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    /* Needed to ensure the memory is coherent for the MI_LOAD_REGISTER_MEM
  60     * command when loading the values into the predicate source registers for
  61     * conditional rendering.
  62     */
  63    brw_emit_pipe_control_flush(brw, PIPE_CONTROL_FLUSH_ENABLE);
  64
  65    brw_load_register_mem64(brw,
  66                            MI_PREDICATE_SRC0,
  67                            query->bo,
  68                            I915_GEM_DOMAIN_INSTRUCTION,
  69                            0, /* write domain */
  70                            0 /* offset */);
  71    brw_load_register_mem64(brw,
  72                            MI_PREDICATE_SRC1,
  73                            query->bo,
  74                            I915_GEM_DOMAIN_INSTRUCTION,
  75                            0, /* write domain */
  76                            8 /* offset */);
  77
  78    if (inverted)
  79       load_op = MI_PREDICATE_LOADOP_LOAD;
  80    else
  81       load_op = MI_PREDICATE_LOADOP_LOADINV;
  82
  83    BEGIN_BATCH(1);
  84    OUT_BATCH(GEN7_MI_PREDICATE |
  85              load_op |
  86              MI_PREDICATE_COMBINEOP_SET |
  87              MI_PREDICATE_COMPAREOP_SRCS_EQUAL);
  88    ADVANCE_BATCH();
  89
  90    brw->predicate.state = BRW_PREDICATE_STATE_USE_BIT;
  91 }
  92
  93 static void
  94 brw_begin_conditional_render(struct gl_context *ctx,
  95                              struct gl_query_object *q,
  96                              GLenum mode)
  97 {
  98    struct brw_context *brw = brw_context(ctx);
  99    struct brw_query_object *query = (struct brw_query_object *) q;
 100    bool inverted;
 101
 102    if (!brw->predicate.supported)
 103       return;
 104
 105    switch (mode) {
 106    case GL_QUERY_WAIT:
 107    case GL_QUERY_NO_WAIT:
 108    case GL_QUERY_BY_REGION_WAIT:
 109    case GL_QUERY_BY_REGION_NO_WAIT:
 110       inverted = false;
 111       break;
 112    case GL_QUERY_WAIT_INVERTED:
 113    case GL_QUERY_NO_WAIT_INVERTED:
 114    case GL_QUERY_BY_REGION_WAIT_INVERTED:
 115    case GL_QUERY_BY_REGION_NO_WAIT_INVERTED:
 116       inverted = true;
 117       break;
 118    default:
 119       unreachable("Unexpected conditional render mode");
 120    }
 121
 122    /* If there are already samples from a BLT operation or if the query object
 123     * is ready then we can avoid looking at the values in the buffer and just
 124     * decide whether to draw using the CPU without stalling.
 125     */
 126    if (query->Base.Result || query->Base.Ready)
 127       set_predicate_enable(brw, (query->Base.Result != 0) ^ inverted);
 128    else
 129       set_predicate_for_result(brw, query, inverted);
 130 }
 131
 132 static void
 133 brw_end_conditional_render(struct gl_context *ctx,
 134                            struct gl_query_object *q)
 135 {
 136    struct brw_context *brw = brw_context(ctx);
 137
 138    /* When there is no longer a conditional render in progress it should
 139     * always render.
 140     */
 141    brw->predicate.state = BRW_PREDICATE_STATE_RENDER;
 142 }
 143
 144 void
 145 brw_init_conditional_render_functions(struct dd_function_table *functions)
 146 {
 147    functions->BeginConditionalRender = brw_begin_conditional_render;
 148    functions->EndConditionalRender = brw_end_conditional_render;
 149 }
 150
 151 bool
 152 brw_check_conditional_render(struct brw_context *brw)
 153 {
 154    if (brw->predicate.supported) {
 155       /* In some cases it is possible to determine that the primitives should
 156        * be skipped without needing the predicate enable bit and still without
 157        * stalling.
 158        */
 159       return brw->predicate.state != BRW_PREDICATE_STATE_DONT_RENDER;
 160    } else if (brw->ctx.Query.CondRenderQuery) {
 161       perf_debug("Conditional rendering is implemented in software and may "
 162                  "stall.\n");
 163       return _mesa_check_conditional_render(&brw->ctx);
 164    } else {
 165       return true;
 166    }
 167 }