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  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  23  * OTHER DEALINGS IN THE SOFTWARE.
  24  */
  25
  26
  27 /**
  28  * Functions for allocating/managing framebuffers and renderbuffers.
  29  * Also, routines for reading/writing renderbuffer data as ubytes,
  30  * ushorts, uints, etc.
  31  */
  32
  33
  34 #include "glheader.h"
  35 #include "imports.h"
  36 #include "blend.h"
  37 #include "buffers.h"
  38 #include "context.h"
  39 #include "enums.h"
  40 #include "formats.h"
  41 #include "macros.h"
  42 #include "mtypes.h"
  43 #include "fbobject.h"
  44 #include "framebuffer.h"
  45 #include "renderbuffer.h"
  46 #include "texobj.h"
  47 #include "glformats.h"
  48
  49
  50
  51 /**
  52  * Compute/set the _DepthMax field for the given framebuffer.
  53  * This value depends on the Z buffer resolution.
  54  */
  55 static void
  56 compute_depth_max(struct gl_framebuffer *fb)
  57 {
  58    if (fb->Visual.depthBits == 0) {
  59       /* Special case.  Even if we don't have a depth buffer we need
  60        * good values for DepthMax for Z vertex transformation purposes
  61        * and for per-fragment fog computation.
  62        */
  63       fb->_DepthMax = (1 << 16) - 1;
  64    }
  65    else if (fb->Visual.depthBits < 32) {
  66       fb->_DepthMax = (1 << fb->Visual.depthBits) - 1;
  67    }
  68    else {
  69       /* Special case since shift values greater than or equal to the
  70        * number of bits in the left hand expression's type are undefined.
  71        */
  72       fb->_DepthMax = 0xffffffff;
  73    }
  74    fb->_DepthMaxF = (GLfloat) fb->_DepthMax;
  75
  76    /* Minimum resolvable depth value, for polygon offset */
  77    fb->_MRD = (GLfloat)1.0 / fb->_DepthMaxF;
  78 }
  79
  80 /**
  81  * Create and initialize a gl_framebuffer object.
  82  * This is intended for creating _window_system_ framebuffers, not generic
  83  * framebuffer objects ala GL_EXT_framebuffer_object.
  84  *
  85  * \sa _mesa_new_framebuffer
  86  */
  87 struct gl_framebuffer *
  88 _mesa_create_framebuffer(const struct gl_config *visual)
  89 {
  90    struct gl_framebuffer *fb = CALLOC_STRUCT(gl_framebuffer);
  91    assert(visual);
  92    if (fb) {
  93       _mesa_initialize_window_framebuffer(fb, visual);
  94    }
  95    return fb;
  96 }
  97
  98
  99 /**
 100  * Allocate a new gl_framebuffer object.
 101  * This is the default function for ctx->Driver.NewFramebuffer().
 102  * This is for allocating user-created framebuffers, not window-system
 103  * framebuffers!
 104  * \sa _mesa_create_framebuffer
 105  */
 106 struct gl_framebuffer *
 107 _mesa_new_framebuffer(struct gl_context *ctx, GLuint name)
 108 {
 109    struct gl_framebuffer *fb;
 110    (void) ctx;
 111    assert(name != 0);
 112    fb = CALLOC_STRUCT(gl_framebuffer);
 113    if (fb) {
 114       _mesa_initialize_user_framebuffer(fb, name);
 115    }
 116    return fb;
 117 }
 118
 119
 120 /**
 121  * Initialize a gl_framebuffer object.  Typically used to initialize
 122  * window system-created framebuffers, not user-created framebuffers.
 123  * \sa _mesa_initialize_user_framebuffer
 124  */
 125 void
 126 _mesa_initialize_window_framebuffer(struct gl_framebuffer *fb,
 127                                      const struct gl_config *visual)
 128 {
 129    assert(fb);
 130    assert(visual);
 131
 132    memset(fb, 0, sizeof(struct gl_framebuffer));
 133
 134    _glthread_INIT_MUTEX(fb->Mutex);
 135
 136    fb->RefCount = 1;
 137
 138    /* save the visual */
 139    fb->Visual = *visual;
 140
 141    /* Init read/draw renderbuffer state */
 142    if (visual->doubleBufferMode) {
 143       fb->_NumColorDrawBuffers = 1;
 144       fb->ColorDrawBuffer[0] = GL_BACK;
 145       fb->_ColorDrawBufferIndexes[0] = BUFFER_BACK_LEFT;
 146       fb->ColorReadBuffer = GL_BACK;
 147       fb->_ColorReadBufferIndex = BUFFER_BACK_LEFT;
 148    }
 149    else {
 150       fb->_NumColorDrawBuffers = 1;
 151       fb->ColorDrawBuffer[0] = GL_FRONT;
 152       fb->_ColorDrawBufferIndexes[0] = BUFFER_FRONT_LEFT;
 153       fb->ColorReadBuffer = GL_FRONT;
 154       fb->_ColorReadBufferIndex = BUFFER_FRONT_LEFT;
 155    }
 156
 157    fb->Delete = _mesa_destroy_framebuffer;
 158    fb->_Status = GL_FRAMEBUFFER_COMPLETE_EXT;
 159    fb->_AllColorBuffersFixedPoint = !visual->floatMode;
 160    fb->_HasSNormOrFloatColorBuffer = visual->floatMode;
 161
 162    compute_depth_max(fb);
 163 }
 164
 165
 166 /**
 167  * Initialize a user-created gl_framebuffer object.
