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    hw_prim = prim_to_hw_prim[prim->mode];
 130
 131    if (hw_prim != brw->primitive) {
 132       brw->primitive = hw_prim;
 133       brw->state.dirty.brw |= BRW_NEW_PRIMITIVE;
 134    }
 135 }
 136
 137
 138 static GLuint trim(GLenum prim, GLuint length)
 139 {
 140    if (prim == GL_QUAD_STRIP)
 141       return length > 3 ? (length - length % 2) : 0;
 142    else if (prim == GL_QUADS)
 143       return length - length % 4;
 144    else
 145       return length;
 146 }
 147
 148
 149 static void brw_emit_prim(struct brw_context *brw,
 150                           const struct _mesa_prim *prim,
 151                           uint32_t hw_prim)
 152 {
 153    struct intel_context *intel = &brw->intel;
 154    int verts_per_instance;
 155    int vertex_access_type;
 156    int start_vertex_location;
 157    int base_vertex_location;
 158
 159    DBG("PRIM: %s %d %d\n", _mesa_lookup_enum_by_nr(prim->mode),
 160        prim->start, prim->count);
 161
 162    start_vertex_location = prim->start;
 163    base_vertex_location = prim->basevertex;
 164    if (prim->indexed) {
 165       vertex_access_type = GEN4_3DPRIM_VERTEXBUFFER_ACCESS_RANDOM;
 166       start_vertex_location += brw->ib.start_vertex_offset;
 167       base_vertex_location += brw->vb.start_vertex_bias;
 168    } else {
 169       vertex_access_type = GEN4_3DPRIM_VERTEXBUFFER_ACCESS_SEQUENTIAL;
 170       start_vertex_location += brw->vb.start_vertex_bias;
 171    }
 172
 173    verts_per_instance = trim(prim->mode, prim->count);
 174
 175    /* If nothing to emit, just return. */
 176    if (verts_per_instance == 0)
 177       return;
 178
 179    /* If we're set to always flush, do it before and after the primitive emit.
 180     * We want to catch both missed flushes that hurt instruction/state cache
 181     * and missed flushes of the render cache as it heads to other parts of
 182     * the besides the draw code.
 183     */
 184    if (intel->always_flush_cache) {
 185       intel_batchbuffer_emit_mi_flush(intel);
 186    }
 187
 188    BEGIN_BATCH(6);
 189    OUT_BATCH(CMD_3D_PRIM << 16 | (6 - 2) |
 190              hw_prim << GEN4_3DPRIM_TOPOLOGY_TYPE_SHIFT |
 191              vertex_access_type);
 192    OUT_BATCH(verts_per_instance);
 193    OUT_BATCH(start_vertex_location);
 194    OUT_BATCH(prim->num_instances);
 195    OUT_BATCH(0); // start instance location
 196    OUT_BATCH(base_vertex_location);
 197    ADVANCE_BATCH();
 198
 199    intel->batch.need_workaround_flush = true;
 200
 201    if (intel->always_flush_cache) {
 202       intel_batchbuffer_emit_mi_flush(intel);
 203    }
 204 }
 205
 206 static void gen7_emit_prim(struct brw_context *brw,
 207                            const struct _mesa_prim *prim,
 208                            uint32_t hw_prim)
 209 {
 210    struct intel_context *intel = &brw->intel;
 211    int verts_per_instance;
 212    int vertex_access_type;
 213    int start_vertex_location;
 214    int base_vertex_location;
 215
 216    DBG("PRIM: %s %d %d\n", _mesa_lookup_enum_by_nr(prim->mode),
 217        prim->start, prim->count);
 218
 219    start_vertex_location = prim->start;
 220    base_vertex_location = prim->basevertex;
 221    if (prim->indexed) {
 222       vertex_access_type = GEN7_3DPRIM_VERTEXBUFFER_ACCESS_RANDOM;
 223       start_vertex_location += brw->ib.start_vertex_offset;
 224       base_vertex_location += brw->vb.start_vertex_bias;
 225    } else {
 226       vertex_access_type = GEN7_3DPRIM_VERTEXBUFFER_ACCESS_SEQUENTIAL;
 227       start_vertex_location += brw->vb.start_vertex_bias;
 228    }
 229
 230    verts_per_instance = trim(prim->mode, prim->count);
 231
 232    /* If nothing to emit, just return. */
 233    if (verts_per_instance == 0)
 234       return;
 235
 236    /* If we're set to always flush, do it before and after the primitive emit.
