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 #include <stdio.h>
  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    mtx_init(&fb->Mutex, mtx_plain);
 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    mtx_init(&fb->Mutex, mtx_plain);
 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    mtx_destroy(&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       mtx_lock(&oldFb->Mutex);
 248       assert(oldFb->RefCount > 0);
 249       oldFb->RefCount--;
 250       deleteFlag = (oldFb->RefCount == 0);
 251       mtx_unlock(&oldFb->Mutex);
 252
 253       if (deleteFlag)
 254          oldFb->Delete(oldFb);
 255
 256       *ptr = NULL;
 257    }
 258    assert(!*ptr);
 259
 260    if (fb) {
 261       mtx_lock(&fb->Mutex);
 262       fb->RefCount++;
 263       mtx_unlock(&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 != ~0U) {
 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  * Calculate the inclusive bounding box for the scissor of a specific viewport
 361  *
 362  * \param ctx     GL context.
 363  * \param buffer  Framebuffer to be checked against
 364  * \param idx     Index of the desired viewport
 365  * \param bbox    Bounding box for the scissored viewport.  Stored as xmin,
 366  *                xmax, ymin, ymax.
 367  *
 368  * \warning This function assumes that the framebuffer dimensions are up to
 369  * date (e.g., update_framebuffer_size has been recently called on \c buffer).
 370  *
 371  * \sa _mesa_clip_to_region
 372  */
 373 void
 374 _mesa_scissor_bounding_box(const struct gl_context *ctx,
 375                            const struct gl_framebuffer *buffer,
 376                            unsigned idx, int *bbox)
 377 {
 378    bbox[0] = 0;
 379    bbox[2] = 0;
 380    bbox[1] = buffer->Width;
 381    bbox[3] = buffer->Height;
 382
 383    if (ctx->Scissor.EnableFlags & (1u << idx)) {
 384       if (ctx->Scissor.ScissorArray[idx].X > bbox[0]) {
 385          bbox[0] = ctx->Scissor.ScissorArray[idx].X;
 386       }
 387       if (ctx->Scissor.ScissorArray[idx].Y > bbox[2]) {
 388          bbox[2] = ctx->Scissor.ScissorArray[idx].Y;
 389       }
 390       if (ctx->Scissor.ScissorArray[idx].X + ctx->Scissor.ScissorArray[idx].Width < bbox[1]) {
 391          bbox[1] = ctx->Scissor.ScissorArray[idx].X + ctx->Scissor.ScissorArray[idx].Width;
 392       }
 393       if (ctx->Scissor.ScissorArray[idx].Y + ctx->Scissor.ScissorArray[idx].Height < bbox[3]) {
 394          bbox[3] = ctx->Scissor.ScissorArray[idx].Y + ctx->Scissor.ScissorArray[idx].Height;
 395       }
 396       /* finally, check for empty region */
 397       if (bbox[0] > bbox[1]) {
 398          bbox[0] = bbox[1];
 399       }
 400       if (bbox[2] > bbox[3]) {
 401          bbox[2] = bbox[3];
 402       }
 403    }
 404
 405    assert(bbox[0] <= bbox[1]);
 406    assert(bbox[2] <= bbox[3]);
 407 }
 408
 409 /**
 410  * Update the context's current drawing buffer's Xmin, Xmax, Ymin, Ymax fields.
 411  * These values are computed from the buffer's width and height and
 412  * the scissor box, if it's enabled.
 413  * \param ctx  the GL context.
 414  */
 415 void
 416 _mesa_update_draw_buffer_bounds(struct gl_context *ctx)
 417 {
 418    struct gl_framebuffer *buffer = ctx->DrawBuffer;
 419    int bbox[4];
 420
 421    if (!buffer)
 422       return;
 423
 424    if (_mesa_is_user_fbo(buffer)) {
 425       /* user-created framebuffer size depends on the renderbuffers */
 426       update_framebuffer_size(ctx, buffer);
 427    }
 428
 429    /* Default to the first scissor as that's always valid */
 430    _mesa_scissor_bounding_box(ctx, buffer, 0, bbox);
 431    buffer->_Xmin = bbox[0];
 432    buffer->_Ymin = bbox[2];
 433    buffer->_Xmax = bbox[1];
 434    buffer->_Ymax = bbox[3];
 435 }
 436
 437
 438 /**
 439  * The glGet queries of the framebuffer red/green/blue size, stencil size,
 440  * etc. are satisfied by the fields of ctx->DrawBuffer->Visual.  These can
 441  * change depending on the renderbuffer bindings.  This function updates
 442  * the given framebuffer's Visual from the current renderbuffer bindings.