 168  * \sa _mesa_initialize_window_framebuffer
 169  */
 170 void
 171 _mesa_initialize_user_framebuffer(struct gl_framebuffer *fb, GLuint name)
 172 {
 173    assert(fb);
 174    assert(name);
 175
 176    memset(fb, 0, sizeof(struct gl_framebuffer));
 177
 178    fb->Name = name;
 179    fb->RefCount = 1;
 180    fb->_NumColorDrawBuffers = 1;
 181    fb->ColorDrawBuffer[0] = GL_COLOR_ATTACHMENT0_EXT;
 182    fb->_ColorDrawBufferIndexes[0] = BUFFER_COLOR0;
 183    fb->ColorReadBuffer = GL_COLOR_ATTACHMENT0_EXT;
 184    fb->_ColorReadBufferIndex = BUFFER_COLOR0;
 185    fb->Delete = _mesa_destroy_framebuffer;
 186    _glthread_INIT_MUTEX(fb->Mutex);
 187 }
 188
 189
 190 /**
 191  * Deallocate buffer and everything attached to it.
 192  * Typically called via the gl_framebuffer->Delete() method.
 193  */
 194 void
 195 _mesa_destroy_framebuffer(struct gl_framebuffer *fb)
 196 {
 197    if (fb) {
 198       _mesa_free_framebuffer_data(fb);
 199       free(fb);
 200    }
 201 }
 202
 203
 204 /**
 205  * Free all the data hanging off the given gl_framebuffer, but don't free
 206  * the gl_framebuffer object itself.
 207  */
 208 void
 209 _mesa_free_framebuffer_data(struct gl_framebuffer *fb)
 210 {
 211    GLuint i;
 212
 213    assert(fb);
 214    assert(fb->RefCount == 0);
 215
 216    _glthread_DESTROY_MUTEX(fb->Mutex);
 217
 218    for (i = 0; i < BUFFER_COUNT; i++) {
 219       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 220       if (att->Renderbuffer) {
 221          _mesa_reference_renderbuffer(&att->Renderbuffer, NULL);
 222       }
 223       if (att->Texture) {
 224          _mesa_reference_texobj(&att->Texture, NULL);
 225       }
 226       ASSERT(!att->Renderbuffer);
 227       ASSERT(!att->Texture);
 228       att->Type = GL_NONE;
 229    }
 230 }
 231
 232
 233 /**
 234  * Set *ptr to point to fb, with refcounting and locking.
 235  * This is normally only called from the _mesa_reference_framebuffer() macro
 236  * when there's a real pointer change.
 237  */
 238 void
 239 _mesa_reference_framebuffer_(struct gl_framebuffer **ptr,
 240                              struct gl_framebuffer *fb)
 241 {
 242    if (*ptr) {
 243       /* unreference old renderbuffer */
 244       GLboolean deleteFlag = GL_FALSE;
 245       struct gl_framebuffer *oldFb = *ptr;
 246
 247       _glthread_LOCK_MUTEX(oldFb->Mutex);
 248       ASSERT(oldFb->RefCount > 0);
 249       oldFb->RefCount--;
 250       deleteFlag = (oldFb->RefCount == 0);
 251       _glthread_UNLOCK_MUTEX(oldFb->Mutex);
 252
 253       if (deleteFlag)
 254          oldFb->Delete(oldFb);
 255
 256       *ptr = NULL;
 257    }
 258    assert(!*ptr);
 259
 260    if (fb) {
 261       _glthread_LOCK_MUTEX(fb->Mutex);
 262       fb->RefCount++;
 263       _glthread_UNLOCK_MUTEX(fb->Mutex);
 264       *ptr = fb;
 265    }
 266 }
 267
 268
 269 /**
 270  * Resize the given framebuffer's renderbuffers to the new width and height.
 271  * This should only be used for window-system framebuffers, not
 272  * user-created renderbuffers (i.e. made with GL_EXT_framebuffer_object).
