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    fb->_HasAttachments = true;
 161
 162    compute_depth_max(fb);
 163 }
 164
 165
 166 /**
 167  * Initialize a user-created gl_framebuffer object.
 168  * \sa _mesa_initialize_window_framebuffer
 169  */
 170 void
 171 _mesa_initialize_user_framebuffer(struct gl_framebuffer *fb, GLuint name)
 172 {
 173    assert(fb);
 174    assert(name);
 175
 176    memset(fb, 0, sizeof(struct gl_framebuffer));
 177
 178    fb->Name = name;
 179    fb->RefCount = 1;
 180    fb->_NumColorDrawBuffers = 1;
 181    fb->ColorDrawBuffer[0] = GL_COLOR_ATTACHMENT0_EXT;
 182    fb->_ColorDrawBufferIndexes[0] = BUFFER_COLOR0;
 183    fb->ColorReadBuffer = GL_COLOR_ATTACHMENT0_EXT;
 184    fb->_ColorReadBufferIndex = BUFFER_COLOR0;
 185    fb->Delete = _mesa_destroy_framebuffer;
 186    mtx_init(&fb->Mutex, mtx_plain);
 187 }
 188
 189
 190 /**
 191  * Deallocate buffer and everything attached to it.
 192  * Typically called via the gl_framebuffer->Delete() method.
 193  */
 194 void
 195 _mesa_destroy_framebuffer(struct gl_framebuffer *fb)
 196 {
 197    if (fb) {
 198       _mesa_free_framebuffer_data(fb);
 199       free(fb->Label);
 200       free(fb);
 201    }
 202 }
 203
 204
 205 /**
 206  * Free all the data hanging off the given gl_framebuffer, but don't free
 207  * the gl_framebuffer object itself.
 208  */
 209 void
 210 _mesa_free_framebuffer_data(struct gl_framebuffer *fb)
 211 {
 212    GLuint i;
 213
 214    assert(fb);
 215    assert(fb->RefCount == 0);
 216
 217    mtx_destroy(&fb->Mutex);
 218
 219    for (i = 0; i < BUFFER_COUNT; i++) {
 220       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 221       if (att->Renderbuffer) {
 222          _mesa_reference_renderbuffer(&att->Renderbuffer, NULL);
 223       }
 224       if (att->Texture) {
 225          _mesa_reference_texobj(&att->Texture, NULL);
 226       }
 227       assert(!att->Renderbuffer);
 228       assert(!att->Texture);
 229       att->Type = GL_NONE;
 230    }
 231 }
 232
 233
 234 /**
 235  * Set *ptr to point to fb, with refcounting and locking.
 236  * This is normally only called from the _mesa_reference_framebuffer() macro
 237  * when there's a real pointer change.
 238  */
 239 void
 240 _mesa_reference_framebuffer_(struct gl_framebuffer **ptr,
 241                              struct gl_framebuffer *fb)
 242 {
 243    if (*ptr) {
 244       /* unreference old renderbuffer */
 245       GLboolean deleteFlag = GL_FALSE;
 246       struct gl_framebuffer *oldFb = *ptr;
 247
 248       mtx_lock(&oldFb->Mutex);
 249       assert(oldFb->RefCount > 0);
 250       oldFb->RefCount--;
 251       deleteFlag = (oldFb->RefCount == 0);
 252       mtx_unlock(&oldFb->Mutex);
 253
 254       if (deleteFlag)
 255          oldFb->Delete(oldFb);
 256
 257       *ptr = NULL;
 258    }
 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 directly 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, ctx->DrawBuffer);
 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  * Examine all the framebuffer's renderbuffers to update the Width/Height
 324  * fields of the framebuffer.  If we have renderbuffers with different
 325  * sizes, set the framebuffer's width and height to the min size.
 326  * Note: this is only intended for user-created framebuffers, not
 327  * window-system framebuffes.
