src/mesa/main/arrayobj.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
   5  * (C) Copyright IBM Corporation 2006
   6  * Copyright (C) 2009  VMware, Inc.  All Rights Reserved.
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a
   9  * copy of this software and associated documentation files (the "Software"),
  10  * to deal in the Software without restriction, including without limitation
  11  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  12  * and/or sell copies of the Software, and to permit persons to whom the
  13  * Software is furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included
  16  * in all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  21  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  22  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  23  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  24  * OTHER DEALINGS IN THE SOFTWARE.
  25  */
  26
  27
  28 /**
  29  * \file arrayobj.c
  30  *
  31  * Implementation of Vertex Array Objects (VAOs), from OpenGL 3.1+,
  32  * the GL_ARB_vertex_array_object extension, or the older
  33  * GL_APPLE_vertex_array_object extension.
  34  *
  35  * \todo
  36  * The code in this file borrows a lot from bufferobj.c.  There's a certain
  37  * amount of cruft left over from that origin that may be unnecessary.
  38  *
  39  * \author Ian Romanick <idr@us.ibm.com>
  40  * \author Brian Paul
  41  */
  42
  43
  44 #include "glheader.h"
  45 #include "hash.h"
  46 #include "image.h"
  47 #include "imports.h"
  48 #include "context.h"
  49 #include "bufferobj.h"
  50 #include "arrayobj.h"
  51 #include "macros.h"
  52 #include "mtypes.h"
  53 #include "varray.h"
  54 #include "main/dispatch.h"
  55 #include "util/bitscan.h"
  56
  57
  58 /**
  59  * Look up the array object for the given ID.
  60  *
  61  * \returns
  62  * Either a pointer to the array object with the specified ID or \c NULL for
  63  * a non-existent ID.  The spec defines ID 0 as being technically
  64  * non-existent.
  65  */
  66
  67 struct gl_vertex_array_object *
  68 _mesa_lookup_vao(struct gl_context *ctx, GLuint id)
  69 {
  70    if (id == 0)
  71       return NULL;
  72    else
  73       return (struct gl_vertex_array_object *)
  74          _mesa_HashLookup(ctx->Array.Objects, id);
  75 }
  76
  77
  78 /**
  79  * Looks up the array object for the given ID.
  80  *
  81  * Unlike _mesa_lookup_vao, this function generates a GL_INVALID_OPERATION
  82  * error if the array object does not exist. It also returns the default
  83  * array object when ctx is a compatibility profile context and id is zero.
  84  */
  85 struct gl_vertex_array_object *
  86 _mesa_lookup_vao_err(struct gl_context *ctx, GLuint id, const char *caller)
  87 {
  88    /* The ARB_direct_state_access specification says:
  89     *
  90     *    "<vaobj> is [compatibility profile:
  91     *     zero, indicating the default vertex array object, or]
  92     *     the name of the vertex array object."
  93     */
  94    if (id == 0) {
  95       if (ctx->API == API_OPENGL_CORE) {
  96          _mesa_error(ctx, GL_INVALID_OPERATION,
  97                      "%s(zero is not valid vaobj name in a core profile "
  98                      "context)", caller);
  99          return NULL;
 100       }
 101
 102       return ctx->Array.DefaultVAO;
 103    } else {
 104       struct gl_vertex_array_object *vao;
 105
 106       if (ctx->Array.LastLookedUpVAO &&
 107           ctx->Array.LastLookedUpVAO->Name == id) {
 108          vao = ctx->Array.LastLookedUpVAO;
 109       } else {
 110          vao = (struct gl_vertex_array_object *)
 111             _mesa_HashLookup(ctx->Array.Objects, id);
 112
 113          /* The ARB_direct_state_access specification says:
 114           *
 115           *    "An INVALID_OPERATION error is generated if <vaobj> is not
 116           *     [compatibility profile: zero or] the name of an existing
 117           *     vertex array object."
