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 "enums.h"
  38 #include "formats.h"
  39 #include "macros.h"
  40 #include "mtypes.h"
  41 #include "fbobject.h"
  42 #include "framebuffer.h"
  43 #include "renderbuffer.h"
  44 #include "texobj.h"
  45 #include "glformats.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    fb->_AllColorBuffersFixedPoint = !visual->floatMode;
 158
 159    compute_depth_max(fb);
 160 }
 161
 162
 163 /**
 164  * Initialize a user-created gl_framebuffer object.
 165  * \sa _mesa_initialize_window_framebuffer
 166  */
 167 void
 168 _mesa_initialize_user_framebuffer(struct gl_framebuffer *fb, GLuint name)
 169 {
 170    assert(fb);
 171    assert(name);
 172
 173    memset(fb, 0, sizeof(struct gl_framebuffer));
 174
 175    fb->Name = name;
 176    fb->RefCount = 1;
 177    fb->_NumColorDrawBuffers = 1;
 178    fb->ColorDrawBuffer[0] = GL_COLOR_ATTACHMENT0_EXT;
 179    fb->_ColorDrawBufferIndexes[0] = BUFFER_COLOR0;
 180    fb->ColorReadBuffer = GL_COLOR_ATTACHMENT0_EXT;
 181    fb->_ColorReadBufferIndex = BUFFER_COLOR0;
 182    fb->Delete = _mesa_destroy_framebuffer;
 183    _glthread_INIT_MUTEX(fb->Mutex);
 184 }
 185
 186
 187 /**
 188  * Deallocate buffer and everything attached to it.
 189  * Typically called via the gl_framebuffer->Delete() method.
 190  */
 191 void
 192 _mesa_destroy_framebuffer(struct gl_framebuffer *fb)
 193 {
 194    if (fb) {
 195       _mesa_free_framebuffer_data(fb);
 196       free(fb);
 197    }
 198 }
 199
 200
 201 /**
 202  * Free all the data hanging off the given gl_framebuffer, but don't free
 203  * the gl_framebuffer object itself.
 204  */
 205 void
 206 _mesa_free_framebuffer_data(struct gl_framebuffer *fb)
 207 {
 208    GLuint i;
 209
 210    assert(fb);
 211    assert(fb->RefCount == 0);
 212
 213    _glthread_DESTROY_MUTEX(fb->Mutex);
 214
 215    for (i = 0; i < BUFFER_COUNT; i++) {
 216       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 217       if (att->Renderbuffer) {
 218          _mesa_reference_renderbuffer(&att->Renderbuffer, NULL);
 219       }
 220       if (att->Texture) {
 221          _mesa_reference_texobj(&att->Texture, NULL);
 222       }
 223       ASSERT(!att->Renderbuffer);
 224       ASSERT(!att->Texture);
 225       att->Type = GL_NONE;
 226    }
 227 }
 228
 229
 230 /**
 231  * Set *ptr to point to fb, with refcounting and locking.
 232  * This is normally only called from the _mesa_reference_framebuffer() macro
 233  * when there's a real pointer change.
 234  */
 235 void
 236 _mesa_reference_framebuffer_(struct gl_framebuffer **ptr,
 237                              struct gl_framebuffer *fb)
 238 {
 239    if (*ptr) {
 240       /* unreference old renderbuffer */
 241       GLboolean deleteFlag = GL_FALSE;
 242       struct gl_framebuffer *oldFb = *ptr;
 243
 244       _glthread_LOCK_MUTEX(oldFb->Mutex);
 245       ASSERT(oldFb->RefCount > 0);
 246       oldFb->RefCount--;
 247       deleteFlag = (oldFb->RefCount == 0);
 248       _glthread_UNLOCK_MUTEX(oldFb->Mutex);
 249
 250       if (deleteFlag)
 251          oldFb->Delete(oldFb);
 252
 253       *ptr = NULL;
 254    }
 255    assert(!*ptr);
 256
 257    if (fb) {
 258       _glthread_LOCK_MUTEX(fb->Mutex);
 259       fb->RefCount++;
 260       _glthread_UNLOCK_MUTEX(fb->Mutex);
 261       *ptr = fb;
 262    }
 263 }
 264
 265
 266 /**
 267  * Resize the given framebuffer's renderbuffers to the new width and height.
