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
  56
  57 /**
  58  * Look up the array object for the given ID.
  59  *
  60  * \returns
  61  * Either a pointer to the array object with the specified ID or \c NULL for
  62  * a non-existent ID.  The spec defines ID 0 as being technically
  63  * non-existent.
  64  */
  65
  66 struct gl_vertex_array_object *
  67 _mesa_lookup_vao(struct gl_context *ctx, GLuint id)
  68 {
  69    if (id == 0)
  70       return NULL;
  71    else
  72       return (struct gl_vertex_array_object *)
  73          _mesa_HashLookup(ctx->Array.Objects, id);
  74 }
  75
  76
  77 /**
  78  * Looks up the array object for the given ID.
  79  *
  80  * Unlike _mesa_lookup_vao, this function generates a GL_INVALID_OPERATION
  81  * error if the array object does not exist. It also returns the default
  82  * array object when ctx is a compatibility profile context and id is zero.
  83  */
  84 struct gl_vertex_array_object *
  85 _mesa_lookup_vao_err(struct gl_context *ctx, GLuint id, const char *caller)
  86 {
  87    /* The ARB_direct_state_access specification says:
  88     *
  89     *    "<vaobj> is [compatibility profile:
  90     *     zero, indicating the default vertex array object, or]
  91     *     the name of the vertex array object."
  92     */
  93    if (id == 0) {
  94       if (ctx->API == API_OPENGL_CORE) {
  95          _mesa_error(ctx, GL_INVALID_OPERATION,
  96                      "%s(zero is not valid vaobj name in a core profile "
  97                      "context)", caller);
  98          return NULL;
  99       }
 100
 101       return ctx->Array.DefaultVAO;
 102    } else {
 103       struct gl_vertex_array_object *vao;
 104
 105       if (ctx->Array.LastLookedUpVAO &&
 106           ctx->Array.LastLookedUpVAO->Name == id) {
 107          vao = ctx->Array.LastLookedUpVAO;
 108       } else {
 109          vao = (struct gl_vertex_array_object *)
 110             _mesa_HashLookup(ctx->Array.Objects, id);
 111
 112          /* The ARB_direct_state_access specification says:
 113           *
 114           *    "An INVALID_OPERATION error is generated if <vaobj> is not
 115           *     [compatibility profile: zero or] the name of an existing
 116           *     vertex array object."
 117           */
 118          if (!vao || !vao->EverBound) {
 119             _mesa_error(ctx, GL_INVALID_OPERATION,
 120                         "%s(non-existent vaobj=%u)", caller, id);
 121             return NULL;
 122          }
 123
 124          _mesa_reference_vao(ctx, &ctx->Array.LastLookedUpVAO, vao);
 125       }
 126
 127       return vao;
 128    }
 129 }
 130
 131
 132 /**
 133  * For all the vertex binding points in the array object, unbind any pointers
 134  * to any buffer objects (VBOs).
 135  * This is done just prior to array object destruction.
 136  */
 137 static void
 138 unbind_array_object_vbos(struct gl_context *ctx, struct gl_vertex_array_object *obj)
 139 {
 140    GLuint i;
 141
 142    for (i = 0; i < ARRAY_SIZE(obj->VertexBinding); i++)
 143       _mesa_reference_buffer_object(ctx, &obj->VertexBinding[i].BufferObj, NULL);
 144
 145    for (i = 0; i < ARRAY_SIZE(obj->_VertexAttrib); i++)
 146       _mesa_reference_buffer_object(ctx, &obj->_VertexAttrib[i].BufferObj, NULL);
 147 }
 148
 149
 150 /**
 151  * Allocate and initialize a new vertex array object.
 152  */
 153 struct gl_vertex_array_object *
 154 _mesa_new_vao(struct gl_context *ctx, GLuint name)
 155 {
 156    struct gl_vertex_array_object *obj = CALLOC_STRUCT(gl_vertex_array_object);
 157    if (obj)
 158       _mesa_initialize_vao(ctx, obj, name);
 159    return obj;
 160 }
 161
 162
 163 /**
 164  * Delete an array object.
