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->Label);
 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  * Examine all the framebuffer's renderbuffers to update the Width/Height
 325  * fields of the framebuffer.  If we have renderbuffers with different
 326  * sizes, set the framebuffer's width and height to the min size.
 327  * Note: this is only intended for user-created framebuffers, not
 328  * window-system framebuffes.
 329  */
 330 static void
 331 update_framebuffer_size(struct gl_context *ctx, struct gl_framebuffer *fb)
 332 {
 333    GLuint minWidth = ~0, minHeight = ~0;
 334    GLuint i;
 335
 336    /* user-created framebuffers only */
 337    assert(_mesa_is_user_fbo(fb));
 338
 339    for (i = 0; i < BUFFER_COUNT; i++) {
 340       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 341       const struct gl_renderbuffer *rb = att->Renderbuffer;
 342       if (rb) {
 343          minWidth = MIN2(minWidth, rb->Width);
 344          minHeight = MIN2(minHeight, rb->Height);
 345       }
 346    }
 347
 348    if (minWidth != ~0) {
 349       fb->Width = minWidth;
 350       fb->Height = minHeight;
 351    }
 352    else {
 353       fb->Width = 0;
 354       fb->Height = 0;
 355    }
 356 }
 357
 358
 359 /**
 360  * Update the context's current drawing buffer's Xmin, Xmax, Ymin, Ymax fields.
 361  * These values are computed from the buffer's width and height and
 362  * the scissor box, if it's enabled.
 363  * \param ctx  the GL context.
 364  */
 365 void
 366 _mesa_update_draw_buffer_bounds(struct gl_context *ctx)
 367 {
 368    struct gl_framebuffer *buffer = ctx->DrawBuffer;
 369
 370    if (!buffer)
 371       return;
 372
 373    if (_mesa_is_user_fbo(buffer)) {
 374       /* user-created framebuffer size depends on the renderbuffers */
 375       update_framebuffer_size(ctx, buffer);
 376    }
 377
 378    buffer->_Xmin = 0;
 379    buffer->_Ymin = 0;
 380    buffer->_Xmax = buffer->Width;
 381    buffer->_Ymax = buffer->Height;
 382
 383    /* Default to the first scissor as that's always valid */
 384    if (ctx->Scissor.EnableFlags & 1) {
 385       if (ctx->Scissor.ScissorArray[0].X > buffer->_Xmin) {
 386          buffer->_Xmin = ctx->Scissor.ScissorArray[0].X;
 387       }
 388       if (ctx->Scissor.ScissorArray[0].Y > buffer->_Ymin) {
 389          buffer->_Ymin = ctx->Scissor.ScissorArray[0].Y;
 390       }
 391       if (ctx->Scissor.ScissorArray[0].X + ctx->Scissor.ScissorArray[0].Width < buffer->_Xmax) {
 392          buffer->_Xmax = ctx->Scissor.ScissorArray[0].X + ctx->Scissor.ScissorArray[0].Width;
 393       }
 394       if (ctx->Scissor.ScissorArray[0].Y + ctx->Scissor.ScissorArray[0].Height < buffer->_Ymax) {
 395          buffer->_Ymax = ctx->Scissor.ScissorArray[0].Y + ctx->Scissor.ScissorArray[0].Height;
 396       }
 397       /* finally, check for empty region */
 398       if (buffer->_Xmin > buffer->_Xmax) {
 399          buffer->_Xmin = buffer->_Xmax;
 400       }
 401       if (buffer->_Ymin > buffer->_Ymax) {
 402          buffer->_Ymin = buffer->_Ymax;
 403       }
 404    }
 405
 406    ASSERT(buffer->_Xmin <= buffer->_Xmax);
 407    ASSERT(buffer->_Ymin <= buffer->_Ymax);
 408 }
 409
 410
 411 /**
 412  * The glGet queries of the framebuffer red/green/blue size, stencil size,
 413  * etc. are satisfied by the fields of ctx->DrawBuffer->Visual.  These can
 414  * change depending on the renderbuffer bindings.  This function updates
 415  * the given framebuffer's Visual from the current renderbuffer bindings.