 268  * This should only be used for window-system framebuffers, not
 269  * user-created renderbuffers (i.e. made with GL_EXT_framebuffer_object).
 270  * This will typically be called via ctx->Driver.ResizeBuffers() or directly
 271  * from a device driver.
 272  *
 273  * \note it's possible for ctx to be null since a window can be resized
 274  * without a currently bound rendering context.
 275  */
 276 void
 277 _mesa_resize_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb,
 278                          GLuint width, GLuint height)
 279 {
 280    GLuint i;
 281
 282    /* XXX I think we could check if the size is not changing
 283     * and return early.
 284     */
 285
 286    /* Can only resize win-sys framebuffer objects */
 287    assert(_mesa_is_winsys_fbo(fb));
 288
 289    for (i = 0; i < BUFFER_COUNT; i++) {
 290       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 291       if (att->Type == GL_RENDERBUFFER_EXT && att->Renderbuffer) {
 292          struct gl_renderbuffer *rb = att->Renderbuffer;
 293          /* only resize if size is changing */
 294          if (rb->Width != width || rb->Height != height) {
 295             if (rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 296                ASSERT(rb->Width == width);
 297                ASSERT(rb->Height == height);
 298             }
 299             else {
 300                _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 301                /* no return */
 302             }
 303          }
 304       }
 305    }
 306
 307    fb->Width = width;
 308    fb->Height = height;
 309
 310    if (ctx) {
 311       /* update scissor / window bounds */
 312       _mesa_update_draw_buffer_bounds(ctx);
 313       /* Signal new buffer state so that swrast will update its clipping
 314        * info (the CLIP_BIT flag).
 315        */
 316       ctx->NewState |= _NEW_BUFFERS;
 317    }
 318 }
 319
 320
 321
 322 /**
 323  * XXX THIS IS OBSOLETE - drivers should take care of detecting window
 324  * size changes and act accordingly, likely calling _mesa_resize_framebuffer().
 325  *
 326  * GL_MESA_resize_buffers extension.
 327  *
 328  * When this function is called, we'll ask the window system how large
 329  * the current window is.  If it's a new size, we'll call the driver's
 330  * ResizeBuffers function.  The driver will then resize its color buffers
 331  * as needed, and maybe call the swrast's routine for reallocating
 332  * swrast-managed depth/stencil/accum/etc buffers.
 333  * \note This function should only be called through the GL API, not
 334  * from device drivers (as was done in the past).
 335  */
 336 void
 337 _mesa_resizebuffers( struct gl_context *ctx )
 338 {
 339    FLUSH_VERTICES(ctx, 0);
 340
 341    if (MESA_VERBOSE & VERBOSE_API)
 342       _mesa_debug(ctx, "glResizeBuffersMESA\n");
 343
 344    if (!ctx->Driver.GetBufferSize) {
 345       return;
 346    }
 347
 348    if (ctx->WinSysDrawBuffer) {
 349       GLuint newWidth, newHeight;
 350       struct gl_framebuffer *buffer = ctx->WinSysDrawBuffer;
 351
 352       assert(_mesa_is_winsys_fbo(buffer));
 353
 354       /* ask device driver for size of output buffer */
 355       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 356
 357       /* see if size of device driver's color buffer (window) has changed */
 358       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 359          if (ctx->Driver.ResizeBuffers)
 360             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 361       }
 362    }
 363
 364    if (ctx->WinSysReadBuffer
 365        && ctx->WinSysReadBuffer != ctx->WinSysDrawBuffer) {
 366       GLuint newWidth, newHeight;
 367       struct gl_framebuffer *buffer = ctx->WinSysReadBuffer;
 368
 369       assert(_mesa_is_winsys_fbo(buffer));
 370
 371       /* ask device driver for size of read buffer */
 372       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 373
 374       /* see if size of device driver's color buffer (window) has changed */
 375       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 376          if (ctx->Driver.ResizeBuffers)
 377             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 378       }
 379    }
 380
 381    ctx->NewState |= _NEW_BUFFERS;  /* to update scissor / window bounds */
 382 }
 383
 384
 385 /*
 386  * XXX THIS IS OBSOLETE
 387  */
 388 void GLAPIENTRY
 389 _mesa_ResizeBuffersMESA( void )
 390 {
 391    GET_CURRENT_CONTEXT(ctx);
 392
 393    if (ctx->Extensions.MESA_resize_buffers)
 394       _mesa_resizebuffers( ctx );
 395 }
 396
 397
 398
 399 /**
 400  * Examine all the framebuffer's renderbuffers to update the Width/Height
 401  * fields of the framebuffer.  If we have renderbuffers with different
 402  * sizes, set the framebuffer's width and height to the min size.
