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