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  * This is normally only called from the _mesa_reference_framebuffer() macro
 236  * when there's a real pointer change.
 237  */
 238 void
 239 _mesa_reference_framebuffer_(struct gl_framebuffer **ptr,
 240                              struct gl_framebuffer *fb)
 241 {
 242    if (*ptr) {
 243       /* unreference old renderbuffer */
 244       GLboolean deleteFlag = GL_FALSE;
 245       struct gl_framebuffer *oldFb = *ptr;
 246
 247       _glthread_LOCK_MUTEX(oldFb->Mutex);
 248       ASSERT(oldFb->RefCount > 0);
 249       oldFb->RefCount--;
 250       deleteFlag = (oldFb->RefCount == 0);
 251       _glthread_UNLOCK_MUTEX(oldFb->Mutex);
 252
 253       if (deleteFlag)
 254          oldFb->Delete(oldFb);
 255
 256       *ptr = NULL;
 257    }
 258    assert(!*ptr);
 259
 260    if (fb) {
 261       _glthread_LOCK_MUTEX(fb->Mutex);
 262       fb->RefCount++;
 263       _glthread_UNLOCK_MUTEX(fb->Mutex);
 264       *ptr = fb;
 265    }
 266 }
 267
 268
 269 /**
 270  * Resize the given framebuffer's renderbuffers to the new width and height.
 271  * This should only be used for window-system framebuffers, not
 272  * user-created renderbuffers (i.e. made with GL_EXT_framebuffer_object).
 273  * This will typically be called via ctx->Driver.ResizeBuffers() or directly
 274  * from a device driver.
 275  *
 276  * \note it's possible for ctx to be null since a window can be resized
 277  * without a currently bound rendering context.
 278  */
 279 void
 280 _mesa_resize_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb,
 281                          GLuint width, GLuint height)
 282 {
 283    GLuint i;
 284
 285    /* XXX I think we could check if the size is not changing
 286     * and return early.
 287     */
 288
 289    /* For window system framebuffers, Name is zero */
 290    assert(fb->Name == 0);
 291
 292    for (i = 0; i < BUFFER_COUNT; i++) {
 293       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 294       if (att->Type == GL_RENDERBUFFER_EXT && att->Renderbuffer) {
 295          struct gl_renderbuffer *rb = att->Renderbuffer;
 296          /* only resize if size is changing */
 297          if (rb->Width != width || rb->Height != height) {
 298             if (rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 299                ASSERT(rb->Width == width);
 300                ASSERT(rb->Height == height);
 301             }
 302             else {
 303                _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 304                /* no return */
 305             }
 306          }
 307       }
 308    }
 309
 310    if (fb->_DepthBuffer) {
 311       struct gl_renderbuffer *rb = fb->_DepthBuffer;
 312       if (rb->Width != width || rb->Height != height) {
 313          if (!rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 314             _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 315          }
 316       }
 317    }
 318
 319    if (fb->_StencilBuffer) {
 320       struct gl_renderbuffer *rb = fb->_StencilBuffer;
 321       if (rb->Width != width || rb->Height != height) {
 322          if (!rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 323             _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 324          }
 325       }
 326    }
 327
 328    fb->Width = width;
 329    fb->Height = height;
 330
 331    if (ctx) {
 332       /* update scissor / window bounds */
 333       _mesa_update_draw_buffer_bounds(ctx);
 334       /* Signal new buffer state so that swrast will update its clipping
 335        * info (the CLIP_BIT flag).
 336        */
 337       ctx->NewState |= _NEW_BUFFERS;
 338    }
 339 }
 340
 341
 342
 343 /**
 344  * XXX THIS IS OBSOLETE - drivers should take care of detecting window
 345  * size changes and act accordingly, likely calling _mesa_resize_framebuffer().
 346  *
 347  * GL_MESA_resize_buffers extension.