 273  * This will typically be called via ctx->Driver.ResizeBuffers() or directly
 274  * from a device driver.
 275  *
 276  * \note it's possible for ctx to be null since a window can be resized
 277  * without a currently bound rendering context.
 278  */
 279 void
 280 _mesa_resize_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb,
 281                          GLuint width, GLuint height)
 282 {
 283    GLuint i;
 284
 285    /* XXX I think we could check if the size is not changing
 286     * and return early.
 287     */
 288
 289    /* Can only resize win-sys framebuffer objects */
 290    assert(_mesa_is_winsys_fbo(fb));
 291
 292    for (i = 0; i < BUFFER_COUNT; i++) {
 293       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 294       if (att->Type == GL_RENDERBUFFER_EXT && att->Renderbuffer) {
 295          struct gl_renderbuffer *rb = att->Renderbuffer;
 296          /* only resize if size is changing */
 297          if (rb->Width != width || rb->Height != height) {
 298             if (rb->AllocStorage(ctx, rb, rb->InternalFormat, width, height)) {
 299                ASSERT(rb->Width == width);
 300                ASSERT(rb->Height == height);
 301             }
 302             else {
 303                _mesa_error(ctx, GL_OUT_OF_MEMORY, "Resizing framebuffer");
 304                /* no return */
 305             }
 306          }
 307       }
 308    }
 309
 310    fb->Width = width;
 311    fb->Height = height;
 312
 313    if (ctx) {
 314       /* update scissor / window bounds */
 315       _mesa_update_draw_buffer_bounds(ctx);
 316       /* Signal new buffer state so that swrast will update its clipping
 317        * info (the CLIP_BIT flag).
 318        */
 319       ctx->NewState |= _NEW_BUFFERS;
 320    }
 321 }
 322
 323
 324
 325 /**
 326  * XXX THIS IS OBSOLETE - drivers should take care of detecting window
 327  * size changes and act accordingly, likely calling _mesa_resize_framebuffer().
 328  *
 329  * GL_MESA_resize_buffers extension.
 330  *
 331  * When this function is called, we'll ask the window system how large
 332  * the current window is.  If it's a new size, we'll call the driver's
 333  * ResizeBuffers function.  The driver will then resize its color buffers
 334  * as needed, and maybe call the swrast's routine for reallocating
 335  * swrast-managed depth/stencil/accum/etc buffers.
 336  * \note This function should only be called through the GL API, not
 337  * from device drivers (as was done in the past).
 338  */
 339 void
 340 _mesa_resizebuffers( struct gl_context *ctx )
 341 {
 342    FLUSH_VERTICES(ctx, 0);
 343
 344    if (MESA_VERBOSE & VERBOSE_API)
 345       _mesa_debug(ctx, "glResizeBuffersMESA\n");
 346
 347    if (!ctx->Driver.GetBufferSize) {
 348       return;
 349    }
 350
 351    if (ctx->WinSysDrawBuffer) {
 352       GLuint newWidth, newHeight;
 353       struct gl_framebuffer *buffer = ctx->WinSysDrawBuffer;
 354
 355       assert(_mesa_is_winsys_fbo(buffer));
 356
 357       /* ask device driver for size of output buffer */
 358       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 359
 360       /* see if size of device driver's color buffer (window) has changed */
 361       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 362          if (ctx->Driver.ResizeBuffers)
 363             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 364       }
 365    }
 366
 367    if (ctx->WinSysReadBuffer
 368        && ctx->WinSysReadBuffer != ctx->WinSysDrawBuffer) {
 369       GLuint newWidth, newHeight;
 370       struct gl_framebuffer *buffer = ctx->WinSysReadBuffer;
 371
 372       assert(_mesa_is_winsys_fbo(buffer));
 373
 374       /* ask device driver for size of read buffer */
 375       ctx->Driver.GetBufferSize( buffer, &newWidth, &newHeight );
 376
 377       /* see if size of device driver's color buffer (window) has changed */
 378       if (buffer->Width != newWidth || buffer->Height != newHeight) {
 379          if (ctx->Driver.ResizeBuffers)
 380             ctx->Driver.ResizeBuffers(ctx, buffer, newWidth, newHeight );
 381       }
 382    }
 383
 384    ctx->NewState |= _NEW_BUFFERS;  /* to update scissor / window bounds */
 385 }
 386
 387
 388 /*
 389  * XXX THIS IS OBSOLETE
 390  */
 391 void GLAPIENTRY
 392 _mesa_ResizeBuffersMESA( void )
 393 {
 394    GET_CURRENT_CONTEXT(ctx);
 395
 396    if (ctx->Extensions.MESA_resize_buffers)
 397       _mesa_resizebuffers( ctx );
 398 }
 399
 400
 401
 402 /**
 403  * Examine all the framebuffer's renderbuffers to update the Width/Height
 404  * fields of the framebuffer.  If we have renderbuffers with different
 405  * sizes, set the framebuffer's width and height to the min size.
