Cycles: Implement preliminary test for volume stack update from SSS

This adds an AABB collision check for objects with volumes and if there's a
collision detected then the object will have SD_OBJECT_INTERSECTS_VOLUME flag.

This solves a speed regression introduced by the fix for T39823 by skipping
volume stack update in cases no volumes intersects the current SSS object.

1 files changed, 5 insertions, 0 deletions

diff --git a/intern/cycles/device/device_memory.h b/intern/cycles/device/device_memory.h
index 8eee6a2c79e..07a6eb36a3c 100644
--- a/intern/cycles/device/device_memory.h
+++ b/intern/cycles/device/device_memory.h
@@ -260,6 +260,11 @@ public:
 		return data.size();
 	}
 
+	T* get_data()
+	{
+		return &data[0];
+	}
+
 private:
 	array<T> data;
 };