 416  *
 417  * This may apply to user-created framebuffers or window system framebuffers.
 418  *
 419  * Also note: ctx->DrawBuffer->Visual.depthBits might not equal
 420  * ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer.DepthBits.
 421  * The former one is used to convert floating point depth values into
 422  * integer Z values.
 423  */
 424 void
 425 _mesa_update_framebuffer_visual(struct gl_context *ctx,
 426                                 struct gl_framebuffer *fb)
 427 {
 428    GLuint i;
 429
 430    memset(&fb->Visual, 0, sizeof(fb->Visual));
 431    fb->Visual.rgbMode = GL_TRUE; /* assume this */
 432
 433 #if 0 /* this _might_ be needed */
 434    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 435       /* leave visual fields zero'd */
 436       return;
 437    }
 438 #endif
 439
 440    /* find first RGB renderbuffer */
 441    for (i = 0; i < BUFFER_COUNT; i++) {
 442       if (fb->Attachment[i].Renderbuffer) {
 443          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 444          const GLenum baseFormat = _mesa_get_format_base_format(rb->Format);
 445          const gl_format fmt = rb->Format;
 446
 447          /* Grab samples and sampleBuffers from any attachment point (assuming
 448           * the framebuffer is complete, we'll get the same answer from all
 449           * attachments).
 450           */
 451          fb->Visual.samples = rb->NumSamples;
 452          fb->Visual.sampleBuffers = rb->NumSamples > 0 ? 1 : 0;
 453
 454          if (_mesa_is_legal_color_format(ctx, baseFormat)) {
 455             fb->Visual.redBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 456             fb->Visual.greenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 457             fb->Visual.blueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 458             fb->Visual.alphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 459             fb->Visual.rgbBits = fb->Visual.redBits
 460                + fb->Visual.greenBits + fb->Visual.blueBits;
 461             if (_mesa_get_format_color_encoding(fmt) == GL_SRGB)
 462                 fb->Visual.sRGBCapable = ctx->Extensions.EXT_framebuffer_sRGB;
 463             break;
 464          }
 465       }
 466    }
 467
 468    fb->Visual.floatMode = GL_FALSE;
 469    for (i = 0; i < BUFFER_COUNT; i++) {
 470       if (fb->Attachment[i].Renderbuffer) {
 471          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 472          const gl_format fmt = rb->Format;
 473
 474          if (_mesa_get_format_datatype(fmt) == GL_FLOAT) {
 475             fb->Visual.floatMode = GL_TRUE;
 476             break;
 477          }
 478       }
 479    }
 480
 481    if (fb->Attachment[BUFFER_DEPTH].Renderbuffer) {
 482       const struct gl_renderbuffer *rb =
 483          fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 484       const gl_format fmt = rb->Format;
 485       fb->Visual.haveDepthBuffer = GL_TRUE;
 486       fb->Visual.depthBits = _mesa_get_format_bits(fmt, GL_DEPTH_BITS);
 487    }
 488
 489    if (fb->Attachment[BUFFER_STENCIL].Renderbuffer) {
 490       const struct gl_renderbuffer *rb =
 491          fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 492       const gl_format fmt = rb->Format;
 493       fb->Visual.haveStencilBuffer = GL_TRUE;
 494       fb->Visual.stencilBits = _mesa_get_format_bits(fmt, GL_STENCIL_BITS);
 495    }
 496
 497    if (fb->Attachment[BUFFER_ACCUM].Renderbuffer) {
 498       const struct gl_renderbuffer *rb =
 499          fb->Attachment[BUFFER_ACCUM].Renderbuffer;
 500       const gl_format fmt = rb->Format;
 501       fb->Visual.haveAccumBuffer = GL_TRUE;
 502       fb->Visual.accumRedBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 503       fb->Visual.accumGreenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 504       fb->Visual.accumBlueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 505       fb->Visual.accumAlphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 506    }
 507
 508    compute_depth_max(fb);
 509 }
 510
 511
 512 /*
 513  * Example DrawBuffers scenarios:
 514  *
 515  * 1. glDrawBuffer(GL_FRONT_AND_BACK), fixed-func or shader writes to
 516  * "gl_FragColor" or program writes to the "result.color" register:
 517  *
 518  *   fragment color output   renderbuffer
 519  *   ---------------------   ---------------
 520  *   color[0]                Front, Back
 521  *
 522  *
 523  * 2. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]), shader writes to
 524  * gl_FragData[i] or program writes to result.color[i] registers:
 525  *
 526  *   fragment color output   renderbuffer
 527  *   ---------------------   ---------------
 528  *   color[0]                Front
 529  *   color[1]                Aux0
 530  *   color[3]                Aux1
 531  *
 532  *
 533  * 3. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]) and shader writes to
 534  * gl_FragColor, or fixed function:
 535  *
 536  *   fragment color output   renderbuffer
 537  *   ---------------------   ---------------
 538  *   color[0]                Front, Aux0, Aux1
 539  *
 540  *
 541  * In either case, the list of renderbuffers is stored in the
 542  * framebuffer->_ColorDrawBuffers[] array and
 543  * framebuffer->_NumColorDrawBuffers indicates the number of buffers.