 348  *
 349  * When this function is called, we'll ask the window system how large
 350  * the current window is.  If it's a new size, we'll call the driver's
 351  * ResizeBuffers function.  The driver will then resize its color buffers
 352  * as needed, and maybe call the swrast's routine for reallocating
 353  * swrast-managed depth/stencil/accum/etc buffers.
 354  * \note This function should only be called through the GL API, not
 355  * from device drivers (as was done in the past).
 356  */
 357 void
 358 _mesa_resizebuffers( struct gl_context *ctx )
 359 {
 360    ASSERT_OUTSIDE_BEGIN_END_AND_FLUSH( ctx );
 361
 362    if (MESA_VERBOSE & VERBOSE_API)
 363       _mesa_debug(ctx, "glResizeBuffersMESA\n");
 364
 365    if (!ctx->Driver.GetBufferSize) {
 366       return;
 367    }
 368
 369    if (ctx->WinSysDrawBuffer) {
 370       GLuint newWidth, newHeight;
 371       struct gl_framebuffer *buffer = ctx->WinSysDrawBuffer;
 372
 373       assert(buffer->Name == 0);
 374
 375       /* ask device driver for size of output buffer */
 376       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 377
 378       /* see if size of device driver's color buffer (window) has changed */
 379       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 380          if (ctx->Driver.ResizeBuffers)
 381             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 382       }
 383    }
 384
 385    if (ctx->WinSysReadBuffer
 386        && ctx->WinSysReadBuffer != ctx->WinSysDrawBuffer) {
 387       GLuint newWidth, newHeight;
 388       struct gl_framebuffer *buffer = ctx->WinSysReadBuffer;
 389
 390       assert(buffer->Name == 0);
 391
 392       /* ask device driver for size of read buffer */
 393       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 394
 395       /* see if size of device driver's color buffer (window) has changed */
 396       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 397          if (ctx->Driver.ResizeBuffers)
 398             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 399       }
 400    }
 401
 402    ctx->NewState |= _NEW_BUFFERS;  /* to update scissor / window bounds */
 403 }
 404
 405
 406 /*
 407  * XXX THIS IS OBSOLETE
 408  */
 409 void GLAPIENTRY
 410 _mesa_ResizeBuffersMESA( void )
 411 {
 412    GET_CURRENT_CONTEXT(ctx);
 413
 414    if (ctx->Extensions.MESA_resize_buffers)
 415       _mesa_resizebuffers( ctx );
 416 }
 417
 418
 419
 420 /**
 421  * Examine all the framebuffer's renderbuffers to update the Width/Height
 422  * fields of the framebuffer.  If we have renderbuffers with different
 423  * sizes, set the framebuffer's width and height to the min size.
 424  * Note: this is only intended for user-created framebuffers, not
 425  * window-system framebuffes.
 426  */
 427 static void
 428 update_framebuffer_size(struct gl_context *ctx, struct gl_framebuffer *fb)
 429 {
 430    GLuint minWidth = ~0, minHeight = ~0;
 431    GLuint i;
 432
 433    /* user-created framebuffers only */
 434    assert(fb->Name);
 435
 436    for (i = 0; i < BUFFER_COUNT; i++) {
 437       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 438       const struct gl_renderbuffer *rb = att->Renderbuffer;
 439       if (rb) {
 440          minWidth = MIN2(minWidth, rb->Width);
 441          minHeight = MIN2(minHeight, rb->Height);
 442       }
 443    }
 444
 445    if (minWidth != ~0) {
 446       fb->Width = minWidth;
 447       fb->Height = minHeight;
 448    }
 449    else {
 450       fb->Width = 0;
 451       fb->Height = 0;
 452    }
 453 }
 454
 455
 456 /**
 457  * Update the context's current drawing buffer's Xmin, Xmax, Ymin, Ymax fields.
 458  * These values are computed from the buffer's width and height and
 459  * the scissor box, if it's enabled.
 460  * \param ctx  the GL context.
