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