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  * This function is intended to be called via
 154  * \c dd_function_table::NewArrayObject.
 155  */
 156 struct gl_vertex_array_object *
 157 _mesa_new_vao(struct gl_context *ctx, GLuint name)
 158 {
 159    struct gl_vertex_array_object *obj = CALLOC_STRUCT(gl_vertex_array_object);
 160    if (obj)
 161       _mesa_initialize_vao(ctx, obj, name);
 162    return obj;
 163 }
 164
 165
 166 /**
 167  * Delete an array object.
 168  *
 169  * This function is intended to be called via
 170  * \c dd_function_table::DeleteArrayObject.
 171  */
 172 void
 173 _mesa_delete_vao(struct gl_context *ctx, struct gl_vertex_array_object *obj)
 174 {
 175    unbind_array_object_vbos(ctx, obj);
 176    _mesa_reference_buffer_object(ctx, &obj->IndexBufferObj, NULL);
 177    mtx_destroy(&obj->Mutex);
 178    free(obj->Label);
 179    free(obj);
 180 }
 181
 182
 183 /**
 184  * Set ptr to vao w/ reference counting.
 185  * Note: this should only be called from the _mesa_reference_vao()
 186  * inline function.
 187  */
 188 void
 189 _mesa_reference_vao_(struct gl_context *ctx,
 190                      struct gl_vertex_array_object **ptr,
 191                      struct gl_vertex_array_object *vao)
 192 {
 193    assert(*ptr != vao);
 194
 195    if (*ptr) {
 196       /* Unreference the old array object */
 197       GLboolean deleteFlag = GL_FALSE;
 198       struct gl_vertex_array_object *oldObj = *ptr;
 199
 200       mtx_lock(&oldObj->Mutex);
 201       assert(oldObj->RefCount > 0);
 202       oldObj->RefCount--;
 203       deleteFlag = (oldObj->RefCount == 0);
 204       mtx_unlock(&oldObj->Mutex);
 205
 206       if (deleteFlag) {
 207          assert(ctx->Driver.DeleteArrayObject);
 208          ctx->Driver.DeleteArrayObject(ctx, oldObj);
 209       }
 210
 211       *ptr = NULL;
 212    }
 213    assert(!*ptr);
 214
 215    if (vao) {
 216       /* reference new array object */
 217       mtx_lock(&vao->Mutex);
 218       if (vao->RefCount == 0) {
 219          /* this array's being deleted (look just above) */
 220          /* Not sure this can every really happen.  Warn if it does. */
 221          _mesa_problem(NULL, "referencing deleted array object");
 222          *ptr = NULL;
 223       }
 224       else {
 225          vao->RefCount++;
 226          *ptr = vao;
 227       }
 228       mtx_unlock(&vao->Mutex);
 229    }
 230 }
 231
 232
 233
 234 static void
 235 init_array(struct gl_context *ctx,
 236            struct gl_vertex_array_object *obj, GLuint index, GLint size, GLint type)
 237 {
 238    struct gl_vertex_attrib_array *array = &obj->VertexAttrib[index];
 239    struct gl_vertex_buffer_binding *binding = &obj->VertexBinding[index];
 240
 241    array->Size = size;
 242    array->Type = type;
 243    array->Format = GL_RGBA; /* only significant for GL_EXT_vertex_array_bgra */
 244    array->Stride = 0;
 245    array->Ptr = NULL;
 246    array->RelativeOffset = 0;
 247    array->Enabled = GL_FALSE;
 248    array->Normalized = GL_FALSE;
 249    array->Integer = GL_FALSE;
 250    array->Doubles = GL_FALSE;
 251    array->_ElementSize = size * _mesa_sizeof_type(type);
 252    array->VertexBinding = index;
 253
 254    binding->Offset = 0;
 255    binding->Stride = array->_ElementSize;
 256    binding->BufferObj = NULL;
 257    binding->_BoundArrays = BITFIELD64_BIT(index);
 258
 259    /* Vertex array buffers */
 260    _mesa_reference_buffer_object(ctx, &binding->BufferObj,
 261                                  ctx->Shared->NullBufferObj);
 262 }
 263
 264
 265 /**
 266  * Initialize a gl_vertex_array_object's arrays.
