src/mesa/drivers/dri/i965/brw_draw.c

   1 /**************************************************************************
   2  *
   3  * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
   4  * 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
   8  * "Software"), to deal in the Software without restriction, including
   9  * without limitation the rights to use, copy, modify, merge, publish,
  10  * distribute, sub license, and/or sell copies of the Software, and to
  11  * permit persons to whom the Software is furnished to do so, subject to
  12  * the following conditions:
  13  *
  14  * The above copyright notice and this permission notice (including the
  15  * next paragraph) shall be included in all copies or substantial portions
  16  * 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
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
  21  * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
  22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
  23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
  24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  **************************************************************************/
  27
  28 #include <sys/errno.h>
  29
  30 #include "main/glheader.h"
  31 #include "main/context.h"
  32 #include "main/condrender.h"
  33 #include "main/samplerobj.h"
  34 #include "main/state.h"
  35 #include "main/enums.h"
  36 #include "main/macros.h"
  37 #include "tnl/tnl.h"
  38 #include "vbo/vbo_context.h"
  39 #include "swrast/swrast.h"
  40 #include "swrast_setup/swrast_setup.h"
  41 #include "drivers/common/meta.h"
  42
  43 #include "brw_draw.h"
  44 #include "brw_defines.h"
  45 #include "brw_context.h"
  46 #include "brw_state.h"
  47
  48 #include "intel_batchbuffer.h"
  49 #include "intel_fbo.h"
  50 #include "intel_mipmap_tree.h"
  51 #include "intel_regions.h"
  52
  53 #define FILE_DEBUG_FLAG DEBUG_PRIMS
  54
  55 static GLuint prim_to_hw_prim[GL_POLYGON+1] = {
  56    _3DPRIM_POINTLIST,
  57    _3DPRIM_LINELIST,
  58    _3DPRIM_LINELOOP,
  59    _3DPRIM_LINESTRIP,
  60    _3DPRIM_TRILIST,
  61    _3DPRIM_TRISTRIP,
  62    _3DPRIM_TRIFAN,
  63    _3DPRIM_QUADLIST,
  64    _3DPRIM_QUADSTRIP,
  65    _3DPRIM_POLYGON
  66 };
  67
  68
  69 static const GLenum reduced_prim[GL_POLYGON+1] = {
  70    GL_POINTS,
  71    GL_LINES,
  72    GL_LINES,
  73    GL_LINES,
  74    GL_TRIANGLES,
  75    GL_TRIANGLES,
  76    GL_TRIANGLES,
  77    GL_TRIANGLES,
  78    GL_TRIANGLES,
  79    GL_TRIANGLES
  80 };
  81
  82
  83 /* When the primitive changes, set a state bit and re-validate.  Not
  84  * the nicest and would rather deal with this by having all the
  85  * programs be immune to the active primitive (ie. cope with all
  86  * possibilities).  That may not be realistic however.
  87  */
  88 static void brw_set_prim(struct brw_context *brw,
  89                          const struct _mesa_prim *prim)
  90 {
  91    struct gl_context *ctx = &brw->intel.ctx;
  92    uint32_t hw_prim = prim_to_hw_prim[prim->mode];
  93
  94    DBG("PRIM: %s\n", _mesa_lookup_enum_by_nr(prim->mode));
  95
  96    /* Slight optimization to avoid the GS program when not needed:
  97     */
  98    if (prim->mode == GL_QUAD_STRIP &&
  99        ctx->Light.ShadeModel != GL_FLAT &&
 100        ctx->Polygon.FrontMode == GL_FILL &&
 101        ctx->Polygon.BackMode == GL_FILL)
 102       hw_prim = _3DPRIM_TRISTRIP;
 103
 104    if (prim->mode == GL_QUADS && prim->count == 4 &&
 105        ctx->Light.ShadeModel != GL_FLAT &&
 106        ctx->Polygon.FrontMode == GL_FILL &&
 107        ctx->Polygon.BackMode == GL_FILL) {
 108       hw_prim = _3DPRIM_TRIFAN;
 109    }
 110
 111    if (hw_prim != brw->primitive) {
 112       brw->primitive = hw_prim;
 113       brw->state.dirty.brw |= BRW_NEW_PRIMITIVE;
 114
 115       if (reduced_prim[prim->mode] != brw->intel.reduced_primitive) {
 116          brw->intel.reduced_primitive = reduced_prim[prim->mode];
 117          brw->state.dirty.brw |= BRW_NEW_REDUCED_PRIMITIVE;
 118       }
 119    }
 120 }
 121
 122 static void gen6_set_prim(struct brw_context *brw,
