src/mesa/main/framebuffer.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  17  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  22  * 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 "blend.h"
  36 #include "buffers.h"
  37 #include "context.h"
  38 #include "enums.h"
  39 #include "formats.h"
  40 #include "macros.h"
  41 #include "mtypes.h"
  42 #include "fbobject.h"
  43 #include "framebuffer.h"
  44 #include "renderbuffer.h"
  45 #include "texobj.h"
  46 #include "glformats.h"
  47
  48
  49
  50 /**
  51  * Compute/set the _DepthMax field for the given framebuffer.
  52  * This value depends on the Z buffer resolution.
  53  */
  54 static void
  55 compute_depth_max(struct gl_framebuffer *fb)
  56 {
  57    if (fb->Visual.depthBits == 0) {
  58       /* Special case.  Even if we don't have a depth buffer we need
  59        * good values for DepthMax for Z vertex transformation purposes
  60        * and for per-fragment fog computation.
  61        */
  62       fb->_DepthMax = (1 << 16) - 1;
  63    }
  64    else if (fb->Visual.depthBits < 32) {
  65       fb->_DepthMax = (1 << fb->Visual.depthBits) - 1;
  66    }
  67    else {
  68       /* Special case since shift values greater than or equal to the
  69        * number of bits in the left hand expression's type are undefined.
  70        */
  71       fb->_DepthMax = 0xffffffff;
  72    }
  73    fb->_DepthMaxF = (GLfloat) fb->_DepthMax;
  74
  75    /* Minimum resolvable depth value, for polygon offset */
  76    fb->_MRD = (GLfloat)1.0 / fb->_DepthMaxF;
  77 }
  78
  79 /**
  80  * Create and initialize a gl_framebuffer object.
  81  * This is intended for creating _window_system_ framebuffers, not generic
  82  * framebuffer objects ala GL_EXT_framebuffer_object.
  83  *
  84  * \sa _mesa_new_framebuffer
  85  */
  86 struct gl_framebuffer *
  87 _mesa_create_framebuffer(const struct gl_config *visual)
  88 {
  89    struct gl_framebuffer *fb = CALLOC_STRUCT(gl_framebuffer);
  90    assert(visual);
  91    if (fb) {
  92       _mesa_initialize_window_framebuffer(fb, visual);
  93    }
  94    return fb;
  95 }
  96
  97
  98 /**
  99  * Allocate a new gl_framebuffer object.
 100  * This is the default function for ctx->Driver.NewFramebuffer().
 101  * This is for allocating user-created framebuffers, not window-system
 102  * framebuffers!
 103  * \sa _mesa_create_framebuffer
 104  */
 105 struct gl_framebuffer *
 106 _mesa_new_framebuffer(struct gl_context *ctx, GLuint name)
 107 {
 108    struct gl_framebuffer *fb;
 109    (void) ctx;
 110    assert(name != 0);
 111    fb = CALLOC_STRUCT(gl_framebuffer);
 112    if (fb) {
 113       _mesa_initialize_user_framebuffer(fb, name);
 114    }
 115    return fb;
 116 }
 117
 118
 119 /**
 120  * Initialize a gl_framebuffer object.  Typically used to initialize
 121  * window system-created framebuffers, not user-created framebuffers.
