Catmull–Clark subdivision surface: Difference between revisions

'mesh points'=. y

face_point=:. avg"2 mesh{points

point_face=:. |: mesh havePoints points

avg_face_points=:. point_face avg@#"1 2 face_point

edges=:. ~.,/meshEdges=:mesh /:~@,"+1|."1 mesh

edge_face=:. *./"2 edges e."0 1/ mesh

edge_center=:. avg"2 edges{points

edge_point=:. (0.5*edge_center) + 0.25 * edge_face +/ .* face_point

point_edge=:. |: edges havePoints points

avg_mid_edges=:. point_edge avg@#"1 2 edge_center

n=:. +/"1 point_edge

'm3 m2 m1'=:. (2,1,:n-3)%"1 n

new_coords=:. (m1 * points) + (m2 * avg_face_points) + (m3 * avg_mid_edges)

pts=:. face_point,edge_point,new_coords

c0=:. (#edge_point)+e0=:#face_point

msh=:. (,c0+mesh),.(,e0+edge i. meshEdges),.((#i.)~/$mesh),.,e0+_1|."1 edge i. meshEdges