Enable occlusion query feature on OpenGL3.3 and later

gpu/command_buffer/service/feature_info.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/command_buffer/service/feature_info.h"
 
 #include <stddef.h>
 
 #include <set>
 #include <vector>
@@ skipping 88 matching lines @@
       npot_ok(false),
       enable_texture_float_linear(false),
       enable_texture_half_float_linear(false),
       angle_translated_shader_source(false),
       angle_pack_reverse_row_order(false),
       arb_texture_rectangle(false),
       angle_instanced_arrays(false),
       occlusion_query_boolean(false),
       use_arb_occlusion_query2_for_occlusion_query_boolean(false),
       use_arb_occlusion_query_for_occlusion_query_boolean(false),
+      no_covert_any_samples_passed_conservative_target_for_es3(false),
+      covert_any_samples_passed_conservative_target_for_low_gl(false),
       native_vertex_array_object(false),
       ext_texture_format_astc(false),
       ext_texture_format_atc(false),
       ext_texture_format_bgra8888(false),
       ext_texture_format_dxt1(false),
       ext_texture_format_dxt5(false),
       enable_shader_name_hashing(false),
       enable_samplers(false),
       ext_draw_buffers(false),
       nv_draw_buffers(false),
@@ skipping 918 matching lines @@
         validators_.texture_internal_format_storage.AddValue(GL_RGBA16F_EXT);
         validators_.texture_internal_format_storage.AddValue(GL_RGB16F_EXT);
         validators_.texture_internal_format_storage.AddValue(GL_ALPHA16F_EXT);
         validators_.texture_internal_format_storage.AddValue(
             GL_LUMINANCE16F_EXT);
         validators_.texture_internal_format_storage.AddValue(
             GL_LUMINANCE_ALPHA16F_EXT);
     }
   }
 
-  bool have_es3_occlusion_query =
-      gl_version_info_->IsAtLeastGLES(3, 0);
+  bool have_occlusion_query =
+      gl_version_info_->IsAtLeastGLES(3, 0) ||
+      gl_version_info_->IsAtLeastGL(3, 3);
   bool have_ext_occlusion_query_boolean =
       extensions.Contains("GL_EXT_occlusion_query_boolean");
   bool have_arb_occlusion_query2 =
       extensions.Contains("GL_ARB_occlusion_query2");
   bool have_arb_occlusion_query =
       extensions.Contains("GL_ARB_occlusion_query");
 
-  if (have_es3_occlusion_query ||
+  if (have_occlusion_query ||
       have_ext_occlusion_query_boolean ||
       have_arb_occlusion_query2 ||
       have_arb_occlusion_query) {
     if (context_type_ == CONTEXT_TYPE_OPENGLES2) {
       AddExtensionString("GL_EXT_occlusion_query_boolean");
     }
     feature_flags_.occlusion_query_boolean = true;
     feature_flags_.use_arb_occlusion_query2_for_occlusion_query_boolean =
         !have_ext_occlusion_query_boolean && have_arb_occlusion_query2;
     feature_flags_.use_arb_occlusion_query_for_occlusion_query_boolean =
         !have_ext_occlusion_query_boolean && have_arb_occlusion_query &&
         !have_arb_occlusion_query2;
+    feature_flags_.no_covert_any_samples_passed_conservative_target_for_es3 =

[Zhenyao Mo, 2016/07/14 18:09:02]

I don't think you need two new flags for this purpose.  You only need to specify
three behaviors

1) core bahavior, either ES3+, or GL4.3+, or have ext_occlusion_query_boolean.

2) arb_occlusion_query2 behavior, not 1, and have arb_occlusion_query2

3) arb_occulision_query bahavior, not 1, and no arb_occlusion_query2, and have
arb_occlusion_query

And you only need two flags (no flag means no mapping, the core behavior).

Hope I explained myself clearly.

+        gl_version_info_->IsAtLeastGLES(3, 0);
+    feature_flags_.covert_any_samples_passed_conservative_target_for_low_gl =
+        gl_version_info_->IsAtLeastGL(3, 3) &&
+        gl_version_info_->IsLowerThanGL(4, 3);
   }
 
   if (!workarounds_.disable_angle_instanced_arrays &&
       (extensions.Contains("GL_ANGLE_instanced_arrays") ||
        (extensions.Contains("GL_ARB_instanced_arrays") &&
         extensions.Contains("GL_ARB_draw_instanced")) ||
        gl_version_info_->is_es3 ||
        gl_version_info_->is_desktop_core_profile)) {
     AddExtensionString("GL_ANGLE_instanced_arrays");
     feature_flags_.angle_instanced_arrays = true;
@@ skipping 338 matching lines @@
   if (pos == std::string::npos) {
     extensions_ += (extensions_.empty() ? "" : " ") + str;
   }
 }
 
 FeatureInfo::~FeatureInfo() {
 }
 
 }  // namespace gles2
 }  // namespace gpu