 461  */
 462 void
 463 _mesa_update_draw_buffer_bounds(struct gl_context *ctx)
 464 {
 465    struct gl_framebuffer *buffer = ctx->DrawBuffer;
 466
 467    if (!buffer)
 468       return;
 469
 470    if (buffer->Name) {
 471       /* user-created framebuffer size depends on the renderbuffers */
 472       update_framebuffer_size(ctx, buffer);
 473    }
 474
 475    buffer->_Xmin = 0;
 476    buffer->_Ymin = 0;
 477    buffer->_Xmax = buffer->Width;
 478    buffer->_Ymax = buffer->Height;
 479
 480    if (ctx->Scissor.Enabled) {
 481       if (ctx->Scissor.X > buffer->_Xmin) {
 482          buffer->_Xmin = ctx->Scissor.X;
 483       }
 484       if (ctx->Scissor.Y > buffer->_Ymin) {
 485          buffer->_Ymin = ctx->Scissor.Y;
 486       }
 487       if (ctx->Scissor.X + ctx->Scissor.Width < buffer->_Xmax) {
 488          buffer->_Xmax = ctx->Scissor.X + ctx->Scissor.Width;
 489       }
 490       if (ctx->Scissor.Y + ctx->Scissor.Height < buffer->_Ymax) {
 491          buffer->_Ymax = ctx->Scissor.Y + ctx->Scissor.Height;
 492       }
 493       /* finally, check for empty region */
 494       if (buffer->_Xmin > buffer->_Xmax) {
 495          buffer->_Xmin = buffer->_Xmax;
 496       }
 497       if (buffer->_Ymin > buffer->_Ymax) {
 498          buffer->_Ymin = buffer->_Ymax;
 499       }
 500    }
 501
 502    ASSERT(buffer->_Xmin <= buffer->_Xmax);
 503    ASSERT(buffer->_Ymin <= buffer->_Ymax);
 504 }
 505
 506
 507 /**
 508  * The glGet queries of the framebuffer red/green/blue size, stencil size,
 509  * etc. are satisfied by the fields of ctx->DrawBuffer->Visual.  These can
 510  * change depending on the renderbuffer bindings.  This function updates
 511  * the given framebuffer's Visual from the current renderbuffer bindings.
 512  *
 513  * This may apply to user-created framebuffers or window system framebuffers.
 514  *
 515  * Also note: ctx->DrawBuffer->Visual.depthBits might not equal
 516  * ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer.DepthBits.
 517  * The former one is used to convert floating point depth values into
 518  * integer Z values.
 519  */
 520 void
 521 _mesa_update_framebuffer_visual(struct gl_context *ctx,
 522                                 struct gl_framebuffer *fb)
 523 {
 524    GLuint i;
 525
 526    memset(&fb->Visual, 0, sizeof(fb->Visual));
 527    fb->Visual.rgbMode = GL_TRUE; /* assume this */
 528
 529 #if 0 /* this _might_ be needed */
 530    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 531       /* leave visual fields zero'd */
 532       return;
 533    }
 534 #endif
 535
 536    /* find first RGB renderbuffer */
 537    for (i = 0; i < BUFFER_COUNT; i++) {
 538       if (fb->Attachment[i].Renderbuffer) {
 539          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 540          const GLenum baseFormat = _mesa_get_format_base_format(rb->Format);
 541          const gl_format fmt = rb->Format;
 542
 543          if (_mesa_is_legal_color_format(ctx, baseFormat)) {
 544             fb->Visual.redBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 545             fb->Visual.greenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 546             fb->Visual.blueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 547             fb->Visual.alphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 548             fb->Visual.rgbBits = fb->Visual.redBits
 549                + fb->Visual.greenBits + fb->Visual.blueBits;
 550             fb->Visual.samples = rb->NumSamples;
 551             fb->Visual.sampleBuffers = rb->NumSamples > 0 ? 1 : 0;
 552             if (_mesa_get_format_color_encoding(fmt) == GL_SRGB)
 553                 fb->Visual.sRGBCapable = ctx->Const.sRGBCapable;
 554             break;
 555          }