 122  * \sa _mesa_initialize_user_framebuffer
 123  */
 124 void
 125 _mesa_initialize_window_framebuffer(struct gl_framebuffer *fb,
 126                                      const struct gl_config *visual)
 127 {
 128    assert(fb);
 129    assert(visual);
 130
 131    memset(fb, 0, sizeof(struct gl_framebuffer));
 132
 133    _glthread_INIT_MUTEX(fb->Mutex);
 134
 135    fb->RefCount = 1;
 136
 137    /* save the visual */
 138    fb->Visual = *visual;
 139
 140    /* Init read/draw renderbuffer state */
 141    if (visual->doubleBufferMode) {
 142       fb->_NumColorDrawBuffers = 1;
 143       fb->ColorDrawBuffer[0] = GL_BACK;
 144       fb->_ColorDrawBufferIndexes[0] = BUFFER_BACK_LEFT;
 145       fb->ColorReadBuffer = GL_BACK;
 146       fb->_ColorReadBufferIndex = BUFFER_BACK_LEFT;
 147    }
 148    else {
 149       fb->_NumColorDrawBuffers = 1;
 150       fb->ColorDrawBuffer[0] = GL_FRONT;
 151       fb->_ColorDrawBufferIndexes[0] = BUFFER_FRONT_LEFT;
 152       fb->ColorReadBuffer = GL_FRONT;
 153       fb->_ColorReadBufferIndex = BUFFER_FRONT_LEFT;
 154    }
 155
 156    fb->Delete = _mesa_destroy_framebuffer;
 157    fb->_Status = GL_FRAMEBUFFER_COMPLETE_EXT;
 158    fb->_AllColorBuffersFixedPoint = !visual->floatMode;
 159    fb->_HasSNormOrFloatColorBuffer = visual->floatMode;
 160
 161    compute_depth_max(fb);
 162 }
 163
 164
 165 /**
 166  * Initialize a user-created gl_framebuffer object.
 167  * \sa _mesa_initialize_window_framebuffer
 168  */
 169 void
 170 _mesa_initialize_user_framebuffer(struct gl_framebuffer *fb, GLuint name)
 171 {
 172    assert(fb);
 173    assert(name);
 174
 175    memset(fb, 0, sizeof(struct gl_framebuffer));
 176
 177    fb->Name = name;
 178    fb->RefCount = 1;
 179    fb->_NumColorDrawBuffers = 1;
 180    fb->ColorDrawBuffer[0] = GL_COLOR_ATTACHMENT0_EXT;
 181    fb->_ColorDrawBufferIndexes[0] = BUFFER_COLOR0;
 182    fb->ColorReadBuffer = GL_COLOR_ATTACHMENT0_EXT;
 183    fb->_ColorReadBufferIndex = BUFFER_COLOR0;
 184    fb->Delete = _mesa_destroy_framebuffer;
 185    _glthread_INIT_MUTEX(fb->Mutex);
 186 }
 187
 188
 189 /**
 190  * Deallocate buffer and everything attached to it.
 191  * Typically called via the gl_framebuffer->Delete() method.
 192  */
 193 void
 194 _mesa_destroy_framebuffer(struct gl_framebuffer *fb)
 195 {
 196    if (fb) {
 197       _mesa_free_framebuffer_data(fb);
 198       free(fb);
 199    }
 200 }
 201
 202
 203 /**
 204  * Free all the data hanging off the given gl_framebuffer, but don't free
 205  * the gl_framebuffer object itself.
 206  */
 207 void
 208 _mesa_free_framebuffer_data(struct gl_framebuffer *fb)
 209 {
 210    GLuint i;
 211
 212    assert(fb);
 213    assert(fb->RefCount == 0);
 214
 215    _glthread_DESTROY_MUTEX(fb->Mutex);
 216
 217    for (i = 0; i < BUFFER_COUNT; i++) {
 218       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 219       if (att->Renderbuffer) {
 220          _mesa_reference_renderbuffer(&att->Renderbuffer, NULL);
 221       }
 222       if (att->Texture) {
 223          _mesa_reference_texobj(&att->Texture, NULL);
 224       }
 225       ASSERT(!att->Renderbuffer);
 226       ASSERT(!att->Texture);
 227       att->Type = GL_NONE;
 228    }
 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    /* Can only resize win-sys framebuffer objects */
 289    assert(_mesa_is_winsys_fbo(fb));
 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    FLUSH_VERTICES(ctx, 0);
 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(_mesa_is_winsys_fbo(buffer));
 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(_mesa_is_winsys_fbo(buffer));
 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(_mesa_is_user_fbo(fb));
 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 (_mesa_is_user_fbo(buffer)) {
 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          /* Grab samples and sampleBuffers from any attachment point (assuming
 525           * the framebuffer is complete, we'll get the same answer from all
 526           * attachments).
