1 ! Copyright (C) 2010 Joe Groff.
2 ! See https://factorcode.org/license.txt for BSD license.
3 USING: accessors arrays fry kernel locals math sequences ;
4 IN: game.models.half-edge
6 TUPLE: edge < identity-tuple face vertex opposite-edge next-edge ;
8 : edge-vertices ( edge -- start end )
9 [ vertex>> ] [ opposite-edge>> vertex>> ] bi ;
11 ! building blocks for edge loop iteration
13 : (collect) ( in quot iterator -- out )
14 [ collector ] dip dip >array ; inline
16 : (reduce) ( in initial quot iterator -- accum )
17 [ swap ] 2dip call ; inline
19 : (count) ( in iterator -- count )
20 [ 0 [ drop 1 + ] ] dip (reduce) ; inline
22 : edge-loop ( ..a edge quot: ( ..a edge -- ..b ) next-edge-quot: ( ..b edge -- ..a edge' ) -- ..a )
23 pick '[ _ _ bi dup _ eq? not ] loop drop ; inline
25 ! iterate over related edges
27 : each-vertex-edge ( ... edge quot: ( ... edge -- ... ) -- ... )
28 [ opposite-edge>> next-edge>> ] edge-loop ; inline
30 : each-face-edge ( ... edge quot: ( ... edge -- ... ) -- ... )
31 [ next-edge>> ] edge-loop ; inline
35 : vertex-edges ( edge -- edges )
36 [ ] [ each-vertex-edge ] (collect) ;
38 : vertex-neighbors ( edge -- edges )
39 [ opposite-edge>> vertex>> ] [ each-vertex-edge ] (collect) ;
41 : vertex-diagonals ( edge -- edges )
42 [ next-edge>> opposite-edge>> vertex>> ] [ each-vertex-edge ] (collect) ;
44 : vertex-valence ( edge -- count )
45 [ each-vertex-edge ] (count) ;
47 : face-edges ( edge -- edges )
48 [ ] [ each-face-edge ] (collect) ;
50 : face-neighbors ( edge -- edges )
51 [ opposite-edge>> face>> ] [ each-face-edge ] (collect) ;
53 : face-sides ( edge -- count )
54 [ each-face-edge ] (count) ;