 556       }
 557    }
 558
 559    fb->Visual.floatMode = GL_FALSE;
 560    for (i = 0; i < BUFFER_COUNT; i++) {
 561       if (fb->Attachment[i].Renderbuffer) {
 562          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 563          const gl_format fmt = rb->Format;
 564
 565          if (_mesa_get_format_datatype(fmt) == GL_FLOAT) {
 566             fb->Visual.floatMode = GL_TRUE;
 567             break;
 568          }
 569       }
 570    }
 571
 572    if (fb->Attachment[BUFFER_DEPTH].Renderbuffer) {
 573       const struct gl_renderbuffer *rb =
 574          fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 575       const gl_format fmt = rb->Format;
 576       fb->Visual.haveDepthBuffer = GL_TRUE;
 577       fb->Visual.depthBits = _mesa_get_format_bits(fmt, GL_DEPTH_BITS);
 578    }
 579
 580    if (fb->Attachment[BUFFER_STENCIL].Renderbuffer) {
 581       const struct gl_renderbuffer *rb =
 582          fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 583       const gl_format fmt = rb->Format;
 584       fb->Visual.haveStencilBuffer = GL_TRUE;
 585       fb->Visual.stencilBits = _mesa_get_format_bits(fmt, GL_STENCIL_BITS);
 586    }
 587
 588    if (fb->Attachment[BUFFER_ACCUM].Renderbuffer) {
 589       const struct gl_renderbuffer *rb =
 590          fb->Attachment[BUFFER_ACCUM].Renderbuffer;
 591       const gl_format fmt = rb->Format;
 592       fb->Visual.haveAccumBuffer = GL_TRUE;
 593       fb->Visual.accumRedBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 594       fb->Visual.accumGreenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 595       fb->Visual.accumBlueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 596       fb->Visual.accumAlphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 597    }
 598
 599    compute_depth_max(fb);
 600 }
 601
 602
 603 /*
 604  * Example DrawBuffers scenarios:
 605  *
 606  * 1. glDrawBuffer(GL_FRONT_AND_BACK), fixed-func or shader writes to
 607  * "gl_FragColor" or program writes to the "result.color" register:
 608  *
 609  *   fragment color output   renderbuffer
 610  *   ---------------------   ---------------
 611  *   color[0]                Front, Back
 612  *
 613  *
 614  * 2. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]), shader writes to
 615  * gl_FragData[i] or program writes to result.color[i] registers:
 616  *
 617  *   fragment color output   renderbuffer
 618  *   ---------------------   ---------------
 619  *   color[0]                Front
 620  *   color[1]                Aux0
 621  *   color[3]                Aux1
 622  *
 623  *
 624  * 3. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]) and shader writes to
 625  * gl_FragColor, or fixed function:
 626  *
 627  *   fragment color output   renderbuffer
 628  *   ---------------------   ---------------
 629  *   color[0]                Front, Aux0, Aux1
 630  *
 631  *
 632  * In either case, the list of renderbuffers is stored in the
 633  * framebuffer->_ColorDrawBuffers[] array and
 634  * framebuffer->_NumColorDrawBuffers indicates the number of buffers.
 635  * The renderer (like swrast) has to look at the current fragment shader
 636  * to see if it writes to gl_FragColor vs. gl_FragData[i] to determine
 637  * how to map color outputs to renderbuffers.
 638  *
 639  * Note that these two calls are equivalent (for fixed function fragment
 640  * shading anyway):
 641  *   a)  glDrawBuffer(GL_FRONT_AND_BACK);  (assuming non-stereo framebuffer)
 642  *   b)  glDrawBuffers(2, [GL_FRONT_LEFT, GL_BACK_LEFT]);
 643  */
 644
 645
 646
 647
 648 /**
 649  * Update the (derived) list of color drawing renderbuffer pointers.
 650  * Later, when we're rendering we'll loop from 0 to _NumColorDrawBuffers
 651  * writing colors.