 118           */
 119          if (!vao || !vao->EverBound) {
 120             _mesa_error(ctx, GL_INVALID_OPERATION,
 121                         "%s(non-existent vaobj=%u)", caller, id);
 122             return NULL;
 123          }
 124
 125          _mesa_reference_vao(ctx, &ctx->Array.LastLookedUpVAO, vao);
 126       }
 127
 128       return vao;
 129    }
 130 }
 131
 132
 133 /**
 134  * For all the vertex binding points in the array object, unbind any pointers
 135  * to any buffer objects (VBOs).
 136  * This is done just prior to array object destruction.
 137  */
 138 static void
 139 unbind_array_object_vbos(struct gl_context *ctx, struct gl_vertex_array_object *obj)
 140 {
 141    GLuint i;
 142
 143    for (i = 0; i < ARRAY_SIZE(obj->BufferBinding); i++)
 144       _mesa_reference_buffer_object(ctx, &obj->BufferBinding[i].BufferObj, NULL);
 145
 146    for (i = 0; i < ARRAY_SIZE(obj->_VertexAttrib); i++)
 147       _mesa_reference_buffer_object(ctx, &obj->_VertexAttrib[i].BufferObj, NULL);
 148 }
 149
 150
 151 /**
 152  * Allocate and initialize a new vertex array object.
 153  */
 154 struct gl_vertex_array_object *
 155 _mesa_new_vao(struct gl_context *ctx, GLuint name)
 156 {
 157    struct gl_vertex_array_object *obj = CALLOC_STRUCT(gl_vertex_array_object);
 158    if (obj)
 159       _mesa_initialize_vao(ctx, obj, name);
 160    return obj;
 161 }
 162
 163
 164 /**
 165  * Delete an array object.
 166  */
 167 void
 168 _mesa_delete_vao(struct gl_context *ctx, struct gl_vertex_array_object *obj)
 169 {
 170    unbind_array_object_vbos(ctx, obj);
 171    _mesa_reference_buffer_object(ctx, &obj->IndexBufferObj, NULL);
 172    free(obj->Label);
 173    free(obj);
 174 }
 175
 176
 177 /**
 178  * Set ptr to vao w/ reference counting.
 179  * Note: this should only be called from the _mesa_reference_vao()
 180  * inline function.
 181  */
 182 void
 183 _mesa_reference_vao_(struct gl_context *ctx,
 184                      struct gl_vertex_array_object **ptr,
 185                      struct gl_vertex_array_object *vao)
 186 {
 187    assert(*ptr != vao);
 188
 189    if (*ptr) {
 190       /* Unreference the old array object */
 191       GLboolean deleteFlag = GL_FALSE;
 192       struct gl_vertex_array_object *oldObj = *ptr;
 193
 194       assert(oldObj->RefCount > 0);
 195       oldObj->RefCount--;
 196       deleteFlag = (oldObj->RefCount == 0);
 197
 198       if (deleteFlag)
 199          _mesa_delete_vao(ctx, oldObj);
 200
 201       *ptr = NULL;
 202    }
 203    assert(!*ptr);
 204
 205    if (vao) {
 206       /* reference new array object */
 207       assert(vao->RefCount > 0);
 208
 209       vao->RefCount++;
 210       *ptr = vao;
 211    }
 212 }
 213
 214
 215 /**
 216  * Initialize attribtes of a vertex array within a vertex array object.
 217  * \param vao  the container vertex array object
 218  * \param index  which array in the VAO to initialize
 219  * \param size  number of components (1, 2, 3 or 4) per attribute
 220  * \param type  datatype of the attribute (GL_FLOAT, GL_INT, etc).