 406  * Note: this is only intended for user-created framebuffers, not
 407  * window-system framebuffes.
 408  */
 409 static void
 410 update_framebuffer_size(struct gl_context *ctx, struct gl_framebuffer *fb)
 411 {
 412    GLuint minWidth = ~0, minHeight = ~0;
 413    GLuint i;
 414
 415    /* user-created framebuffers only */
 416    assert(_mesa_is_user_fbo(fb));
 417
 418    for (i = 0; i < BUFFER_COUNT; i++) {
 419       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 420       const struct gl_renderbuffer *rb = att->Renderbuffer;
 421       if (rb) {
 422          minWidth = MIN2(minWidth, rb->Width);
 423          minHeight = MIN2(minHeight, rb->Height);
 424       }
 425    }
 426
 427    if (minWidth != ~0) {
 428       fb->Width = minWidth;
 429       fb->Height = minHeight;
 430    }
 431    else {
 432       fb->Width = 0;
 433       fb->Height = 0;
 434    }
 435 }
 436
 437
 438 /**
 439  * Update the context's current drawing buffer's Xmin, Xmax, Ymin, Ymax fields.
 440  * These values are computed from the buffer's width and height and
 441  * the scissor box, if it's enabled.
 442  * \param ctx  the GL context.
 443  */
 444 void
 445 _mesa_update_draw_buffer_bounds(struct gl_context *ctx)
 446 {
 447    struct gl_framebuffer *buffer = ctx->DrawBuffer;
 448
 449    if (!buffer)
 450       return;
 451
 452    if (_mesa_is_user_fbo(buffer)) {
 453       /* user-created framebuffer size depends on the renderbuffers */
 454       update_framebuffer_size(ctx, buffer);
 455    }
 456
 457    buffer->_Xmin = 0;
 458    buffer->_Ymin = 0;
 459    buffer->_Xmax = buffer->Width;
 460    buffer->_Ymax = buffer->Height;
 461
 462    if (ctx->Scissor.Enabled) {
 463       if (ctx->Scissor.X > buffer->_Xmin) {
 464          buffer->_Xmin = ctx->Scissor.X;
 465       }
 466       if (ctx->Scissor.Y > buffer->_Ymin) {
 467          buffer->_Ymin = ctx->Scissor.Y;
 468       }
 469       if (ctx->Scissor.X + ctx->Scissor.Width < buffer->_Xmax) {
 470          buffer->_Xmax = ctx->Scissor.X + ctx->Scissor.Width;
 471       }
 472       if (ctx->Scissor.Y + ctx->Scissor.Height < buffer->_Ymax) {
 473          buffer->_Ymax = ctx->Scissor.Y + ctx->Scissor.Height;
 474       }
 475       /* finally, check for empty region */
 476       if (buffer->_Xmin > buffer->_Xmax) {
 477          buffer->_Xmin = buffer->_Xmax;
 478       }
 479       if (buffer->_Ymin > buffer->_Ymax) {
 480          buffer->_Ymin = buffer->_Ymax;
 481       }
 482    }
 483
 484    ASSERT(buffer->_Xmin <= buffer->_Xmax);
 485    ASSERT(buffer->_Ymin <= buffer->_Ymax);
 486 }
 487
 488
 489 /**
 490  * The glGet queries of the framebuffer red/green/blue size, stencil size,
 491  * etc. are satisfied by the fields of ctx->DrawBuffer->Visual.  These can
 492  * change depending on the renderbuffer bindings.  This function updates
 493  * the given framebuffer's Visual from the current renderbuffer bindings.
 494  *
 495  * This may apply to user-created framebuffers or window system framebuffers.
 496  *
 497  * Also note: ctx->DrawBuffer->Visual.depthBits might not equal
 498  * ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer.DepthBits.
 499  * The former one is used to convert floating point depth values into
 500  * integer Z values.
 501  */
 502 void
 503 _mesa_update_framebuffer_visual(struct gl_context *ctx,
 504                                 struct gl_framebuffer *fb)
 505 {
 506    GLuint i;
 507
 508    memset(&fb->Visual, 0, sizeof(fb->Visual));
 509    fb->Visual.rgbMode = GL_TRUE; /* assume this */
 510
 511 #if 0 /* this _might_ be needed */
 512    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 513       /* leave visual fields zero'd */
 514       return;
 515    }
 516 #endif
 517
 518    /* find first RGB renderbuffer */
 519    for (i = 0; i < BUFFER_COUNT; i++) {
 520       if (fb->Attachment[i].Renderbuffer) {
 521          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 522          const GLenum baseFormat = _mesa_get_format_base_format(rb->Format);
 523          const gl_format fmt = rb->Format;
 524
 525          /* Grab samples and sampleBuffers from any attachment point (assuming
 526           * the framebuffer is complete, we'll get the same answer from all
 527           * attachments).
