射线检测完善

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

@@ -312,6 +312,99 @@ module es {
             return new Rectangle(topLeft.x, topLeft.y, fullSize.x, fullSize.y)
         }
 
+        public static lineToPoly(start: Vector2, end: Vector2, polygon: Polygon, hit: RaycastHit): boolean {
+            let normal = Vector2.zero;
+            let intersectionPoint = Vector2.zero;
+            let fraction = Number.MAX_VALUE;
+            let hasIntersection = false;
+
+            for (let j = polygon.points.length - 1, i = 0; i < polygon.points.length; j = i, i ++){
+                let edge1 = Vector2.add(polygon.position, polygon.points[j]);
+                let edge2 = Vector2.add(polygon.position, polygon.points[i]);
+                let intersection: Vector2 = Vector2.zero;
+                if (this.lineToLine(edge1, edge2, start, end, intersection)){
+                    hasIntersection = true;
+
+                    // TODO: 这是得到分数的正确和最有效的方法吗?
+                    // 先检查x分数。如果是NaN，就用y代替
+                    let distanceFraction = (intersection.x - start.x) / (end.x - start.x);
+                    if (Number.isNaN(distanceFraction) || Number.isFinite(distanceFraction))
+                        distanceFraction = (intersection.y - start.y) / (end.y - start.y);
+
+                    if (distanceFraction < fraction){
+                        let edge = Vector2.subtract(edge2, edge1);
+                        normal = new Vector2(edge.y, -edge.x);
+                        fraction = distanceFraction;
+                        intersectionPoint = intersection;
+                    }
+                }
+            }
+
+            if (hasIntersection){
+                normal = normal.normalize();
+                let distance = Vector2.distance(start, intersectionPoint);
+                hit.setValuesNonCollider(fraction, distance, intersectionPoint, normal);
+                return true;
+            }
+
+            return false;
+        }
+
+        public static lineToLine(a1: Vector2, a2: Vector2, b1: Vector2, b2: Vector2, intersection: Vector2){
+            let b = Vector2.subtract(a2, a1);
+            let d = Vector2.subtract(b2, b1);
+            let bDotDPerp = b.x * d.y - b.y * d.x;
+
+            // 如果b*d = 0，表示这两条直线平行，因此有无穷个交点
+            if (bDotDPerp == 0)
+                return false;
+
+            let c = Vector2.subtract(b1, a1);
+            let t = (c.x * d.y - c.y * d.x) / bDotDPerp;
+            if (t < 0 || t > 1)
+                return false;
+
+            let u = (c.x * b.y - c.y * b.x) / bDotDPerp;
+            if (u < 0 || u > 1)
+                return false;
+
+            intersection = intersection.add(a1).add(Vector2.multiply(new Vector2(t), b));
+
+            return true;
+        }
+
+        public static lineToCircle(start: Vector2, end: Vector2, s: Circle, hit: RaycastHit): boolean{
+            // 计算这里的长度并分别对d进行标准化，因为如果我们命中了我们需要它来得到分数
+            let lineLength = Vector2.distance(start, end);
+            let d = Vector2.divide(Vector2.subtract(end, start), new Vector2(lineLength));
+            let m = Vector2.subtract(start, s.position);
+            let b = Vector2.dot(m, d);
+            let c = Vector2.dot(m, m) - s.radius * s.radius;
+
+            // 如果r的原点在s之外，(c>0)和r指向s (b>0) 则返回
+            if (c > 0 && b > 0)
+                return false;
+
+            let discr = b * b - c;
+            // 线不在圆圈上
+            if (discr < 0)
+                return false;
+
+            // 射线相交圆
+            hit.fraction = -b - Math.sqrt(discr);
+
+            // 如果分数为负数，射线从圈内开始，
+            if (hit.fraction < 0)
+                hit.fraction = 0;
+
+            hit.point = Vector2.add(start, Vector2.multiply(new Vector2(hit.fraction), d));
+            hit.distance = Vector2.distance(start, hit.point);
+            hit.normal = Vector2.normalize(Vector2.subtract(hit.point, s.position));
+            hit.fraction = hit.distance / lineLength;
+
+            return true;
+        }
+
         /**
          * 用second检查被deltaMovement移动的框的结果
          * @param first