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_overflow_query(struct brw_context *brw,
  52                                  struct brw_query_object *query,
  53                                  int stream_start, int count)
  54 {
  55    hsw_overflow_result_to_gpr0(brw, query, count);
  56    brw_load_register_reg64(brw, HSW_CS_GPR(0), MI_PREDICATE_SRC0);
  57    brw_load_register_imm64(brw, MI_PREDICATE_SRC1, 0ull);
  58 }
  59
  60 static void
  61 set_predicate_for_occlusion_query(struct brw_context *brw,
  62                                   struct brw_query_object *query)
  63 {
  64    brw_load_register_mem64(brw,
  65                            MI_PREDICATE_SRC0,
  66                            query->bo,
  67                            I915_GEM_DOMAIN_INSTRUCTION,
  68                            0, /* write domain */
  69                            0 /* offset */);
  70    brw_load_register_mem64(brw,
  71                            MI_PREDICATE_SRC1,
  72                            query->bo,
  73                            I915_GEM_DOMAIN_INSTRUCTION,
  74                            0, /* write domain */
  75                            8 /* offset */);
  76 }
  77
  78 static void
  79 set_predicate_for_result(struct brw_context *brw,
  80                          struct brw_query_object *query,
  81                          bool inverted)
  82 {
  83
  84    int load_op;
  85
  86    assert(query->bo != NULL);
  87
  88    /* Needed to ensure the memory is coherent for the MI_LOAD_REGISTER_MEM
  89     * command when loading the values into the predicate source registers for
  90     * conditional rendering.
  91     */
  92    brw_emit_pipe_control_flush(brw, PIPE_CONTROL_FLUSH_ENABLE);
  93
  94    switch (query->Base.Target) {
  95    case GL_TRANSFORM_FEEDBACK_STREAM_OVERFLOW_ARB:
  96       set_predicate_for_overflow_query(brw, query, 0, 1);
  97       break;
  98    case GL_TRANSFORM_FEEDBACK_OVERFLOW_ARB:
  99       set_predicate_for_overflow_query(brw, query, 0, MAX_VERTEX_STREAMS);
 100       break;
 101    default:
 102       set_predicate_for_occlusion_query(brw, query);
 103    }
 104
 105    if (inverted)
 106       load_op = MI_PREDICATE_LOADOP_LOAD;
 107    else
 108       load_op = MI_PREDICATE_LOADOP_LOADINV;
 109
 110    BEGIN_BATCH(1);
 111    OUT_BATCH(GEN7_MI_PREDICATE |
 112              load_op |
 113              MI_PREDICATE_COMBINEOP_SET |
 114              MI_PREDICATE_COMPAREOP_SRCS_EQUAL);
 115    ADVANCE_BATCH();
 116
 117    brw->predicate.state = BRW_PREDICATE_STATE_USE_BIT;
 118 }
 119
 120 static void
 121 brw_begin_conditional_render(struct gl_context *ctx,
 122                              struct gl_query_object *q,
 123                              GLenum mode)
 124 {
 125    struct brw_context *brw = brw_context(ctx);
 126    struct brw_query_object *query = (struct brw_query_object *) q;
 127    bool inverted;
 128
 129    if (!brw->predicate.supported)
 130       return;
 131
 132    if ((query->Base.Target == GL_TRANSFORM_FEEDBACK_OVERFLOW_ARB ||
 133         query->Base.Target == GL_TRANSFORM_FEEDBACK_STREAM_OVERFLOW_ARB) &&
 134        !can_do_mi_math_and_lrr(brw->screen))
 135       return;
 136
 137    switch (mode) {
 138    case GL_QUERY_WAIT:
 139    case GL_QUERY_NO_WAIT:
 140    case GL_QUERY_BY_REGION_WAIT:
 141    case GL_QUERY_BY_REGION_NO_WAIT:
 142       inverted = false;
 143       break;
 144    case GL_QUERY_WAIT_INVERTED:
 145    case GL_QUERY_NO_WAIT_INVERTED:
 146    case GL_QUERY_BY_REGION_WAIT_INVERTED:
 147    case GL_QUERY_BY_REGION_NO_WAIT_INVERTED:
 148       inverted = true;
 149       break;
 150    default:
 151       unreachable("Unexpected conditional render mode");
 152    }
 153
 154    /* If there are already samples from a BLT operation or if the query object
 155     * is ready then we can avoid looking at the values in the buffer and just
 156     * decide whether to draw using the CPU without stalling.
 157     */
 158    if (query->Base.Result || query->Base.Ready)
 159       set_predicate_enable(brw, (query->Base.Result != 0) ^ inverted);
 160    else
 161       set_predicate_for_result(brw, query, inverted);
 162 }
 163
 164 static void
 165 brw_end_conditional_render(struct gl_context *ctx,
 166                            struct gl_query_object *q)
 167 {
 168    struct brw_context *brw = brw_context(ctx);
 169
 170    /* When there is no longer a conditional render in progress it should
 171     * always render.
 172     */
 173    brw->predicate.state = BRW_PREDICATE_STATE_RENDER;
 174 }
 175
 176 void
 177 brw_init_conditional_render_functions(struct dd_function_table *functions)
 178 {
 179    functions->BeginConditionalRender = brw_begin_conditional_render;
 180    functions->EndConditionalRender = brw_end_conditional_render;
 181 }
 182
 183 bool
 184 brw_check_conditional_render(struct brw_context *brw)
 185 {
 186    const struct gl_query_object *query = brw->ctx.Query.CondRenderQuery;
 187
 188    const bool query_is_xfb = query &&
 189       (query->Target == GL_TRANSFORM_FEEDBACK_OVERFLOW_ARB ||
 190        query->Target == GL_TRANSFORM_FEEDBACK_STREAM_OVERFLOW_ARB);
 191
 192    if (brw->predicate.supported &&
 193        (can_do_mi_math_and_lrr(brw->screen) || !query_is_xfb)) {
 194       /* In some cases it is possible to determine that the primitives should
 195        * be skipped without needing the predicate enable bit and still without
 196        * stalling.
 197        */
 198       return brw->predicate.state != BRW_PREDICATE_STATE_DONT_RENDER;
 199    } else if (query) {
 200       perf_debug("Conditional rendering is implemented in software and may "
 201                  "stall.\n");
 202       return _mesa_check_conditional_render(&brw->ctx);
 203    } else {
 204       return true;
 205    }
 206 }