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
  32 #include "brw_context.h"
  33 #include "brw_defines.h"
  34 #include "brw_draw.h"
  35
  36 #include "intel_batchbuffer.h"
  37
  38 /**
  39  * Check if the hardware's cut index support can handle the primitive
  40  * restart index value (pre-Haswell only).
  41  */
  42 static bool
  43 can_cut_index_handle_restart_index(struct gl_context *ctx,
  44                                    const struct _mesa_index_buffer *ib)
  45 {
  46    /* The FixedIndex variant means 0xFF, 0xFFFF, or 0xFFFFFFFF based on
  47     * the index buffer type, which corresponds exactly to the hardware.
  48     */
  49    if (ctx->Array.PrimitiveRestartFixedIndex)
  50       return true;
  51
  52    bool cut_index_will_work;
  53
  54    switch (ib->type) {
  55    case GL_UNSIGNED_BYTE:
  56       cut_index_will_work = ctx->Array.RestartIndex == 0xff;
  57       break;
  58    case GL_UNSIGNED_SHORT:
  59       cut_index_will_work = ctx->Array.RestartIndex == 0xffff;
  60       break;
  61    case GL_UNSIGNED_INT:
  62       cut_index_will_work = ctx->Array.RestartIndex == 0xffffffff;
  63       break;
  64    default:
  65       unreachable("not reached");
  66    }
  67
  68    return cut_index_will_work;
  69 }
  70
  71 /**
  72  * Check if the hardware's cut index support can handle the primitive
  73  * restart case.
  74  */
  75 static bool
  76 can_cut_index_handle_prims(struct gl_context *ctx,
  77                            const struct _mesa_prim *prim,
  78                            GLuint nr_prims,
  79                            const struct _mesa_index_buffer *ib)
  80 {
  81    struct brw_context *brw = brw_context(ctx);
  82
  83    /* Otherwise Haswell can do it all. */
  84    if (brw->gen >= 8 || brw->is_haswell)
  85       return true;
  86
  87    if (!can_cut_index_handle_restart_index(ctx, ib)) {
  88       /* The primitive restart index can't be handled, so take
  89        * the software path
  90        */
  91       return false;
  92    }
  93
  94    for (int i = 0; i < nr_prims; i++) {
  95       switch (prim[i].mode) {
  96       case GL_POINTS:
  97       case GL_LINES:
  98       case GL_LINE_STRIP:
  99       case GL_TRIANGLES:
 100       case GL_TRIANGLE_STRIP:
 101       case GL_LINES_ADJACENCY:
 102       case GL_LINE_STRIP_ADJACENCY:
 103       case GL_TRIANGLES_ADJACENCY:
 104       case GL_TRIANGLE_STRIP_ADJACENCY:
 105          /* Cut index supports these primitive types */
 106          break;
 107       default:
 108          /* Cut index does not support these primitive types */
 109       //case GL_LINE_LOOP:
 110       //case GL_TRIANGLE_FAN:
 111       //case GL_QUADS:
 112       //case GL_QUAD_STRIP:
 113       //case GL_POLYGON:
 114          return false;
 115       }
 116    }
 117
 118    return true;
 119 }
 120
 121 /**
 122  * Check if primitive restart is enabled, and if so, handle it properly.
 123  *
 124  * In some cases the support will be handled in software. When available
 125  * hardware will handle primitive restart.
 126  */
 127 GLboolean
 128 brw_handle_primitive_restart(struct gl_context *ctx,
 129                              const struct _mesa_prim *prims,
 130                              GLuint nr_prims,
 131                              const struct _mesa_index_buffer *ib,
 132                              struct gl_buffer_object *indirect)
 133 {
 134    struct brw_context *brw = brw_context(ctx);
 135
 136    /* We only need to handle cases where there is an index buffer. */
 137    if (ib == NULL) {
 138       return GL_FALSE;
 139    }
 140
 141    /* If we have set the in_progress flag, then we are in the middle
 142     * of handling the primitive restart draw.
 143     */
 144    if (brw->prim_restart.in_progress) {
 145       return GL_FALSE;
 146    }
 147
 148    /* If PrimitiveRestart is not enabled, then we aren't concerned about
 149     * handling this draw.
 150     */
 151    if (!(ctx->Array._PrimitiveRestart)) {
 152       return GL_FALSE;
 153    }
 154
 155    /* Signal that we are in the process of handling the
 156     * primitive restart draw
 157     */
 158    brw->prim_restart.in_progress = true;
 159
 160    if (can_cut_index_handle_prims(ctx, prims, nr_prims, ib)) {
 161       /* Cut index should work for primitive restart, so use it
 162        */
 163       brw->prim_restart.enable_cut_index = true;
 164       brw_draw_prims(ctx, prims, nr_prims, ib, GL_FALSE, -1, -1, NULL, indirect);
 165       brw->prim_restart.enable_cut_index = false;
 166    } else {
 167       /* Not all the primitive draw modes are supported by the cut index,
 168        * so take the software path
 169        */
 170       vbo_sw_primitive_restart(ctx, prims, nr_prims, ib, indirect);
 171    }
 172
 173    brw->prim_restart.in_progress = false;
 174
 175    /* The primitive restart draw was completed, so return true. */
 176    return GL_TRUE;
 177 }
 178
 179 static void
 180 haswell_upload_cut_index(struct brw_context *brw)
 181 {
 182    struct gl_context *ctx = &brw->ctx;
 183
 184    /* Don't trigger on Ivybridge */
 185    if (brw->gen < 8 && !brw->is_haswell)
 186       return;
 187
 188    const unsigned cut_index_setting =
 189       ctx->Array._PrimitiveRestart ? HSW_CUT_INDEX_ENABLE : 0;
 190
 191    /* BRW_NEW_INDEX_BUFFER */
 192    unsigned cut_index;
 193    if (brw->ib.ib) {
 194       cut_index = _mesa_primitive_restart_index(ctx, brw->ib.type);
 195    } else {
 196       /* There's no index buffer, but primitive restart may still apply
 197        * to glDrawArrays and such.  FIXED_INDEX mode only applies to drawing
 198        * operations that use an index buffer, so we can ignore it and use
 199        * the GL restart index directly.
 200        */
 201       cut_index = ctx->Array.RestartIndex;
 202    }
 203
 204    BEGIN_BATCH(2);
 205    OUT_BATCH(_3DSTATE_VF << 16 | cut_index_setting | (2 - 2));
 206    OUT_BATCH(cut_index);
 207    ADVANCE_BATCH();
 208 }
 209
 210 const struct brw_tracked_state haswell_cut_index = {
 211    .dirty = {
 212       .mesa  = _NEW_TRANSFORM,
 213       .brw   = BRW_NEW_INDEX_BUFFER,
 214    },
 215    .emit = haswell_upload_cut_index,
 216 };