 221  */
 222 static void
 223 init_array(struct gl_context *ctx,
 224            struct gl_vertex_array_object *vao,
 225            GLuint index, GLint size, GLint type)
 226 {
 227    struct gl_array_attributes *array = &vao->VertexAttrib[index];
 228    struct gl_vertex_buffer_binding *binding = &vao->BufferBinding[index];
 229
 230    array->Size = size;
 231    array->Type = type;
 232    array->Format = GL_RGBA; /* only significant for GL_EXT_vertex_array_bgra */
 233    array->Stride = 0;
 234    array->Ptr = NULL;
 235    array->RelativeOffset = 0;
 236    array->Enabled = GL_FALSE;
 237    array->Normalized = GL_FALSE;
 238    array->Integer = GL_FALSE;
 239    array->Doubles = GL_FALSE;
 240    array->_ElementSize = size * _mesa_sizeof_type(type);
 241    array->BufferBindingIndex = index;
 242
 243    binding->Offset = 0;
 244    binding->Stride = array->_ElementSize;
 245    binding->BufferObj = NULL;
 246    binding->_BoundArrays = BITFIELD64_BIT(index);
 247
 248    /* Vertex array buffers */
 249    _mesa_reference_buffer_object(ctx, &binding->BufferObj,
 250                                  ctx->Shared->NullBufferObj);
 251 }
 252
 253
 254 /**
 255  * Initialize a gl_vertex_array_object's arrays.
 256  */
 257 void
 258 _mesa_initialize_vao(struct gl_context *ctx,
 259                      struct gl_vertex_array_object *vao,
 260                      GLuint name)
 261 {
 262    GLuint i;
 263
 264    vao->Name = name;
 265
 266    vao->RefCount = 1;
 267
 268    /* Init the individual arrays */
 269    for (i = 0; i < ARRAY_SIZE(vao->VertexAttrib); i++) {
 270       switch (i) {
 271       case VERT_ATTRIB_WEIGHT:
 272          init_array(ctx, vao, VERT_ATTRIB_WEIGHT, 1, GL_FLOAT);
 273          break;
 274       case VERT_ATTRIB_NORMAL:
 275          init_array(ctx, vao, VERT_ATTRIB_NORMAL, 3, GL_FLOAT);
 276          break;
 277       case VERT_ATTRIB_COLOR1:
 278          init_array(ctx, vao, VERT_ATTRIB_COLOR1, 3, GL_FLOAT);
 279          break;
 280       case VERT_ATTRIB_FOG:
 281          init_array(ctx, vao, VERT_ATTRIB_FOG, 1, GL_FLOAT);
 282          break;
 283       case VERT_ATTRIB_COLOR_INDEX:
 284          init_array(ctx, vao, VERT_ATTRIB_COLOR_INDEX, 1, GL_FLOAT);
 285          break;
 286       case VERT_ATTRIB_EDGEFLAG:
 287          init_array(ctx, vao, VERT_ATTRIB_EDGEFLAG, 1, GL_BOOL);
 288          break;
 289       case VERT_ATTRIB_POINT_SIZE:
 290          init_array(ctx, vao, VERT_ATTRIB_POINT_SIZE, 1, GL_FLOAT);
 291          break;
 292       default:
 293          init_array(ctx, vao, i, 4, GL_FLOAT);
 294          break;
 295       }
 296    }
 297
 298    _mesa_reference_buffer_object(ctx, &vao->IndexBufferObj,
 299                                  ctx->Shared->NullBufferObj);
 300 }
 301
 302
 303 /**
 304  * Add the given array object to the array object pool.
 305  */
 306 static void
 307 save_array_object(struct gl_context *ctx, struct gl_vertex_array_object *vao)
 308 {
 309    if (vao->Name > 0) {
 310       /* insert into hash table */
 311       _mesa_HashInsert(ctx->Array.Objects, vao->Name, vao);
 312    }
 313 }
 314
 315
 316 /**
 317  * Remove the given array object from the array object pool.
 318  * Do not deallocate the array object though.
 319  */
 320 static void
 321 remove_array_object(struct gl_context *ctx, struct gl_vertex_array_object *vao)
 322 {
 323    if (vao->Name > 0) {
 324       /* remove from hash table */
 325       _mesa_HashRemove(ctx->Array.Objects, vao->Name);
 326    }
 327 }
 328
 329
 330 /**
 331  * Updates the derived gl_vertex_arrays when a gl_vertex_attrib_array
 332  * or a gl_vertex_buffer_binding has changed.