 237     * We want to catch both missed flushes that hurt instruction/state cache
 238     * and missed flushes of the render cache as it heads to other parts of
 239     * the besides the draw code.
 240     */
 241    if (intel->always_flush_cache) {
 242       intel_batchbuffer_emit_mi_flush(intel);
 243    }
 244
 245    BEGIN_BATCH(7);
 246    OUT_BATCH(CMD_3D_PRIM << 16 | (7 - 2));
 247    OUT_BATCH(hw_prim | vertex_access_type);
 248    OUT_BATCH(verts_per_instance);
 249    OUT_BATCH(start_vertex_location);
 250    OUT_BATCH(prim->num_instances);
 251    OUT_BATCH(0); // start instance location
 252    OUT_BATCH(base_vertex_location);
 253    ADVANCE_BATCH();
 254
 255    if (intel->always_flush_cache) {
 256       intel_batchbuffer_emit_mi_flush(intel);
 257    }
 258 }
 259
 260
 261 static void brw_merge_inputs( struct brw_context *brw,
 262                        const struct gl_client_array *arrays[])
 263 {
 264    struct brw_vertex_info old = brw->vb.info;
 265    GLuint i;
 266
 267    for (i = 0; i < brw->vb.nr_buffers; i++) {
 268       drm_intel_bo_unreference(brw->vb.buffers[i].bo);
 269       brw->vb.buffers[i].bo = NULL;
 270    }
 271    brw->vb.nr_buffers = 0;
 272
 273    memset(&brw->vb.info, 0, sizeof(brw->vb.info));
 274
 275    for (i = 0; i < VERT_ATTRIB_MAX; i++) {
 276       brw->vb.inputs[i].buffer = -1;
 277       brw->vb.inputs[i].glarray = arrays[i];
 278       brw->vb.inputs[i].attrib = (gl_vert_attrib) i;
 279
 280       if (arrays[i]->StrideB != 0)
 281          brw->vb.info.sizes[i/16] |= (brw->vb.inputs[i].glarray->Size - 1) <<
 282             ((i%16) * 2);
 283    }
 284
 285    /* Raise statechanges if input sizes have changed. */
 286    if (memcmp(brw->vb.info.sizes, old.sizes, sizeof(old.sizes)) != 0)
 287       brw->state.dirty.brw |= BRW_NEW_INPUT_DIMENSIONS;
 288 }
 289
 290 /*
 291  * \brief Resolve buffers before drawing.
 292  *
 293  * Resolve the depth buffer's HiZ buffer and resolve the depth buffer of each
 294  * enabled depth texture.
 295  *
 296  * (In the future, this will also perform MSAA resolves).
 297  */
 298 static void
 299 brw_predraw_resolve_buffers(struct brw_context *brw)
 300 {
 301    struct gl_context *ctx = &brw->intel.ctx;
 302    struct intel_context *intel = &brw->intel;
 303    struct intel_renderbuffer *depth_irb;
 304    struct intel_texture_object *tex_obj;
 305
 306    /* Resolve the depth buffer's HiZ buffer. */
 307    depth_irb = intel_get_renderbuffer(ctx->DrawBuffer, BUFFER_DEPTH);
 308    if (depth_irb)
 309       intel_renderbuffer_resolve_hiz(intel, depth_irb);
 310
 311    /* Resolve depth buffer of each enabled depth texture. */
 312    for (int i = 0; i < BRW_MAX_TEX_UNIT; i++) {
 313       if (!ctx->Texture.Unit[i]._ReallyEnabled)
 314          continue;
 315       tex_obj = intel_texture_object(ctx->Texture.Unit[i]._Current);
 316       if (!tex_obj || !tex_obj->mt)
 317          continue;
 318       intel_miptree_all_slices_resolve_depth(intel, tex_obj->mt);
 319    }
 320 }
 321
 322 /**
 323  * \brief Call this after drawing to mark which buffers need resolving
 324  *
 325  * If the depth buffer was written to and if it has an accompanying HiZ
 326  * buffer, then mark that it needs a depth resolve.
