converted intersection to return point pointers

collision.go

@@ -4,14 +4,15 @@ import (
 	"math"
 )
 
-func Intersection(p1, p2 Point2d, v1, v2 Vector2d) (bool, Point2d) {
+func Intersection(p1, p2 Point2d, v1, v2 Vector2d) (bool, *Point2d) {
 	t := p2.Sub(p1).Cross(v2) / v1.Cross(v2)
 	s := p2.Sub(p1).Cross(v1) / v1.Cross(v2)
 	if t > 0 && t < 1 && s > 0 && s < 1 {
-		return true, p1.Add(v1.Scale(t))
+		intersection := p1.Add(v1.Scale(t))
+		return true, &intersection
 	}
 
-	return false, Point2d{0, 0}
+	return false, nil
 }
 
 func RectRectIntersection(r1 AABB2d, r2 AABB2d) bool {
@@ -20,14 +21,14 @@ func RectRectIntersection(r1 AABB2d, r2 AABB2d) bool {
 }
 
 // returns collision, inside, point of collision
-func RectIntersection(r AABB2d, p Point2d, v Vector2d) (bool, bool, Point2d) {
+func RectIntersection(r AABB2d, p Point2d, v Vector2d) (bool, bool, *Point2d) {
 	collision := false
 	inside := false
 	start_inside := PointInRect(p, r)
 	end_inside := PointInRect(p.Add(v), r)
 	if start_inside && end_inside {
 		inside = true
-		return collision, inside, p
+		return collision, inside, nil
 	} else {
 		wall_left, col1 := Intersection(p, r.A, v, Vector2d{X: 0, Y: r.B.Y - r.A.Y})
 		if wall_left {
@@ -46,7 +47,7 @@ func RectIntersection(r AABB2d, p Point2d, v Vector2d) (bool, bool, Point2d) {
 			return wall_bottom, inside, col4
 		}
 
-		return false, false, p
+		return false, false, nil
 	}
 }
 
@@ -66,11 +67,11 @@ func ProjectPolygon(axis Vector2d, p Polygon2d) (min float32, max float32) {
 	return min, max
 }
 
-func PolygonIntersection(r Polygon2d, p Point2d, v Vector2d) (bool, Point2d) {
+func PolygonIntersection(r Polygon2d, p Point2d, v Vector2d) (bool, *Point2d) {
 	// TODO - need to test point in polygon for start and end to detect wholly
 	// inside situations
 	intersection := false
-	i_point := Point2d{}
+	var iPoint *Point2d
 	distance_sq := float32(math.MaxFloat32)
 
 	for point, _ := range r.Points {
@@ -80,13 +81,13 @@ func PolygonIntersection(r Polygon2d, p Point2d, v Vector2d) (bool, Point2d) {
 			intersection = true
 			d_sq := pt.Sub(p).MagSquared()
 			if d_sq < distance_sq {
-				i_point = pt
+				iPoint = pt
 				distance_sq = d_sq
 			}
 		}
 	}
 
-	return intersection, i_point
+	return intersection, iPoint
 }
 
 func PointInPolygon(p Point2d, py Polygon2d) bool {