 528           */
 529          fb->Visual.samples = rb->NumSamples;
 530          fb->Visual.sampleBuffers = rb->NumSamples > 0 ? 1 : 0;
 531
 532          if (_mesa_is_legal_color_format(ctx, baseFormat)) {
 533             fb->Visual.redBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 534             fb->Visual.greenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 535             fb->Visual.blueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 536             fb->Visual.alphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 537             fb->Visual.rgbBits = fb->Visual.redBits
 538                + fb->Visual.greenBits + fb->Visual.blueBits;
 539             if (_mesa_get_format_color_encoding(fmt) == GL_SRGB)
 540                 fb->Visual.sRGBCapable = ctx->Extensions.EXT_framebuffer_sRGB;
 541             break;
 542          }
 543       }
 544    }
 545
 546    fb->Visual.floatMode = GL_FALSE;
 547    for (i = 0; i < BUFFER_COUNT; i++) {
 548       if (fb->Attachment[i].Renderbuffer) {
 549          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 550          const gl_format fmt = rb->Format;
 551
 552          if (_mesa_get_format_datatype(fmt) == GL_FLOAT) {
 553             fb->Visual.floatMode = GL_TRUE;
 554             break;
 555          }
 556       }
 557    }
 558
 559    if (fb->Attachment[BUFFER_DEPTH].Renderbuffer) {
 560       const struct gl_renderbuffer *rb =
 561          fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 562       const gl_format fmt = rb->Format;
 563       fb->Visual.haveDepthBuffer = GL_TRUE;
 564       fb->Visual.depthBits = _mesa_get_format_bits(fmt, GL_DEPTH_BITS);
 565    }
 566
 567    if (fb->Attachment[BUFFER_STENCIL].Renderbuffer) {
 568       const struct gl_renderbuffer *rb =
 569          fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 570       const gl_format fmt = rb->Format;
 571       fb->Visual.haveStencilBuffer = GL_TRUE;
 572       fb->Visual.stencilBits = _mesa_get_format_bits(fmt, GL_STENCIL_BITS);
 573    }
 574
 575    if (fb->Attachment[BUFFER_ACCUM].Renderbuffer) {
 576       const struct gl_renderbuffer *rb =
 577          fb->Attachment[BUFFER_ACCUM].Renderbuffer;
 578       const gl_format fmt = rb->Format;
 579       fb->Visual.haveAccumBuffer = GL_TRUE;
 580       fb->Visual.accumRedBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 581       fb->Visual.accumGreenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 582       fb->Visual.accumBlueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 583       fb->Visual.accumAlphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 584    }
 585
 586    compute_depth_max(fb);
 587 }
 588
 589
 590 /*
 591  * Example DrawBuffers scenarios:
 592  *
 593  * 1. glDrawBuffer(GL_FRONT_AND_BACK), fixed-func or shader writes to
 594  * "gl_FragColor" or program writes to the "result.color" register:
 595  *
 596  *   fragment color output   renderbuffer
 597  *   ---------------------   ---------------
 598  *   color[0]                Front, Back
 599  *
 600  *
 601  * 2. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]), shader writes to
 602  * gl_FragData[i] or program writes to result.color[i] registers:
 603  *
 604  *   fragment color output   renderbuffer
 605  *   ---------------------   ---------------
 606  *   color[0]                Front
 607  *   color[1]                Aux0
 608  *   color[3]                Aux1
 609  *
 610  *
 611  * 3. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]) and shader writes to
 612  * gl_FragColor, or fixed function:
 613  *
 614  *   fragment color output   renderbuffer
 615  *   ---------------------   ---------------
 616  *   color[0]                Front, Aux0, Aux1
 617  *
 618  *
 619  * In either case, the list of renderbuffers is stored in the
 620  * framebuffer->_ColorDrawBuffers[] array and
 621  * framebuffer->_NumColorDrawBuffers indicates the number of buffers.
 622  * The renderer (like swrast) has to look at the current fragment shader
 623  * to see if it writes to gl_FragColor vs. gl_FragData[i] to determine
 624  * how to map color outputs to renderbuffers.
