VFACE semantic VPOS or SV_Position VFACE semantic ClipDistance VFACE semantic Semantics MSDN - VPOS & SV_POSITION semantics ClipDistance VFACE semantic VPOS or SV_Position VPOS or SV_Position VPOS or SV_Position docs for semantics VFACE semantic MSDN VPOS or SV_Position ClipDistance MSDN VPOS or SV_Position VFACE semantic VPOS or SV_Position Shader's Semantic names (for in / out data) The documentation says ClipDistance VPOS or SV_Position docs for semantics off by half a pixel ClipDistance ClipDistance SV_Position