 527           */
 528          fb->Visual.samples = rb->NumSamples;
 529          fb->Visual.sampleBuffers = rb->NumSamples > 0 ? 1 : 0;
 530
 531          if (_mesa_is_legal_color_format(ctx, baseFormat)) {
 532             fb->Visual.redBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 533             fb->Visual.greenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 534             fb->Visual.blueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 535             fb->Visual.alphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 536             fb->Visual.rgbBits = fb->Visual.redBits
 537                + fb->Visual.greenBits + fb->Visual.blueBits;
 538             if (_mesa_get_format_color_encoding(fmt) == GL_SRGB)
 539                 fb->Visual.sRGBCapable = ctx->Extensions.EXT_framebuffer_sRGB;
 540             break;
 541          }
 542       }
 543    }
 544
 545    fb->Visual.floatMode = GL_FALSE;
 546    for (i = 0; i < BUFFER_COUNT; i++) {
 547       if (fb->Attachment[i].Renderbuffer) {
 548          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 549          const gl_format fmt = rb->Format;
 550
 551          if (_mesa_get_format_datatype(fmt) == GL_FLOAT) {
 552             fb->Visual.floatMode = GL_TRUE;
 553             break;
 554          }
 555       }
 556    }
 557
 558    if (fb->Attachment[BUFFER_DEPTH].Renderbuffer) {
 559       const struct gl_renderbuffer *rb =
 560          fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 561       const gl_format fmt = rb->Format;
 562       fb->Visual.haveDepthBuffer = GL_TRUE;
 563       fb->Visual.depthBits = _mesa_get_format_bits(fmt, GL_DEPTH_BITS);
 564    }
 565
 566    if (fb->Attachment[BUFFER_STENCIL].Renderbuffer) {
 567       const struct gl_renderbuffer *rb =
 568          fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 569       const gl_format fmt = rb->Format;
 570       fb->Visual.haveStencilBuffer = GL_TRUE;
 571       fb->Visual.stencilBits = _mesa_get_format_bits(fmt, GL_STENCIL_BITS);
 572    }
 573
 574    if (fb->Attachment[BUFFER_ACCUM].Renderbuffer) {
 575       const struct gl_renderbuffer *rb =
 576          fb->Attachment[BUFFER_ACCUM].Renderbuffer;
 577       const gl_format fmt = rb->Format;
 578       fb->Visual.haveAccumBuffer = GL_TRUE;
 579       fb->Visual.accumRedBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 580       fb->Visual.accumGreenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 581       fb->Visual.accumBlueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 582       fb->Visual.accumAlphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 583    }
 584
 585    compute_depth_max(fb);
 586 }
 587
 588
 589 /*
 590  * Example DrawBuffers scenarios:
 591  *
 592  * 1. glDrawBuffer(GL_FRONT_AND_BACK), fixed-func or shader writes to
 593  * "gl_FragColor" or program writes to the "result.color" register:
 594  *
 595  *   fragment color output   renderbuffer
 596  *   ---------------------   ---------------
 597  *   color[0]                Front, Back
 598  *
 599  *
 600  * 2. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]), shader writes to
 601  * gl_FragData[i] or program writes to result.color[i] registers:
 602  *
 603  *   fragment color output   renderbuffer
 604  *   ---------------------   ---------------
 605  *   color[0]                Front
 606  *   color[1]                Aux0
 607  *   color[3]                Aux1
 608  *
 609  *
 610  * 3. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]) and shader writes to
 611  * gl_FragColor, or fixed function:
 612  *
 613  *   fragment color output   renderbuffer
 614  *   ---------------------   ---------------
 615  *   color[0]                Front, Aux0, Aux1
 616  *
 617  *
 618  * In either case, the list of renderbuffers is stored in the
 619  * framebuffer->_ColorDrawBuffers[] array and
 620  * framebuffer->_NumColorDrawBuffers indicates the number of buffers.