 625  *
 626  * Note that these two calls are equivalent (for fixed function fragment
 627  * shading anyway):
 628  *   a)  glDrawBuffer(GL_FRONT_AND_BACK);  (assuming non-stereo framebuffer)
 629  *   b)  glDrawBuffers(2, [GL_FRONT_LEFT, GL_BACK_LEFT]);
 630  */
 631
 632
 633
 634
 635 /**
 636  * Update the (derived) list of color drawing renderbuffer pointers.
 637  * Later, when we're rendering we'll loop from 0 to _NumColorDrawBuffers
 638  * writing colors.
 639  */
 640 static void
 641 update_color_draw_buffers(struct gl_context *ctx, struct gl_framebuffer *fb)
 642 {
 643    GLuint output;
 644
 645    /* set 0th buffer to NULL now in case _NumColorDrawBuffers is zero */
 646    fb->_ColorDrawBuffers[0] = NULL;
 647
 648    for (output = 0; output < fb->_NumColorDrawBuffers; output++) {
 649       GLint buf = fb->_ColorDrawBufferIndexes[output];
 650       if (buf >= 0) {
 651          fb->_ColorDrawBuffers[output] = fb->Attachment[buf].Renderbuffer;
 652       }
 653       else {
 654          fb->_ColorDrawBuffers[output] = NULL;
 655       }
 656    }
 657 }
 658
 659
 660 /**
 661  * Update the (derived) color read renderbuffer pointer.
 662  * Unlike the DrawBuffer, we can only read from one (or zero) color buffers.
 663  */
 664 static void
 665 update_color_read_buffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 666 {
 667    (void) ctx;
 668    if (fb->_ColorReadBufferIndex == -1 ||
 669        fb->DeletePending ||
 670        fb->Width == 0 ||
 671        fb->Height == 0) {
 672       fb->_ColorReadBuffer = NULL; /* legal! */
 673    }
 674    else {
 675       ASSERT(fb->_ColorReadBufferIndex >= 0);
 676       ASSERT(fb->_ColorReadBufferIndex < BUFFER_COUNT);
 677       fb->_ColorReadBuffer
 678          = fb->Attachment[fb->_ColorReadBufferIndex].Renderbuffer;
 679    }
 680 }
 681
 682
 683 /**
 684  * Update a gl_framebuffer's derived state.
 685  *
 686  * Specifically, update these framebuffer fields:
 687  *    _ColorDrawBuffers
 688  *    _NumColorDrawBuffers
 689  *    _ColorReadBuffer
 690  *
 691  * If the framebuffer is user-created, make sure it's complete.
 692  *
 693  * The following functions (at least) can effect framebuffer state:
 694  * glReadBuffer, glDrawBuffer, glDrawBuffersARB, glFramebufferRenderbufferEXT,
 695  * glRenderbufferStorageEXT.
 696  */
 697 static void
 698 update_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 699 {
 700    if (_mesa_is_winsys_fbo(fb)) {
 701       /* This is a window-system framebuffer */
 702       /* Need to update the FB's GL_DRAW_BUFFER state to match the
 703        * context state (GL_READ_BUFFER too).
 704        */
 705       if (fb->ColorDrawBuffer[0] != ctx->Color.DrawBuffer[0]) {
 706          _mesa_drawbuffers(ctx, ctx->Const.MaxDrawBuffers,
 707                            ctx->Color.DrawBuffer, NULL);
 708       }
 709    }
 710    else {
 711       /* This is a user-created framebuffer.
 712        * Completeness only matters for user-created framebuffers.
 713        */
 714       if (fb->_Status != GL_FRAMEBUFFER_COMPLETE) {
 715          _mesa_test_framebuffer_completeness(ctx, fb);
 716       }
 717    }
 718
 719    /* Strictly speaking, we don't need to update the draw-state
 720     * if this FB is bound as ctx->ReadBuffer (and conversely, the
 721     * read-state if this FB is bound as ctx->DrawBuffer), but no
 722     * harm.
 723     */
 724    update_color_draw_buffers(ctx, fb);
 725    update_color_read_buffer(ctx, fb);
 726
 727    compute_depth_max(fb);
 728 }
 729
 730
 731 /**
 732  * Update state related to the current draw/read framebuffers.
 733  */
 734 void
 735 _mesa_update_framebuffer(struct gl_context *ctx)
 736 {
 737    struct gl_framebuffer *drawFb;
 738    struct gl_framebuffer *readFb;
 739
 740    assert(ctx);
 741    drawFb = ctx->DrawBuffer;
 742    readFb = ctx->ReadBuffer;
 743
 744    update_framebuffer(ctx, drawFb);
 745    if (readFb != drawFb)
 746       update_framebuffer(ctx, readFb);
 747
 748    _mesa_update_clamp_vertex_color(ctx);
 749    _mesa_update_clamp_fragment_color(ctx);
 750 }
 751
 752
 753 /**
 754  * Check if the renderbuffer for a read/draw operation exists.
