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       cut_index_will_work = false;
  66       assert(0);
  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 ( ; nr_prims > 0; nr_prims--) {
  96       switch(prim->mode) {
  97       case GL_POINTS:
  98       case GL_LINES:
  99       case GL_LINE_STRIP:
 100       case GL_TRIANGLES:
 101       case GL_TRIANGLE_STRIP:
 102          /* Cut index supports these primitive types */
 103          break;
 104       default:
 105          /* Cut index does not support these primitive types */
 106       //case GL_LINE_LOOP:
 107       //case GL_TRIANGLE_FAN:
 108       //case GL_QUADS:
 109       //case GL_QUAD_STRIP:
 110       //case GL_POLYGON:
 111          return false;
 112       }
 113    }
 114
 115    return true;
 116 }
 117
 118 /**
 119  * Check if primitive restart is enabled, and if so, handle it properly.
 120  *
 121  * In some cases the support will be handled in software. When available
 122  * hardware will handle primitive restart.
 123  */
 124 GLboolean
 125 brw_handle_primitive_restart(struct gl_context *ctx,
 126                              const struct _mesa_prim *prim,
 127                              GLuint nr_prims,
 128                              const struct _mesa_index_buffer *ib)
 129 {
 130    struct brw_context *brw = brw_context(ctx);
 131
 132    /* We only need to handle cases where there is an index buffer. */
 133    if (ib == NULL) {
 134       return GL_FALSE;
 135    }
 136
 137    /* If the driver has requested software handling of primitive restarts,
 138     * then the VBO module has already taken care of things, and we can
 139     * just draw as normal.
 140     */
 141    if (ctx->Const.PrimitiveRestartInSoftware) {
 142       return GL_FALSE;
 143    }
 144
 145    /* If we have set the in_progress flag, then we are in the middle
 146     * of handling the primitive restart draw.
 147     */
 148    if (brw->prim_restart.in_progress) {
 149       return GL_FALSE;
 150    }
 151
 152    /* If PrimitiveRestart is not enabled, then we aren't concerned about
 153     * handling this draw.
 154     */
 155    if (!(ctx->Array._PrimitiveRestart)) {
 156       return GL_FALSE;
 157    }
 158
 159    /* Signal that we are in the process of handling the
 160     * primitive restart draw
 161     */
 162    brw->prim_restart.in_progress = true;
 163
 164    if (can_cut_index_handle_prims(ctx, prim, nr_prims, ib)) {
 165       /* Cut index should work for primitive restart, so use it
 166        */
 167       brw->prim_restart.enable_cut_index = true;
 168       brw_draw_prims(ctx, prim, nr_prims, ib, GL_FALSE, -1, -1, NULL);
 169       brw->prim_restart.enable_cut_index = false;
 170    } else {
 171       /* Not all the primitive draw modes are supported by the cut index,
 172        * so take the software path
 173        */
 174       vbo_sw_primitive_restart(ctx, prim, nr_prims, ib);
 175    }
 176
 177    brw->prim_restart.in_progress = false;
 178
 179    /* The primitive restart draw was completed, so return true. */
 180    return GL_TRUE;
 181 }
 182
 183 static void
 184 haswell_upload_cut_index(struct brw_context *brw)
 185 {
 186    struct gl_context *ctx = &brw->ctx;
 187
 188    /* Don't trigger on Ivybridge */
 189    if (!brw->is_haswell)
 190       return;
 191
 192    const unsigned cut_index_setting =
 193       ctx->Array._PrimitiveRestart ? HSW_CUT_INDEX_ENABLE : 0;
 194
 195    /* BRW_NEW_INDEX_BUFFER */
 196    unsigned cut_index;
 197    if (brw->ib.ib) {
 198       cut_index = _mesa_primitive_restart_index(ctx, brw->ib.type);
 199    } else {
 200       /* There's no index buffer, but primitive restart may still apply
 201        * to glDrawArrays and such.  FIXED_INDEX mode only applies to drawing
 202        * operations that use an index buffer, so we can ignore it and use
 203        * the GL restart index directly.
 204        */
 205       cut_index = ctx->Array.RestartIndex;
 206    }
 207
 208    BEGIN_BATCH(2);
 209    OUT_BATCH(_3DSTATE_VF << 16 | cut_index_setting | (2 - 2));
 210    OUT_BATCH(cut_index);
 211    ADVANCE_BATCH();
 212 }
 213
 214 const struct brw_tracked_state haswell_cut_index = {
 215    .dirty = {
 216       .mesa  = _NEW_TRANSFORM,
 217       .brw   = BRW_NEW_INDEX_BUFFER,
 218       .cache = 0,
 219    },
 220    .emit = haswell_upload_cut_index,
 221 };