 333  */
 334 void
 335 _mesa_update_vao_client_arrays(struct gl_context *ctx,
 336                                struct gl_vertex_array_object *vao)
 337 {
 338    GLbitfield64 arrays = vao->NewArrays;
 339
 340    while (arrays) {
 341       const int attrib = u_bit_scan64(&arrays);
 342       struct gl_vertex_array *client_array = &vao->_VertexAttrib[attrib];
 343       const struct gl_array_attributes *attrib_array =
 344          &vao->VertexAttrib[attrib];
 345       const struct gl_vertex_buffer_binding *buffer_binding =
 346          &vao->BufferBinding[attrib_array->BufferBindingIndex];
 347
 348       _mesa_update_client_array(ctx, client_array, attrib_array,
 349                                 buffer_binding);
 350    }
 351 }
 352
 353
 354 bool
 355 _mesa_all_varyings_in_vbos(const struct gl_vertex_array_object *vao)
 356 {
 357    /* Walk those enabled arrays that have the default vbo attached */
 358    GLbitfield64 mask = vao->_Enabled & ~vao->VertexAttribBufferMask;
 359
 360    while (mask) {
 361       /* Do not use u_bit_scan64 as we can walk multiple
 362        * attrib arrays at once
 363        */
 364       const int i = ffsll(mask) - 1;
 365       const struct gl_array_attributes *attrib_array =
 366          &vao->VertexAttrib[i];
 367       const struct gl_vertex_buffer_binding *buffer_binding =
 368          &vao->BufferBinding[attrib_array->BufferBindingIndex];
 369
 370       /* Only enabled arrays shall appear in the _Enabled bitmask */
 371       assert(attrib_array->Enabled);
 372       /* We have already masked out vao->VertexAttribBufferMask  */
 373       assert(!_mesa_is_bufferobj(buffer_binding->BufferObj));
 374
 375       /* Bail out once we find the first non vbo with a non zero stride */
 376       if (buffer_binding->Stride != 0)
 377          return false;
 378
 379       /* Note that we cannot use the xor variant since the _BoundArray mask
 380        * may contain array attributes that are bound but not enabled.
 381        */
 382       mask &= ~buffer_binding->_BoundArrays;
 383    }
 384
 385    return true;
 386 }
 387
 388 bool
 389 _mesa_all_buffers_are_unmapped(const struct gl_vertex_array_object *vao)
 390 {
 391    /* Walk the enabled arrays that have a vbo attached */
 392    GLbitfield64 mask = vao->_Enabled & vao->VertexAttribBufferMask;
 393
 394    while (mask) {
 395       const int i = ffsll(mask) - 1;
 396       const struct gl_array_attributes *attrib_array =
 397          &vao->VertexAttrib[i];
 398       const struct gl_vertex_buffer_binding *buffer_binding =
 399          &vao->BufferBinding[attrib_array->BufferBindingIndex];
 400
 401       /* Only enabled arrays shall appear in the _Enabled bitmask */
 402       assert(attrib_array->Enabled);
 403       /* We have already masked with vao->VertexAttribBufferMask  */
 404       assert(_mesa_is_bufferobj(buffer_binding->BufferObj));
 405
 406       /* Bail out once we find the first disallowed mapping */
 407       if (_mesa_check_disallowed_mapping(buffer_binding->BufferObj))
 408          return false;
 409
 410       /* We have handled everything that is bound to this buffer_binding. */
 411       mask &= ~buffer_binding->_BoundArrays;
 412    }
 413
 414    return true;
 415 }
 416
 417 /**********************************************************************/
 418 /* API Functions                                                      */
 419 /**********************************************************************/
 420
 421
 422 /**
 423  * Helper for _mesa_BindVertexArray() and _mesa_BindVertexArrayAPPLE().
 424  * \param genRequired  specifies behavour when id was not generated with
 425  *                     glGenVertexArrays().
 426  */
 427 static void
 428 bind_vertex_array(struct gl_context *ctx, GLuint id, GLboolean genRequired)
 429 {
 430    struct gl_vertex_array_object * const oldObj = ctx->Array.VAO;
 431    struct gl_vertex_array_object *newObj = NULL;
 432
 433    assert(oldObj != NULL);
 434
 435    if ( oldObj->Name == id )
 436       return;   /* rebinding the same array object- no change */
 437
 438    /*
 439     * Get pointer to new array object (newObj)
 440     */
 441    if (id == 0) {
 442       /* The spec says there is no array object named 0, but we use
 443        * one internally because it simplifies things.
