新增shapecollision 用于计算多边形碰撞

source/src/Physics/Shapes/ShapeCollisions/ShapeCollisions.ts

@@ -0,0 +1,60 @@
+class ShapeCollisions {
+    public static circleToRect(circle: Circle, box: Rect): CollisionResult{
+        let result = new CollisionResult();
+        let closestPointOnBounds = box.bounds.getClosestPointOnRectangleBorderToPoint(circle.position).res;
+
+        if (box.containsPoint(circle.position)){
+            result.point = closestPointOnBounds;
+
+            let safePlace = Vector2.add(closestPointOnBounds, Vector2.subtract(result.normal, new Vector2(circle.radius, circle.radius)));
+        }
+
+        return result;
+    }
+
+    public static pointToCicle(point: Vector2, circle: Circle){
+        let result = new CollisionResult();
+
+        let distanceSquared = Vector2.distanceSquared(point, circle.position);
+        let sumOfRadii = 1 + circle.radius;
+        let collided = distanceSquared < sumOfRadii * sumOfRadii;
+        if (collided){
+            result.normal = Vector2.normalize(Vector2.subtract(point, circle.position));
+            let depth = sumOfRadii - Math.sqrt(distanceSquared);
+            result.minimumTranslationVector = Vector2.multiply(new Vector2(-depth, -depth), result.normal);
+            result.point = Vector2.add(circle.position, Vector2.multiply(result.normal, new Vector2(circle.radius, circle.radius)));
+
+            return result;
+        }
+
+        return result;
+    }
+
+    public static closestPointOnLine(lineA: Vector2, lineB: Vector2, closestTo: Vector2){
+        let v = Vector2.subtract(lineB, lineA);
+        let w = Vector2.subtract(closestTo, lineA);
+        let t = Vector2.dot(w, v) / Vector2.dot(v, v);
+        t = MathHelper.clamp(t, 0, 1);
+
+        return Vector2.add(lineA, Vector2.multiply(v, new Vector2(t, t)));
+    }
+
+    public static pointToPoly(point: Vector2, poly: Polygon){
+        let result = new CollisionResult();
+
+        if (poly.containsPoint(point)){
+            let distanceSquared: number;
+            let gpp = Polygon.getClosestPointOnPolygonToPoint(poly.points, Vector2.subtract(point, poly.position));
+            let closestPoint = gpp.closestPoint;
+            distanceSquared = gpp.distanceSquared;
+            result.normal = gpp.edgeNormal;
+
+            result.minimumTranslationVector = Vector2.multiply(result.normal, new Vector2(Math.sqrt(distanceSquared), Math.sqrt(distanceSquared)));
+            result.point = Vector2.add(closestPoint, poly.position);
+
+            return result;
+        }
+
+        return result;
+    }
+}