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

   1 /*
   2  * Copyright © 2014 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  *    Neil Roberts <neil@linux.intel.com>
  25  */
  26
  27 /** @file brw_conditional_render.c
  28  *
  29  * Support for conditional rendering based on query objects
  30  * (GL_NV_conditional_render, GL_ARB_conditional_render_inverted) on Gen7+.
  31  */
  32
  33 #include "main/imports.h"
  34 #include "main/condrender.h"
  35
  36 #include "brw_context.h"
  37 #include "brw_defines.h"
  38 #include "intel_batchbuffer.h"
  39
  40 static void
  41 set_predicate_enable(struct brw_context *brw,
  42                      bool value)
  43 {
  44    if (value)
  45       brw->predicate.state = BRW_PREDICATE_STATE_RENDER;
  46    else
  47       brw->predicate.state = BRW_PREDICATE_STATE_DONT_RENDER;
  48 }
  49
  50 static void
  51 set_predicate_for_result(struct brw_context *brw,
  52                          struct brw_query_object *query,
  53                          bool inverted)
  54 {
  55    int load_op;
  56
  57    assert(query->bo != NULL);
  58
  59    brw_load_register_mem64(brw,
  60                            MI_PREDICATE_SRC0,
  61                            query->bo,
  62                            I915_GEM_DOMAIN_INSTRUCTION,
  63                            0, /* write domain */
  64                            0 /* offset */);
  65    brw_load_register_mem64(brw,
  66                            MI_PREDICATE_SRC1,
  67                            query->bo,
  68                            I915_GEM_DOMAIN_INSTRUCTION,
  69                            0, /* write domain */
  70                            8 /* offset */);
  71
  72    if (inverted)
  73       load_op = MI_PREDICATE_LOADOP_LOAD;
  74    else
  75       load_op = MI_PREDICATE_LOADOP_LOADINV;
  76
  77    BEGIN_BATCH(1);
  78    OUT_BATCH(GEN7_MI_PREDICATE |
  79              load_op |
  80              MI_PREDICATE_COMBINEOP_SET |
  81              MI_PREDICATE_COMPAREOP_SRCS_EQUAL);
  82    ADVANCE_BATCH();
  83
  84    brw->predicate.state = BRW_PREDICATE_STATE_USE_BIT;
  85 }
  86
  87 static void
  88 brw_begin_conditional_render(struct gl_context *ctx,
  89                              struct gl_query_object *q,
  90                              GLenum mode)
  91 {
  92    struct brw_context *brw = brw_context(ctx);
  93    struct brw_query_object *query = (struct brw_query_object *) q;
  94    bool inverted;
  95
  96    if (!brw->predicate.supported)
  97       return;
  98
  99    switch (mode) {
 100    case GL_QUERY_WAIT:
 101    case GL_QUERY_NO_WAIT:
 102    case GL_QUERY_BY_REGION_WAIT:
 103    case GL_QUERY_BY_REGION_NO_WAIT:
 104       inverted = false;
 105       break;
 106    case GL_QUERY_WAIT_INVERTED:
 107    case GL_QUERY_NO_WAIT_INVERTED:
 108    case GL_QUERY_BY_REGION_WAIT_INVERTED:
 109    case GL_QUERY_BY_REGION_NO_WAIT_INVERTED:
 110       inverted = true;
 111       break;
 112    default:
 113       unreachable("Unexpected conditional render mode");
 114    }
 115
 116    /* If there are already samples from a BLT operation or if the query object
 117     * is ready then we can avoid looking at the values in the buffer and just
 118     * decide whether to draw using the CPU without stalling.
 119     */
 120    if (query->Base.Result || query->Base.Ready)
 121       set_predicate_enable(brw, (query->Base.Result != 0) ^ inverted);
 122    else
 123       set_predicate_for_result(brw, query, inverted);
 124 }
 125
 126 static void
 127 brw_end_conditional_render(struct gl_context *ctx,
 128                            struct gl_query_object *q)
 129 {
 130    struct brw_context *brw = brw_context(ctx);
 131
 132    /* When there is no longer a conditional render in progress it should
 133     * always render.
 134     */
 135    brw->predicate.state = BRW_PREDICATE_STATE_RENDER;
 136 }
 137
 138 void
 139 brw_init_conditional_render_functions(struct dd_function_table *functions)
 140 {
 141    functions->BeginConditionalRender = brw_begin_conditional_render;
 142    functions->EndConditionalRender = brw_end_conditional_render;
 143 }
 144
 145 bool
 146 brw_check_conditional_render(struct brw_context *brw)
 147 {
 148    if (brw->predicate.supported) {
 149       /* In some cases it is possible to determine that the primitives should
 150        * be skipped without needing the predicate enable bit and still without
 151        * stalling.
 152        */
 153       return brw->predicate.state != BRW_PREDICATE_STATE_DONT_RENDER;
 154    } else if (brw->ctx.Query.CondRenderQuery) {
 155       perf_debug("Conditional rendering is implemented in software and may "
 156                  "stall.\n");
 157       return _mesa_check_conditional_render(&brw->ctx);
 158    } else {
 159       return true;
 160    }
 161 }