 328  */
 329 static void
 330 update_framebuffer_size(struct gl_context *ctx, struct gl_framebuffer *fb)
 331 {
 332    GLuint minWidth = ~0, minHeight = ~0;
 333    GLuint i;
 334
 335    /* user-created framebuffers only */
 336    assert(_mesa_is_user_fbo(fb));
 337
 338    for (i = 0; i < BUFFER_COUNT; i++) {
 339       struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 340       const struct gl_renderbuffer *rb = att->Renderbuffer;
 341       if (rb) {
 342          minWidth = MIN2(minWidth, rb->Width);
 343          minHeight = MIN2(minHeight, rb->Height);
 344       }
 345    }
 346
 347    if (minWidth != ~0U) {
 348       fb->Width = minWidth;
 349       fb->Height = minHeight;
 350    }
 351    else {
 352       fb->Width = 0;
 353       fb->Height = 0;
 354    }
 355 }
 356
 357
 358
 359 /**
 360  * Given a bounding box, intersect the bounding box with the scissor of
 361  * a specified vieport.
 362  *
 363  * \param ctx     GL context.
 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 void
 369 _mesa_intersect_scissor_bounding_box(const struct gl_context *ctx,
 370                                      unsigned idx, int *bbox)
 371 {
 372    if (ctx->Scissor.EnableFlags & (1u << idx)) {
 373       if (ctx->Scissor.ScissorArray[idx].X > bbox[0]) {
 374          bbox[0] = ctx->Scissor.ScissorArray[idx].X;
 375       }
 376       if (ctx->Scissor.ScissorArray[idx].Y > bbox[2]) {
 377          bbox[2] = ctx->Scissor.ScissorArray[idx].Y;
 378       }
 379       if (ctx->Scissor.ScissorArray[idx].X + ctx->Scissor.ScissorArray[idx].Width < bbox[1]) {
 380          bbox[1] = ctx->Scissor.ScissorArray[idx].X + ctx->Scissor.ScissorArray[idx].Width;
 381       }
 382       if (ctx->Scissor.ScissorArray[idx].Y + ctx->Scissor.ScissorArray[idx].Height < bbox[3]) {
 383          bbox[3] = ctx->Scissor.ScissorArray[idx].Y + ctx->Scissor.ScissorArray[idx].Height;
 384       }
 385       /* finally, check for empty region */
 386       if (bbox[0] > bbox[1]) {
 387          bbox[0] = bbox[1];
 388       }
 389       if (bbox[2] > bbox[3]) {
 390          bbox[2] = bbox[3];
 391       }
 392    }
 393 }
 394
 395 /**
 396  * Calculate the inclusive bounding box for the scissor of a specific viewport
 397  *
 398  * \param ctx     GL context.
 399  * \param buffer  Framebuffer to be checked against
 400  * \param idx     Index of the desired viewport
 401  * \param bbox    Bounding box for the scissored viewport.  Stored as xmin,
 402  *                xmax, ymin, ymax.
 403  *
 404  * \warning This function assumes that the framebuffer dimensions are up to
 405  * date (e.g., update_framebuffer_size has been recently called on \c buffer).
 406  *
 407  * \sa _mesa_clip_to_region
 408  */
 409 void
 410 _mesa_scissor_bounding_box(const struct gl_context *ctx,
 411                            const struct gl_framebuffer *buffer,
 412                            unsigned idx, int *bbox)
 413 {
 414    bbox[0] = 0;
 415    bbox[2] = 0;
 416    bbox[1] = buffer->Width;
 417    bbox[3] = buffer->Height;
 418
 419    _mesa_intersect_scissor_bounding_box(ctx, idx, bbox);
 420
 421    assert(bbox[0] <= bbox[1]);
 422    assert(bbox[2] <= bbox[3]);
 423 }
 424
 425 /**
 426  * Update the context's current drawing buffer's Xmin, Xmax, Ymin, Ymax fields.
 427  * These values are computed from the buffer's width and height and
 428  * the scissor box, if it's enabled.
 429  * \param ctx  the GL context.