 652  */
 653 static void
 654 update_color_draw_buffers(struct gl_context *ctx, struct gl_framebuffer *fb)
 655 {
 656    GLuint output;
 657
 658    /* set 0th buffer to NULL now in case _NumColorDrawBuffers is zero */
 659    fb->_ColorDrawBuffers[0] = NULL;
 660
 661    for (output = 0; output < fb->_NumColorDrawBuffers; output++) {
 662       GLint buf = fb->_ColorDrawBufferIndexes[output];
 663       if (buf >= 0) {
 664          fb->_ColorDrawBuffers[output] = fb->Attachment[buf].Renderbuffer;
 665       }
 666       else {
 667          fb->_ColorDrawBuffers[output] = NULL;
 668       }
 669    }
 670 }
 671
 672
 673 /**
 674  * Update the (derived) color read renderbuffer pointer.
 675  * Unlike the DrawBuffer, we can only read from one (or zero) color buffers.
 676  */
 677 static void
 678 update_color_read_buffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 679 {
 680    (void) ctx;
 681    if (fb->_ColorReadBufferIndex == -1 ||
 682        fb->DeletePending ||
 683        fb->Width == 0 ||
 684        fb->Height == 0) {
 685       fb->_ColorReadBuffer = NULL; /* legal! */
 686    }
 687    else {
 688       ASSERT(fb->_ColorReadBufferIndex >= 0);
 689       ASSERT(fb->_ColorReadBufferIndex < BUFFER_COUNT);
 690       fb->_ColorReadBuffer
 691          = fb->Attachment[fb->_ColorReadBufferIndex].Renderbuffer;
 692    }
 693 }
 694
 695
 696 /**
 697  * Update a gl_framebuffer's derived state.
 698  *
 699  * Specifically, update these framebuffer fields:
 700  *    _ColorDrawBuffers
 701  *    _NumColorDrawBuffers
 702  *    _ColorReadBuffer
 703  *    _DepthBuffer
 704  *    _StencilBuffer
 705  *
 706  * If the framebuffer is user-created, make sure it's complete.
 707  *
 708  * The following functions (at least) can effect framebuffer state:
 709  * glReadBuffer, glDrawBuffer, glDrawBuffersARB, glFramebufferRenderbufferEXT,
 710  * glRenderbufferStorageEXT.
 711  */
 712 static void
 713 update_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 714 {
 715    if (fb->Name == 0) {
 716       /* This is a window-system framebuffer */
 717       /* Need to update the FB's GL_DRAW_BUFFER state to match the
 718        * context state (GL_READ_BUFFER too).
 719        */
 720       if (fb->ColorDrawBuffer[0] != ctx->Color.DrawBuffer[0]) {
 721          _mesa_drawbuffers(ctx, ctx->Const.MaxDrawBuffers,
 722                            ctx->Color.DrawBuffer, NULL);
 723       }
 724    }
 725    else {
 726       /* This is a user-created framebuffer.
 727        * Completeness only matters for user-created framebuffers.
 728        */
 729       if (fb->_Status != GL_FRAMEBUFFER_COMPLETE) {
 730          _mesa_test_framebuffer_completeness(ctx, fb);
 731       }
 732    }
 733
 734    /* Strictly speaking, we don't need to update the draw-state
 735     * if this FB is bound as ctx->ReadBuffer (and conversely, the
 736     * read-state if this FB is bound as ctx->DrawBuffer), but no
 737     * harm.
 738     */
 739    update_color_draw_buffers(ctx, fb);
 740    update_color_read_buffer(ctx, fb);
 741    _mesa_update_depth_buffer(ctx, fb);
 742    _mesa_update_stencil_buffer(ctx, fb);
 743
 744    compute_depth_max(fb);
 745 }
 746
 747
 748 /**
 749  * Update state related to the current draw/read framebuffers.
 750  */
 751 void
 752 _mesa_update_framebuffer(struct gl_context *ctx)
 753 {
 754    struct gl_framebuffer *drawFb;
 755    struct gl_framebuffer *readFb;
 756
 757    assert(ctx);
 758    drawFb = ctx->DrawBuffer;
 759    readFb = ctx->ReadBuffer;
 760
 761    update_framebuffer(ctx, drawFb);
 762    if (readFb != drawFb)
 763       update_framebuffer(ctx, readFb);
 764 }
 765
 766
 767 /**
 768  * Check if the renderbuffer for a read/draw operation exists.