 444        */
 445       newObj = ctx->Array.DefaultVAO;
 446    }
 447    else {
 448       /* non-default array object */
 449       newObj = _mesa_lookup_vao(ctx, id);
 450       if (!newObj) {
 451          if (genRequired) {
 452             _mesa_error(ctx, GL_INVALID_OPERATION,
 453                         "glBindVertexArray(non-gen name)");
 454             return;
 455          }
 456
 457          /* For APPLE version, generate a new array object now */
 458          newObj = _mesa_new_vao(ctx, id);
 459          if (!newObj) {
 460             _mesa_error(ctx, GL_OUT_OF_MEMORY, "glBindVertexArrayAPPLE");
 461             return;
 462          }
 463
 464          save_array_object(ctx, newObj);
 465       }
 466
 467       if (!newObj->EverBound) {
 468          /* The "Interactions with APPLE_vertex_array_object" section of the
 469           * GL_ARB_vertex_array_object spec says:
 470           *
 471           *     "The first bind call, either BindVertexArray or
 472           *     BindVertexArrayAPPLE, determines the semantic of the object."
 473           */
 474          newObj->ARBsemantics = genRequired;
 475          newObj->EverBound = GL_TRUE;
 476       }
 477    }
 478
 479    if (ctx->Array.DrawMethod == DRAW_ARRAYS) {
 480       /* The _DrawArrays pointer is pointing at the VAO being unbound and
 481        * that VAO may be in the process of being deleted. If it's not going
 482        * to be deleted, this will have no effect, because the pointer needs
 483        * to be updated by the VBO module anyway.
 484        *
 485        * Before the VBO module can update the pointer, we have to set it
 486        * to NULL for drivers not to set up arrays which are not bound,
 487        * or to prevent a crash if the VAO being unbound is going to be
 488        * deleted.
 489        */
 490       ctx->Array._DrawArrays = NULL;
 491       ctx->Array.DrawMethod = DRAW_NONE;
 492    }
 493
 494    ctx->NewState |= _NEW_ARRAY;
 495    _mesa_reference_vao(ctx, &ctx->Array.VAO, newObj);
 496 }
 497
 498
 499 /**
 500  * ARB version of glBindVertexArray()
 501  * This function behaves differently from glBindVertexArrayAPPLE() in
 502  * that this function requires all ids to have been previously generated
 503  * by glGenVertexArrays[APPLE]().
 504  */
 505 void GLAPIENTRY
 506 _mesa_BindVertexArray( GLuint id )
 507 {
 508    GET_CURRENT_CONTEXT(ctx);
 509    bind_vertex_array(ctx, id, GL_TRUE);
 510 }
 511
 512
 513 /**
 514  * Bind a new array.
 515  *
 516  * \todo
 517  * The binding could be done more efficiently by comparing the non-NULL
 518  * pointers in the old and new objects.  The only arrays that are "dirty" are
 519  * the ones that are non-NULL in either object.
 520  */
 521 void GLAPIENTRY
 522 _mesa_BindVertexArrayAPPLE( GLuint id )
 523 {
 524    GET_CURRENT_CONTEXT(ctx);
 525    bind_vertex_array(ctx, id, GL_FALSE);
 526 }
 527
 528
 529 /**
 530  * Delete a set of array objects.
 531  *
 532  * \param n      Number of array objects to delete.
 533  * \param ids    Array of \c n array object IDs.