 165  */
 166 void
 167 _mesa_delete_vao(struct gl_context *ctx, struct gl_vertex_array_object *obj)
 168 {
 169    unbind_array_object_vbos(ctx, obj);
 170    _mesa_reference_buffer_object(ctx, &obj->IndexBufferObj, NULL);
 171    mtx_destroy(&obj->Mutex);
 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       mtx_lock(&oldObj->Mutex);
 195       assert(oldObj->RefCount > 0);
 196       oldObj->RefCount--;
 197       deleteFlag = (oldObj->RefCount == 0);
 198       mtx_unlock(&oldObj->Mutex);
 199
 200       if (deleteFlag)
 201          _mesa_delete_vao(ctx, oldObj);
 202
 203       *ptr = NULL;
 204    }
 205    assert(!*ptr);
 206
 207    if (vao) {
 208       /* reference new array object */
 209       mtx_lock(&vao->Mutex);
 210       if (vao->RefCount == 0) {
 211          /* this array's being deleted (look just above) */
 212          /* Not sure this can every really happen.  Warn if it does. */
 213          _mesa_problem(NULL, "referencing deleted array object");
 214          *ptr = NULL;
 215       }
 216       else {
 217          vao->RefCount++;
 218          *ptr = vao;
 219       }
 220       mtx_unlock(&vao->Mutex);
 221    }
 222 }
 223
 224
 225
 226 static void
 227 init_array(struct gl_context *ctx,
 228            struct gl_vertex_array_object *obj, GLuint index, GLint size, GLint type)
 229 {
 230    struct gl_vertex_attrib_array *array = &obj->VertexAttrib[index];
 231    struct gl_vertex_buffer_binding *binding = &obj->VertexBinding[index];
 232
 233    array->Size = size;
 234    array->Type = type;
 235    array->Format = GL_RGBA; /* only significant for GL_EXT_vertex_array_bgra */
 236    array->Stride = 0;
 237    array->Ptr = NULL;
 238    array->RelativeOffset = 0;
 239    array->Enabled = GL_FALSE;
 240    array->Normalized = GL_FALSE;
 241    array->Integer = GL_FALSE;
 242    array->Doubles = GL_FALSE;
 243    array->_ElementSize = size * _mesa_sizeof_type(type);
 244    array->VertexBinding = index;
 245
 246    binding->Offset = 0;
 247    binding->Stride = array->_ElementSize;
 248    binding->BufferObj = NULL;
 249    binding->_BoundArrays = BITFIELD64_BIT(index);
 250
 251    /* Vertex array buffers */
 252    _mesa_reference_buffer_object(ctx, &binding->BufferObj,
 253                                  ctx->Shared->NullBufferObj);
 254 }
 255
 256
 257 /**
 258  * Initialize a gl_vertex_array_object's arrays.
