shill-lucasfilm

The same issue was fixed in Falcor's implementation (`perp_stark`) in 4.4: https://github.com/NVIDIAGameWorks/Falcor/pull/278 Code here: https://github.com/NVIDIAGameWorks/Falcor/blob/5236495554f57a734cc815522d95ae9a7dfe458a/Source/Falcor/Utils/Math/MathHelpers.h#L42-L54