 403  * Note: this is only intended for user-created framebuffers, not
 404  * window-system framebuffes.
 405  */
 406 static void
 407 update_framebuffer_size(struct gl_context *ctx, struct gl_framebuffer *fb)
 408 {
 409    GLuint minWidth = ~0, minHeight = ~0;
 410    GLuint i;
 411
 412    /* user-created framebuffers only */
 413    assert(_mesa_is_user_fbo(fb));
 414
 415    for (i = 0; i < BUFFER_COUNT; i++) {
 416       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 417       const struct gl_renderbuffer *rb = att->Renderbuffer;
 418       if (rb) {
 419          minWidth = MIN2(minWidth, rb->Width);
 420          minHeight = MIN2(minHeight, rb->Height);
 421       }
 422    }
 423
 424    if (minWidth != ~0) {
 425       fb->Width = minWidth;
 426       fb->Height = minHeight;
 427    }
 428    else {
 429       fb->Width = 0;
 430       fb->Height = 0;
 431    }
 432 }
 433
 434
 435 /**
 436  * Update the context's current drawing buffer's Xmin, Xmax, Ymin, Ymax fields.
 437  * These values are computed from the buffer's width and height and
 438  * the scissor box, if it's enabled.
 439  * \param ctx  the GL context.
 440  */
 441 void
 442 _mesa_update_draw_buffer_bounds(struct gl_context *ctx)
 443 {
 444    struct gl_framebuffer *buffer = ctx->DrawBuffer;
 445
 446    if (!buffer)
 447       return;
 448
 449    if (_mesa_is_user_fbo(buffer)) {
 450       /* user-created framebuffer size depends on the renderbuffers */
 451       update_framebuffer_size(ctx, buffer);
 452    }
 453
 454    buffer->_Xmin = 0;
 455    buffer->_Ymin = 0;
 456    buffer->_Xmax = buffer->Width;
 457    buffer->_Ymax = buffer->Height;
 458
 459    if (ctx->Scissor.Enabled) {
 460       if (ctx->Scissor.X > buffer->_Xmin) {
 461          buffer->_Xmin = ctx->Scissor.X;
 462       }
 463       if (ctx->Scissor.Y > buffer->_Ymin) {
 464          buffer->_Ymin = ctx->Scissor.Y;
 465       }
 466       if (ctx->Scissor.X + ctx->Scissor.Width < buffer->_Xmax) {
 467          buffer->_Xmax = ctx->Scissor.X + ctx->Scissor.Width;
 468       }
 469       if (ctx->Scissor.Y + ctx->Scissor.Height < buffer->_Ymax) {
 470          buffer->_Ymax = ctx->Scissor.Y + ctx->Scissor.Height;
 471       }
 472       /* finally, check for empty region */
 473       if (buffer->_Xmin > buffer->_Xmax) {
 474          buffer->_Xmin = buffer->_Xmax;
 475       }
 476       if (buffer->_Ymin > buffer->_Ymax) {
 477          buffer->_Ymin = buffer->_Ymax;
 478       }
 479    }
 480
 481    ASSERT(buffer->_Xmin <= buffer->_Xmax);
 482    ASSERT(buffer->_Ymin <= buffer->_Ymax);
 483 }
 484
 485
 486 /**
 487  * The glGet queries of the framebuffer red/green/blue size, stencil size,
 488  * etc. are satisfied by the fields of ctx->DrawBuffer->Visual.  These can
 489  * change depending on the renderbuffer bindings.  This function updates
 490  * the given framebuffer's Visual from the current renderbuffer bindings.