 123                           const struct _mesa_prim *prim)
 124 {
 125    uint32_t hw_prim;
 126
 127    DBG("PRIM: %s\n", _mesa_lookup_enum_by_nr(prim->mode));
 128
 129    if (brw->hiz.op) {
 130       assert(prim->mode == GL_TRIANGLES);
 131       hw_prim = _3DPRIM_RECTLIST;
 132    } else {
 133       hw_prim = prim_to_hw_prim[prim->mode];
 134    }
 135
 136    if (hw_prim != brw->primitive) {
 137       brw->primitive = hw_prim;
 138       brw->state.dirty.brw |= BRW_NEW_PRIMITIVE;
 139    }
 140 }
 141
 142
 143 static GLuint trim(GLenum prim, GLuint length)
 144 {
 145    if (prim == GL_QUAD_STRIP)
 146       return length > 3 ? (length - length % 2) : 0;
 147    else if (prim == GL_QUADS)
 148       return length - length % 4;
 149    else
 150       return length;
 151 }
 152
 153
 154 static void brw_emit_prim(struct brw_context *brw,
 155                           const struct _mesa_prim *prim,
 156                           uint32_t hw_prim)
 157 {
 158    struct intel_context *intel = &brw->intel;
 159    int verts_per_instance;
 160    int vertex_access_type;
 161    int start_vertex_location;
 162    int base_vertex_location;
 163
 164    DBG("PRIM: %s %d %d\n", _mesa_lookup_enum_by_nr(prim->mode),
 165        prim->start, prim->count);
 166
 167    start_vertex_location = prim->start;
 168    base_vertex_location = prim->basevertex;
 169    if (prim->indexed) {
 170       vertex_access_type = GEN4_3DPRIM_VERTEXBUFFER_ACCESS_RANDOM;
 171       start_vertex_location += brw->ib.start_vertex_offset;
 172       base_vertex_location += brw->vb.start_vertex_bias;
 173    } else {
 174       vertex_access_type = GEN4_3DPRIM_VERTEXBUFFER_ACCESS_SEQUENTIAL;
 175       start_vertex_location += brw->vb.start_vertex_bias;
 176    }
 177
 178    verts_per_instance = trim(prim->mode, prim->count);
 179
 180    /* If nothing to emit, just return. */
 181    if (verts_per_instance == 0)
 182       return;
 183
 184    /* If we're set to always flush, do it before and after the primitive emit.
 185     * We want to catch both missed flushes that hurt instruction/state cache
 186     * and missed flushes of the render cache as it heads to other parts of
 187     * the besides the draw code.
 188     */
 189    if (intel->always_flush_cache) {
 190       intel_batchbuffer_emit_mi_flush(intel);
 191    }
 192
 193    BEGIN_BATCH(6);
 194    OUT_BATCH(CMD_3D_PRIM << 16 | (6 - 2) |
 195              hw_prim << GEN4_3DPRIM_TOPOLOGY_TYPE_SHIFT |
 196              vertex_access_type);
 197    OUT_BATCH(verts_per_instance);
 198    OUT_BATCH(start_vertex_location);
 199    OUT_BATCH(1); // instance count
 200    OUT_BATCH(0); // start instance location
 201    OUT_BATCH(base_vertex_location);
 202    ADVANCE_BATCH();
 203
 204    intel->batch.need_workaround_flush = true;
 205
 206    if (intel->always_flush_cache) {
 207       intel_batchbuffer_emit_mi_flush(intel);
 208    }
 209 }
 210
 211 static void gen7_emit_prim(struct brw_context *brw,
 212                            const struct _mesa_prim *prim,
 213                            uint32_t hw_prim)
 214 {
 215    struct intel_context *intel = &brw->intel;
 216    int verts_per_instance;
 217    int vertex_access_type;
 218    int start_vertex_location;
 219    int base_vertex_location;
 220
 221    DBG("PRIM: %s %d %d\n", _mesa_lookup_enum_by_nr(prim->mode),
 222        prim->start, prim->count);
 223
 224    start_vertex_location = prim->start;
 225    base_vertex_location = prim->basevertex;
 226    if (prim->indexed) {
 227       vertex_access_type = GEN7_3DPRIM_VERTEXBUFFER_ACCESS_RANDOM;
 228       start_vertex_location += brw->ib.start_vertex_offset;
 229       base_vertex_location += brw->vb.start_vertex_bias;
 230    } else {
 231       vertex_access_type = GEN7_3DPRIM_VERTEXBUFFER_ACCESS_SEQUENTIAL;
 232       start_vertex_location += brw->vb.start_vertex_bias;
 233    }
 234
 235    verts_per_instance = trim(prim->mode, prim->count);
 236
 237    /* If nothing to emit, just return. */
 238    if (verts_per_instance == 0)
 239       return;
 240
 241    /* If we're set to always flush, do it before and after the primitive emit.
