Cycles: Store time in BVH nodes

This way we can stop traversing BVH node early on.

Gives about 2-2.5x times render time improvement with 3 BVH steps.
Hopefully this gives no measurable performance loss for scenes with
single BVH step.

Traversal is currently only implemented for QBVH, meaning old CPUs
and GPU do not benefit from this change.

1 files changed, 6 insertions, 1 deletions

diff --git a/intern/cycles/bvh/bvh_node.h b/intern/cycles/bvh/bvh_node.h
index 2faa40ab657..090c426de56 100644
--- a/intern/cycles/bvh/bvh_node.h
+++ b/intern/cycles/bvh/bvh_node.h
@@ -47,7 +47,9 @@ class BVHNode
 {
 public:
 	BVHNode() : m_is_unaligned(false),
-	            m_aligned_space(NULL)
+	            m_aligned_space(NULL),
+	            m_time_from(0.0f),
+	            m_time_to(1.0f)
 	{
 	}
 
@@ -91,12 +93,15 @@ public:
 	void deleteSubtree();
 
 	uint update_visibility();
+	void update_time();
 
 	bool m_is_unaligned;
 
 	// TODO(sergey): Can be stored as 3x3 matrix, but better to have some
 	// utilities and type defines in util_transform first.
 	Transform *m_aligned_space;
+
+	float m_time_from, m_time_to;
 };
 
 class InnerNode : public BVHNode