 327  *
 328  * If the color buffer is a multisample window system buffer, then
 329  * mark that it needs a downsample.
 330  */
 331 static void brw_postdraw_set_buffers_need_resolve(struct brw_context *brw)
 332 {
 333    struct intel_context *intel = &brw->intel;
 334    struct gl_context *ctx = &brw->intel.ctx;
 335    struct gl_framebuffer *fb = ctx->DrawBuffer;
 336
 337    struct intel_renderbuffer *front_irb = NULL;
 338    struct intel_renderbuffer *back_irb = intel_get_renderbuffer(fb, BUFFER_BACK_LEFT);
 339    struct intel_renderbuffer *depth_irb = intel_get_renderbuffer(fb, BUFFER_DEPTH);
 340
 341    if (intel->is_front_buffer_rendering)
 342       front_irb = intel_get_renderbuffer(fb, BUFFER_FRONT_LEFT);
 343
 344    if (front_irb)
 345       intel_renderbuffer_set_needs_downsample(front_irb);
 346    if (back_irb)
 347       intel_renderbuffer_set_needs_downsample(back_irb);
 348    if (depth_irb && ctx->Depth.Mask)
 349       intel_renderbuffer_set_needs_depth_resolve(depth_irb);
 350 }
 351
 352 static int
 353 verts_per_prim(GLenum mode)
 354 {
 355    switch (mode) {
 356    case GL_POINTS:
 357       return 1;
 358    case GL_LINE_STRIP:
 359    case GL_LINE_LOOP:
 360    case GL_LINES:
 361       return 2;
 362    case GL_TRIANGLE_STRIP:
 363    case GL_TRIANGLE_FAN:
 364    case GL_POLYGON:
 365    case GL_TRIANGLES:
 366    case GL_QUADS:
 367    case GL_QUAD_STRIP:
 368       return 3;
 369    default:
 370       _mesa_problem(NULL,
 371                     "unknown prim type in transform feedback primitive count");
 372       return 0;
 373    }
 374 }
 375
 376 /**
 377  * Update internal counters based on the the drawing operation described in
 378  * prim.
 379  */
 380 static void
 381 brw_update_primitive_count(struct brw_context *brw,
 382                            const struct _mesa_prim *prim)
 383 {
 384    uint32_t count = vbo_count_tessellated_primitives(prim);
 385    brw->sol.primitives_generated += count;
 386    if (brw->intel.ctx.TransformFeedback.CurrentObject->Active &&
 387        !brw->intel.ctx.TransformFeedback.CurrentObject->Paused) {
 388       /* Update brw->sol.svbi_0_max_index to reflect the amount by which the
 389        * hardware is going to increment SVBI 0 when this drawing operation
 390        * occurs.  This is necessary because the kernel does not (yet) save and
 391        * restore GPU registers when context switching, so we'll need to be
 392        * able to reload SVBI 0 with the correct value in case we have to start
 393        * a new batch buffer.
 394        */
 395       unsigned verts = verts_per_prim(prim->mode);
 396       uint32_t space_avail =
 397          (brw->sol.svbi_0_max_index - brw->sol.svbi_0_starting_index) / verts;
 398       uint32_t primitives_written = MIN2 (space_avail, count);
 399       brw->sol.svbi_0_starting_index += verts * primitives_written;
 400
 401       /* And update the TRANSFORM_FEEDBACK_PRIMITIVES_WRITTEN query. */
 402       brw->sol.primitives_written += primitives_written;
 403    }
 404 }
 405
 406 /* May fail if out of video memory for texture or vbo upload, or on
 407  * fallback conditions.
