Fix #33344: cycles motion blur was still crashing on CUDA sm 2.0. Solution now

is also an optimization, use quaternion nlerp instead of slerp, there's no good
reason to use slerp, and nlerp is faster too.

diff --git a/intern/cycles/util/util_transform.h b/intern/cycles/util/util_transform.h
index dbf88cb67a0c8ecd31273dd4bc81e3eaede9761d..a1c12ddf0e1f1fce0a3390a4c4d86274edd75a46 100644 (file)
--- a/intern/cycles/util/util_transform.h
+++ b/intern/cycles/util/util_transform.h
@@ -311,6 +311,10 @@ __device_inline Transform transform_clear_scale(const Transform& tfm)
 
 __device_inline float4 quat_interpolate(float4 q1, float4 q2, float t)
 {
+       /* use simpe nlerp instead of slerp. it's faster and almost the same */
+       return normalize((1.0f - t)*q1 + t*q2);
+
+#if 0
        /* note: this does not ensure rotation around shortest angle, q1 and q2
         * are assumed to be matched already in transform_motion_decompose */
        float costheta = dot(q1, q2);
@@ -328,6 +332,7 @@ __device_inline float4 quat_interpolate(float4 q1, float4 q2, float t)
                float thetap = theta * t;
                return q1 * cosf(thetap) + qperp * sinf(thetap);
        }
+#endif
 }
 
 __device_inline Transform transform_quick_inverse(Transform M)