 259  */
 260 void
 261 _mesa_initialize_vao(struct gl_context *ctx,
 262                      struct gl_vertex_array_object *obj,
 263                      GLuint name)
 264 {
 265    GLuint i;
 266
 267    obj->Name = name;
 268
 269    mtx_init(&obj->Mutex, mtx_plain);
 270    obj->RefCount = 1;
 271
 272    /* Init the individual arrays */
 273    for (i = 0; i < ARRAY_SIZE(obj->VertexAttrib); i++) {
 274       switch (i) {
 275       case VERT_ATTRIB_WEIGHT:
 276          init_array(ctx, obj, VERT_ATTRIB_WEIGHT, 1, GL_FLOAT);
 277          break;
 278       case VERT_ATTRIB_NORMAL:
 279          init_array(ctx, obj, VERT_ATTRIB_NORMAL, 3, GL_FLOAT);
 280          break;
 281       case VERT_ATTRIB_COLOR1:
 282          init_array(ctx, obj, VERT_ATTRIB_COLOR1, 3, GL_FLOAT);
 283          break;
 284       case VERT_ATTRIB_FOG:
 285          init_array(ctx, obj, VERT_ATTRIB_FOG, 1, GL_FLOAT);
 286          break;
 287       case VERT_ATTRIB_COLOR_INDEX:
 288          init_array(ctx, obj, VERT_ATTRIB_COLOR_INDEX, 1, GL_FLOAT);
 289          break;
 290       case VERT_ATTRIB_EDGEFLAG:
 291          init_array(ctx, obj, VERT_ATTRIB_EDGEFLAG, 1, GL_BOOL);
 292          break;
 293       case VERT_ATTRIB_POINT_SIZE:
 294          init_array(ctx, obj, VERT_ATTRIB_POINT_SIZE, 1, GL_FLOAT);
 295          break;
 296       default:
 297          init_array(ctx, obj, i, 4, GL_FLOAT);
 298          break;
 299       }
 300    }
 301
 302    _mesa_reference_buffer_object(ctx, &obj->IndexBufferObj,
 303                                  ctx->Shared->NullBufferObj);
 304 }
 305
 306
 307 /**
 308  * Add the given array object to the array object pool.
 309  */
 310 static void
 311 save_array_object( struct gl_context *ctx, struct gl_vertex_array_object *obj )
 312 {
 313    if (obj->Name > 0) {
 314       /* insert into hash table */
 315       _mesa_HashInsert(ctx->Array.Objects, obj->Name, obj);
 316    }
 317 }
 318
 319
 320 /**
 321  * Remove the given array object from the array object pool.
 322  * Do not deallocate the array object though.
 323  */
 324 static void
 325 remove_array_object( struct gl_context *ctx, struct gl_vertex_array_object *obj )
 326 {
 327    if (obj->Name > 0) {
 328       /* remove from hash table */
 329       _mesa_HashRemove(ctx->Array.Objects, obj->Name);
 330    }
 331 }
 332
 333
 334 /**
 335  * Updates the derived gl_client_arrays when a gl_vertex_attrib_array
 336  * or a gl_vertex_buffer_binding has changed.
 337  */
 338 void
 339 _mesa_update_vao_client_arrays(struct gl_context *ctx,
 340                                struct gl_vertex_array_object *vao)
 341 {
 342    GLbitfield64 arrays = vao->NewArrays;
 343
 344    while (arrays) {
 345       struct gl_client_array *client_array;
 346       struct gl_vertex_attrib_array *attrib_array;
 347       struct gl_vertex_buffer_binding *buffer_binding;
 348
 349       GLint attrib = ffsll(arrays) - 1;
 350       arrays ^= BITFIELD64_BIT(attrib);
 351
 352       attrib_array = &vao->VertexAttrib[attrib];
 353       buffer_binding = &vao->VertexBinding[attrib_array->VertexBinding];
 354       client_array = &vao->_VertexAttrib[attrib];
 355
 356       _mesa_update_client_array(ctx, client_array, attrib_array,
 357                                 buffer_binding);
 358    }
 359 }
 360
 361
 362 /**********************************************************************/
 363 /* API Functions                                                      */
 364 /**********************************************************************/
 365
 366
 367 /**
 368  * Helper for _mesa_BindVertexArray() and _mesa_BindVertexArrayAPPLE().
 369  * \param genRequired  specifies behavour when id was not generated with
 370  *                     glGenVertexArrays().
 371  */
 372 static void
 373 bind_vertex_array(struct gl_context *ctx, GLuint id, GLboolean genRequired)
 374 {
 375    struct gl_vertex_array_object * const oldObj = ctx->Array.VAO;
 376    struct gl_vertex_array_object *newObj = NULL;
 377
 378    assert(oldObj != NULL);
 379
 380    if ( oldObj->Name == id )
 381       return;   /* rebinding the same array object- no change */
 382
 383    /*
 384     * Get pointer to new array object (newObj)
 385     */
 386    if (id == 0) {
 387       /* The spec says there is no array object named 0, but we use
 388        * one internally because it simplifies things.