 430  */
 431 void
 432 _mesa_update_draw_buffer_bounds(struct gl_context *ctx,
 433                                 struct gl_framebuffer *buffer)
 434 {
 435    int bbox[4];
 436
 437    if (!buffer)
 438       return;
 439
 440    if (_mesa_is_user_fbo(buffer)) {
 441       /* user-created framebuffer size depends on the renderbuffers */
 442       update_framebuffer_size(ctx, buffer);
 443    }
 444
 445    /* Default to the first scissor as that's always valid */
 446    _mesa_scissor_bounding_box(ctx, buffer, 0, bbox);
 447    buffer->_Xmin = bbox[0];
 448    buffer->_Ymin = bbox[2];
 449    buffer->_Xmax = bbox[1];
 450    buffer->_Ymax = bbox[3];
 451 }
 452
 453
 454 /**
 455  * The glGet queries of the framebuffer red/green/blue size, stencil size,
 456  * etc. are satisfied by the fields of ctx->DrawBuffer->Visual.  These can
 457  * change depending on the renderbuffer bindings.  This function updates
 458  * the given framebuffer's Visual from the current renderbuffer bindings.
 459  *
 460  * This may apply to user-created framebuffers or window system framebuffers.
 461  *
 462  * Also note: ctx->DrawBuffer->Visual.depthBits might not equal
 463  * ctx->DrawBuffer->Attachment[BUFFER_DEPTH].Renderbuffer.DepthBits.
 464  * The former one is used to convert floating point depth values into
 465  * integer Z values.
 466  */
 467 void
 468 _mesa_update_framebuffer_visual(struct gl_context *ctx,
 469                                 struct gl_framebuffer *fb)
 470 {
 471    GLuint i;
 472
 473    memset(&fb->Visual, 0, sizeof(fb->Visual));
 474    fb->Visual.rgbMode = GL_TRUE; /* assume this */
 475
 476 #if 0 /* this _might_ be needed */
 477    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 478       /* leave visual fields zero'd */
 479       return;
 480    }
 481 #endif
 482
 483    /* find first RGB renderbuffer */
 484    for (i = 0; i < BUFFER_COUNT; i++) {
 485       if (fb->Attachment[i].Renderbuffer) {
 486          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 487          const GLenum baseFormat = _mesa_get_format_base_format(rb->Format);
 488          const mesa_format fmt = rb->Format;
 489
 490          /* Grab samples and sampleBuffers from any attachment point (assuming
 491           * the framebuffer is complete, we'll get the same answer from all
 492           * attachments).
 493           */
 494          fb->Visual.samples = rb->NumSamples;
 495          fb->Visual.sampleBuffers = rb->NumSamples > 0 ? 1 : 0;
 496
 497          if (_mesa_is_legal_color_format(ctx, baseFormat)) {
 498             fb->Visual.redBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 499             fb->Visual.greenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 500             fb->Visual.blueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 501             fb->Visual.alphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 502             fb->Visual.rgbBits = fb->Visual.redBits
 503                + fb->Visual.greenBits + fb->Visual.blueBits;
 504             if (_mesa_get_format_color_encoding(fmt) == GL_SRGB)
 505                 fb->Visual.sRGBCapable = ctx->Extensions.EXT_framebuffer_sRGB;
 506             break;
 507          }
 508       }
 509    }
 510
 511    fb->Visual.floatMode = GL_FALSE;
 512    for (i = 0; i < BUFFER_COUNT; i++) {
 513       if (fb->Attachment[i].Renderbuffer) {
 514          const struct gl_renderbuffer *rb = fb->Attachment[i].Renderbuffer;
 515          const mesa_format fmt = rb->Format;
 516
 517          if (_mesa_get_format_datatype(fmt) == GL_FLOAT) {
 518             fb->Visual.floatMode = GL_TRUE;
 519             break;
 520          }
 521       }
 522    }
 523
 524    if (fb->Attachment[BUFFER_DEPTH].Renderbuffer) {
 525       const struct gl_renderbuffer *rb =