 491  *
 492  * This may apply to user-created framebuffers or window system framebuffers.
 493  *
 494  * Also note: ctx->DrawBuffer->Visual.depthBits might not equal
 495  * ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer.DepthBits.
 496  * The former one is used to convert floating point depth values into
 497  * integer Z values.
 498  */
 499 void
 500 _mesa_update_framebuffer_visual(struct gl_context *ctx,
 501                                 struct gl_framebuffer *fb)
 502 {
 503    GLuint i;
 504
 505    memset(&fb->Visual, 0, sizeof(fb->Visual));
 506    fb->Visual.rgbMode = GL_TRUE; /* assume this */
 507
 508 #if 0 /* this _might_ be needed */
 509    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 510       /* leave visual fields zero'd */
 511       return;
 512    }
 513 #endif
 514
 515    /* find first RGB renderbuffer */
 516    for (i = 0; i < BUFFER_COUNT; i++) {
 517       if (fb->Attachment[i].Renderbuffer) {
 518          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 519          const GLenum baseFormat = _mesa_get_format_base_format(rb->Format);
 520          const gl_format fmt = rb->Format;
 521
 522          /* Grab samples and sampleBuffers from any attachment point (assuming
 523           * the framebuffer is complete, we'll get the same answer from all
 524           * attachments).
 525           */
 526          fb->Visual.samples = rb->NumSamples;
 527          fb->Visual.sampleBuffers = rb->NumSamples > 0 ? 1 : 0;
 528
 529          if (_mesa_is_legal_color_format(ctx, baseFormat)) {
 530             fb->Visual.redBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 531             fb->Visual.greenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 532             fb->Visual.blueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 533             fb->Visual.alphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 534             fb->Visual.rgbBits = fb->Visual.redBits
 535                + fb->Visual.greenBits + fb->Visual.blueBits;
 536             if (_mesa_get_format_color_encoding(fmt) == GL_SRGB)
 537                 fb->Visual.sRGBCapable = ctx->Extensions.EXT_framebuffer_sRGB;
 538             break;
 539          }
 540       }
 541    }
 542
 543    fb->Visual.floatMode = GL_FALSE;
 544    for (i = 0; i < BUFFER_COUNT; i++) {
 545       if (fb->Attachment[i].Renderbuffer) {
 546          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 547          const gl_format fmt = rb->Format;
 548
 549          if (_mesa_get_format_datatype(fmt) == GL_FLOAT) {
 550             fb->Visual.floatMode = GL_TRUE;
 551             break;
 552          }
 553       }
 554    }
 555
 556    if (fb->Attachment[BUFFER_DEPTH].Renderbuffer) {
 557       const struct gl_renderbuffer *rb =
 558          fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 559       const gl_format fmt = rb->Format;
 560       fb->Visual.haveDepthBuffer = GL_TRUE;
 561       fb->Visual.depthBits = _mesa_get_format_bits(fmt, GL_DEPTH_BITS);
 562    }
 563
 564    if (fb->Attachment[BUFFER_STENCIL].Renderbuffer) {
 565       const struct gl_renderbuffer *rb =
 566          fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 567       const gl_format fmt = rb->Format;
 568       fb->Visual.haveStencilBuffer = GL_TRUE;
 569       fb->Visual.stencilBits = _mesa_get_format_bits(fmt, GL_STENCIL_BITS);
 570    }
 571
 572    if (fb->Attachment[BUFFER_ACCUM].Renderbuffer) {
 573       const struct gl_renderbuffer *rb =
 574          fb->Attachment[BUFFER_ACCUM].Renderbuffer;
 575       const gl_format fmt = rb->Format;
 576       fb->Visual.haveAccumBuffer = GL_TRUE;
