 
 struct ControlVertex {
     vec4 position;
-    vec4 patchCoord; // u, v, level, faceID
+    centroid vec4 patchCoord; // u, v, level, faceID
     ivec4 ptexInfo;  // U offset, V offset, 2^ptexlevel', rotation
     ivec3 clipFlag;
 #if OSD_NUM_VARYINGS > 0

    vec4 position;
    vec3 normal;
    vec3 tangent;
    vec4 patchCoord; // u, v, level, faceID
    noperspective vec4 edgeDistance;
#if OSD_NUM_VARYINGS > 0
    float varyings[OSD_NUM_VARYINGS];

    vec3 Em;
    vec3 Fp;
    vec3 Fm;
    centroid vec4 patchCoord;
    ivec4 ptexInfo;
#if OSD_NUM_VARYINGS > 0
    float varyings[OSD_NUM_VARYINGS];