 526          fb->Attachment[BUFFER_DEPTH].Renderbuffer;
 527       const mesa_format fmt = rb->Format;
 528       fb->Visual.haveDepthBuffer = GL_TRUE;
 529       fb->Visual.depthBits = _mesa_get_format_bits(fmt, GL_DEPTH_BITS);
 530    }
 531
 532    if (fb->Attachment[BUFFER_STENCIL].Renderbuffer) {
 533       const struct gl_renderbuffer *rb =
 534          fb->Attachment[BUFFER_STENCIL].Renderbuffer;
 535       const mesa_format fmt = rb->Format;
 536       fb->Visual.haveStencilBuffer = GL_TRUE;
 537       fb->Visual.stencilBits = _mesa_get_format_bits(fmt, GL_STENCIL_BITS);
 538    }
 539
 540    if (fb->Attachment[BUFFER_ACCUM].Renderbuffer) {
 541       const struct gl_renderbuffer *rb =
 542          fb->Attachment[BUFFER_ACCUM].Renderbuffer;
 543       const mesa_format fmt = rb->Format;
 544       fb->Visual.haveAccumBuffer = GL_TRUE;
 545       fb->Visual.accumRedBits = _mesa_get_format_bits(fmt, GL_RED_BITS);
 546       fb->Visual.accumGreenBits = _mesa_get_format_bits(fmt, GL_GREEN_BITS);
 547       fb->Visual.accumBlueBits = _mesa_get_format_bits(fmt, GL_BLUE_BITS);
 548       fb->Visual.accumAlphaBits = _mesa_get_format_bits(fmt, GL_ALPHA_BITS);
 549    }
 550
 551    compute_depth_max(fb);
 552 }
 553
 554
 555 /*
 556  * Example DrawBuffers scenarios:
 557  *
 558  * 1. glDrawBuffer(GL_FRONT_AND_BACK), fixed-func or shader writes to
 559  * "gl_FragColor" or program writes to the "result.color" register:
 560  *
 561  *   fragment color output   renderbuffer
 562  *   ---------------------   ---------------
 563  *   color[0]                Front, Back
 564  *
 565  *
 566  * 2. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]), shader writes to
 567  * gl_FragData[i] or program writes to result.color[i] registers:
 568  *
 569  *   fragment color output   renderbuffer
 570  *   ---------------------   ---------------
 571  *   color[0]                Front
 572  *   color[1]                Aux0
 573  *   color[3]                Aux1
 574  *
 575  *
 576  * 3. glDrawBuffers(3, [GL_FRONT, GL_AUX0, GL_AUX1]) and shader writes to
 577  * gl_FragColor, or fixed function:
 578  *
 579  *   fragment color output   renderbuffer
 580  *   ---------------------   ---------------
 581  *   color[0]                Front, Aux0, Aux1
 582  *
 583  *
 584  * In either case, the list of renderbuffers is stored in the
 585  * framebuffer->_ColorDrawBuffers[] array and
 586  * framebuffer->_NumColorDrawBuffers indicates the number of buffers.
 587  * The renderer (like swrast) has to look at the current fragment shader
 588  * to see if it writes to gl_FragColor vs. gl_FragData[i] to determine
 589  * how to map color outputs to renderbuffers.
 590  *
 591  * Note that these two calls are equivalent (for fixed function fragment
 592  * shading anyway):
 593  *   a)  glDrawBuffer(GL_FRONT_AND_BACK);  (assuming non-stereo framebuffer)
 594  *   b)  glDrawBuffers(2, [GL_FRONT_LEFT, GL_BACK_LEFT]);
 595  */
 596
 597
 598
 599
 600 /**
 601  * Update the (derived) list of color drawing renderbuffer pointers.
 602  * Later, when we're rendering we'll loop from 0 to _NumColorDrawBuffers
 603  * writing colors.
 604  */
 605 static void
 606 update_color_draw_buffers(struct gl_context *ctx, struct gl_framebuffer *fb)
 607 {
 608    GLuint output;
 609
 610    /* set 0th buffer to NULL now in case _NumColorDrawBuffers is zero */
 611    fb->_ColorDrawBuffers[0] = NULL;
 612
 613    for (output = 0; output < fb->_NumColorDrawBuffers; output++) {
 614       GLint buf = fb->_ColorDrawBufferIndexes[output];
 615       if (buf >= 0) {
 616          fb->_ColorDrawBuffers[output] = fb->Attachment[buf].Renderbuffer;
 617       }
 618       else {
 619          fb->_ColorDrawBuffers[output] = NULL;
 620       }
 621    }
 622 }
 623
 624
 625 /**
 626  * Update the (derived) color read renderbuffer pointer.