 621  * The renderer (like swrast) has to look at the current fragment shader
 622  * to see if it writes to gl_FragColor vs. gl_FragData[i] to determine
 623  * how to map color outputs to renderbuffers.
 624  *
 625  * Note that these two calls are equivalent (for fixed function fragment
 626  * shading anyway):
 627  *   a)  glDrawBuffer(GL_FRONT_AND_BACK);  (assuming non-stereo framebuffer)
 628  *   b)  glDrawBuffers(2, [GL_FRONT_LEFT, GL_BACK_LEFT]);
 629  */
 630
 631
 632
 633
 634 /**
 635  * Update the (derived) list of color drawing renderbuffer pointers.
 636  * Later, when we're rendering we'll loop from 0 to _NumColorDrawBuffers
 637  * writing colors.
 638  */
 639 static void
 640 update_color_draw_buffers(struct gl_context *ctx, struct gl_framebuffer *fb)
 641 {
 642    GLuint output;
 643
 644    /* set 0th buffer to NULL now in case _NumColorDrawBuffers is zero */
 645    fb->_ColorDrawBuffers[0] = NULL;
 646
 647    for (output = 0; output < fb->_NumColorDrawBuffers; output++) {
 648       GLint buf = fb->_ColorDrawBufferIndexes[output];
 649       if (buf >= 0) {
 650          fb->_ColorDrawBuffers[output] = fb->Attachment[buf].Renderbuffer;
 651       }
 652       else {
 653          fb->_ColorDrawBuffers[output] = NULL;
 654       }
 655    }
 656 }
 657
 658
 659 /**
 660  * Update the (derived) color read renderbuffer pointer.
 661  * Unlike the DrawBuffer, we can only read from one (or zero) color buffers.
 662  */
 663 static void
 664 update_color_read_buffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 665 {
 666    (void) ctx;
 667    if (fb->_ColorReadBufferIndex == -1 ||
 668        fb->DeletePending ||
 669        fb->Width == 0 ||
 670        fb->Height == 0) {
 671       fb->_ColorReadBuffer = NULL; /* legal! */
 672    }
 673    else {
 674       ASSERT(fb->_ColorReadBufferIndex >= 0);
 675       ASSERT(fb->_ColorReadBufferIndex < BUFFER_COUNT);
 676       fb->_ColorReadBuffer
 677          = fb->Attachment[fb->_ColorReadBufferIndex].Renderbuffer;
 678    }
 679 }
 680
 681
 682 /**
 683  * Update a gl_framebuffer's derived state.
 684  *
 685  * Specifically, update these framebuffer fields:
 686  *    _ColorDrawBuffers
 687  *    _NumColorDrawBuffers
 688  *    _ColorReadBuffer
 689  *
 690  * If the framebuffer is user-created, make sure it's complete.
 691  *
 692  * The following functions (at least) can effect framebuffer state:
 693  * glReadBuffer, glDrawBuffer, glDrawBuffersARB, glFramebufferRenderbufferEXT,
 694  * glRenderbufferStorageEXT.
 695  */
 696 static void
 697 update_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 698 {
 699    if (_mesa_is_winsys_fbo(fb)) {
 700       /* This is a window-system framebuffer */
 701       /* Need to update the FB's GL_DRAW_BUFFER state to match the
 702        * context state (GL_READ_BUFFER too).
 703        */
 704       if (fb->ColorDrawBuffer[0] != ctx->Color.DrawBuffer[0]) {
 705          _mesa_drawbuffers(ctx, ctx->Const.MaxDrawBuffers,
 706                            ctx->Color.DrawBuffer, NULL);
 707       }
 708    }
 709    else {
 710       /* This is a user-created framebuffer.