 544  * The renderer (like swrast) has to look at the current fragment shader
 545  * to see if it writes to gl_FragColor vs. gl_FragData[i] to determine
 546  * how to map color outputs to renderbuffers.
 547  *
 548  * Note that these two calls are equivalent (for fixed function fragment
 549  * shading anyway):
 550  *   a)  glDrawBuffer(GL_FRONT_AND_BACK);  (assuming non-stereo framebuffer)
 551  *   b)  glDrawBuffers(2, [GL_FRONT_LEFT, GL_BACK_LEFT]);
 552  */
 553
 554
 555
 556
 557 /**
 558  * Update the (derived) list of color drawing renderbuffer pointers.
 559  * Later, when we're rendering we'll loop from 0 to _NumColorDrawBuffers
 560  * writing colors.
 561  */
 562 static void
 563 update_color_draw_buffers(struct gl_context *ctx, struct gl_framebuffer *fb)
 564 {
 565    GLuint output;
 566
 567    /* set 0th buffer to NULL now in case _NumColorDrawBuffers is zero */
 568    fb->_ColorDrawBuffers[0] = NULL;
 569
 570    for (output = 0; output < fb->_NumColorDrawBuffers; output++) {
 571       GLint buf = fb->_ColorDrawBufferIndexes[output];
 572       if (buf >= 0) {
 573          fb->_ColorDrawBuffers[output] = fb->Attachment[buf].Renderbuffer;
 574       }
 575       else {
 576          fb->_ColorDrawBuffers[output] = NULL;
 577       }
 578    }
 579 }
 580
 581
 582 /**
 583  * Update the (derived) color read renderbuffer pointer.
 584  * Unlike the DrawBuffer, we can only read from one (or zero) color buffers.
 585  */
 586 static void
 587 update_color_read_buffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 588 {
 589    (void) ctx;
 590    if (fb->_ColorReadBufferIndex == -1 ||
 591        fb->DeletePending ||
 592        fb->Width == 0 ||
 593        fb->Height == 0) {
 594       fb->_ColorReadBuffer = NULL; /* legal! */
 595    }
 596    else {
 597       ASSERT(fb->_ColorReadBufferIndex >= 0);
 598       ASSERT(fb->_ColorReadBufferIndex < BUFFER_COUNT);
 599       fb->_ColorReadBuffer
 600          = fb->Attachment[fb->_ColorReadBufferIndex].Renderbuffer;
 601    }
 602 }
 603
 604
 605 /**
 606  * Update a gl_framebuffer's derived state.
 607  *
 608  * Specifically, update these framebuffer fields:
 609  *    _ColorDrawBuffers
 610  *    _NumColorDrawBuffers
 611  *    _ColorReadBuffer
 612  *
 613  * If the framebuffer is user-created, make sure it's complete.
 614  *
 615  * The following functions (at least) can effect framebuffer state:
 616  * glReadBuffer, glDrawBuffer, glDrawBuffersARB, glFramebufferRenderbufferEXT,
 617  * glRenderbufferStorageEXT.