 627  * Unlike the DrawBuffer, we can only read from one (or zero) color buffers.
 628  */
 629 static void
 630 update_color_read_buffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 631 {
 632    (void) ctx;
 633    if (fb->_ColorReadBufferIndex == -1 ||
 634        fb->DeletePending ||
 635        fb->Width == 0 ||
 636        fb->Height == 0) {
 637       fb->_ColorReadBuffer = NULL; /* legal! */
 638    }
 639    else {
 640       assert(fb->_ColorReadBufferIndex >= 0);
 641       assert(fb->_ColorReadBufferIndex < BUFFER_COUNT);
 642       fb->_ColorReadBuffer
 643          = fb->Attachment[fb->_ColorReadBufferIndex].Renderbuffer;
 644    }
 645 }
 646
 647
 648 /**
 649  * Update a gl_framebuffer's derived state.
 650  *
 651  * Specifically, update these framebuffer fields:
 652  *    _ColorDrawBuffers
 653  *    _NumColorDrawBuffers
 654  *    _ColorReadBuffer
 655  *
 656  * If the framebuffer is user-created, make sure it's complete.
 657  *
 658  * The following functions (at least) can effect framebuffer state:
 659  * glReadBuffer, glDrawBuffer, glDrawBuffersARB, glFramebufferRenderbufferEXT,
 660  * glRenderbufferStorageEXT.
 661  */
 662 static void
 663 update_framebuffer(struct gl_context *ctx, struct gl_framebuffer *fb)
 664 {
 665    if (_mesa_is_winsys_fbo(fb)) {
 666       /* This is a window-system framebuffer */
 667       /* Need to update the FB's GL_DRAW_BUFFER state to match the
 668        * context state (GL_READ_BUFFER too).
 669        */
 670       if (fb->ColorDrawBuffer[0] != ctx->Color.DrawBuffer[0]) {
 671          _mesa_drawbuffers(ctx, fb, ctx->Const.MaxDrawBuffers,
 672                            ctx->Color.DrawBuffer, NULL);
 673       }
 674    }
 675    else {
 676       /* This is a user-created framebuffer.
 677        * Completeness only matters for user-created framebuffers.
 678        */
 679       if (fb->_Status != GL_FRAMEBUFFER_COMPLETE) {
 680          _mesa_test_framebuffer_completeness(ctx, fb);
 681       }
 682    }
 683
 684    /* Strictly speaking, we don't need to update the draw-state
 685     * if this FB is bound as ctx->ReadBuffer (and conversely, the
 686     * read-state if this FB is bound as ctx->DrawBuffer), but no
 687     * harm.
 688     */
 689    update_color_draw_buffers(ctx, fb);
 690    update_color_read_buffer(ctx, fb);
 691
 692    compute_depth_max(fb);
 693 }
 694
 695
 696 /**
 697  * Update state related to the draw/read framebuffers.
 698  */
 699 void
 700 _mesa_update_framebuffer(struct gl_context *ctx,
 701                          struct gl_framebuffer *readFb,
 702                          struct gl_framebuffer *drawFb)
 703 {
 704    assert(ctx);
 705
 706    update_framebuffer(ctx, drawFb);
 707    if (readFb != drawFb)
 708       update_framebuffer(ctx, readFb);
 709
 710    _mesa_update_clamp_vertex_color(ctx, drawFb);
 711    _mesa_update_clamp_fragment_color(ctx, drawFb);
 712 }
 713
 714
 715 /**
 716  * Check if the renderbuffer for a read/draw operation exists.
 717  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 718  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 719  * \param reading  if TRUE, we're going to read from the buffer,
 720                    if FALSE, we're going to write to the buffer.