 242     * We want to catch both missed flushes that hurt instruction/state cache
 243     * and missed flushes of the render cache as it heads to other parts of
 244     * the besides the draw code.
 245     */
 246    if (intel->always_flush_cache) {
 247       intel_batchbuffer_emit_mi_flush(intel);
 248    }
 249
 250    BEGIN_BATCH(7);
 251    OUT_BATCH(CMD_3D_PRIM << 16 | (7 - 2));
 252    OUT_BATCH(hw_prim | vertex_access_type);
 253    OUT_BATCH(verts_per_instance);
 254    OUT_BATCH(start_vertex_location);
 255    OUT_BATCH(1); // instance count
 256    OUT_BATCH(0); // start instance location
 257    OUT_BATCH(base_vertex_location);
 258    ADVANCE_BATCH();
 259
 260    if (intel->always_flush_cache) {
 261       intel_batchbuffer_emit_mi_flush(intel);
 262    }
 263 }
 264
 265
 266 static void brw_merge_inputs( struct brw_context *brw,
 267                        const struct gl_client_array *arrays[])
 268 {
 269    struct brw_vertex_info old = brw->vb.info;
 270    GLuint i;
 271
 272    for (i = 0; i < brw->vb.nr_buffers; i++) {
 273       drm_intel_bo_unreference(brw->vb.buffers[i].bo);
 274       brw->vb.buffers[i].bo = NULL;
 275    }
 276    brw->vb.nr_buffers = 0;
 277
 278    memset(&brw->vb.info, 0, sizeof(brw->vb.info));
 279
 280    for (i = 0; i < VERT_ATTRIB_MAX; i++) {
 281       brw->vb.inputs[i].buffer = -1;
 282       brw->vb.inputs[i].glarray = arrays[i];
 283       brw->vb.inputs[i].attrib = (gl_vert_attrib) i;
 284
 285       if (arrays[i]->StrideB != 0)
 286          brw->vb.info.sizes[i/16] |= (brw->vb.inputs[i].glarray->Size - 1) <<
 287             ((i%16) * 2);
 288    }
 289
 290    /* Raise statechanges if input sizes have changed. */
 291    if (memcmp(brw->vb.info.sizes, old.sizes, sizeof(old.sizes)) != 0)
 292       brw->state.dirty.brw |= BRW_NEW_INPUT_DIMENSIONS;
 293 }
 294
 295 /*
 296  * \brief Resolve buffers before drawing.
 297  *
 298  * Resolve the depth buffer's HiZ buffer and resolve the depth buffer of each
 299  * enabled depth texture.
 300  *
 301  * (In the future, this will also perform MSAA resolves).