 769  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 770  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 771  * \param reading  if TRUE, we're going to read from the buffer,
 772                    if FALSE, we're going to write to the buffer.
 773  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 774  */
 775 static GLboolean
 776 renderbuffer_exists(struct gl_context *ctx,
 777                     struct gl_framebuffer *fb,
 778                     GLenum format,
 779                     GLboolean reading)
 780 {
 781    const struct gl_renderbuffer_attachment *att = fb->Attachment;
 782
 783    /* If we don't know the framebuffer status, update it now */
 784    if (fb->_Status == 0) {
 785       _mesa_test_framebuffer_completeness(ctx, fb);
 786    }
 787
 788    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 789       return GL_FALSE;
 790    }
 791
 792    switch (format) {
 793    case GL_COLOR:
 794    case GL_RED:
 795    case GL_GREEN:
 796    case GL_BLUE:
 797    case GL_ALPHA:
 798    case GL_LUMINANCE:
 799    case GL_LUMINANCE_ALPHA:
 800    case GL_INTENSITY:
 801    case GL_RG:
 802    case GL_RGB:
 803    case GL_BGR:
 804    case GL_RGBA:
 805    case GL_BGRA:
 806    case GL_ABGR_EXT:
 807    case GL_RED_INTEGER_EXT:
 808    case GL_RG_INTEGER:
 809    case GL_GREEN_INTEGER_EXT:
 810    case GL_BLUE_INTEGER_EXT:
 811    case GL_ALPHA_INTEGER_EXT:
 812    case GL_RGB_INTEGER_EXT:
 813    case GL_RGBA_INTEGER_EXT:
 814    case GL_BGR_INTEGER_EXT:
 815    case GL_BGRA_INTEGER_EXT:
 816    case GL_LUMINANCE_INTEGER_EXT:
 817    case GL_LUMINANCE_ALPHA_INTEGER_EXT:
 818       if (reading) {
 819          /* about to read from a color buffer */
 820          const struct gl_renderbuffer *readBuf = fb->_ColorReadBuffer;
 821          if (!readBuf) {
 822             return GL_FALSE;
 823          }
 824          ASSERT(_mesa_get_format_bits(readBuf->Format, GL_RED_BITS) > 0 ||
 825                 _mesa_get_format_bits(readBuf->Format, GL_ALPHA_BITS) > 0 ||
 826                 _mesa_get_format_bits(readBuf->Format, GL_TEXTURE_LUMINANCE_SIZE) > 0 ||
 827                 _mesa_get_format_bits(readBuf->Format, GL_TEXTURE_INTENSITY_SIZE) > 0 ||
 828                 _mesa_get_format_bits(readBuf->Format, GL_INDEX_BITS) > 0);
 829       }
 830       else {
 831          /* about to draw to zero or more color buffers (none is OK) */
 832          return GL_TRUE;
 833       }
 834       break;
 835    case GL_DEPTH:
 836    case GL_DEPTH_COMPONENT:
 837       if (att[BUFFER_DEPTH].Type == GL_NONE) {
 838          return GL_FALSE;
 839       }
 840       break;
 841    case GL_STENCIL:
 842    case GL_STENCIL_INDEX:
 843       if (att[BUFFER_STENCIL].Type == GL_NONE) {
 844          return GL_FALSE;
 845       }
 846       break;
 847    case GL_DEPTH_STENCIL_EXT:
 848       if (att[BUFFER_DEPTH].Type == GL_NONE ||
 849           att[BUFFER_STENCIL].Type == GL_NONE) {
 850          return GL_FALSE;
 851       }
 852       break;
 853    default:
 854       _mesa_problem(ctx,
 855                     "Unexpected format 0x%x in renderbuffer_exists",
 856                     format);
 857       return GL_FALSE;
 858    }
 859
 860    /* OK */
 861    return GL_TRUE;
 862 }
 863
 864
 865 /**
 866  * Check if the renderbuffer for a read operation (glReadPixels, glCopyPixels,
 867  * glCopyTex[Sub]Image, etc) exists.