 618  */
 619 static void
 620 update_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 621 {
 622    if (_mesa_is_winsys_fbo(fb)) {
 623       /* This is a window-system framebuffer */
 624       /* Need to update the FB's GL_DRAW_BUFFER state to match the
 625        * context state (GL_READ_BUFFER too).
 626        */
 627       if (fb->ColorDrawBuffer[0] != ctx->Color.DrawBuffer[0]) {
 628          _mesa_drawbuffers(ctx, ctx->Const.MaxDrawBuffers,
 629                            ctx->Color.DrawBuffer, NULL);
 630       }
 631    }
 632    else {
 633       /* This is a user-created framebuffer.
 634        * Completeness only matters for user-created framebuffers.
 635        */
 636       if (fb->_Status != GL_FRAMEBUFFER_COMPLETE) {
 637          _mesa_test_framebuffer_completeness(ctx, fb);
 638       }
 639    }
 640
 641    /* Strictly speaking, we don't need to update the draw-state
 642     * if this FB is bound as ctx->ReadBuffer (and conversely, the
 643     * read-state if this FB is bound as ctx->DrawBuffer), but no
 644     * harm.
 645     */
 646    update_color_draw_buffers(ctx, fb);
 647    update_color_read_buffer(ctx, fb);
 648
 649    compute_depth_max(fb);
 650 }
 651
 652
 653 /**
 654  * Update state related to the current draw/read framebuffers.
 655  */
 656 void
 657 _mesa_update_framebuffer(struct gl_context *ctx)
 658 {
 659    struct gl_framebuffer *drawFb;
 660    struct gl_framebuffer *readFb;
 661
 662    assert(ctx);
 663    drawFb = ctx->DrawBuffer;
 664    readFb = ctx->ReadBuffer;
 665
 666    update_framebuffer(ctx, drawFb);
 667    if (readFb != drawFb)
 668       update_framebuffer(ctx, readFb);
 669
 670    _mesa_update_clamp_vertex_color(ctx);
 671    _mesa_update_clamp_fragment_color(ctx);
 672 }
 673
 674
 675 /**
 676  * Check if the renderbuffer for a read/draw operation exists.
 677  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 678  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 679  * \param reading  if TRUE, we're going to read from the buffer,
 680                    if FALSE, we're going to write to the buffer.
 681  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 682  */
 683 static GLboolean
 684 renderbuffer_exists(struct gl_context *ctx,
 685                     struct gl_framebuffer *fb,
 686                     GLenum format,
 687                     GLboolean reading)
 688 {
 689    const struct gl_renderbuffer_attachment *att = fb->Attachment;
 690
 691    /* If we don't know the framebuffer status, update it now */
 692    if (fb->_Status == 0) {
 693       _mesa_test_framebuffer_completeness(ctx, fb);
 694    }
 695
 696    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 697       return GL_FALSE;
 698    }
 699
 700    switch (format) {
 701    case GL_COLOR:
 702    case GL_RED:
 703    case GL_GREEN:
 704    case GL_BLUE:
 705    case GL_ALPHA:
 706    case GL_LUMINANCE:
 707    case GL_LUMINANCE_ALPHA:
 708    case GL_INTENSITY:
 709    case GL_RG:
 710    case GL_RGB:
 711    case GL_BGR:
 712    case GL_RGBA:
 713    case GL_BGRA:
 714    case GL_ABGR_EXT:
 715    case GL_RED_INTEGER_EXT:
 716    case GL_RG_INTEGER:
 717    case GL_GREEN_INTEGER_EXT:
 718    case GL_BLUE_INTEGER_EXT:
 719    case GL_ALPHA_INTEGER_EXT:
 720    case GL_RGB_INTEGER_EXT:
 721    case GL_RGBA_INTEGER_EXT:
 722    case GL_BGR_INTEGER_EXT:
 723    case GL_BGRA_INTEGER_EXT:
 724    case GL_LUMINANCE_INTEGER_EXT:
 725    case GL_LUMINANCE_ALPHA_INTEGER_EXT:
 726       if (reading) {
 727          /* about to read from a color buffer */