 755  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 756  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 757  * \param reading  if TRUE, we're going to read from the buffer,
 758                    if FALSE, we're going to write to the buffer.
 759  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 760  */
 761 static GLboolean
 762 renderbuffer_exists(struct gl_context *ctx,
 763                     struct gl_framebuffer *fb,
 764                     GLenum format,
 765                     GLboolean reading)
 766 {
 767    const struct gl_renderbuffer_attachment *att = fb->Attachment;
 768
 769    /* If we don't know the framebuffer status, update it now */
 770    if (fb->_Status == 0) {
 771       _mesa_test_framebuffer_completeness(ctx, fb);
 772    }
 773
 774    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 775       return GL_FALSE;
 776    }
 777
 778    switch (format) {
 779    case GL_COLOR:
 780    case GL_RED:
 781    case GL_GREEN:
 782    case GL_BLUE:
 783    case GL_ALPHA:
 784    case GL_LUMINANCE:
 785    case GL_LUMINANCE_ALPHA:
 786    case GL_INTENSITY:
 787    case GL_RG:
 788    case GL_RGB:
 789    case GL_BGR:
 790    case GL_RGBA:
 791    case GL_BGRA:
 792    case GL_ABGR_EXT:
 793    case GL_RED_INTEGER_EXT:
 794    case GL_RG_INTEGER:
 795    case GL_GREEN_INTEGER_EXT:
 796    case GL_BLUE_INTEGER_EXT:
 797    case GL_ALPHA_INTEGER_EXT:
 798    case GL_RGB_INTEGER_EXT:
 799    case GL_RGBA_INTEGER_EXT:
 800    case GL_BGR_INTEGER_EXT:
 801    case GL_BGRA_INTEGER_EXT:
 802    case GL_LUMINANCE_INTEGER_EXT:
 803    case GL_LUMINANCE_ALPHA_INTEGER_EXT:
 804       if (reading) {
 805          /* about to read from a color buffer */
 806          const struct gl_renderbuffer *readBuf = fb->_ColorReadBuffer;
 807          if (!readBuf) {
 808             return GL_FALSE;
 809          }
 810          ASSERT(_mesa_get_format_bits(readBuf->Format, GL_RED_BITS) > 0 ||
 811                 _mesa_get_format_bits(readBuf->Format, GL_ALPHA_BITS) > 0 ||
 812                 _mesa_get_format_bits(readBuf->Format, GL_TEXTURE_LUMINANCE_SIZE) > 0 ||
 813                 _mesa_get_format_bits(readBuf->Format, GL_TEXTURE_INTENSITY_SIZE) > 0 ||
 814                 _mesa_get_format_bits(readBuf->Format, GL_INDEX_BITS) > 0);
 815       }
 816       else {
 817          /* about to draw to zero or more color buffers (none is OK) */
 818          return GL_TRUE;
 819       }
 820       break;
 821    case GL_DEPTH:
 822    case GL_DEPTH_COMPONENT:
 823       if (att[BUFFER_DEPTH].Type == GL_NONE) {
 824          return GL_FALSE;
 825       }
 826       break;
 827    case GL_STENCIL:
 828    case GL_STENCIL_INDEX:
 829       if (att[BUFFER_STENCIL].Type == GL_NONE) {
 830          return GL_FALSE;
 831       }
 832       break;
 833    case GL_DEPTH_STENCIL_EXT:
 834       if (att[BUFFER_DEPTH].Type == GL_NONE ||
 835           att[BUFFER_STENCIL].Type == GL_NONE) {
 836          return GL_FALSE;
 837       }
 838       break;
 839    default:
 840       _mesa_problem(ctx,
 841                     "Unexpected format 0x%x in renderbuffer_exists",
 842                     format);
 843       return GL_FALSE;
 844    }
 845
 846    /* OK */
 847    return GL_TRUE;
 848 }
 849
 850
 851 /**
 852  * Check if the renderbuffer for a read operation (glReadPixels, glCopyPixels,
 853  * glCopyTex[Sub]Image, etc) exists.
 854  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 855  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 856  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 857  */
 858 GLboolean
 859 _mesa_source_buffer_exists(struct gl_context *ctx, GLenum format)
 860 {
 861    return renderbuffer_exists(ctx, ctx->ReadBuffer, format, GL_TRUE);
 862 }
 863
 864
 865 /**
 866  * As above, but for drawing operations.