 868  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 869  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 870  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 871  */
 872 GLboolean
 873 _mesa_source_buffer_exists(struct gl_context *ctx, GLenum format)
 874 {
 875    return renderbuffer_exists(ctx, ctx->ReadBuffer, format, GL_TRUE);
 876 }
 877
 878
 879 /**
 880  * As above, but for drawing operations.
 881  * XXX could do some code merging w/ above function.
 882  */
 883 GLboolean
 884 _mesa_dest_buffer_exists(struct gl_context *ctx, GLenum format)
 885 {
 886    return renderbuffer_exists(ctx, ctx->DrawBuffer, format, GL_FALSE);
 887 }
 888
 889
 890 /**
 891  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_FORMAT_OES query.
 892  */
 893 GLenum
 894 _mesa_get_color_read_format(struct gl_context *ctx)
 895 {
 896    switch (ctx->ReadBuffer->_ColorReadBuffer->Format) {
 897    case MESA_FORMAT_ARGB8888:
 898       return GL_BGRA;
 899    case MESA_FORMAT_RGB565:
 900       return GL_BGR;
 901    default:
 902       return GL_RGBA;
 903    }
 904 }
 905
 906
 907 /**
 908  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_TYPE_OES query.
 909  */
 910 GLenum
 911 _mesa_get_color_read_type(struct gl_context *ctx)
 912 {
 913    switch (ctx->ReadBuffer->_ColorReadBuffer->Format) {
 914    case MESA_FORMAT_ARGB8888:
 915       return GL_UNSIGNED_BYTE;
 916    case MESA_FORMAT_RGB565:
 917       return GL_UNSIGNED_SHORT_5_6_5_REV;
 918    default:
 919       return GL_UNSIGNED_BYTE;
 920    }
 921 }
 922
 923
 924 /**
 925  * Print framebuffer info to stderr, for debugging.
 926  */
 927 void
 928 _mesa_print_framebuffer(const struct gl_framebuffer *fb)
 929 {
 930    GLuint i;
 931
 932    fprintf(stderr, "Mesa Framebuffer %u at %p\n", fb->Name, (void *) fb);
 933    fprintf(stderr, "  Size: %u x %u  Status: %s\n", fb->Width, fb->Height,
 934            _mesa_lookup_enum_by_nr(fb->_Status));
 935    fprintf(stderr, "  Attachments:\n");
 936
 937    for (i = 0; i < BUFFER_COUNT; i++) {
 938       const struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 939       if (att->Type == GL_TEXTURE) {
 940          const struct gl_texture_image *texImage =
 941             _mesa_get_attachment_teximage_const(att);
 942          fprintf(stderr,
 943                  "  %2d: Texture %u, level %u, face %u, slice %u, complete %d\n",
 944                  i, att->Texture->Name, att->TextureLevel, att->CubeMapFace,
 945                  att->Zoffset, att->Complete);
 946          fprintf(stderr, "       Size: %u x %u x %u  Format %s\n",
 947                  texImage->Width, texImage->Height, texImage->Depth,
 948                  _mesa_get_format_name(texImage->TexFormat));
 949       }
 950       else if (att->Type == GL_RENDERBUFFER) {
 951          fprintf(stderr, "  %2d: Renderbuffer %u, complete %d\n",
 952                  i, att->Renderbuffer->Name, att->Complete);
 953          fprintf(stderr, "       Size: %u x %u  Format %s\n",
 954                  att->Renderbuffer->Width, att->Renderbuffer->Height,
 955                  _mesa_get_format_name(att->Renderbuffer->Format));
 956       }
 957       else {
 958          fprintf(stderr, "  %2d: none\n", i);
 959       }
 960    }
 961 }