 408  */
 409 static bool brw_try_draw_prims( struct gl_context *ctx,
 410                                      const struct gl_client_array *arrays[],
 411                                      const struct _mesa_prim *prim,
 412                                      GLuint nr_prims,
 413                                      const struct _mesa_index_buffer *ib,
 414                                      GLuint min_index,
 415                                      GLuint max_index )
 416 {
 417    struct intel_context *intel = intel_context(ctx);
 418    struct brw_context *brw = brw_context(ctx);
 419    bool retval = true;
 420    GLuint i;
 421    bool fail_next = false;
 422
 423    if (ctx->NewState)
 424       _mesa_update_state( ctx );
 425
 426    /* We have to validate the textures *before* checking for fallbacks;
 427     * otherwise, the software fallback won't be able to rely on the
 428     * texture state, the firstLevel and lastLevel fields won't be
 429     * set in the intel texture object (they'll both be 0), and the
 430     * software fallback will segfault if it attempts to access any
 431     * texture level other than level 0.
 432     */
 433    brw_validate_textures( brw );
 434
 435    intel_prepare_render(intel);
 436
 437    /* Resolves must occur after updating renderbuffers, updating context state,
 438     * and finalizing textures but before setting up any hardware state for
 439     * this draw call.
 440     */
 441    brw_predraw_resolve_buffers(brw);
 442
 443    /* Bind all inputs, derive varying and size information:
 444     */
 445    brw_merge_inputs( brw, arrays );
 446
 447    brw->ib.ib = ib;
 448    brw->state.dirty.brw |= BRW_NEW_INDICES;
 449
 450    brw->vb.min_index = min_index;
 451    brw->vb.max_index = max_index;
 452    brw->state.dirty.brw |= BRW_NEW_VERTICES;
 453
 454    /* Have to validate state quite late.  Will rebuild tnl_program,
 455     * which depends on varying information.
 456     *
 457     * Note this is where brw->vs->prog_data.inputs_read is calculated,
 458     * so can't access it earlier.
 459     */
 460
 461    for (i = 0; i < nr_prims; i++) {
 462       int estimated_max_prim_size;
 463
 464       estimated_max_prim_size = 512; /* batchbuffer commands */
 465       estimated_max_prim_size += (BRW_MAX_TEX_UNIT *
 466                                   (sizeof(struct brw_sampler_state) +
 467                                    sizeof(struct gen5_sampler_default_color)));
 468       estimated_max_prim_size += 1024; /* gen6 VS push constants */
 469       estimated_max_prim_size += 1024; /* gen6 WM push constants */
 470       estimated_max_prim_size += 512; /* misc. pad */
 471
 472       /* Flush the batch if it's approaching full, so that we don't wrap while
 473        * we've got validated state that needs to be in the same batch as the
 474        * primitives.
 475        */
 476       intel_batchbuffer_require_space(intel, estimated_max_prim_size, false);
 477       intel_batchbuffer_save_state(intel);
 478
 479       brw->num_instances = prim->num_instances;
 480       if (intel->gen < 6)
 481          brw_set_prim(brw, &prim[i]);
 482       else
 483          gen6_set_prim(brw, &prim[i]);
 484
 485 retry:
 486       /* Note that before the loop, brw->state.dirty.brw was set to != 0, and
 487        * that the state updated in the loop outside of this block is that in
 488        * *_set_prim or intel_batchbuffer_flush(), which only impacts
 489        * brw->state.dirty.brw.