 443  *
 444  * This may apply to user-created framebuffers or window system framebuffers.
 445  *
 446  * Also note: ctx->DrawBuffer->Visual.depthBits might not equal
 447  * ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer.DepthBits.
 448  * The former one is used to convert floating point depth values into
 449  * integer Z values.
 450  */
 451 void
 452 _mesa_update_framebuffer_visual(struct gl_context *ctx,
 453                                 struct gl_framebuffer *fb)
 454 {
 455    GLuint i;
 456
 457    memset(&fb->Visual, 0, sizeof(fb->Visual));
 458    fb->Visual.rgbMode = GL_TRUE; /* assume this */
 459
 460 #if 0 /* this _might_ be needed */
 461    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 462       /* leave visual fields zero'd */
 463       return;
 464    }
 465 #endif
 466
 467    /* find first RGB renderbuffer */
 468    for (i = 0; i < BUFFER_COUNT; i++) {
 469       if (fb->Attachment[i].Renderbuffer) {
 470          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 471          const GLenum baseFormat = _mesa_get_format_base_format(rb->Format);
 472          const mesa_format fmt = rb->Format;
 473
 474          /* Grab samples and sampleBuffers from any attachment point (assuming
 475           * the framebuffer is complete, we'll get the same answer from all
 476           * attachments).
 477           */
 478          fb->Visual.samples = rb->NumSamples;
 479          fb->Visual.sampleBuffers = rb->NumSamples > 0 ? 1 : 0;
 480
 481          if (_mesa_is_legal_color_format(ctx, baseFormat)) {
 482             fb->Visual.redBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 483             fb->Visual.greenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 484             fb->Visual.blueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 485             fb->Visual.alphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 486             fb->Visual.rgbBits = fb->Visual.redBits
 487                + fb->Visual.greenBits + fb->Visual.blueBits;
 488             if (_mesa_get_format_color_encoding(fmt) == GL_SRGB)
 489                 fb->Visual.sRGBCapable = ctx->Extensions.EXT_framebuffer_sRGB;
 490             break;
 491          }
 492       }
 493    }
 494
 495    fb->Visual.floatMode = GL_FALSE;
 496    for (i = 0; i < BUFFER_COUNT; i++) {
 497       if (fb->Attachment[i].Renderbuffer) {
 498          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 499          const mesa_format fmt = rb->Format;
 500
 501          if (_mesa_get_format_datatype(fmt) == GL_FLOAT) {
 502             fb->Visual.floatMode = GL_TRUE;
 503             break;
 504          }
 505       }
 506    }
 507
 508    if (fb->Attachment[BUFFER_DEPTH].Renderbuffer) {
 509       const struct gl_renderbuffer *rb =
 510          fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 511       const mesa_format fmt = rb->Format;
 512       fb->Visual.haveDepthBuffer = GL_TRUE;
 513       fb->Visual.depthBits = _mesa_get_format_bits(fmt, GL_DEPTH_BITS);
 514    }
 515
 516    if (fb->Attachment[BUFFER_STENCIL].Renderbuffer) {
 517       const struct gl_renderbuffer *rb =
 518          fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 519       const mesa_format fmt = rb->Format;
 520       fb->Visual.haveStencilBuffer = GL_TRUE;
 521       fb->Visual.stencilBits = _mesa_get_format_bits(fmt, GL_STENCIL_BITS);
 522    }
 523
 524    if (fb->Attachment[BUFFER_ACCUM].Renderbuffer) {
 525       const struct gl_renderbuffer *rb =
 526          fb->Attachment[BUFFER_ACCUM].Renderbuffer;
 527       const mesa_format fmt = rb->Format;
 528       fb->Visual.haveAccumBuffer = GL_TRUE;