 267  */
 268 void
 269 _mesa_initialize_vao(struct gl_context *ctx,
 270                      struct gl_vertex_array_object *obj,
 271                      GLuint name)
 272 {
 273    GLuint i;
 274
 275    obj->Name = name;
 276
 277    mtx_init(&obj->Mutex, mtx_plain);
 278    obj->RefCount = 1;
 279
 280    /* Init the individual arrays */
 281    for (i = 0; i < ARRAY_SIZE(obj->VertexAttrib); i++) {
 282       switch (i) {
 283       case VERT_ATTRIB_WEIGHT:
 284          init_array(ctx, obj, VERT_ATTRIB_WEIGHT, 1, GL_FLOAT);
 285          break;
 286       case VERT_ATTRIB_NORMAL:
 287          init_array(ctx, obj, VERT_ATTRIB_NORMAL, 3, GL_FLOAT);
 288          break;
 289       case VERT_ATTRIB_COLOR1:
 290          init_array(ctx, obj, VERT_ATTRIB_COLOR1, 3, GL_FLOAT);
 291          break;
 292       case VERT_ATTRIB_FOG:
 293          init_array(ctx, obj, VERT_ATTRIB_FOG, 1, GL_FLOAT);
 294          break;
 295       case VERT_ATTRIB_COLOR_INDEX:
 296          init_array(ctx, obj, VERT_ATTRIB_COLOR_INDEX, 1, GL_FLOAT);
 297          break;
 298       case VERT_ATTRIB_EDGEFLAG:
 299          init_array(ctx, obj, VERT_ATTRIB_EDGEFLAG, 1, GL_BOOL);
 300          break;
 301       case VERT_ATTRIB_POINT_SIZE:
 302          init_array(ctx, obj, VERT_ATTRIB_POINT_SIZE, 1, GL_FLOAT);
 303          break;
 304       default:
 305          init_array(ctx, obj, i, 4, GL_FLOAT);
 306          break;
 307       }
 308    }
 309
 310    _mesa_reference_buffer_object(ctx, &obj->IndexBufferObj,
 311                                  ctx->Shared->NullBufferObj);
 312 }
 313
 314
 315 /**
 316  * Add the given array object to the array object pool.
 317  */
 318 static void
 319 save_array_object( struct gl_context *ctx, struct gl_vertex_array_object *obj )
 320 {
 321    if (obj->Name > 0) {
 322       /* insert into hash table */
 323       _mesa_HashInsert(ctx->Array.Objects, obj->Name, obj);
 324    }
 325 }
 326
 327
 328 /**
 329  * Remove the given array object from the array object pool.
 330  * Do not deallocate the array object though.
 331  */
 332 static void
 333 remove_array_object( struct gl_context *ctx, struct gl_vertex_array_object *obj )
 334 {
 335    if (obj->Name > 0) {
 336       /* remove from hash table */
 337       _mesa_HashRemove(ctx->Array.Objects, obj->Name);
 338    }
 339 }
 340
 341
 342 /**
 343  * Updates the derived gl_client_arrays when a gl_vertex_attrib_array
 344  * or a gl_vertex_buffer_binding has changed.
 345  */
 346 void
 347 _mesa_update_vao_client_arrays(struct gl_context *ctx,
 348                                struct gl_vertex_array_object *vao)
 349 {
 350    GLbitfield64 arrays = vao->NewArrays;
 351
 352    while (arrays) {
 353       struct gl_client_array *client_array;
 354       struct gl_vertex_attrib_array *attrib_array;
 355       struct gl_vertex_buffer_binding *buffer_binding;
 356
 357       GLint attrib = ffsll(arrays) - 1;
 358       arrays ^= BITFIELD64_BIT(attrib);
 359
 360       attrib_array = &vao->VertexAttrib[attrib];
 361       buffer_binding = &vao->VertexBinding[attrib_array->VertexBinding];
 362       client_array = &vao->_VertexAttrib[attrib];
 363
 364       _mesa_update_client_array(ctx, client_array, attrib_array,
 365                                 buffer_binding);
 366    }
 367 }
 368
 369
 370 /**********************************************************************/
 371 /* API Functions                                                      */
 372 /**********************************************************************/
 373
 374
 375 /**
 376  * Helper for _mesa_BindVertexArray() and _mesa_BindVertexArrayAPPLE().