 728          const struct gl_renderbuffer *readBuf = fb->_ColorReadBuffer;
 729          if (!readBuf) {
 730             return GL_FALSE;
 731          }
 732          ASSERT(_mesa_get_format_bits(readBuf->Format, GL_RED_BITS) > 0 ||
 733                 _mesa_get_format_bits(readBuf->Format, GL_ALPHA_BITS) > 0 ||
 734                 _mesa_get_format_bits(readBuf->Format, GL_TEXTURE_LUMINANCE_SIZE) > 0 ||
 735                 _mesa_get_format_bits(readBuf->Format, GL_TEXTURE_INTENSITY_SIZE) > 0 ||
 736                 _mesa_get_format_bits(readBuf->Format, GL_INDEX_BITS) > 0);
 737       }
 738       else {
 739          /* about to draw to zero or more color buffers (none is OK) */
 740          return GL_TRUE;
 741       }
 742       break;
 743    case GL_DEPTH:
 744    case GL_DEPTH_COMPONENT:
 745       if (att[BUFFER_DEPTH].Type == GL_NONE) {
 746          return GL_FALSE;
 747       }
 748       break;
 749    case GL_STENCIL:
 750    case GL_STENCIL_INDEX:
 751       if (att[BUFFER_STENCIL].Type == GL_NONE) {
 752          return GL_FALSE;
 753       }
 754       break;
 755    case GL_DEPTH_STENCIL_EXT:
 756       if (att[BUFFER_DEPTH].Type == GL_NONE ||
 757           att[BUFFER_STENCIL].Type == GL_NONE) {
 758          return GL_FALSE;
 759       }
 760       break;
 761    default:
 762       _mesa_problem(ctx,
 763                     "Unexpected format 0x%x in renderbuffer_exists",
 764                     format);
 765       return GL_FALSE;
 766    }
 767
 768    /* OK */
 769    return GL_TRUE;
 770 }
 771
 772
 773 /**
 774  * Check if the renderbuffer for a read operation (glReadPixels, glCopyPixels,
 775  * glCopyTex[Sub]Image, etc) exists.
 776  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 777  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 778  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 779  */
 780 GLboolean
 781 _mesa_source_buffer_exists(struct gl_context *ctx, GLenum format)
 782 {
 783    return renderbuffer_exists(ctx, ctx->ReadBuffer, format, GL_TRUE);
 784 }
 785
 786
 787 /**
 788  * As above, but for drawing operations.
 789  */
 790 GLboolean
 791 _mesa_dest_buffer_exists(struct gl_context *ctx, GLenum format)
 792 {
 793    return renderbuffer_exists(ctx, ctx->DrawBuffer, format, GL_FALSE);
 794 }
 795
 796
 797 /**
 798  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_FORMAT_OES query.
 799  */
 800 GLenum
 801 _mesa_get_color_read_format(struct gl_context *ctx)
 802 {
 803    if (!ctx->ReadBuffer || !ctx->ReadBuffer->_ColorReadBuffer) {
 804       /* The spec is unclear how to handle this case, but NVIDIA's
 805        * driver generates GL_INVALID_OPERATION.
 806        */
 807       _mesa_error(ctx, GL_INVALID_OPERATION,
 808                   "glGetIntegerv(GL_IMPLEMENTATION_COLOR_READ_FORMAT: "
 809                   "no GL_READ_BUFFER)");
 810       return GL_NONE;
 811    }
 812    else {
 813       const GLenum format = ctx->ReadBuffer->_ColorReadBuffer->Format;
 814       const GLenum data_type = _mesa_get_format_datatype(format);
 815
 816       if (format == MESA_FORMAT_ARGB8888)
 817          return GL_BGRA;
 818       else if (format == MESA_FORMAT_RGB565)
 819          return GL_BGR;
 820
 821       switch (data_type) {
 822       case GL_UNSIGNED_INT:
 823       case GL_INT:
 824          return GL_RGBA_INTEGER;
 825       default:
 826          return GL_RGBA;
 827       }
 828    }
 829 }
 830
 831
 832 /**
 833  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_TYPE_OES query.