 389        */
 390       newObj = ctx->Array.DefaultVAO;
 391    }
 392    else {
 393       /* non-default array object */
 394       newObj = _mesa_lookup_vao(ctx, id);
 395       if (!newObj) {
 396          if (genRequired) {
 397             _mesa_error(ctx, GL_INVALID_OPERATION,
 398                         "glBindVertexArray(non-gen name)");
 399             return;
 400          }
 401
 402          /* For APPLE version, generate a new array object now */
 403          newObj = _mesa_new_vao(ctx, id);
 404          if (!newObj) {
 405             _mesa_error(ctx, GL_OUT_OF_MEMORY, "glBindVertexArrayAPPLE");
 406             return;
 407          }
 408
 409          save_array_object(ctx, newObj);
 410       }
 411
 412       if (!newObj->EverBound) {
 413          /* The "Interactions with APPLE_vertex_array_object" section of the
 414           * GL_ARB_vertex_array_object spec says:
 415           *
 416           *     "The first bind call, either BindVertexArray or
 417           *     BindVertexArrayAPPLE, determines the semantic of the object."
 418           */
 419          newObj->ARBsemantics = genRequired;
 420          newObj->EverBound = GL_TRUE;
 421       }
 422    }
 423
 424    if (ctx->Array.DrawMethod == DRAW_ARRAYS) {
 425       /* The _DrawArrays pointer is pointing at the VAO being unbound and
 426        * that VAO may be in the process of being deleted. If it's not going
 427        * to be deleted, this will have no effect, because the pointer needs
 428        * to be updated by the VBO module anyway.
 429        *
 430        * Before the VBO module can update the pointer, we have to set it
 431        * to NULL for drivers not to set up arrays which are not bound,
 432        * or to prevent a crash if the VAO being unbound is going to be
 433        * deleted.
 434        */
 435       ctx->Array._DrawArrays = NULL;
 436       ctx->Array.DrawMethod = DRAW_NONE;
 437    }
 438
 439    ctx->NewState |= _NEW_ARRAY;
 440    _mesa_reference_vao(ctx, &ctx->Array.VAO, newObj);
 441 }
 442
 443
 444 /**
 445  * ARB version of glBindVertexArray()
 446  * This function behaves differently from glBindVertexArrayAPPLE() in
 447  * that this function requires all ids to have been previously generated
 448  * by glGenVertexArrays[APPLE]().
 449  */
 450 void GLAPIENTRY
 451 _mesa_BindVertexArray( GLuint id )
 452 {
 453    GET_CURRENT_CONTEXT(ctx);
 454    bind_vertex_array(ctx, id, GL_TRUE);
 455 }
 456
 457
 458 /**
 459  * Bind a new array.
 460  *
 461  * \todo
 462  * The binding could be done more efficiently by comparing the non-NULL
 463  * pointers in the old and new objects.  The only arrays that are "dirty" are
 464  * the ones that are non-NULL in either object.
 465  */
 466 void GLAPIENTRY
 467 _mesa_BindVertexArrayAPPLE( GLuint id )
 468 {
 469    GET_CURRENT_CONTEXT(ctx);
 470    bind_vertex_array(ctx, id, GL_FALSE);
 471 }
 472
 473
 474 /**
 475  * Delete a set of array objects.
 476  *
 477  * \param n      Number of array objects to delete.
 478  * \param ids    Array of \c n array object IDs.
 479  */
 480 void GLAPIENTRY
 481 _mesa_DeleteVertexArrays(GLsizei n, const GLuint *ids)
 482 {
 483    GET_CURRENT_CONTEXT(ctx);
 484    GLsizei i;
 485
 486    if (n < 0) {
 487       _mesa_error(ctx, GL_INVALID_VALUE, "glDeleteVertexArray(n)");
 488       return;
 489    }
 490
 491    for (i = 0; i < n; i++) {
 492       struct gl_vertex_array_object *obj = _mesa_lookup_vao(ctx, ids[i]);
 493
 494       if ( obj != NULL ) {
 495          assert( obj->Name == ids[i] );
 496
 497          /* If the array object is currently bound, the spec says "the binding
 498           * for that object reverts to zero and the default vertex array
 499           * becomes current."