 721  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 722  */
 723 static GLboolean
 724 renderbuffer_exists(struct gl_context *ctx,
 725                     struct gl_framebuffer *fb,
 726                     GLenum format,
 727                     GLboolean reading)
 728 {
 729    const struct gl_renderbuffer_attachment *att = fb->Attachment;
 730
 731    /* If we don't know the framebuffer status, update it now */
 732    if (fb->_Status == 0) {
 733       _mesa_test_framebuffer_completeness(ctx, fb);
 734    }
 735
 736    if (fb->_Status != GL_FRAMEBUFFER_COMPLETE_EXT) {
 737       return GL_FALSE;
 738    }
 739
 740    switch (format) {
 741    case GL_COLOR:
 742    case GL_RED:
 743    case GL_GREEN:
 744    case GL_BLUE:
 745    case GL_ALPHA:
 746    case GL_LUMINANCE:
 747    case GL_LUMINANCE_ALPHA:
 748    case GL_INTENSITY:
 749    case GL_RG:
 750    case GL_RGB:
 751    case GL_BGR:
 752    case GL_RGBA:
 753    case GL_BGRA:
 754    case GL_ABGR_EXT:
 755    case GL_RED_INTEGER_EXT:
 756    case GL_RG_INTEGER:
 757    case GL_GREEN_INTEGER_EXT:
 758    case GL_BLUE_INTEGER_EXT:
 759    case GL_ALPHA_INTEGER_EXT:
 760    case GL_RGB_INTEGER_EXT:
 761    case GL_RGBA_INTEGER_EXT:
 762    case GL_BGR_INTEGER_EXT:
 763    case GL_BGRA_INTEGER_EXT:
 764    case GL_LUMINANCE_INTEGER_EXT:
 765    case GL_LUMINANCE_ALPHA_INTEGER_EXT:
 766       if (reading) {
 767          /* about to read from a color buffer */
 768          const struct gl_renderbuffer *readBuf = fb->_ColorReadBuffer;
 769          if (!readBuf) {
 770             return GL_FALSE;
 771          }
 772          assert(_mesa_get_format_bits(readBuf->Format, GL_RED_BITS) > 0 ||
 773                 _mesa_get_format_bits(readBuf->Format, GL_ALPHA_BITS) > 0 ||
 774                 _mesa_get_format_bits(readBuf->Format, GL_TEXTURE_LUMINANCE_SIZE) > 0 ||
 775                 _mesa_get_format_bits(readBuf->Format, GL_TEXTURE_INTENSITY_SIZE) > 0 ||
 776                 _mesa_get_format_bits(readBuf->Format, GL_INDEX_BITS) > 0);
 777       }
 778       else {
 779          /* about to draw to zero or more color buffers (none is OK) */
 780          return GL_TRUE;
 781       }
 782       break;
 783    case GL_DEPTH:
 784    case GL_DEPTH_COMPONENT:
 785       if (att[BUFFER_DEPTH].Type == GL_NONE) {
 786          return GL_FALSE;
 787       }
 788       break;
 789    case GL_STENCIL:
 790    case GL_STENCIL_INDEX:
 791       if (att[BUFFER_STENCIL].Type == GL_NONE) {
 792          return GL_FALSE;
 793       }
 794       break;
 795    case GL_DEPTH_STENCIL_EXT:
 796       if (att[BUFFER_DEPTH].Type == GL_NONE ||
 797           att[BUFFER_STENCIL].Type == GL_NONE) {
 798          return GL_FALSE;
 799       }
 800       break;
 801    default:
 802       _mesa_problem(ctx,
 803                     "Unexpected format 0x%x in renderbuffer_exists",
 804                     format);
 805       return GL_FALSE;
 806    }
 807
 808    /* OK */
 809    return GL_TRUE;
 810 }
 811
 812
 813 /**
 814  * Check if the renderbuffer for a read operation (glReadPixels, glCopyPixels,
 815  * glCopyTex[Sub]Image, etc) exists.
 816  * \param format  a basic image format such as GL_RGB, GL_RGBA, GL_ALPHA,
 817  *                GL_DEPTH_COMPONENT, etc. or GL_COLOR, GL_DEPTH, GL_STENCIL.