 834  */
 835 GLenum
 836 _mesa_get_color_read_type(struct gl_context *ctx)
 837 {
 838    if (!ctx->ReadBuffer || !ctx->ReadBuffer->_ColorReadBuffer) {
 839       /* The spec is unclear how to handle this case, but NVIDIA's
 840        * driver generates GL_INVALID_OPERATION.
 841        */
 842       _mesa_error(ctx, GL_INVALID_OPERATION,
 843                   "glGetIntegerv(GL_IMPLEMENTATION_COLOR_READ_TYPE: "
 844                   "no GL_READ_BUFFER)");
 845       return GL_NONE;
 846    }
 847    else {
 848       const GLenum format = ctx->ReadBuffer->_ColorReadBuffer->Format;
 849       const GLenum data_type = _mesa_get_format_datatype(format);
 850
 851       if (format == MESA_FORMAT_RGB565)
 852          return GL_UNSIGNED_SHORT_5_6_5_REV;
 853
 854       switch (data_type) {
 855       case GL_SIGNED_NORMALIZED:
 856          return GL_BYTE;
 857       case GL_UNSIGNED_INT:
 858       case GL_INT:
 859       case GL_FLOAT:
 860          return data_type;
 861       case GL_UNSIGNED_NORMALIZED:
 862       default:
 863          return GL_UNSIGNED_BYTE;
 864       }
 865    }
 866 }
 867
 868
 869 /**
 870  * Returns the read renderbuffer for the specified format.
 871  */
 872 struct gl_renderbuffer *
 873 _mesa_get_read_renderbuffer_for_format(const struct gl_context *ctx,
 874                                        GLenum format)
 875 {
 876    const struct gl_framebuffer *rfb = ctx->ReadBuffer;
 877
 878    if (_mesa_is_color_format(format)) {
 879       return rfb->Attachment[rfb->_ColorReadBufferIndex].Renderbuffer;
 880    } else if (_mesa_is_depth_format(format) ||
 881               _mesa_is_depthstencil_format(format)) {
 882       return rfb->Attachment[BUFFER_DEPTH].Renderbuffer;
 883    } else {
 884       return rfb->Attachment[BUFFER_STENCIL].Renderbuffer;
 885    }
 886 }
 887
 888
 889 /**
 890  * Print framebuffer info to stderr, for debugging.
 891  */
 892 void
 893 _mesa_print_framebuffer(const struct gl_framebuffer *fb)
 894 {
 895    GLuint i;
 896
 897    fprintf(stderr, "Mesa Framebuffer %u at %p\n", fb->Name, (void *) fb);
 898    fprintf(stderr, "  Size: %u x %u  Status: %s\n", fb->Width, fb->Height,
 899            _mesa_lookup_enum_by_nr(fb->_Status));
 900    fprintf(stderr, "  Attachments:\n");
 901
 902    for (i = 0; i < BUFFER_COUNT; i++) {
 903       const struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 904       if (att->Type == GL_TEXTURE) {
 905          const struct gl_texture_image *texImage = att->Renderbuffer->TexImage;
 906          fprintf(stderr,
 907                  "  %2d: Texture %u, level %u, face %u, slice %u, complete %d\n",
 908                  i, att->Texture->Name, att->TextureLevel, att->CubeMapFace,
 909                  att->Zoffset, att->Complete);
 910          fprintf(stderr, "       Size: %u x %u x %u  Format %s\n",
 911                  texImage->Width, texImage->Height, texImage->Depth,
 912                  _mesa_get_format_name(texImage->TexFormat));
 913       }
 914       else if (att->Type == GL_RENDERBUFFER) {
 915          fprintf(stderr, "  %2d: Renderbuffer %u, complete %d\n",
 916                  i, att->Renderbuffer->Name, att->Complete);
 917          fprintf(stderr, "       Size: %u x %u  Format %s\n",
 918                  att->Renderbuffer->Width, att->Renderbuffer->Height,
 919                  _mesa_get_format_name(att->Renderbuffer->Format));
 920       }
 921       else {
 922          fprintf(stderr, "  %2d: none\n", i);
 923       }
 924    }
 925 }