Fix bug when forming convex hull of game room bounds

2021-09-30 23:46:59 +01:00
parent cb23960bd7
commit 1414d08d88
14 changed files with 51 additions and 16 deletions
@@ -121,6 +121,10 @@ orderPolygonAround
 orderPolygonAround _ [] = []
 orderPolygonAround cen ps = sortOn (\p -> argV (p -.- cen)) ps

+orderAroundFirstReverse :: [Point2] -> [Point2]
+orderAroundFirstReverse [] = []
+orderAroundFirstReverse (a:as) = a : reverse (orderPolygonAround a as)
+
 orderAroundFirst :: [Point2] -> [Point2]
 orderAroundFirst [] = []
 orderAroundFirst (a:as) = a : orderPolygonAround a as
@@ -141,8 +145,9 @@ convexHull :: [Point2] -> [Point2]
 convexHull (x:y:z:xs) = grahamScan $ orderAroundFirst $ sortOn (\(V2 a b) -> (b,a)) (x:y:z:xs)
 convexHull _ = error "Tried to create the convex hull of two or fewer points"
 -- | Creates the convex hull of a set of points.
-- it appears that the output may NOT be ordered
+-- assumes no repetition of points: try nubbing!
 convexHullSafe :: [Point2] -> [Point2]
+--convexHullSafe (x:y:z:xs) = grahamScan $ orderAroundFirst $ sortOn (\(V2 a b) -> (b,a)) (x:y:z:xs)
 convexHullSafe (x:y:z:xs) = grahamScan $ orderAroundFirst $ sortOn (\(V2 a b) -> (b,a)) (x:y:z:xs)
 convexHullSafe _ = []