Cycles: support arbitrary number of motion blur steps for objects.

1 files changed, 21 insertions, 20 deletions

diff --git a/intern/cycles/blender/blender_util.h b/intern/cycles/blender/blender_util.h
index c4c45035b5a..c418b19a637 100644
--- a/intern/cycles/blender/blender_util.h
+++ b/intern/cycles/blender/blender_util.h
@@ -484,33 +484,34 @@ static inline void mesh_texture_space(BL::Mesh& b_mesh,
 	loc = loc*size - make_float3(0.5f, 0.5f, 0.5f);
 }
 
-/* object used for motion blur */
-static inline bool object_use_motion(BL::Object& b_parent, BL::Object& b_ob)
+/* Object motion steps, returns 0 if no motion blur needed. */
+static inline uint object_motion_steps(BL::Object& b_parent, BL::Object& b_ob)
 {
+	/* Get motion enabled and steps from object itself. */
 	PointerRNA cobject = RNA_pointer_get(&b_ob.ptr, "cycles");
 	bool use_motion = get_boolean(cobject, "use_motion_blur");
-	/* If motion blur is enabled for the object we also check
-	 * whether it's enabled for the parent object as well.
-	 *
-	 * This way we can control motion blur from the dupligroup
-	 * duplicator much easier.
-	 */
-	if(use_motion && b_parent.ptr.data != b_ob.ptr.data) {
+	if(!use_motion) {
+		return 0;
+	}
+
+	uint steps = max(1, get_int(cobject, "motion_steps"));
+
+	/* Also check parent object, so motion blur and steps can be
+	 * controlled by dupligroup duplicator for linked groups. */
+	if(b_parent.ptr.data != b_ob.ptr.data) {
 		PointerRNA parent_cobject = RNA_pointer_get(&b_parent.ptr, "cycles");
 		use_motion &= get_boolean(parent_cobject, "use_motion_blur");
-	}
-	return use_motion;
-}
 
-/* object motion steps */
-static inline uint object_motion_steps(BL::Object& b_ob)
-{
-	PointerRNA cobject = RNA_pointer_get(&b_ob.ptr, "cycles");
-	uint steps = get_int(cobject, "motion_steps");
+		if(!use_motion) {
+			return 0;
+		}
+
+		steps = max(steps, get_int(parent_cobject, "motion_steps"));
+	}
 
-	/* use uneven number of steps so we get one keyframe at the current frame,
-	 * and ue 2^(steps - 1) so objects with more/fewer steps still have samples
-	 * at the same times, to avoid sampling at many different times */
+	/* Use uneven number of steps so we get one keyframe at the current frame,
+	 * and use 2^(steps - 1) so objects with more/fewer steps still have samples
+	 * at the same times, to avoid sampling at many different times. */
 	return (2 << (steps - 1)) + 1;
 }