 377  * \param genRequired  specifies behavour when id was not generated with
 378  *                     glGenVertexArrays().
 379  */
 380 static void
 381 bind_vertex_array(struct gl_context *ctx, GLuint id, GLboolean genRequired)
 382 {
 383    struct gl_vertex_array_object * const oldObj = ctx->Array.VAO;
 384    struct gl_vertex_array_object *newObj = NULL;
 385
 386    assert(oldObj != NULL);
 387
 388    if ( oldObj->Name == id )
 389       return;   /* rebinding the same array object- no change */
 390
 391    /*
 392     * Get pointer to new array object (newObj)
 393     */
 394    if (id == 0) {
 395       /* The spec says there is no array object named 0, but we use
 396        * one internally because it simplifies things.
 397        */
 398       newObj = ctx->Array.DefaultVAO;
 399    }
 400    else {
 401       /* non-default array object */
 402       newObj = _mesa_lookup_vao(ctx, id);
 403       if (!newObj) {
 404          if (genRequired) {
 405             _mesa_error(ctx, GL_INVALID_OPERATION,
 406                         "glBindVertexArray(non-gen name)");
 407             return;
 408          }
 409
 410          /* For APPLE version, generate a new array object now */
 411          newObj = (*ctx->Driver.NewArrayObject)(ctx, id);
 412          if (!newObj) {
 413             _mesa_error(ctx, GL_OUT_OF_MEMORY, "glBindVertexArrayAPPLE");
 414             return;
 415          }
 416
 417          save_array_object(ctx, newObj);
 418       }
 419
 420       if (!newObj->EverBound) {
 421          /* The "Interactions with APPLE_vertex_array_object" section of the
 422           * GL_ARB_vertex_array_object spec says:
 423           *
 424           *     "The first bind call, either BindVertexArray or
 425           *     BindVertexArrayAPPLE, determines the semantic of the object."
 426           */
 427          newObj->ARBsemantics = genRequired;
 428          newObj->EverBound = GL_TRUE;
 429       }
 430    }
 431
 432    if (ctx->Array.DrawMethod == DRAW_ARRAYS) {
 433       /* The _DrawArrays pointer is pointing at the VAO being unbound and
 434        * that VAO may be in the process of being deleted. If it's not going
 435        * to be deleted, this will have no effect, because the pointer needs
 436        * to be updated by the VBO module anyway.
 437        *
 438        * Before the VBO module can update the pointer, we have to set it
 439        * to NULL for drivers not to set up arrays which are not bound,
 440        * or to prevent a crash if the VAO being unbound is going to be
 441        * deleted.
 442        */
 443       ctx->Array._DrawArrays = NULL;
 444       ctx->Array.DrawMethod = DRAW_NONE;
 445    }
 446
 447    ctx->NewState |= _NEW_ARRAY;
 448    _mesa_reference_vao(ctx, &ctx->Array.VAO, newObj);
 449
 450    /* Pass BindVertexArray call to device driver */
 451    if (ctx->Driver.BindArrayObject && newObj)
 452       ctx->Driver.BindArrayObject(ctx, newObj);
 453 }
 454
 455
 456 /**
 457  * ARB version of glBindVertexArray()
 458  * This function behaves differently from glBindVertexArrayAPPLE() in
 459  * that this function requires all ids to have been previously generated
 460  * by glGenVertexArrays[APPLE]().
 461  */
 462 void GLAPIENTRY
 463 _mesa_BindVertexArray( GLuint id )
 464 {
 465    GET_CURRENT_CONTEXT(ctx);
 466    bind_vertex_array(ctx, id, GL_TRUE);
 467 }
 468
 469
 470 /**
 471  * Bind a new array.
 472  *
 473  * \todo
 474  * The binding could be done more efficiently by comparing the non-NULL
 475  * pointers in the old and new objects.  The only arrays that are "dirty" are
 476  * the ones that are non-NULL in either object.
 477  */
 478 void GLAPIENTRY
 479 _mesa_BindVertexArrayAPPLE( GLuint id )
 480 {
 481    GET_CURRENT_CONTEXT(ctx);
 482    bind_vertex_array(ctx, id, GL_FALSE);
 483 }
 484
 485
 486 /**
 487  * Delete a set of array objects.
 488  *
 489  * \param n      Number of array objects to delete.