 529       fb->Visual.accumRedBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 530       fb->Visual.accumGreenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 531       fb->Visual.accumBlueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 532       fb->Visual.accumAlphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 533    }
 534
 535    compute_depth_max(fb);
 536 }
 537
 538
 539 /*
 540  * Example DrawBuffers scenarios:
 541  *
 542  * 1. glDrawBuffer(GL_FRONT_AND_BACK), fixed-func or shader writes to
 543  * "gl_FragColor" or program writes to the "result.color" register:
 544  *
 545  *   fragment color output   renderbuffer
 546  *   ---------------------   ---------------
 547  *   color[0]                Front, Back
 548  *
 549  *
 550  * 2. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]), shader writes to
 551  * gl_FragData[i] or program writes to result.color[i] registers:
 552  *
 553  *   fragment color output   renderbuffer
 554  *   ---------------------   ---------------
 555  *   color[0]                Front
 556  *   color[1]                Aux0
 557  *   color[3]                Aux1
 558  *
 559  *
 560  * 3. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]) and shader writes to
 561  * gl_FragColor, or fixed function:
 562  *
 563  *   fragment color output   renderbuffer
 564  *   ---------------------   ---------------
 565  *   color[0]                Front, Aux0, Aux1
 566  *
 567  *
 568  * In either case, the list of renderbuffers is stored in the
 569  * framebuffer->_ColorDrawBuffers[] array and
 570  * framebuffer->_NumColorDrawBuffers indicates the number of buffers.
 571  * The renderer (like swrast) has to look at the current fragment shader
 572  * to see if it writes to gl_FragColor vs. gl_FragData[i] to determine
 573  * how to map color outputs to renderbuffers.
 574  *
 575  * Note that these two calls are equivalent (for fixed function fragment
 576  * shading anyway):
 577  *   a)  glDrawBuffer(GL_FRONT_AND_BACK);  (assuming non-stereo framebuffer)
 578  *   b)  glDrawBuffers(2, [GL_FRONT_LEFT, GL_BACK_LEFT]);
 579  */
 580
 581
 582
 583
 584 /**
 585  * Update the (derived) list of color drawing renderbuffer pointers.
 586  * Later, when we're rendering we'll loop from 0 to _NumColorDrawBuffers
 587  * writing colors.
 588  */
 589 static void
 590 update_color_draw_buffers(struct gl_context *ctx, struct gl_framebuffer *fb)
 591 {
 592    GLuint output;
 593
 594    /* set 0th buffer to NULL now in case _NumColorDrawBuffers is zero */
 595    fb->_ColorDrawBuffers[0] = NULL;
 596
 597    for (output = 0; output < fb->_NumColorDrawBuffers; output++) {
 598       GLint buf = fb->_ColorDrawBufferIndexes[output];
 599       if (buf >= 0) {
 600          fb->_ColorDrawBuffers[output] = fb->Attachment[buf].Renderbuffer;
 601       }
 602       else {
 603          fb->_ColorDrawBuffers[output] = NULL;
 604       }
 605    }
 606 }
 607
 608
 609 /**
 610  * Update the (derived) color read renderbuffer pointer.
 611  * Unlike the DrawBuffer, we can only read from one (or zero) color buffers.
 612  */
 613 static void
 614 update_color_read_buffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 615 {
 616    (void) ctx;
 617    if (fb->_ColorReadBufferIndex == -1 ||
 618        fb->DeletePending ||
 619        fb->Width == 0 ||
 620        fb->Height == 0) {
 621       fb->_ColorReadBuffer = NULL; /* legal! */
 622    }
 623    else {
 624       assert(fb->_ColorReadBufferIndex >= 0);
 625       assert(fb->_ColorReadBufferIndex < BUFFER_COUNT);
 626       fb->_ColorReadBuffer
 627          = fb->Attachment[fb->_ColorReadBufferIndex].Renderbuffer;
 628    }
 629 }
 630
 631
 632 /**
 633  * Update a gl_framebuffer's derived state.
 634  *
 635  * Specifically, update these framebuffer fields:
 636  *    _ColorDrawBuffers
 637  *    _NumColorDrawBuffers
 638  *    _ColorReadBuffer
 639  *
 640  * If the framebuffer is user-created, make sure it's complete.