 711        * Completeness only matters for user-created framebuffers.
 712        */
 713       if (fb->_Status != GL_FRAMEBUFFER_COMPLETE) {
 714          _mesa_test_framebuffer_completeness(ctx, fb);
 715       }
 716    }
 717
 718    /* Strictly speaking, we don't need to update the draw-state
 719     * if this FB is bound as ctx->ReadBuffer (and conversely, the
 720     * read-state if this FB is bound as ctx->DrawBuffer), but no
 721     * harm.
 722     */
 723    update_color_draw_buffers(ctx, fb);
 724    update_color_read_buffer(ctx, fb);
 725
 726    compute_depth_max(fb);
 727 }
 728
 729
 730 /**
 731  * Update state related to the current draw/read framebuffers.
 732  */
 733 void
 734 _mesa_update_framebuffer(struct gl_context *ctx)
 735 {
 736    struct gl_framebuffer *drawFb;
 737    struct gl_framebuffer *readFb;
 738
 739    assert(ctx);
 740    drawFb = ctx->DrawBuffer;
 741    readFb = ctx->ReadBuffer;
 742
 743    update_framebuffer(ctx, drawFb);
 744    if (readFb != drawFb)
 745       update_framebuffer(ctx, readFb);
 746
 747    _mesa_update_clamp_vertex_color(ctx);
 748    _mesa_update_clamp_fragment_color(ctx);
 749 }
 750
 751
 752 /**
 753  * Check if the renderbuffer for a read/draw operation exists.
 754  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 755  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 756  * \param reading  if TRUE, we're going to read from the buffer,
 757                    if FALSE, we're going to write to the buffer.
 758  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 759  */
 760 static GLboolean
 761 renderbuffer_exists(struct gl_context *ctx,
 762                     struct gl_framebuffer *fb,
 763                     GLenum format,
 764                     GLboolean reading)
 765 {
 766    const struct gl_renderbuffer_attachment *att = fb->Attachment;
 767
 768    /* If we don't know the framebuffer status, update it now */
 769    if (fb->_Status == 0) {
 770       _mesa_test_framebuffer_completeness(ctx, fb);
 771    }
 772
 773    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 774       return GL_FALSE;
 775    }
 776
 777    switch (format) {
 778    case GL_COLOR:
 779    case GL_RED:
 780    case GL_GREEN:
 781    case GL_BLUE:
 782    case GL_ALPHA:
 783    case GL_LUMINANCE:
 784    case GL_LUMINANCE_ALPHA:
 785    case GL_INTENSITY:
 786    case GL_RG:
 787    case GL_RGB:
 788    case GL_BGR:
 789    case GL_RGBA:
 790    case GL_BGRA:
 791    case GL_ABGR_EXT:
 792    case GL_RED_INTEGER_EXT:
 793    case GL_RG_INTEGER:
 794    case GL_GREEN_INTEGER_EXT:
 795    case GL_BLUE_INTEGER_EXT:
 796    case GL_ALPHA_INTEGER_EXT:
 797    case GL_RGB_INTEGER_EXT:
 798    case GL_RGBA_INTEGER_EXT:
 799    case GL_BGR_INTEGER_EXT:
 800    case GL_BGRA_INTEGER_EXT:
 801    case GL_LUMINANCE_INTEGER_EXT:
 802    case GL_LUMINANCE_ALPHA_INTEGER_EXT:
 803       if (reading) {
 804          /* about to read from a color buffer */
 805          const struct gl_renderbuffer *readBuf = fb->_ColorReadBuffer;
 806          if (!readBuf) {
 807             return GL_FALSE;
 808          }
 809          ASSERT(_mesa_get_format_bits(readBuf->Format, GL_RED_BITS) > 0 ||
 810                 _mesa_get_format_bits(readBuf->Format, GL_ALPHA_BITS) > 0 ||
 811                 _mesa_get_format_bits(readBuf->Format, GL_TEXTURE_LUMINANCE_SIZE) > 0 ||