 490  * \param ids    Array of \c n array object IDs.
 491  */
 492 void GLAPIENTRY
 493 _mesa_DeleteVertexArrays(GLsizei n, const GLuint *ids)
 494 {
 495    GET_CURRENT_CONTEXT(ctx);
 496    GLsizei i;
 497
 498    if (n < 0) {
 499       _mesa_error(ctx, GL_INVALID_VALUE, "glDeleteVertexArray(n)");
 500       return;
 501    }
 502
 503    for (i = 0; i < n; i++) {
 504       struct gl_vertex_array_object *obj = _mesa_lookup_vao(ctx, ids[i]);
 505
 506       if ( obj != NULL ) {
 507          assert( obj->Name == ids[i] );
 508
 509          /* If the array object is currently bound, the spec says "the binding
 510           * for that object reverts to zero and the default vertex array
 511           * becomes current."
 512           */
 513          if ( obj == ctx->Array.VAO ) {
 514             _mesa_BindVertexArray(0);
 515          }
 516
 517          /* The ID is immediately freed for re-use */
 518          remove_array_object(ctx, obj);
 519
 520          if (ctx->Array.LastLookedUpVAO == obj)
 521             _mesa_reference_vao(ctx, &ctx->Array.LastLookedUpVAO, NULL);
 522
 523          /* Unreference the array object.
 524           * If refcount hits zero, the object will be deleted.
 525           */
 526          _mesa_reference_vao(ctx, &obj, NULL);
 527       }
 528    }
 529 }
 530
 531
 532 /**
 533  * Generate a set of unique array object IDs and store them in \c arrays.
 534  * Helper for _mesa_GenVertexArrays[APPLE]() and _mesa_CreateVertexArrays()
 535  * below.
 536  *
 537  * \param n       Number of IDs to generate.
 538  * \param arrays  Array of \c n locations to store the IDs.
 539  * \param create  Indicates that the objects should also be created.
 540  * \param func    The name of the GL entry point.
 541  */
 542 static void
 543 gen_vertex_arrays(struct gl_context *ctx, GLsizei n, GLuint *arrays,
 544                   bool create, const char *func)
 545 {
 546    GLuint first;
 547    GLint i;
 548
 549    if (n < 0) {
 550       _mesa_error(ctx, GL_INVALID_VALUE, "%s(n < 0)", func);
 551       return;
 552    }
 553
 554    if (!arrays) {
 555       return;
 556    }
 557
 558    first = _mesa_HashFindFreeKeyBlock(ctx->Array.Objects, n);
 559
 560    /* For the sake of simplicity we create the array objects in both
 561     * the Gen* and Create* cases.  The only difference is the value of
 562     * EverBound, which is set to true in the Create* case.
 563     */
 564    for (i = 0; i < n; i++) {
 565       struct gl_vertex_array_object *obj;
 566       GLuint name = first + i;
 567
 568       obj = (*ctx->Driver.NewArrayObject)( ctx, name );
 569       if (!obj) {
 570          _mesa_error(ctx, GL_OUT_OF_MEMORY, "%s", func);
 571          return;
 572       }
 573       obj->EverBound = create;
 574       save_array_object(ctx, obj);
 575       arrays[i] = first + i;
 576    }
 577 }
 578
 579
 580 /**
 581  * ARB version of glGenVertexArrays()
 582  * All arrays will be required to live in VBOs.
 583  */
 584 void GLAPIENTRY
 585 _mesa_GenVertexArrays(GLsizei n, GLuint *arrays)
 586 {
 587    GET_CURRENT_CONTEXT(ctx);
 588    gen_vertex_arrays(ctx, n, arrays, false, "glGenVertexArrays");
 589 }
 590
 591
 592 /**
 593  * APPLE version of glGenVertexArraysAPPLE()
 594  * Arrays may live in VBOs or ordinary memory.
 595  */
 596 void GLAPIENTRY
 597 _mesa_GenVertexArraysAPPLE(GLsizei n, GLuint *arrays)
 598 {
 599    GET_CURRENT_CONTEXT(ctx);
 600    gen_vertex_arrays(ctx, n, arrays, false, "glGenVertexArraysAPPLE");
 601 }
 602
 603
 604 /**
 605  * ARB_direct_state_access
 606  * Generates ID's and creates the array objects.