 302  */
 303 static void
 304 brw_predraw_resolve_buffers(struct brw_context *brw)
 305 {
 306    struct gl_context *ctx = &brw->intel.ctx;
 307    struct intel_context *intel = &brw->intel;
 308    struct intel_renderbuffer *depth_irb;
 309    struct intel_texture_object *tex_obj;
 310    bool did_resolve = false;
 311
 312    /* Avoid recursive HiZ op. */
 313    if (brw->hiz.op) {
 314       return;
 315    }
 316
 317    /* Resolve the depth buffer's HiZ buffer. */
 318    depth_irb = intel_get_renderbuffer(ctx->DrawBuffer, BUFFER_DEPTH);
 319    if (depth_irb && depth_irb->mt) {
 320       did_resolve |= intel_renderbuffer_resolve_hiz(intel, depth_irb);
 321    }
 322
 323    /* Resolve depth buffer of each enabled depth texture. */
 324    for (int i = 0; i < BRW_MAX_TEX_UNIT; i++) {
 325       if (!ctx->Texture.Unit[i]._ReallyEnabled)
 326          continue;
 327       tex_obj = intel_texture_object(ctx->Texture.Unit[i]._Current);
 328       if (!tex_obj || !tex_obj->mt)
 329          continue;
 330       did_resolve |= intel_miptree_all_slices_resolve_depth(intel, tex_obj->mt);
 331    }
 332
 333    if (did_resolve) {
 334       /* Call vbo_bind_array() to synchronize the vbo module's vertex
 335        * attributes to the gl_context's.
 336        *
 337        * Details
 338        * -------
 339        * The vbo module tracks vertex attributes separately from the
 340        * gl_context.  Specifically, the vbo module maintins vertex attributes
 341        * in vbo_exec_context::array::inputs, which is synchronized with
 342        * gl_context::Array::ArrayObj::VertexAttrib by vbo_bind_array().
 343        * vbo_draw_arrays() calls vbo_bind_array() to perform the
 344        * synchronization before calling the real draw call,
 345        * vbo_context::draw_arrays.
 346        *
 347        * At this point (after performing a resolve meta-op but before calling
 348        * vbo_bind_array), the gl_context's vertex attributes have been
 349        * restored to their original state (that is, their state before the
 350        * meta-op began), but the vbo module's vertex attribute are those used
 351        * in the last meta-op. Therefore we must manually synchronize the two with
 352        * vbo_bind_array() before continuing with the original draw command.
 353        */
 354       _mesa_update_state(ctx);
 355       vbo_bind_arrays(ctx);
 356       _mesa_update_state(ctx);
 357    }
 358 }
 359
 360 /**
 361  * \brief Call this after drawing to mark which buffers need resolving
 362  *
 363  * If the depth buffer was written to and if it has an accompanying HiZ
 364  * buffer, then mark that it needs a depth resolve.
 365  *
 366  * (In the future, this will also mark needed MSAA resolves).
 367  */
 368 static void brw_postdraw_set_buffers_need_resolve(struct brw_context *brw)
 369 {
 370    struct gl_context *ctx = &brw->intel.ctx;
 371    struct gl_framebuffer *fb = ctx->DrawBuffer;
 372    struct intel_renderbuffer *depth_irb =
 373          intel_get_renderbuffer(fb, BUFFER_DEPTH);
 374
 375    if (depth_irb &&
 376        ctx->Depth.Mask &&
 377        !brw->hiz.op) {
 378       intel_renderbuffer_set_needs_depth_resolve(depth_irb);
 379    }
 380 }
 381
 382 /**
 383  * Update internal counters based on the the drawing operation described in
 384  * prim.
 385  */
 386 static void
 387 brw_update_primitive_count(struct brw_context *brw,
 388                            const struct _mesa_prim *prim)
 389 {
 390    uint32_t count = count_tessellated_primitives(prim);
 391    brw->sol.primitives_generated += count;
 392    if (brw->intel.ctx.TransformFeedback.CurrentObject->Active) {
 393       /* Update brw->sol.svbi_0_max_index to reflect the amount by which the
 394        * hardware is going to increment SVBI 0 when this drawing operation
 395        * occurs.  This is necessary because the kernel does not (yet) save and
 396        * restore GPU registers when context switching, so we'll need to be
 397        * able to reload SVBI 0 with the correct value in case we have to start
 398        * a new batch buffer.
 399        */
 400       unsigned svbi_postincrement_value =
 401          brw->gs.prog_data->svbi_postincrement_value;
 402       uint32_t space_avail =
 403          (brw->sol.svbi_0_max_index - brw->sol.svbi_0_starting_index)
 404          / svbi_postincrement_value;
 405       uint32_t primitives_written = MIN2 (space_avail, count);
 406       brw->sol.svbi_0_starting_index +=
 407          svbi_postincrement_value * primitives_written;
 408
 409       /* And update the TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN query. */
 410       brw->sol.primitives_written += primitives_written;
 411    }
 412 }
 413
 414 /* May fail if out of video memory for texture or vbo upload, or on
 415  * fallback conditions.