 490        */
 491       if (brw->state.dirty.brw) {
 492          intel->no_batch_wrap = true;
 493          brw_upload_state(brw);
 494       }
 495
 496       if (intel->gen >= 7)
 497          gen7_emit_prim(brw, &prim[i], brw->primitive);
 498       else
 499          brw_emit_prim(brw, &prim[i], brw->primitive);
 500
 501       intel->no_batch_wrap = false;
 502
 503       if (dri_bufmgr_check_aperture_space(&intel->batch.bo, 1)) {
 504          if (!fail_next) {
 505             intel_batchbuffer_reset_to_saved(intel);
 506             intel_batchbuffer_flush(intel);
 507             fail_next = true;
 508             goto retry;
 509          } else {
 510             if (intel_batchbuffer_flush(intel) == -ENOSPC) {
 511                static bool warned = false;
 512
 513                if (!warned) {
 514                   fprintf(stderr, "i965: Single primitive emit exceeded"
 515                           "available aperture space\n");
 516                   warned = true;
 517                }
 518
 519                retval = false;
 520             }
 521          }
 522       }
 523
 524       if (!_mesa_meta_in_progress(ctx))
 525          brw_update_primitive_count(brw, &prim[i]);
 526    }
 527
 528    if (intel->always_flush_batch)
 529       intel_batchbuffer_flush(intel);
 530
 531    brw_state_cache_check_size(brw);
 532    brw_postdraw_set_buffers_need_resolve(brw);
 533
 534    return retval;
 535 }
 536
 537 void brw_draw_prims( struct gl_context *ctx,
 538                      const struct _mesa_prim *prim,
 539                      GLuint nr_prims,
 540                      const struct _mesa_index_buffer *ib,
 541                      GLboolean index_bounds_valid,
 542                      GLuint min_index,
 543                      GLuint max_index,
 544                      struct gl_transform_feedback_object *tfb_vertcount )
 545 {
 546    const struct gl_client_array **arrays = ctx->Array._DrawArrays;
 547
 548    if (!_mesa_check_conditional_render(ctx))
 549       return;
 550
 551    /* Handle primitive restart if needed */
 552    if (brw_handle_primitive_restart(ctx, prim, nr_prims, ib)) {
 553       /* The draw was handled, so we can exit now */
 554       return;
 555    }
 556
 557    if (!vbo_all_varyings_in_vbos(arrays)) {
 558       if (!index_bounds_valid)
 559          vbo_get_minmax_indices(ctx, prim, ib, &min_index, &max_index, nr_prims);
 560
 561       /* Decide if we want to rebase.  If so we end up recursing once
 562        * only into this function.
 563        */
 564       if (min_index != 0 && !vbo_any_varyings_in_vbos(arrays)) {
 565          vbo_rebase_prims(ctx, arrays,
 566                           prim, nr_prims,
 567                           ib, min_index, max_index,
 568                           brw_draw_prims );
 569          return;
 570       }
 571    }
 572
 573    /* Do GL_SELECT and GL_FEEDBACK rendering using swrast, even though it
 574     * won't support all the extensions we support.
 575     */
 576    if (ctx->RenderMode != GL_RENDER) {
 577       perf_debug("%s render mode not supported in hardware\n",
 578                  _mesa_lookup_enum_by_nr(ctx->RenderMode));
 579       _swsetup_Wakeup(ctx);
 580       _tnl_wakeup(ctx);
 581       _tnl_draw_prims(ctx, arrays, prim, nr_prims, ib, min_index, max_index);
 582       return;
 583    }
 584
 585    /* Try drawing with the hardware, but don't do anything else if we can't
 586     * manage it.  swrast doesn't support our featureset, so we can't fall back
 587     * to it.
 588     */
 589    brw_try_draw_prims(ctx, arrays, prim, nr_prims, ib, min_index, max_index);
 590 }
 591
 592 void brw_draw_init( struct brw_context *brw )
 593 {
 594    struct gl_context *ctx = &brw->intel.ctx;
 595    struct vbo_context *vbo = vbo_context(ctx);
 596    int i;
 597
 598    /* Register our drawing function:
 599     */
 600    vbo->draw_prims = brw_draw_prims;
 601
 602    for (i = 0; i < VERT_ATTRIB_MAX; i++)
 603       brw->vb.inputs[i].buffer = -1;
 604    brw->vb.nr_buffers = 0;
 605    brw->vb.nr_enabled = 0;
 606 }
 607
 608 void brw_draw_destroy( struct brw_context *brw )
 609 {
 610    int i;
 611
 612    for (i = 0; i < brw->vb.nr_buffers; i++) {
 613       drm_intel_bo_unreference(brw->vb.buffers[i].bo);
 614       brw->vb.buffers[i].bo = NULL;
 615    }
 616    brw->vb.nr_buffers = 0;
 617
 618    for (i = 0; i < brw->vb.nr_enabled; i++) {
 619       brw->vb.enabled[i]->buffer = -1;
 620    }
 621    brw->vb.nr_enabled = 0;
 622
 623    drm_intel_bo_unreference(brw->ib.bo);
 624    brw->ib.bo = NULL;
 625 }