 867  */
 868 GLboolean
 869 _mesa_dest_buffer_exists(struct gl_context *ctx, GLenum format)
 870 {
 871    return renderbuffer_exists(ctx, ctx->DrawBuffer, format, GL_FALSE);
 872 }
 873
 874
 875 /**
 876  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_FORMAT_OES query.
 877  */
 878 GLenum
 879 _mesa_get_color_read_format(struct gl_context *ctx)
 880 {
 881    const GLenum data_type = _mesa_get_format_datatype(
 882                                ctx->ReadBuffer->_ColorReadBuffer->Format);
 883
 884    switch (ctx->ReadBuffer->_ColorReadBuffer->Format) {
 885    case MESA_FORMAT_ARGB8888:
 886       return GL_BGRA;
 887    case MESA_FORMAT_RGB565:
 888       return GL_BGR;
 889    default:
 890       if (data_type == GL_UNSIGNED_INT || data_type == GL_INT) {
 891          return GL_RGBA_INTEGER;
 892       } else {
 893          return GL_RGBA;
 894       }
 895    }
 896 }
 897
 898
 899 /**
 900  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_TYPE_OES query.
 901  */
 902 GLenum
 903 _mesa_get_color_read_type(struct gl_context *ctx)
 904 {
 905    const GLenum data_type = _mesa_get_format_datatype(
 906                                ctx->ReadBuffer->_ColorReadBuffer->Format);
 907
 908    switch (ctx->ReadBuffer->_ColorReadBuffer->Format) {
 909    case MESA_FORMAT_RGB565:
 910       return GL_UNSIGNED_SHORT_5_6_5_REV;
 911    default:
 912       break;
 913    }
 914
 915    switch (data_type) {
 916    case GL_SIGNED_NORMALIZED:
 917       return GL_BYTE;
 918    case GL_UNSIGNED_INT:
 919    case GL_INT:
 920    case GL_FLOAT:
 921       return data_type;
 922    case GL_UNSIGNED_NORMALIZED:
 923    default:
 924       return GL_UNSIGNED_BYTE;
 925    }
 926 }
 927
 928
 929 /**
 930  * Returns the read renderbuffer for the specified format.
 931  */
 932 struct gl_renderbuffer *
 933 _mesa_get_read_renderbuffer_for_format(const struct gl_context *ctx,
 934                                        GLenum format)
 935 {
 936    const struct gl_framebuffer *rfb = ctx->ReadBuffer;
 937
 938    if (_mesa_is_color_format(format)) {
 939       return rfb->Attachment[rfb->_ColorReadBufferIndex].Renderbuffer;
 940    } else if (_mesa_is_depth_format(format) ||
 941               _mesa_is_depthstencil_format(format)) {
 942       return rfb->Attachment[BUFFER_DEPTH].Renderbuffer;
 943    } else {
 944       return rfb->Attachment[BUFFER_STENCIL].Renderbuffer;
 945    }
 946 }
 947
 948
 949 /**
 950  * Print framebuffer info to stderr, for debugging.
 951  */
 952 void
 953 _mesa_print_framebuffer(const struct gl_framebuffer *fb)
 954 {
 955    GLuint i;
 956
 957    fprintf(stderr, "Mesa Framebuffer %u at %p\n", fb->Name, (void *) fb);
 958    fprintf(stderr, "  Size: %u x %u  Status: %s\n", fb->Width, fb->Height,
 959            _mesa_lookup_enum_by_nr(fb->_Status));
 960    fprintf(stderr, "  Attachments:\n");
 961
 962    for (i = 0; i < BUFFER_COUNT; i++) {
 963       const struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 964       if (att->Type == GL_TEXTURE) {
 965          const struct gl_texture_image *texImage = att->Renderbuffer->TexImage;
 966          fprintf(stderr,
 967                  "  %2d: Texture %u, level %u, face %u, slice %u, complete %d\n",
 968                  i, att->Texture->Name, att->TextureLevel, att->CubeMapFace,
 969                  att->Zoffset, att->Complete);
 970          fprintf(stderr, "       Size: %u x %u x %u  Format %s\n",
 971                  texImage->Width, texImage->Height, texImage->Depth,
 972                  _mesa_get_format_name(texImage->TexFormat));
 973       }
 974       else if (att->Type == GL_RENDERBUFFER) {
 975          fprintf(stderr, "  %2d: Renderbuffer %u, complete %d\n",
 976                  i, att->Renderbuffer->Name, att->Complete);
 977          fprintf(stderr, "       Size: %u x %u  Format %s\n",
 978                  att->Renderbuffer->Width, att->Renderbuffer->Height,
 979                  _mesa_get_format_name(att->Renderbuffer->Format));
 980       }
 981       else {
 982          fprintf(stderr, "  %2d: none\n", i);
 983       }
 984    }
 985 }