 812                 _mesa_get_format_bits(readBuf->Format, GL_TEXTURE_INTENSITY_SIZE) > 0 ||
 813                 _mesa_get_format_bits(readBuf->Format, GL_INDEX_BITS) > 0);
 814       }
 815       else {
 816          /* about to draw to zero or more color buffers (none is OK) */
 817          return GL_TRUE;
 818       }
 819       break;
 820    case GL_DEPTH:
 821    case GL_DEPTH_COMPONENT:
 822       if (att[BUFFER_DEPTH].Type == GL_NONE) {
 823          return GL_FALSE;
 824       }
 825       break;
 826    case GL_STENCIL:
 827    case GL_STENCIL_INDEX:
 828       if (att[BUFFER_STENCIL].Type == GL_NONE) {
 829          return GL_FALSE;
 830       }
 831       break;
 832    case GL_DEPTH_STENCIL_EXT:
 833       if (att[BUFFER_DEPTH].Type == GL_NONE ||
 834           att[BUFFER_STENCIL].Type == GL_NONE) {
 835          return GL_FALSE;
 836       }
 837       break;
 838    default:
 839       _mesa_problem(ctx,
 840                     "Unexpected format 0x%x in renderbuffer_exists",
 841                     format);
 842       return GL_FALSE;
 843    }
 844
 845    /* OK */
 846    return GL_TRUE;
 847 }
 848
 849
 850 /**
 851  * Check if the renderbuffer for a read operation (glReadPixels, glCopyPixels,
 852  * glCopyTex[Sub]Image, etc) exists.
 853  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 854  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 855  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 856  */
 857 GLboolean
 858 _mesa_source_buffer_exists(struct gl_context *ctx, GLenum format)
 859 {
 860    return renderbuffer_exists(ctx, ctx->ReadBuffer, format, GL_TRUE);
 861 }
 862
 863
 864 /**
 865  * As above, but for drawing operations.
 866  */
 867 GLboolean
 868 _mesa_dest_buffer_exists(struct gl_context *ctx, GLenum format)
 869 {
 870    return renderbuffer_exists(ctx, ctx->DrawBuffer, format, GL_FALSE);
 871 }
 872
 873
 874 /**
 875  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_FORMAT_OES query.
 876  */
 877 GLenum
 878 _mesa_get_color_read_format(struct gl_context *ctx)
 879 {
 880    if (!ctx->ReadBuffer || !ctx->ReadBuffer->_ColorReadBuffer) {
 881       /* The spec is unclear how to handle this case, but NVIDIA's
 882        * driver generates GL_INVALID_OPERATION.
 883        */
 884       _mesa_error(ctx, GL_INVALID_OPERATION,
 885                   "glGetIntegerv(GL_IMPLEMENTATION_COLOR_READ_FORMAT: "
 886                   "no GL_READ_BUFFER)");
 887       return GL_NONE;
 888    }
 889    else {
 890       const GLenum format = ctx->ReadBuffer->_ColorReadBuffer->Format;
 891       const GLenum data_type = _mesa_get_format_datatype(format);
 892
 893       if (format == MESA_FORMAT_ARGB8888)
 894          return GL_BGRA;
 895       else if (format == MESA_FORMAT_RGB565)
 896          return GL_BGR;
 897
 898       switch (data_type) {
 899       case GL_UNSIGNED_INT:
 900       case GL_INT:
 901          return GL_RGBA_INTEGER;
 902       default:
 903          return GL_RGBA;
 904       }
 905    }
 906 }
 907
 908
 909 /**
 910  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_TYPE_OES query.
 911  */
 912 GLenum
 913 _mesa_get_color_read_type(struct gl_context *ctx)
 914 {
 915    if (!ctx->ReadBuffer || !ctx->ReadBuffer->_ColorReadBuffer) {
 916       /* The spec is unclear how to handle this case, but NVIDIA's
 917        * driver generates GL_INVALID_OPERATION.