 577       fb->Visual.accumRedBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 578       fb->Visual.accumGreenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 579       fb->Visual.accumBlueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 580       fb->Visual.accumAlphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 581    }
 582
 583    compute_depth_max(fb);
 584 }
 585
 586
 587 /*
 588  * Example DrawBuffers scenarios:
 589  *
 590  * 1. glDrawBuffer(GL_FRONT_AND_BACK), fixed-func or shader writes to
 591  * "gl_FragColor" or program writes to the "result.color" register:
 592  *
 593  *   fragment color output   renderbuffer
 594  *   ---------------------   ---------------
 595  *   color[0]                Front, Back
 596  *
 597  *
 598  * 2. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]), shader writes to
 599  * gl_FragData[i] or program writes to result.color[i] registers:
 600  *
 601  *   fragment color output   renderbuffer
 602  *   ---------------------   ---------------
 603  *   color[0]                Front
 604  *   color[1]                Aux0
 605  *   color[3]                Aux1
 606  *
 607  *
 608  * 3. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]) and shader writes to
 609  * gl_FragColor, or fixed function:
 610  *
 611  *   fragment color output   renderbuffer
 612  *   ---------------------   ---------------
 613  *   color[0]                Front, Aux0, Aux1
 614  *
 615  *
 616  * In either case, the list of renderbuffers is stored in the
 617  * framebuffer->_ColorDrawBuffers[] array and
 618  * framebuffer->_NumColorDrawBuffers indicates the number of buffers.
 619  * The renderer (like swrast) has to look at the current fragment shader
 620  * to see if it writes to gl_FragColor vs. gl_FragData[i] to determine
 621  * how to map color outputs to renderbuffers.
 622  *
 623  * Note that these two calls are equivalent (for fixed function fragment
 624  * shading anyway):
 625  *   a)  glDrawBuffer(GL_FRONT_AND_BACK);  (assuming non-stereo framebuffer)
 626  *   b)  glDrawBuffers(2, [GL_FRONT_LEFT, GL_BACK_LEFT]);
 627  */
 628
 629
 630
 631
 632 /**
 633  * Update the (derived) list of color drawing renderbuffer pointers.
 634  * Later, when we're rendering we'll loop from 0 to _NumColorDrawBuffers
 635  * writing colors.
 636  */
 637 static void
 638 update_color_draw_buffers(struct gl_context *ctx, struct gl_framebuffer *fb)
 639 {
 640    GLuint output;
 641
 642    /* set 0th buffer to NULL now in case _NumColorDrawBuffers is zero */
 643    fb->_ColorDrawBuffers[0] = NULL;
 644
 645    for (output = 0; output < fb->_NumColorDrawBuffers; output++) {
 646       GLint buf = fb->_ColorDrawBufferIndexes[output];
 647       if (buf >= 0) {
 648          fb->_ColorDrawBuffers[output] = fb->Attachment[buf].Renderbuffer;
 649       }
 650       else {
 651          fb->_ColorDrawBuffers[output] = NULL;
 652       }
 653    }
 654 }
 655
 656
 657 /**
 658  * Update the (derived) color read renderbuffer pointer.
 659  * Unlike the DrawBuffer, we can only read from one (or zero) color buffers.
 660  */
 661 static void
 662 update_color_read_buffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 663 {
 664    (void) ctx;
 665    if (fb->_ColorReadBufferIndex == -1 ||
 666        fb->DeletePending ||
 667        fb->Width == 0 ||
 668        fb->Height == 0) {
 669       fb->_ColorReadBuffer = NULL; /* legal! */
 670    }
 671    else {
 672       ASSERT(fb->_ColorReadBufferIndex >= 0);
 673       ASSERT(fb->_ColorReadBufferIndex < BUFFER_COUNT);
 674       fb->_ColorReadBuffer
 675          = fb->Attachment[fb->_ColorReadBufferIndex].Renderbuffer;
 676    }
 677 }
 678
 679
 680 /**
 681  * Update a gl_framebuffer's derived state.
