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

   1 /*
   2  * Copyright © 2012 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *    Jordan Justen <jordan.l.justen@intel.com>
  25  *
  26  */
  27
  28 #include "main/imports.h"
  29 #include "main/bufferobj.h"
  30 #include "main/varray.h"
  31 #include "vbo/vbo.h"
  32
  33 #include "brw_context.h"
  34 #include "brw_defines.h"
  35 #include "brw_draw.h"
  36
  37 #include "intel_batchbuffer.h"
  38
  39 /**
  40  * Check if the hardware's cut index support can handle the primitive
  41  * restart index value (pre-Haswell only).
  42  */
  43 static bool
  44 can_cut_index_handle_restart_index(struct gl_context *ctx,
  45                                    const struct _mesa_index_buffer *ib)
  46 {
  47    /* The FixedIndex variant means 0xFF, 0xFFFF, or 0xFFFFFFFF based on
  48     * the index buffer type, which corresponds exactly to the hardware.
  49     */
  50    if (ctx->Array.PrimitiveRestartFixedIndex)
  51       return true;
  52
  53    bool cut_index_will_work;
  54
  55    switch (ib->type) {
  56    case GL_UNSIGNED_BYTE:
  57       cut_index_will_work = ctx->Array.RestartIndex == 0xff;
  58       break;
  59    case GL_UNSIGNED_SHORT:
  60       cut_index_will_work = ctx->Array.RestartIndex == 0xffff;
  61       break;
  62    case GL_UNSIGNED_INT:
  63       cut_index_will_work = ctx->Array.RestartIndex == 0xffffffff;
  64       break;
  65    default:
  66       unreachable("not reached");
  67    }
  68
  69    return cut_index_will_work;
  70 }
  71
  72 /**
  73  * Check if the hardware's cut index support can handle the primitive
  74  * restart case.
  75  */
  76 static bool
  77 can_cut_index_handle_prims(struct gl_context *ctx,
  78                            const struct _mesa_prim *prim,
  79                            GLuint nr_prims,
  80                            const struct _mesa_index_buffer *ib)
  81 {
  82    struct brw_context *brw = brw_context(ctx);
  83
  84    /* Otherwise Haswell can do it all. */
  85    if (brw->gen >= 8 || brw->is_haswell)
  86       return true;
  87
  88    if (!can_cut_index_handle_restart_index(ctx, ib)) {
  89       /* The primitive restart index can't be handled, so take
  90        * the software path
  91        */
  92       return false;
  93    }
  94
  95    for (unsigned i = 0; i < nr_prims; i++) {
  96       switch (prim[i].mode) {
  97       case GL_POINTS:
  98       case GL_LINES:
  99       case GL_LINE_STRIP:
 100       case GL_TRIANGLES:
 101       case GL_TRIANGLE_STRIP:
 102       case GL_LINES_ADJACENCY:
 103       case GL_LINE_STRIP_ADJACENCY:
 104       case GL_TRIANGLES_ADJACENCY:
 105       case GL_TRIANGLE_STRIP_ADJACENCY:
 106          /* Cut index supports these primitive types */
 107          break;
 108       default:
 109          /* Cut index does not support these primitive types */
 110       //case GL_LINE_LOOP:
 111       //case GL_TRIANGLE_FAN:
 112       //case GL_QUADS:
 113       //case GL_QUAD_STRIP:
 114       //case GL_POLYGON:
 115          return false;
 116       }
 117    }
 118
 119    return true;
 120 }
 121
 122 /**
 123  * Check if primitive restart is enabled, and if so, handle it properly.
 124  *
 125  * In some cases the support will be handled in software. When available
 126  * hardware will handle primitive restart.
 127  */
 128 GLboolean
 129 brw_handle_primitive_restart(struct gl_context *ctx,
 130                              const struct _mesa_prim *prims,
 131                              GLuint nr_prims,
 132                              const struct _mesa_index_buffer *ib,
 133                              struct gl_buffer_object *indirect)
 134 {
 135    struct brw_context *brw = brw_context(ctx);
 136
 137    /* We only need to handle cases where there is an index buffer. */
 138    if (ib == NULL) {
 139       return GL_FALSE;
 140    }
 141
 142    /* If we have set the in_progress flag, then we are in the middle
 143     * of handling the primitive restart draw.
 144     */
 145    if (brw->prim_restart.in_progress) {
 146       return GL_FALSE;
 147    }
 148
 149    /* If PrimitiveRestart is not enabled, then we aren't concerned about
 150     * handling this draw.
 151     */
 152    if (!(ctx->Array._PrimitiveRestart)) {
 153       return GL_FALSE;
 154    }
 155
 156    /* Signal that we are in the process of handling the
 157     * primitive restart draw
 158     */
 159    brw->prim_restart.in_progress = true;
 160
 161    if (can_cut_index_handle_prims(ctx, prims, nr_prims, ib)) {
 162       /* Cut index should work for primitive restart, so use it
 163        */
 164       brw->prim_restart.enable_cut_index = true;
 165       brw_draw_prims(ctx, prims, nr_prims, ib, GL_FALSE, -1, -1, NULL, 0,
 166                      indirect);
 167       brw->prim_restart.enable_cut_index = false;
 168    } else {
 169       /* Not all the primitive draw modes are supported by the cut index,
 170        * so take the software path
 171        */
 172       vbo_sw_primitive_restart(ctx, prims, nr_prims, ib, indirect);
 173    }
 174
 175    brw->prim_restart.in_progress = false;
 176
 177    /* The primitive restart draw was completed, so return true. */
 178    return GL_TRUE;
 179 }
 180
 181 static void
 182 haswell_upload_cut_index(struct brw_context *brw)
 183 {
 184    struct gl_context *ctx = &brw->ctx;
 185
 186    /* Don't trigger on Ivybridge */
 187    if (brw->gen < 8 && !brw->is_haswell)
 188       return;
 189
 190    const unsigned cut_index_setting =
 191       ctx->Array._PrimitiveRestart ? HSW_CUT_INDEX_ENABLE : 0;
 192
 193    /* BRW_NEW_INDEX_BUFFER */
 194    unsigned cut_index;
 195    if (brw->ib.ib) {
 196       cut_index = _mesa_primitive_restart_index(ctx, brw->ib.type);
 197    } else {
 198       /* There's no index buffer, but primitive restart may still apply
 199        * to glDrawArrays and such.  FIXED_INDEX mode only applies to drawing
 200        * operations that use an index buffer, so we can ignore it and use
 201        * the GL restart index directly.
 202        */
 203       cut_index = ctx->Array.RestartIndex;
 204    }
 205
 206    BEGIN_BATCH(2);
 207    OUT_BATCH(_3DSTATE_VF << 16 | cut_index_setting | (2 - 2));
 208    OUT_BATCH(cut_index);
 209    ADVANCE_BATCH();
 210 }
 211
 212 const struct brw_tracked_state haswell_cut_index = {
 213    .dirty = {
 214       .mesa  = _NEW_TRANSFORM,
 215       .brw   = BRW_NEW_BLORP |
 216                BRW_NEW_INDEX_BUFFER,
 217    },
 218    .emit = haswell_upload_cut_index,
 219 };