 534  */
 535 void GLAPIENTRY
 536 _mesa_DeleteVertexArrays(GLsizei n, const GLuint *ids)
 537 {
 538    GET_CURRENT_CONTEXT(ctx);
 539    GLsizei i;
 540
 541    if (n < 0) {
 542       _mesa_error(ctx, GL_INVALID_VALUE, "glDeleteVertexArray(n)");
 543       return;
 544    }
 545
 546    for (i = 0; i < n; i++) {
 547       struct gl_vertex_array_object *obj = _mesa_lookup_vao(ctx, ids[i]);
 548
 549       if ( obj != NULL ) {
 550          assert( obj->Name == ids[i] );
 551
 552          /* If the array object is currently bound, the spec says "the binding
 553           * for that object reverts to zero and the default vertex array
 554           * becomes current."
 555           */
 556          if ( obj == ctx->Array.VAO ) {
 557             _mesa_BindVertexArray(0);
 558          }
 559
 560          /* The ID is immediately freed for re-use */
 561          remove_array_object(ctx, obj);
 562
 563          if (ctx->Array.LastLookedUpVAO == obj)
 564             _mesa_reference_vao(ctx, &ctx->Array.LastLookedUpVAO, NULL);
 565
 566          /* Unreference the array object.
 567           * If refcount hits zero, the object will be deleted.
 568           */
 569          _mesa_reference_vao(ctx, &obj, NULL);
 570       }
 571    }
 572 }
 573
 574
 575 /**
 576  * Generate a set of unique array object IDs and store them in \c arrays.
 577  * Helper for _mesa_GenVertexArrays[APPLE]() and _mesa_CreateVertexArrays()
 578  * below.
 579  *
 580  * \param n       Number of IDs to generate.
 581  * \param arrays  Array of \c n locations to store the IDs.
 582  * \param create  Indicates that the objects should also be created.
 583  * \param func    The name of the GL entry point.
 584  */
 585 static void
 586 gen_vertex_arrays(struct gl_context *ctx, GLsizei n, GLuint *arrays,
 587                   bool create, const char *func)
 588 {
 589    GLuint first;
 590    GLint i;
 591
 592    if (n < 0) {
 593       _mesa_error(ctx, GL_INVALID_VALUE, "%s(n < 0)", func);
 594       return;
 595    }
 596
 597    if (!arrays) {
 598       return;
 599    }
 600
 601    first = _mesa_HashFindFreeKeyBlock(ctx->Array.Objects, n);
 602
 603    /* For the sake of simplicity we create the array objects in both
 604     * the Gen* and Create* cases.  The only difference is the value of
 605     * EverBound, which is set to true in the Create* case.
 606     */
 607    for (i = 0; i < n; i++) {
 608       struct gl_vertex_array_object *obj;
 609       GLuint name = first + i;
 610
 611       obj = _mesa_new_vao(ctx, name);
 612       if (!obj) {
 613          _mesa_error(ctx, GL_OUT_OF_MEMORY, "%s", func);
 614          return;
 615       }
 616       obj->EverBound = create;
 617       save_array_object(ctx, obj);
 618       arrays[i] = first + i;
 619    }
 620 }
 621
 622
 623 /**
 624  * ARB version of glGenVertexArrays()
 625  * All arrays will be required to live in VBOs.
 626  */
 627 void GLAPIENTRY
 628 _mesa_GenVertexArrays(GLsizei n, GLuint *arrays)
 629 {
 630    GET_CURRENT_CONTEXT(ctx);
 631    gen_vertex_arrays(ctx, n, arrays, false, "glGenVertexArrays");
 632 }
 633
 634
 635 /**
 636  * APPLE version of glGenVertexArraysAPPLE()
 637  * Arrays may live in VBOs or ordinary memory.
 638  */
 639 void GLAPIENTRY
 640 _mesa_GenVertexArraysAPPLE(GLsizei n, GLuint *arrays)
 641 {
 642    GET_CURRENT_CONTEXT(ctx);
 643    gen_vertex_arrays(ctx, n, arrays, false, "glGenVertexArraysAPPLE");
 644 }
 645
 646
 647 /**
 648  * ARB_direct_state_access
 649  * Generates ID's and creates the array objects.
 650  */
 651 void GLAPIENTRY
 652 _mesa_CreateVertexArrays(GLsizei n, GLuint *arrays)
 653 {
 654    GET_CURRENT_CONTEXT(ctx);
 655    gen_vertex_arrays(ctx, n, arrays, true, "glCreateVertexArrays");
 656 }
 657
 658
 659 /**
 660  * Determine if ID is the name of an array object.