 682  *
 683  * Specifically, update these framebuffer fields:
 684  *    _ColorDrawBuffers
 685  *    _NumColorDrawBuffers
 686  *    _ColorReadBuffer
 687  *
 688  * If the framebuffer is user-created, make sure it's complete.
 689  *
 690  * The following functions (at least) can effect framebuffer state:
 691  * glReadBuffer, glDrawBuffer, glDrawBuffersARB, glFramebufferRenderbufferEXT,
 692  * glRenderbufferStorageEXT.
 693  */
 694 static void
 695 update_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 696 {
 697    if (_mesa_is_winsys_fbo(fb)) {
 698       /* This is a window-system framebuffer */
 699       /* Need to update the FB's GL_DRAW_BUFFER state to match the
 700        * context state (GL_READ_BUFFER too).
 701        */
 702       if (fb->ColorDrawBuffer[0] != ctx->Color.DrawBuffer[0]) {
 703          _mesa_drawbuffers(ctx, ctx->Const.MaxDrawBuffers,
 704                            ctx->Color.DrawBuffer, NULL);
 705       }
 706    }
 707    else {
 708       /* This is a user-created framebuffer.
 709        * Completeness only matters for user-created framebuffers.
 710        */
 711       if (fb->_Status != GL_FRAMEBUFFER_COMPLETE) {
 712          _mesa_test_framebuffer_completeness(ctx, fb);
 713       }
 714    }
 715
 716    /* Strictly speaking, we don't need to update the draw-state
 717     * if this FB is bound as ctx->ReadBuffer (and conversely, the
 718     * read-state if this FB is bound as ctx->DrawBuffer), but no
 719     * harm.
 720     */
 721    update_color_draw_buffers(ctx, fb);
 722    update_color_read_buffer(ctx, fb);
 723
 724    compute_depth_max(fb);
 725 }
 726
 727
 728 /**
 729  * Update state related to the current draw/read framebuffers.
 730  */
 731 void
 732 _mesa_update_framebuffer(struct gl_context *ctx)
 733 {
 734    struct gl_framebuffer *drawFb;
 735    struct gl_framebuffer *readFb;
 736
 737    assert(ctx);
 738    drawFb = ctx->DrawBuffer;
 739    readFb = ctx->ReadBuffer;
 740
 741    update_framebuffer(ctx, drawFb);
 742    if (readFb != drawFb)
 743       update_framebuffer(ctx, readFb);
 744 }
 745
 746
 747 /**
 748  * Check if the renderbuffer for a read/draw operation exists.
 749  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 750  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 751  * \param reading  if TRUE, we're going to read from the buffer,
 752                    if FALSE, we're going to write to the buffer.
