height,
 907            _mesa_lookup_enum_by_nr(fb->_Status));
 908    fprintf(stderr, "  Attachments:\n");
 909
 910    for (i = 0; i < BUFFER_COUNT; i++) {
 911       const struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 912       if (att->Type == GL_TEXTURE) {
 913          const struct gl_texture_image *texImage = att->Renderbuffer->TexImage;
 914          fprintf(stderr,
 915                  "  %2d: Texture %u, level %u, face %u, slice %u, complete %d\n",
 916                  i, att->Texture->Name, att->TextureLevel, att->CubeMapFace,
 917                  att->Zoffset, att->Complete);
 918          fprintf(stderr, "       Size: %u x %u x %u  Format %s\n",
 919                  texImage->Width, texImage->Height, texImage->Depth,
 920                  _mesa_get_format_name(texImage->TexFormat));
 921       }
 922       else if (att->Type == GL_RENDERBUFFER) {
 923          fprintf(stderr, "  %2d: Renderbuffer %u, complete %d\n",
 924                  i, att->Renderbuffer->Name, att->Complete);
 925          fprintf(stderr, "       Size: %u x %u  Format %s\n",
 926                  att->Renderbuffer->Width, att->Renderbuffer->Height,
 927                  _mesa_get_format_name(att->Renderbuffer->Format));
 928       }
 929       else {
 930          fprintf(stderr, "  %2d: none\n", i);
 931       }
 932    }
 933 }