 416  */
 417 static bool brw_try_draw_prims( struct gl_context *ctx,
 418                                      const struct gl_client_array *arrays[],
 419                                      const struct _mesa_prim *prim,
 420                                      GLuint nr_prims,
 421                                      const struct _mesa_index_buffer *ib,
 422                                      GLuint min_index,
 423                                      GLuint max_index )
 424 {
 425    struct intel_context *intel = intel_context(ctx);
 426    struct brw_context *brw = brw_context(ctx);
 427    bool retval = true;
 428    GLuint i;
 429    bool fail_next = false;
 430
 431    if (ctx->NewState)
 432       _mesa_update_state( ctx );
 433
 434    /* We have to validate the textures *before* checking for fallbacks;
 435     * otherwise, the software fallback won't be able to rely on the
 436     * texture state, the firstLevel and lastLevel fields won't be
 437     * set in the intel texture object (they'll both be 0), and the
 438     * software fallback will segfault if it attempts to access any
 439     * texture level other than level 0.
 440     */
 441    brw_validate_textures( brw );
 442
 443    /* Resolves must occur after updating state and finalizing textures but
 444     * before setting up any hardware state for this draw call.
 445     */
 446    brw_predraw_resolve_buffers(brw);
 447
 448    /* Bind all inputs, derive varying and size information:
 449     */
 450    brw_merge_inputs( brw, arrays );
 451
 452    brw->ib.ib = ib;
 453    brw->state.dirty.brw |= BRW_NEW_INDICES;
 454
 455    brw->vb.min_index = min_index;
 456    brw->vb.max_index = max_index;
 457    brw->state.dirty.brw |= BRW_NEW_VERTICES;
 458
 459    /* Have to validate state quite late.  Will rebuild tnl_program,
 460     * which depends on varying information.
 461     *
 462     * Note this is where brw->vs->prog_data.inputs_read is calculated,
 463     * so can't access it earlier.
 464     */
 465
 466    intel_prepare_render(intel);
 467
 468    for (i = 0; i < nr_prims; i++) {
 469       int estimated_max_prim_size;
 470
 471       estimated_max_prim_size = 512; /* batchbuffer commands */
 472       estimated_max_prim_size += (BRW_MAX_TEX_UNIT *
 473                                   (sizeof(struct brw_sampler_state) +
 474                                    sizeof(struct gen5_sampler_default_color)));
 475       estimated_max_prim_size += 1024; /* gen6 VS push constants */
 476       estimated_max_prim_size += 1024; /* gen6 WM push constants */
 477       estimated_max_prim_size += 512; /* misc. pad */
 478
 479       /* Flush the batch if it's approaching full, so that we don't wrap while
 480        * we've got validated state that needs to be in the same batch as the
 481        * primitives.
 482        */
 483       intel_batchbuffer_require_space(intel, estimated_max_prim_size, false);
 484       intel_batchbuffer_save_state(intel);
 485
 486       if (intel->gen < 6)
 487          brw_set_prim(brw, &prim[i]);
 488       else
 489          gen6_set_prim(brw, &prim[i]);
 490
 491 retry:
 492       /* Note that before the loop, brw->state.dirty.brw was set to != 0, and
 493        * that the state updated in the loop outside of this block is that in
 494        * *_set_prim or intel_batchbuffer_flush(), which only impacts
 495        * brw->state.dirty.brw.