 818  * \return GL_TRUE if buffer exists, GL_FALSE otherwise
 819  */
 820 GLboolean
 821 _mesa_source_buffer_exists(struct gl_context *ctx, GLenum format)
 822 {
 823    return renderbuffer_exists(ctx, ctx->ReadBuffer, format, GL_TRUE);
 824 }
 825
 826
 827 /**
 828  * As above, but for drawing operations.
 829  */
 830 GLboolean
 831 _mesa_dest_buffer_exists(struct gl_context *ctx, GLenum format)
 832 {
 833    return renderbuffer_exists(ctx, ctx->DrawBuffer, format, GL_FALSE);
 834 }
 835
 836
 837 /**
 838  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_FORMAT_OES query.
 839  */
 840 GLenum
 841 _mesa_get_color_read_format(struct gl_context *ctx)
 842 {
 843    if (!ctx->ReadBuffer || !ctx->ReadBuffer->_ColorReadBuffer) {
 844       /* The spec is unclear how to handle this case, but NVIDIA's
 845        * driver generates GL_INVALID_OPERATION.
 846        */
 847       _mesa_error(ctx, GL_INVALID_OPERATION,
 848                   "glGetIntegerv(GL_IMPLEMENTATION_COLOR_READ_FORMAT: "
 849                   "no GL_READ_BUFFER)");
 850       return GL_NONE;
 851    }
 852    else {
 853       const mesa_format format = ctx->ReadBuffer->_ColorReadBuffer->Format;
 854       const GLenum data_type = _mesa_get_format_datatype(format);
 855
 856       if (format == MESA_FORMAT_B8G8R8A8_UNORM)
 857          return GL_BGRA;
 858       else if (format == MESA_FORMAT_B5G6R5_UNORM)
 859          return GL_RGB;
 860       else if (format == MESA_FORMAT_R_UNORM8)
 861          return GL_RED;
 862
 863       switch (data_type) {
 864       case GL_UNSIGNED_INT:
 865       case GL_INT:
 866          return GL_RGBA_INTEGER;
 867       default:
 868          return GL_RGBA;
 869       }
 870    }
 871 }
 872
 873
 874 /**
 875  * Used to answer the GL_IMPLEMENTATION_COLOR_READ_TYPE_OES query.
 876  */
 877 GLenum
 878 _mesa_get_color_read_type(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_TYPE: "
 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_B5G6R5_UNORM)
 894          return GL_UNSIGNED_SHORT_5_6_5;
 895
 896       switch (data_type) {
 897       case GL_SIGNED_NORMALIZED:
 898          return GL_BYTE;
 899       case GL_UNSIGNED_INT:
 900       case GL_INT:
 901       case GL_FLOAT:
 902          return data_type;
 903       case GL_UNSIGNED_NORMALIZED:
 904       default:
 905          return GL_UNSIGNED_BYTE;
 906       }
 907    }
 908 }
 909
 910
 911 /**
 912  * Returns the read renderbuffer for the specified format.
 913  */
 914 struct gl_renderbuffer *
 915 _mesa_get_read_renderbuffer_for_format(const struct gl_context *ctx,
 916                                        GLenum format)
 917 {
 918    const struct gl_framebuffer *rfb = ctx->ReadBuffer;
 919
 920    if (_mesa_is_color_format(format)) {
 921       return rfb->Attachment[rfb->_ColorReadBufferIndex].Renderbuffer;
 922    } else if (_mesa_is_depth_format(format) ||
 923               _mesa_is_depthstencil_format(format)) {
 924       return rfb->Attachment[BUFFER_DEPTH].Renderbuffer;
 925    } else {
 926       return rfb->Attachment[BUFFER_STENCIL].Renderbuffer;
 927    }
 928 }
 929
 930
 931 /**
 932  * Print framebuffer info to stderr, for debugging.