 641  *
 642  * The following functions (at least) can effect framebuffer state:
 643  * glReadBuffer, glDrawBuffer, glDrawBuffersARB, glFramebufferRenderbufferEXT,
 644  * glRenderbufferStorageEXT.
 645  */
 646 static void
 647 update_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 648 {
 649    if (_mesa_is_winsys_fbo(fb)) {
 650       /* This is a window-system framebuffer */
 651       /* Need to update the FB's GL_DRAW_BUFFER state to match the
 652        * context state (GL_READ_BUFFER too).
 653        */
 654       if (fb->ColorDrawBuffer[0] != ctx->Color.DrawBuffer[0]) {
 655          _mesa_drawbuffers(ctx, ctx->Const.MaxDrawBuffers,
 656                            ctx->Color.DrawBuffer, NULL);
 657       }
 658    }
 659    else {
 660       /* This is a user-created framebuffer.
 661        * Completeness only matters for user-created framebuffers.
 662        */
 663       if (fb->_Status != GL_FRAMEBUFFER_COMPLETE) {
 664          _mesa_test_framebuffer_completeness(ctx, fb);
 665       }
 666    }
 667
 668    /* Strictly speaking, we don't need to update the draw-state
 669     * if this FB is bound as ctx->ReadBuffer (and conversely, the
 670     * read-state if this FB is bound as ctx->DrawBuffer), but no
 671     * harm.
 672     */
 673    update_color_draw_buffers(ctx, fb);
 674    update_color_read_buffer(ctx, fb);
 675
 676    compute_depth_max(fb);
 677 }
 678
 679
 680 /**
 681  * Update state related to the current draw/read framebuffers.
 682  */
 683 void
 684 _mesa_update_framebuffer(struct gl_context *ctx)
 685 {
 686    struct gl_framebuffer *drawFb;
 687    struct gl_framebuffer *readFb;
 688
 689    assert(ctx);
 690    drawFb = ctx->DrawBuffer;
 691    readFb = ctx->ReadBuffer;
 692
 693    update_framebuffer(ctx, drawFb);
 694    if (readFb != drawFb)
 695       update_framebuffer(ctx, readFb);
 696
 697    _mesa_update_clamp_vertex_color(ctx);
 698    _mesa_update_clamp_fragment_color(ctx);
 699 }
 700
 701
 702 /**
 703  * Check if the renderbuffer for a read/draw operation exists.
 704  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 705  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 706  * \param reading  if TRUE, we're going to read from the buffer,
 707                    if FALSE, we're going to write to the buffer.
 708  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 709  */
 710 static GLboolean
 711 renderbuffer_exists(struct gl_context *ctx,
 712                     struct gl_framebuffer *fb,
 713                     GLenum format,
 714                     GLboolean reading)
 715 {
 716    const struct gl_renderbuffer_attachment *att = fb->Attachment;
 717
 718    /* If we don't know the framebuffer status, update it now */
 719    if (fb->_Status == 0) {
 720       _mesa_test_framebuffer_completeness(ctx, fb);
 721    }
 722
 723    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 724       return GL_FALSE;
 725    }
 726
 727    switch (format) {
 728    case GL_COLOR:
 729    case GL_RED:
 730    case GL_GREEN:
 731    case GL_BLUE:
 732    case GL_ALPHA:
 733    case GL_LUMINANCE:
 734    case GL_LUMINANCE_ALPHA:
 735    case GL_INTENSITY:
 736    case GL_RG:
 737    case GL_RGB:
 738    case GL_BGR:
 739    case GL_RGBA:
 740    case GL_BGRA:
 741    case GL_ABGR_EXT:
 742    case GL_RED_INTEGER_EXT:
 743    case GL_RG_INTEGER:
 744    case GL_GREEN_INTEGER_EXT:
 745    case GL_BLUE_INTEGER_EXT:
 746    case GL_ALPHA_INTEGER_EXT:
 747    case GL_RGB_INTEGER_EXT:
 748    case GL_RGBA_INTEGER_EXT:
 749    case GL_BGR_INTEGER_EXT:
 750    case GL_BGRA_INTEGER_EXT:
 751    case GL_LUMINANCE_INTEGER_EXT:
