gemma: pkg/octree/polygon.go comparison

Fixed handling of none-closed polygons in containment test.

author	Sascha L. Teichmann <teichmann@intevation.de>
date	Sat, 19 Oct 2019 19:40:51 +0200
parents	1137c5a18242
children	db6c2955ee31

comparison

equal deleted inserted replaced

-:d786c37b02c0
+:5c80a33edd44
 		return IntersectionInside
 	}
 	return IntersectionOutSide
 }
-func (rng ring) closed() bool {
-	return (len(rng) / 2) >= 3
-}
 func (rng ring) length() int {
 	return len(rng) / 2
 }
 func (rng ring) point(i int) (float64, float64) {
 	i *= 2
 	return rng[i], rng[i+1]
 }
 type segments interface {
-	closed() bool
 	length() int
 	point(int) (float64, float64)
 }
 func contains(s segments, pX, pY float64) bool {
-	if !s.closed() {
-		return false
-	}
 	n := s.length()
+	if n < 3 {
+		return false
+	}
 	sX, sY := s.point(0)
 	eX, eY := s.point(n - 1)
-	contains := intersectsWithRaycast(pX, pY, sX, sY, eX, eY)
+	const eps = 0.0000001
+	if math.Abs(sX-eX) > eps && math.Abs(sY-eY) > eps {
+		// It's not closed!
+		return false
+	}
+	var inside bool
 	for i := 1; i < n; i++ {
-		sX, sY := s.point(i - 1)
 		eX, eY := s.point(i)
 		if intersectsWithRaycast(pX, pY, sX, sY, eX, eY) {
-			contains = !contains
+			inside = !inside
 		}
-	}
+		sX, sY = eX, eY
+	}
-	return contains
+	return inside
 }
 // Using the raycast algorithm, this returns whether or not the passed in point
 // Intersects with the edge drawn by the passed in start and end points.
 // Original implementation: http://rosettacode.org/wiki/Ray-casting_algorithm#Go

Mercurial > gemma