 607  */
 608 void GLAPIENTRY
 609 _mesa_CreateVertexArrays(GLsizei n, GLuint *arrays)
 610 {
 611    GET_CURRENT_CONTEXT(ctx);
 612    gen_vertex_arrays(ctx, n, arrays, true, "glCreateVertexArrays");
 613 }
 614
 615
 616 /**
 617  * Determine if ID is the name of an array object.
 618  *
 619  * \param id  ID of the potential array object.
 620  * \return  \c GL_TRUE if \c id is the name of a array object,
 621  *          \c GL_FALSE otherwise.
 622  */
 623 GLboolean GLAPIENTRY
 624 _mesa_IsVertexArray( GLuint id )
 625 {
 626    struct gl_vertex_array_object * obj;
 627    GET_CURRENT_CONTEXT(ctx);
 628    ASSERT_OUTSIDE_BEGIN_END_WITH_RETVAL(ctx, GL_FALSE);
 629
 630    if (id == 0)
 631       return GL_FALSE;
 632
 633    obj = _mesa_lookup_vao(ctx, id);
 634    if (obj == NULL)
 635       return GL_FALSE;
 636
 637    return obj->EverBound;
 638 }
 639
 640
 641 /**
 642  * Sets the element array buffer binding of a vertex array object.
 643  *
 644  * This is the ARB_direct_state_access equivalent of
 645  * glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffer).
 646  */
 647 void GLAPIENTRY
 648 _mesa_VertexArrayElementBuffer(GLuint vaobj, GLuint buffer)
 649 {
 650    GET_CURRENT_CONTEXT(ctx);
 651    struct gl_vertex_array_object *vao;
 652    struct gl_buffer_object *bufObj;
 653
 654    ASSERT_OUTSIDE_BEGIN_END(ctx);
 655
 656    /* The GL_ARB_direct_state_access specification says:
 657     *
 658     *    "An INVALID_OPERATION error is generated by VertexArrayElementBuffer
 659     *     if <vaobj> is not [compatibility profile: zero or] the name of an
 660     *     existing vertex array object."
 661     */
 662    vao =_mesa_lookup_vao_err(ctx, vaobj, "glVertexArrayElementBuffer");
 663    if (!vao)
 664       return;
 665
 666    /* The GL_ARB_direct_state_access specification says:
 667     *
 668     *    "An INVALID_OPERATION error is generated if <buffer> is not zero or
 669     *     the name of an existing buffer object."
 670     */
 671    if (buffer != 0)
 672       bufObj = _mesa_lookup_bufferobj_err(ctx, buffer,
 673                                           "glVertexArrayElementBuffer");
 674    else
 675       bufObj = ctx->Shared->NullBufferObj;
 676
 677    if (bufObj)
 678       _mesa_reference_buffer_object(ctx, &vao->IndexBufferObj, bufObj);
 679 }
 680
 681
 682 void GLAPIENTRY
 683 _mesa_GetVertexArrayiv(GLuint vaobj, GLenum pname, GLint *param)
 684 {
 685    GET_CURRENT_CONTEXT(ctx);
 686    struct gl_vertex_array_object *vao;
 687
 688    ASSERT_OUTSIDE_BEGIN_END(ctx);
 689
 690    /* The GL_ARB_direct_state_access specification says:
 691     *
 692     *   "An INVALID_OPERATION error is generated if <vaobj> is not
 693     *    [compatibility profile: zero or] the name of an existing
 694     *    vertex array object."
 695     */
 696    vao =_mesa_lookup_vao_err(ctx, vaobj, "glGetVertexArrayiv");
 697    if (!vao)
 698       return;
 699
 700    /* The GL_ARB_direct_state_access specification says:
 701     *
 702     *   "An INVALID_ENUM error is generated if <pname> is not
 703     *    ELEMENT_ARRAY_BUFFER_BINDING."
 704     */
 705    if (pname != GL_ELEMENT_ARRAY_BUFFER_BINDING) {
 706       _mesa_error(ctx, GL_INVALID_ENUM,
 707                   "glGetVertexArrayiv(pname != "
 708                   "GL_ELEMENT_ARRAY_BUFFER_BINDING)");
 709       return;
 710    }
 711
 712    param[0] = vao->IndexBufferObj->Name;
 713 }