 752    case GL_LUMINANCE_ALPHA_INTEGER_EXT:
 753       if (reading) {
 754          /* about to read from a color buffer */
 755          const struct gl_renderbuffer *readBuf = fb->_ColorReadBuffer;
 756          if (!readBuf) {
 757             return GL_FALSE;
 758          }
 759          assert(_mesa_get_format_bits(readBuf->Format, GL_RED_BITS) > 0 ||
 760                 _mesa_get_format_bits(readBuf->Format, GL_ALPHA_BITS) > 0 ||
 761                 _mesa_get_format_bits(readBuf->Format, GL_TEXTURE_LUMINANCE_SIZE) > 0 ||
 762                 _mesa_get_format_bits(readBuf->Format, GL_TEXTURE_INTENSITY_SIZE) > 0 ||
 763                 _mesa_get_format_bits(readBuf->Format, GL_INDEX_BITS) > 0);
 764       }
 765       else {
 766          /* about to draw to zero or more color buffers (none is OK) */
 767          return GL_TRUE;
 768       }
 769       break;
 770    case GL_DEPTH:
 771    case GL_DEPTH_COMPONENT:
 772       if (att[BUFFER_DEPTH].Type == GL_NONE) {
 773          return GL_FALSE;
 774       }
 775       break;
 776    case GL_STENCIL:
 777    case GL_STENCIL_INDEX:
 778       if (att[BUFFER_STENCIL].Type == GL_NONE) {
 779          return GL_FALSE;
 780       }
 781       break;
 782    case GL_DEPTH_STENCIL_EXT:
 783       if (att[BUFFER_DEPTH].Type == GL_NONE ||
 784           att[BUFFER_STENCIL].Type == GL_NONE) {
 785          return GL_FALSE;
 786       }
 787       break;
 788    default:
 789       _mesa_problem(ctx,
 790                     "Unexpected format 0x%x in renderbuffer_exists",
 791                     format);
 792       return GL_FALSE;
 793    }
 794
 795    /* OK */
 796    return GL_TRUE;
 797 }
 798
 799
 800 /**
 801  * Check if the renderbuffer for a read operation (glReadPixels, glCopyPixels,
 802  * glCopyTex[Sub]Image, etc) exists.
 803  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 804  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 805  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 806  */
 807 GLboolean
 808 _mesa_source_buffer_exists(struct gl_context *ctx, GLenum format)
 809 {
 810    return renderbuffer_exists(ctx, ctx->ReadBuffer, format, GL_TRUE);
 811 }
 812
 813
 814 /**
 815  * As above, but for drawing operations.
 816  */
 817 GLboolean
 818 _mesa_dest_buffer_exists(struct gl_context *ctx, GLenum format)
 819 {
 820    return renderbuffer_exists(ctx, ctx->DrawBuffer, format, GL_FALSE);
 821 }
 822
 823
 824 /**
 825  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_FORMAT_OES query.
 826  */
 827 GLenum
 828 _mesa_get_color_read_format(struct gl_context *ctx)
 829 {
 830    if (!ctx->ReadBuffer || !ctx->ReadBuffer->_ColorReadBuffer) {
 831       /* The spec is unclear how to handle this case, but NVIDIA's
 832        * driver generates GL_INVALID_OPERATION.
 833        */
 834       _mesa_error(ctx, GL_INVALID_OPERATION,
 835                   "glGetIntegerv(GL_IMPLEMENTATION_COLOR_READ_FORMAT: "
 836                   "no GL_READ_BUFFER)");
 837       return GL_NONE;
 838    }
 839    else {
 840       const GLenum format = ctx->ReadBuffer->_ColorReadBuffer->Format;
 841       const GLenum data_type = _mesa_get_format_datatype(format);
 842
 843       if (format == MESA_FORMAT_B8G8R8A8_UNORM)
 844          return GL_BGRA;
 845       else if (format == MESA_FORMAT_B5G6R5_UNORM)
 846          return GL_BGR;
 847
 848       switch (data_type) {
 849       case GL_UNSIGNED_INT:
 850       case GL_INT:
 851          return GL_RGBA_INTEGER;
 852       default:
 853          return GL_RGBA;
 854       }
 855    }
 856 }
 857
 858
 859 /**
 860  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_TYPE_OES query.