 661  *
 662  * \param id  ID of the potential array object.
 663  * \return  \c GL_TRUE if \c id is the name of a array object,
 664  *          \c GL_FALSE otherwise.
 665  */
 666 GLboolean GLAPIENTRY
 667 _mesa_IsVertexArray( GLuint id )
 668 {
 669    struct gl_vertex_array_object * obj;
 670    GET_CURRENT_CONTEXT(ctx);
 671    ASSERT_OUTSIDE_BEGIN_END_WITH_RETVAL(ctx, GL_FALSE);
 672
 673    if (id == 0)
 674       return GL_FALSE;
 675
 676    obj = _mesa_lookup_vao(ctx, id);
 677    if (obj == NULL)
 678       return GL_FALSE;
 679
 680    return obj->EverBound;
 681 }
 682
 683
 684 /**
 685  * Sets the element array buffer binding of a vertex array object.
 686  *
 687  * This is the ARB_direct_state_access equivalent of
 688  * glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffer).
 689  */
 690 void GLAPIENTRY
 691 _mesa_VertexArrayElementBuffer(GLuint vaobj, GLuint buffer)
 692 {
 693    GET_CURRENT_CONTEXT(ctx);
 694    struct gl_vertex_array_object *vao;
 695    struct gl_buffer_object *bufObj;
 696
 697    ASSERT_OUTSIDE_BEGIN_END(ctx);
 698
 699    /* The GL_ARB_direct_state_access specification says:
 700     *
 701     *    "An INVALID_OPERATION error is generated by VertexArrayElementBuffer
 702     *     if <vaobj> is not [compatibility profile: zero or] the name of an
 703     *     existing vertex array object."
 704     */
 705    vao =_mesa_lookup_vao_err(ctx, vaobj, "glVertexArrayElementBuffer");
 706    if (!vao)
 707       return;
 708
 709    /* The GL_ARB_direct_state_access specification says:
 710     *
 711     *    "An INVALID_OPERATION error is generated if <buffer> is not zero or
 712     *     the name of an existing buffer object."
 713     */
 714    if (buffer != 0)
 715       bufObj = _mesa_lookup_bufferobj_err(ctx, buffer,
 716                                           "glVertexArrayElementBuffer");
 717    else
 718       bufObj = ctx->Shared->NullBufferObj;
 719
 720    if (bufObj)
 721       _mesa_reference_buffer_object(ctx, &vao->IndexBufferObj, bufObj);
 722 }
 723
 724
 725 void GLAPIENTRY
 726 _mesa_GetVertexArrayiv(GLuint vaobj, GLenum pname, GLint *param)
 727 {
 728    GET_CURRENT_CONTEXT(ctx);
 729    struct gl_vertex_array_object *vao;
 730
 731    ASSERT_OUTSIDE_BEGIN_END(ctx);
 732
 733    /* The GL_ARB_direct_state_access specification says:
 734     *
 735     *   "An INVALID_OPERATION error is generated if <vaobj> is not
 736     *    [compatibility profile: zero or] the name of an existing
 737     *    vertex array object."
 738     */
 739    vao =_mesa_lookup_vao_err(ctx, vaobj, "glGetVertexArrayiv");
 740    if (!vao)
 741       return;
 742
 743    /* The GL_ARB_direct_state_access specification says:
 744     *
 745     *   "An INVALID_ENUM error is generated if <pname> is not
 746     *    ELEMENT_ARRAY_BUFFER_BINDING."
 747     */
 748    if (pname != GL_ELEMENT_ARRAY_BUFFER_BINDING) {
 749       _mesa_error(ctx, GL_INVALID_ENUM,
 750                   "glGetVertexArrayiv(pname != "
 751                   "GL_ELEMENT_ARRAY_BUFFER_BINDING)");
 752       return;
 753    }
 754
 755    param[0] = vao->IndexBufferObj->Name;
 756 }