 496        */
 497       if (brw->state.dirty.brw) {
 498          intel->no_batch_wrap = true;
 499          brw_upload_state(brw);
 500
 501          if (unlikely(brw->intel.Fallback)) {
 502             intel->no_batch_wrap = false;
 503             retval = false;
 504             goto out;
 505          }
 506       }
 507
 508       if (intel->gen >= 7)
 509          gen7_emit_prim(brw, &prim[i], brw->primitive);
 510       else
 511          brw_emit_prim(brw, &prim[i], brw->primitive);
 512
 513       intel->no_batch_wrap = false;
 514
 515       if (dri_bufmgr_check_aperture_space(&intel->batch.bo, 1)) {
 516          if (!fail_next) {
 517             intel_batchbuffer_reset_to_saved(intel);
 518             intel_batchbuffer_flush(intel);
 519             fail_next = true;
 520             goto retry;
 521          } else {
 522             if (intel_batchbuffer_flush(intel) == -ENOSPC) {
 523                static bool warned = false;
 524
 525                if (!warned) {
 526                   fprintf(stderr, "i965: Single primitive emit exceeded"
 527                           "available aperture space\n");
 528                   warned = true;
 529                }
 530
 531                retval = false;
 532             }
 533          }
 534       }
 535
 536       if (!_mesa_meta_in_progress(ctx))
 537          brw_update_primitive_count(brw, &prim[i]);
 538    }
 539
 540    if (intel->always_flush_batch)
 541       intel_batchbuffer_flush(intel);
 542  out:
 543
 544    brw_state_cache_check_size(brw);
 545    brw_postdraw_set_buffers_need_resolve(brw);
 546
 547    return retval;
 548 }
 549
 550 void brw_draw_prims( struct gl_context *ctx,
 551                      const struct gl_client_array *arrays[],
 552                      const struct _mesa_prim *prim,
 553                      GLuint nr_prims,
 554                      const struct _mesa_index_buffer *ib,
 555                      GLboolean index_bounds_valid,
 556                      GLuint min_index,
 557                      GLuint max_index,
 558                      struct gl_transform_feedback_object *tfb_vertcount )
 559 {
 560    bool retval;
 561
 562    if (!_mesa_check_conditional_render(ctx))
 563       return;
 564
 565    if (!vbo_all_varyings_in_vbos(arrays)) {
 566       if (!index_bounds_valid)
 567          vbo_get_minmax_index(ctx, prim, ib, &min_index, &max_index);
 568
 569       /* Decide if we want to rebase.  If so we end up recursing once
 570        * only into this function.
 571        */
 572       if (min_index != 0 && !vbo_any_varyings_in_vbos(arrays)) {
 573          vbo_rebase_prims(ctx, arrays,
 574                           prim, nr_prims,
 575                           ib, min_index, max_index,
 576                           brw_draw_prims );
 577          return;
 578       }
 579    }
 580
 581    /* Make a first attempt at drawing:
 582     */
 583    retval = brw_try_draw_prims(ctx, arrays, prim, nr_prims, ib, min_index, max_index);
 584
 585    /* Otherwise, we really are out of memory.  Pass the drawing
 586     * command to the software tnl module and which will in turn call
 587     * swrast to do the drawing.
 588     */
 589    if (!retval) {
 590        _swsetup_Wakeup(ctx);
 591        _tnl_wakeup(ctx);
 592       _tnl_draw_prims(ctx, arrays, prim, nr_prims, ib, min_index, max_index);
 593    }
 594
 595 }
 596
 597 void brw_draw_init( struct brw_context *brw )
 598 {
 599    struct gl_context *ctx = &brw->intel.ctx;
 600    struct vbo_context *vbo = vbo_context(ctx);
 601    int i;
 602
 603    /* Register our drawing function:
 604     */
 605    vbo->draw_prims = brw_draw_prims;
 606
 607    for (i = 0; i < VERT_ATTRIB_MAX; i++)
 608       brw->vb.inputs[i].buffer = -1;
 609    brw->vb.nr_buffers = 0;
 610    brw->vb.nr_enabled = 0;
 611 }
 612
 613 void brw_draw_destroy( struct brw_context *brw )
 614 {
 615    int i;
 616
 617    for (i = 0; i < brw->vb.nr_buffers; i++) {
 618       drm_intel_bo_unreference(brw->vb.buffers[i].bo);
 619       brw->vb.buffers[i].bo = NULL;
 620    }
 621    brw->vb.nr_buffers = 0;
 622
 623    for (i = 0; i < brw->vb.nr_enabled; i++) {
 624       brw->vb.enabled[i]->buffer = -1;
 625    }
 626    brw->vb.nr_enabled = 0;
 627
 628    drm_intel_bo_unreference(brw->ib.bo);
 629    brw->ib.bo = NULL;
 630 }