 933  */
 934 void
 935 _mesa_print_framebuffer(const struct gl_framebuffer *fb)
 936 {
 937    GLuint i;
 938
 939    fprintf(stderr, "Mesa Framebuffer %u at %p\n", fb->Name, (void *) fb);
 940    fprintf(stderr, "  Size: %u x %u  Status: %s\n", fb->Width, fb->Height,
 941            _mesa_enum_to_string(fb->_Status));
 942    fprintf(stderr, "  Attachments:\n");
 943
 944    for (i = 0; i < BUFFER_COUNT; i++) {
 945       const struct gl_renderbuffer_attachment *att = &fb->Attachment[i];
 946       if (att->Type == GL_TEXTURE) {
 947          const struct gl_texture_image *texImage = att->Renderbuffer->TexImage;
 948          fprintf(stderr,
 949                  "  %2d: Texture %u, level %u, face %u, slice %u, complete %d\n",
 950                  i, att->Texture->Name, att->TextureLevel, att->CubeMapFace,
 951                  att->Zoffset, att->Complete);
 952          fprintf(stderr, "       Size: %u x %u x %u  Format %s\n",
 953                  texImage->Width, texImage->Height, texImage->Depth,
 954                  _mesa_get_format_name(texImage->TexFormat));
 955       }
 956       else if (att->Type == GL_RENDERBUFFER) {
 957          fprintf(stderr, "  %2d: Renderbuffer %u, complete %d\n",
 958                  i, att->Renderbuffer->Name, att->Complete);
 959          fprintf(stderr, "       Size: %u x %u  Format %s\n",
 960                  att->Renderbuffer->Width, att->Renderbuffer->Height,
 961                  _mesa_get_format_name(att->Renderbuffer->Format));
 962       }
 963       else {
 964          fprintf(stderr, "  %2d: none\n", i);
 965       }
 966    }
 967 }
 968
 969 bool
 970 _mesa_is_front_buffer_reading(const struct gl_framebuffer *fb)
 971 {
 972    if (!fb || _mesa_is_user_fbo(fb))
 973       return false;
 974
 975    return fb->_ColorReadBufferIndex == BUFFER_FRONT_LEFT;
 976 }
 977
 978 bool
 979 _mesa_is_front_buffer_drawing(const struct gl_framebuffer *fb)
 980 {
 981    if (!fb || _mesa_is_user_fbo(fb))
 982       return false;
 983
 984    return (fb->_NumColorDrawBuffers >= 1 &&
 985            fb->_ColorDrawBufferIndexes[0] == BUFFER_FRONT_LEFT);
 986 }
 987
 988 static inline GLuint
 989 _mesa_geometric_nonvalidated_samples(const struct gl_framebuffer *buffer)
 990 {
 991    return buffer->_HasAttachments ?
 992       buffer->Visual.samples :
 993       buffer->DefaultGeometry.NumSamples;
 994 }
 995
 996 bool
 997 _mesa_is_multisample_enabled(const struct gl_context *ctx)
 998 {
 999    /* The sample count may not be validated by the driver, but when it is set,
1000     * we know that is in a valid range and no driver should ever validate a
1001     * multisampled framebuffer to non-multisampled and vice-versa.
1002     */
1003    return ctx->Multisample.Enabled &&
1004           ctx->DrawBuffer &&
1005           _mesa_geometric_nonvalidated_samples(ctx->DrawBuffer) >= 1;
1006 }
1007
1008 /**
1009  * Is alpha testing enabled and applicable to the currently bound
1010  * framebuffer?
1011  */
1012 bool
1013 _mesa_is_alpha_test_enabled(const struct gl_context *ctx)
1014 {
1015    bool buffer0_is_integer = ctx->DrawBuffer->_IntegerBuffers & 0x1;
1016    return (ctx->Color.AlphaEnabled && !buffer0_is_integer);
1017 }
1018
1019 /**
1020  * Is alpha to coverage enabled and applicable to the currently bound
1021  * framebuffer?
1022  */
1023 bool
1024 _mesa_is_alpha_to_coverage_enabled(const struct gl_context *ctx)
1025 {
1026    bool buffer0_is_integer = ctx->DrawBuffer->_IntegerBuffers & 0x1;
1027    return (ctx->Multisample.SampleAlphaToCoverage &&
1028            _mesa_is_multisample_enabled(ctx) &&
1029            !buffer0_is_integer);
1030 }