Cycles: Expose QBVH on/off switch to the UI.

We might remove this again in the future, but for testing purposes
during the release cycle, this will be useful.

The setting defaults to QBVH, and can be found in the Performance panel.

3 files changed, 7 insertions, 1 deletions

diff --git a/intern/cycles/blender/addon/properties.py b/intern/cycles/blender/addon/properties.py
index 9459b750bd1..0829f1cfbed 100644
--- a/intern/cycles/blender/addon/properties.py
+++ b/intern/cycles/blender/addon/properties.py
@@ -456,6 +456,11 @@ class CyclesRenderSettings(bpy.types.PropertyGroup):
                 description="Use BVH spatial splits: longer builder time, faster render",
                 default=False,
                 )
+        cls.use_qbvh = BoolProperty(
+                name="Use QBVH",
+                description="Use QBVH acceleration structure",
+                default=True,
+                )
         cls.use_cache = BoolProperty(
                 name="Cache BVH",
                 description="Cache last built BVH to disk for faster re-render if no geometry changed",
diff --git a/intern/cycles/blender/addon/ui.py b/intern/cycles/blender/addon/ui.py
index 9b1e20d3c8f..52964ca0df4 100644
--- a/intern/cycles/blender/addon/ui.py
+++ b/intern/cycles/blender/addon/ui.py
@@ -320,6 +320,7 @@ class CyclesRender_PT_performance(CyclesButtonsPanel, Panel):
 
         col.label(text="Acceleration structure:")
         col.prop(cscene, "debug_use_spatial_splits")
+        col.prop(cscene, "use_qbvh")
 
 
 class CyclesRender_PT_layer_options(CyclesButtonsPanel, Panel):
diff --git a/intern/cycles/blender/blender_sync.cpp b/intern/cycles/blender/blender_sync.cpp
index f83eb113a88..2fb2b6d840d 100644
--- a/intern/cycles/blender/blender_sync.cpp
+++ b/intern/cycles/blender/blender_sync.cpp
@@ -379,7 +379,7 @@ SceneParams BlenderSync::get_scene_params(BL::Scene b_scene, bool background, bo
 		params.persistent_data = false;
 
 	if(is_cpu) {
-		params.use_qbvh = system_cpu_support_sse2();
+		params.use_qbvh = system_cpu_support_sse2() && RNA_boolean_get(&cscene, "use_qbvh");
 	}
 	else {
 		params.use_qbvh = false;