 500           */
 501          if ( obj == ctx->Array.VAO ) {
 502             _mesa_BindVertexArray(0);
 503          }
 504
 505          /* The ID is immediately freed for re-use */
 506          remove_array_object(ctx, obj);
 507
 508          if (ctx->Array.LastLookedUpVAO == obj)
 509             _mesa_reference_vao(ctx, &ctx->Array.LastLookedUpVAO, NULL);
 510
 511          /* Unreference the array object.
 512           * If refcount hits zero, the object will be deleted.
 513           */
 514          _mesa_reference_vao(ctx, &obj, NULL);
 515       }
 516    }
 517 }
 518
 519
 520 /**
 521  * Generate a set of unique array object IDs and store them in \c arrays.
 522  * Helper for _mesa_GenVertexArrays[APPLE]() and _mesa_CreateVertexArrays()
 523  * below.
 524  *
 525  * \param n       Number of IDs to generate.
 526  * \param arrays  Array of \c n locations to store the IDs.
 527  * \param create  Indicates that the objects should also be created.
 528  * \param func    The name of the GL entry point.
 529  */
 530 static void
 531 gen_vertex_arrays(struct gl_context *ctx, GLsizei n, GLuint *arrays,
 532                   bool create, const char *func)
 533 {
 534    GLuint first;
 535    GLint i;
 536
 537    if (n < 0) {
 538       _mesa_error(ctx, GL_INVALID_VALUE, "%s(n < 0)", func);
 539       return;
 540    }
 541
 542    if (!arrays) {
 543       return;
 544    }
 545
 546    first = _mesa_HashFindFreeKeyBlock(ctx->Array.Objects, n);
 547
 548    /* For the sake of simplicity we create the array objects in both
 549     * the Gen* and Create* cases.  The only difference is the value of
 550     * EverBound, which is set to true in the Create* case.
 551     */
 552    for (i = 0; i < n; i++) {
 553       struct gl_vertex_array_object *obj;
 554       GLuint name = first + i;
 555
 556       obj = _mesa_new_vao(ctx, name);
 557       if (!obj) {
 558          _mesa_error(ctx, GL_OUT_OF_MEMORY, "%s", func);
 559          return;
 560       }
 561       obj->EverBound = create;
 562       save_array_object(ctx, obj);
 563       arrays[i] = first + i;
 564    }
 565 }
 566
 567
 568 /**
 569  * ARB version of glGenVertexArrays()
 570  * All arrays will be required to live in VBOs.
 571  */
 572 void GLAPIENTRY
 573 _mesa_GenVertexArrays(GLsizei n, GLuint *arrays)
 574 {
 575    GET_CURRENT_CONTEXT(ctx);
 576    gen_vertex_arrays(ctx, n, arrays, false, "glGenVertexArrays");
 577 }
 578
 579
 580 /**
 581  * APPLE version of glGenVertexArraysAPPLE()
 582  * Arrays may live in VBOs or ordinary memory.
 583  */
 584 void GLAPIENTRY
 585 _mesa_GenVertexArraysAPPLE(GLsizei n, GLuint *arrays)
 586 {
 587    GET_CURRENT_CONTEXT(ctx);
 588    gen_vertex_arrays(ctx, n, arrays, false, "glGenVertexArraysAPPLE");
 589 }
 590
 591
 592 /**
 593  * ARB_direct_state_access
 594  * Generates ID's and creates the array objects.
 595  */
 596 void GLAPIENTRY
 597 _mesa_CreateVertexArrays(GLsizei n, GLuint *arrays)
 598 {
 599    GET_CURRENT_CONTEXT(ctx);
 600    gen_vertex_arrays(ctx, n, arrays, true, "glCreateVertexArrays");
 601 }
 602
 603
 604 /**
 605  * Determine if ID is the name of an array object.