 861  */
 862 GLenum
 863 _mesa_get_color_read_type(struct gl_context *ctx)
 864 {
 865    if (!ctx->ReadBuffer || !ctx->ReadBuffer->_ColorReadBuffer) {
 866       /* The spec is unclear how to handle this case, but NVIDIA's
 867        * driver generates GL_INVALID_OPERATION.
 868        */
 869       _mesa_error(ctx, GL_INVALID_OPERATION,
 870                   "glGetIntegerv(GL_IMPLEMENTATION_COLOR_READ_TYPE: "
 871                   "no GL_READ_BUFFER)");
 872       return GL_NONE;
 873    }
 874    else {
 875       const GLenum format = ctx->ReadBuffer->_ColorReadBuffer->Format;
 876       const GLenum data_type = _mesa_get_format_datatype(format);
 877
 878       if (format == MESA_FORMAT_B5G6R5_UNORM)
 879          return GL_UNSIGNED_SHORT_5_6_5_REV;
 880
 881       switch (data_type) {
 882       case GL_SIGNED_NORMALIZED:
 883          return GL_BYTE;
 884       case GL_UNSIGNED_INT:
 885       case GL_INT:
 886       case GL_FLOAT:
 887          return data_type;
 888       case GL_UNSIGNED_NORMALIZED:
 889       default:
 890          return GL_UNSIGNED_BYTE;
 891       }
 892    }
 893 }
 894
 895
 896 /**
 897  * Returns the read renderbuffer for the specified format.
 898  */
 899 struct gl_renderbuffer *
 900 _mesa_get_read_renderbuffer_for_format(const struct gl_context *ctx,
 901                                        GLenum format)
 902 {
 903    const struct gl_framebuffer *rfb = ctx->ReadBuffer;
 904
 905    if (_mesa_is_color_format(format)) {
 906       return rfb->Attachment[rfb->_ColorReadBufferIndex].Renderbuffer;
 907    } else if (_mesa_is_depth_format(format) ||
 908               _mesa_is_depthstencil_format(format)) {
 909       return rfb->Attachment[BUFFER_DEPTH].Renderbuffer;
 910    } else {
 911       return rfb->Attachment[BUFFER_STENCIL].Renderbuffer;
 912    }
 913 }
 914
 915
 916 /**
 917  * Print framebuffer info to stderr, for debugging.
 918  */
 919 void
 920 _mesa_print_framebuffer(const struct gl_framebuffer *fb)
 921 {
 922    GLuint i;
 923
 924    fprintf(stderr, "Mesa Framebuffer %u at %p\n", fb->Name, (void *) fb);
 925    fprintf(stderr, "  Size: %u x %u  Status: %s\n", fb->Width, fb->Height,
 926            _mesa_lookup_enum_by_nr(fb->_Status));
 927    fprintf(stderr, "  Attachments:\n");
 928
 929    for (i = 0; i < BUFFER_COUNT; i++) {
 930       const struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 931       if (att->Type == GL_TEXTURE) {
 932          const struct gl_texture_image *texImage = att->Renderbuffer->TexImage;
 933          fprintf(stderr,
 934                  "  %2d: Texture %u, level %u, face %u, slice %u, complete %d\n",
 935                  i, att->Texture->Name, att->TextureLevel, att->CubeMapFace,
 936                  att->Zoffset, att->Complete);
 937          fprintf(stderr, "       Size: %u x %u x %u  Format %s\n",
 938                  texImage->Width, texImage->Height, texImage->Depth,
 939                  _mesa_get_format_name(texImage->TexFormat));
 940       }
 941       else if (att->Type == GL_RENDERBUFFER) {
 942          fprintf(stderr, "  %2d: Renderbuffer %u, complete %d\n",
 943                  i, att->Renderbuffer->Name, att->Complete);
 944          fprintf(stderr, "       Size: %u x %u  Format %s\n",
 945                  att->Renderbuffer->Width, att->Renderbuffer->Height,
 946                  _mesa_get_format_name(att->Renderbuffer->Format));
 947       }
 948       else {
 949          fprintf(stderr, "  %2d: none\n", i);
 950       }
 951    }
 952 }