 753  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 754  */
 755 static GLboolean
 756 renderbuffer_exists(struct gl_context *ctx,
 757                     struct gl_framebuffer *fb,
 758                     GLenum format,
 759                     GLboolean reading)
 760 {
 761    const struct gl_renderbuffer_attachment *att = fb->Attachment;
 762
 763    /* If we don't know the framebuffer status, update it now */
 764    if (fb->_Status == 0) {
 765       _mesa_test_framebuffer_completeness(ctx, fb);
 766    }
 767
 768    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 769       return GL_FALSE;
 770    }
 771
 772    switch (format) {
 773    case GL_COLOR:
 774    case GL_RED:
 775    case GL_GREEN:
 776    case GL_BLUE:
 777    case GL_ALPHA:
 778    case GL_LUMINANCE:
 779    case GL_LUMINANCE_ALPHA:
 780    case GL_INTENSITY:
 781    case GL_RG:
 782    case GL_RGB:
 783    case GL_BGR:
 784    case GL_RGBA:
 785    case GL_BGRA:
 786    case GL_ABGR_EXT:
 787    case GL_RED_INTEGER_EXT:
 788    case GL_RG_INTEGER:
 789    case GL_GREEN_INTEGER_EXT:
 790    case GL_BLUE_INTEGER_EXT:
 791    case GL_ALPHA_INTEGER_EXT:
 792    case GL_RGB_INTEGER_EXT:
 793    case GL_RGBA_INTEGER_EXT:
 794    case GL_BGR_INTEGER_EXT:
 795    case GL_BGRA_INTEGER_EXT:
 796    case GL_LUMINANCE_INTEGER_EXT:
 797    case GL_LUMINANCE_ALPHA_INTEGER_EXT:
 798       if (reading) {
 799          /* about to read from a color buffer */
 800          const struct gl_renderbuffer *readBuf = fb->_ColorReadBuffer;
 801          if (!readBuf) {
 802             return GL_FALSE;
 803          }
 804          ASSERT(_mesa_get_format_bits(readBuf->Format, GL_RED_BITS) > 0 ||
 805                 _mesa_get_format_bits(readBuf->Format, GL_ALPHA_BITS) > 0 ||
 806                 _mesa_get_format_bits(readBuf->Format, GL_TEXTURE_LUMINANCE_SIZE) > 0 ||
 807                 _mesa_get_format_bits(readBuf->Format, GL_TEXTURE_INTENSITY_SIZE) > 0 ||
 808                 _mesa_get_format_bits(readBuf->Format, GL_INDEX_BITS) > 0);
 809       }
 810       else {
 811          /* about to draw to zero or more color buffers (none is OK) */
 812          return GL_TRUE;
 813       }
 814       break;
 815    case GL_DEPTH:
 816    case GL_DEPTH_COMPONENT:
 817       if (att[BUFFER_DEPTH].Type == GL_NONE) {
 818          return GL_FALSE;
 819       }
 820       break;
 821    case GL_STENCIL:
 822    case GL_STENCIL_INDEX:
 823       if (att[BUFFER_STENCIL].Type == GL_NONE) {
 824          return GL_FALSE;
 825       }
 826       break;
 827    case GL_DEPTH_STENCIL_EXT:
 828       if (att[BUFFER_DEPTH].Type == GL_NONE ||
 829           att[BUFFER_STENCIL].Type == GL_NONE) {
 830          return GL_FALSE;
 831       }
 832       break;
 833    default:
 834       _mesa_problem(ctx,
 835                     "Unexpected format 0x%x in renderbuffer_exists",
 836                     format);
 837       return GL_FALSE;
 838    }
 839
 840    /* OK */
 841    return GL_TRUE;
 842 }
 843
 844
 845 /**
 846  * Check if the renderbuffer for a read operation (glReadPixels, glCopyPixels,
 847  * glCopyTex[Sub]Image, etc) exists.
 848  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 849  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 850  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 851  */
 852 GLboolean
 853 _mesa_source_buffer_exists(struct gl_context *ctx, GLenum format)
 854 {
 855    return renderbuffer_exists(ctx, ctx->ReadBuffer, format, GL_TRUE);
 856 }
 857
 858
 859 /**
 860  * As above, but for drawing operations.
 861  */
 862 GLboolean
 863 _mesa_dest_buffer_exists(struct gl_context *ctx, GLenum format)
 864 {
 865    return renderbuffer_exists(ctx, ctx->DrawBuffer, format, GL_FALSE);
 866 }
 867
 868
 869 /**
 870  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_FORMAT_OES query.
 871  */
 872 GLenum
 873 _mesa_get_color_read_format(struct gl_context *ctx)
 874 {
 875    const GLenum data_type = _mesa_get_format_datatype(
 876                                ctx->ReadBuffer->_ColorReadBuffer->Format);
 877
 878    switch (ctx->ReadBuffer->_ColorReadBuffer->Format) {
 879    case MESA_FORMAT_ARGB8888:
 880       return GL_BGRA;
 881    case MESA_FORMAT_RGB565:
 882       return GL_BGR;
 883    default:
 884       if (data_type == GL_UNSIGNED_INT || data_type == GL_INT) {
 885          return GL_RGBA_INTEGER;
 886       } else {
 887          return GL_RGBA;
 888       }
 889    }
 890 }
 891
 892
 893 /**
 894  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_TYPE_OES query.