 606  *
 607  * \param id  ID of the potential array object.
 608  * \return  \c GL_TRUE if \c id is the name of a array object,
 609  *          \c GL_FALSE otherwise.
 610  */
 611 GLboolean GLAPIENTRY
 612 _mesa_IsVertexArray( GLuint id )
 613 {
 614    struct gl_vertex_array_object * obj;
 615    GET_CURRENT_CONTEXT(ctx);
 616    ASSERT_OUTSIDE_BEGIN_END_WITH_RETVAL(ctx, GL_FALSE);
 617
 618    if (id == 0)
 619       return GL_FALSE;
 620
 621    obj = _mesa_lookup_vao(ctx, id);
 622    if (obj == NULL)
 623       return GL_FALSE;
 624
 625    return obj->EverBound;
 626 }
 627
 628
 629 /**
 630  * Sets the element array buffer binding of a vertex array object.
 631  *
 632  * This is the ARB_direct_state_access equivalent of
 633  * glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffer).
 634  */
 635 void GLAPIENTRY
 636 _mesa_VertexArrayElementBuffer(GLuint vaobj, GLuint buffer)
 637 {
 638    GET_CURRENT_CONTEXT(ctx);
 639    struct gl_vertex_array_object *vao;
 640    struct gl_buffer_object *bufObj;
 641
 642    ASSERT_OUTSIDE_BEGIN_END(ctx);
 643
 644    /* The GL_ARB_direct_state_access specification says:
 645     *
 646     *    "An INVALID_OPERATION error is generated by VertexArrayElementBuffer
 647     *     if <vaobj> is not [compatibility profile: zero or] the name of an
 648     *     existing vertex array object."
 649     */
 650    vao =_mesa_lookup_vao_err(ctx, vaobj, "glVertexArrayElementBuffer");
 651    if (!vao)
 652       return;
 653
 654    /* The GL_ARB_direct_state_access specification says:
 655     *
 656     *    "An INVALID_OPERATION error is generated if <buffer> is not zero or
 657     *     the name of an existing buffer object."
 658     */
 659    if (buffer != 0)
 660       bufObj = _mesa_lookup_bufferobj_err(ctx, buffer,
 661                                           "glVertexArrayElementBuffer");
 662    else
 663       bufObj = ctx->Shared->NullBufferObj;
 664
 665    if (bufObj)
 666       _mesa_reference_buffer_object(ctx, &vao->IndexBufferObj, bufObj);
 667 }
 668
 669
 670 void GLAPIENTRY
 671 _mesa_GetVertexArrayiv(GLuint vaobj, GLenum pname, GLint *param)
 672 {
 673    GET_CURRENT_CONTEXT(ctx);
 674    struct gl_vertex_array_object *vao;
 675
 676    ASSERT_OUTSIDE_BEGIN_END(ctx);
 677
 678    /* The GL_ARB_direct_state_access specification says:
 679     *
 680     *   "An INVALID_OPERATION error is generated if <vaobj> is not
 681     *    [compatibility profile: zero or] the name of an existing
 682     *    vertex array object."
 683     */
 684    vao =_mesa_lookup_vao_err(ctx, vaobj, "glGetVertexArrayiv");
 685    if (!vao)
 686       return;
 687
 688    /* The GL_ARB_direct_state_access specification says:
 689     *
 690     *   "An INVALID_ENUM error is generated if <pname> is not
 691     *    ELEMENT_ARRAY_BUFFER_BINDING."
 692     */
 693    if (pname != GL_ELEMENT_ARRAY_BUFFER_BINDING) {
 694       _mesa_error(ctx, GL_INVALID_ENUM,
 695                   "glGetVertexArrayiv(pname != "
 696                   "GL_ELEMENT_ARRAY_BUFFER_BINDING)");
 697       return;
 698    }
 699
 700    param[0] = vao->IndexBufferObj->Name;
 701 }