 918        */
 919       _mesa_error(ctx, GL_INVALID_OPERATION,
 920                   "glGetIntegerv(GL_IMPLEMENTATION_COLOR_READ_TYPE: "
 921                   "no GL_READ_BUFFER)");
 922       return GL_NONE;
 923    }
 924    else {
 925       const GLenum format = ctx->ReadBuffer->_ColorReadBuffer->Format;
 926       const GLenum data_type = _mesa_get_format_datatype(format);
 927
 928       if (format == MESA_FORMAT_RGB565)
 929          return GL_UNSIGNED_SHORT_5_6_5_REV;
 930
 931       switch (data_type) {
 932       case GL_SIGNED_NORMALIZED:
 933          return GL_BYTE;
 934       case GL_UNSIGNED_INT:
 935       case GL_INT:
 936       case GL_FLOAT:
 937          return data_type;
 938       case GL_UNSIGNED_NORMALIZED:
 939       default:
 940          return GL_UNSIGNED_BYTE;
 941       }
 942    }
 943 }
 944
 945
 946 /**
 947  * Returns the read renderbuffer for the specified format.
 948  */
 949 struct gl_renderbuffer *
 950 _mesa_get_read_renderbuffer_for_format(const struct gl_context *ctx,
 951                                        GLenum format)
 952 {
 953    const struct gl_framebuffer *rfb = ctx->ReadBuffer;
 954
 955    if (_mesa_is_color_format(format)) {
 956       return rfb->Attachment[rfb->_ColorReadBufferIndex].Renderbuffer;
 957    } else if (_mesa_is_depth_format(format) ||
 958               _mesa_is_depthstencil_format(format)) {
 959       return rfb->Attachment[BUFFER_DEPTH].Renderbuffer;
 960    } else {
 961       return rfb->Attachment[BUFFER_STENCIL].Renderbuffer;
 962    }
 963 }
 964
 965
 966 /**
 967  * Print framebuffer info to stderr, for debugging.
 968  */
 969 void
 970 _mesa_print_framebuffer(const struct gl_framebuffer *fb)
 971 {
 972    GLuint i;
 973
 974    fprintf(stderr, "Mesa Framebuffer %u at %p\n", fb->Name, (void *) fb);
 975    fprintf(stderr, "  Size: %u x %u  Status: %s\n", fb->Width, fb->Height,
 976            _mesa_lookup_enum_by_nr(fb->_Status));
 977    fprintf(stderr, "  Attachments:\n");
 978
 979    for (i = 0; i < BUFFER_COUNT; i++) {
 980       const struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 981       if (att->Type == GL_TEXTURE) {
 982          const struct gl_texture_image *texImage = att->Renderbuffer->TexImage;
 983          fprintf(stderr,
 984                  "  %2d: Texture %u, level %u, face %u, slice %u, complete %d\n",
 985                  i, att->Texture->Name, att->TextureLevel, att->CubeMapFace,
 986                  att->Zoffset, att->Complete);
 987          fprintf(stderr, "       Size: %u x %u x %u  Format %s\n",
 988                  texImage->Width, texImage->Height, texImage->Depth,
 989                  _mesa_get_format_name(texImage->TexFormat));
 990       }
 991       else if (att->Type == GL_RENDERBUFFER) {
 992          fprintf(stderr, "  %2d: Renderbuffer %u, complete %d\n",
 993                  i, att->Renderbuffer->Name, att->Complete);
 994          fprintf(stderr, "       Size: %u x %u  Format %s\n",
 995                  att->Renderbuffer->Width, att->Renderbuffer->Height,
 996                  _mesa_get_format_name(att->Renderbuffer->Format));
 997       }
 998       else {
 999          fprintf(stderr, "  %2d: none\n", i);
1000       }
1001    }
1002 }