 895  */
 896 GLenum
 897 _mesa_get_color_read_type(struct gl_context *ctx)
 898 {
 899    const GLenum data_type = _mesa_get_format_datatype(
 900                                ctx->ReadBuffer->_ColorReadBuffer->Format);
 901
 902    switch (ctx->ReadBuffer->_ColorReadBuffer->Format) {
 903    case MESA_FORMAT_RGB565:
 904       return GL_UNSIGNED_SHORT_5_6_5_REV;
 905    default:
 906       break;
 907    }
 908
 909    switch (data_type) {
 910    case GL_SIGNED_NORMALIZED:
 911       return GL_BYTE;
 912    case GL_UNSIGNED_INT:
 913    case GL_INT:
 914    case GL_FLOAT:
 915       return data_type;
 916    case GL_UNSIGNED_NORMALIZED:
 917    default:
 918       return GL_UNSIGNED_BYTE;
 919    }
 920 }
 921
 922
 923 /**
 924  * Returns the read renderbuffer for the specified format.
 925  */
 926 struct gl_renderbuffer *
 927 _mesa_get_read_renderbuffer_for_format(const struct gl_context *ctx,
 928                                        GLenum format)
 929 {
 930    const struct gl_framebuffer *rfb = ctx->ReadBuffer;
 931
 932    if (_mesa_is_color_format(format)) {
 933       return rfb->Attachment[rfb->_ColorReadBufferIndex].Renderbuffer;
 934    } else if (_mesa_is_depth_format(format) ||
 935               _mesa_is_depthstencil_format(format)) {
 936       return rfb->Attachment[BUFFER_DEPTH].Renderbuffer;
 937    } else {
 938       return rfb->Attachment[BUFFER_STENCIL].Renderbuffer;
 939    }
 940 }
 941
 942
 943 /**
 944  * Print framebuffer info to stderr, for debugging.
 945  */
 946 void
 947 _mesa_print_framebuffer(const struct gl_framebuffer *fb)
 948 {
 949    GLuint i;
 950
 951    fprintf(stderr, "Mesa Framebuffer %u at %p\n", fb->Name, (void *) fb);
 952    fprintf(stderr, "  Size: %u x %u  Status: %s\n", fb->Width, fb->Height,
 953            _mesa_lookup_enum_by_nr(fb->_Status));
 954    fprintf(stderr, "  Attachments:\n");
 955
 956    for (i = 0; i < BUFFER_COUNT; i++) {
 957       const struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 958       if (att->Type == GL_TEXTURE) {
 959          const struct gl_texture_image *texImage =
 960             _mesa_get_attachment_teximage_const(att);
 961          fprintf(stderr,
 962                  "  %2d: Texture %u, level %u, face %u, slice %u, complete %d\n",
 963                  i, att->Texture->Name, att->TextureLevel, att->CubeMapFace,
 964                  att->Zoffset, att->Complete);
 965          fprintf(stderr, "       Size: %u x %u x %u  Format %s\n",
 966                  texImage->Width, texImage->Height, texImage->Depth,
 967                  _mesa_get_format_name(texImage->TexFormat));
 968       }
 969       else if (att->Type == GL_RENDERBUFFER) {
 970          fprintf(stderr, "  %2d: Renderbuffer %u, complete %d\n",
 971                  i, att->Renderbuffer->Name, att->Complete);
 972          fprintf(stderr, "       Size: %u x %u  Format %s\n",
 973                  att->Renderbuffer->Width, att->Renderbuffer->Height,
 974                  _mesa_get_format_name(att->Renderbuffer->Format));
 975       }
 976       else {
 977          fprintf(stderr, "  %2d: none\n", i);
 978       }
 979    }
 980 }