added Query.collides, closes #478

Author: liabru

src/collision/Query.js

@@ -19,35 +19,26 @@ var Vertices = require('../geometry/Vertices');
 (function() {
 
     /**
-     * Casts a ray segment against a set of bodies and returns all collisions, ray width is optional. Intersection points are not provided.
-     * @method ray
+     * Returns a list of collisions between `body` and `bodies`.
+     * @method collides
+     * @param {body} body
      * @param {body[]} bodies
-     * @param {vector} startPoint
-     * @param {vector} endPoint
-     * @param {number} [rayWidth]
      * @return {object[]} Collisions
      */
-    Query.ray = function(bodies, startPoint, endPoint, rayWidth) {
-        rayWidth = rayWidth || 1e-100;
-
-        var rayAngle = Vector.angle(startPoint, endPoint),
-            rayLength = Vector.magnitude(Vector.sub(startPoint, endPoint)),
-            rayX = (endPoint.x + startPoint.x) * 0.5,
-            rayY = (endPoint.y + startPoint.y) * 0.5,
-            ray = Bodies.rectangle(rayX, rayY, rayLength, rayWidth, { angle: rayAngle }),
-            collisions = [];
+    Query.collides = function(body, bodies) {
+        var collisions = [];
 
         for (var i = 0; i < bodies.length; i++) {
             var bodyA = bodies[i];
 
-            if (Bounds.overlaps(bodyA.bounds, ray.bounds)) {
+            if (Bounds.overlaps(bodyA.bounds, body.bounds)) {
                 for (var j = bodyA.parts.length === 1 ? 0 : 1; j < bodyA.parts.length; j++) {
                     var part = bodyA.parts[j];
 
-                    if (Bounds.overlaps(part.bounds, ray.bounds)) {
-                        var collision = SAT.collides(part, ray);
+                    if (Bounds.overlaps(part.bounds, body.bounds)) {
+                        var collision = SAT.collides(part, body);
+
                         if (collision.collided) {
-                            collision.body = collision.bodyA = collision.bodyB = bodyA;
                             collisions.push(collision);
                             break;
                         }
@@ -59,6 +50,33 @@ var Vertices = require('../geometry/Vertices');
         return collisions;
     };
 
+    /**
+     * Casts a ray segment against a set of bodies and returns all collisions, ray width is optional. Intersection points are not provided.
+     * @method ray
+     * @param {body[]} bodies
+     * @param {vector} startPoint
+     * @param {vector} endPoint
+     * @param {number} [rayWidth]
+     * @return {object[]} Collisions
+     */
+    Query.ray = function(bodies, startPoint, endPoint, rayWidth) {
+        rayWidth = rayWidth || 1e-100;
+
+        var rayAngle = Vector.angle(startPoint, endPoint),
+            rayLength = Vector.magnitude(Vector.sub(startPoint, endPoint)),
+            rayX = (endPoint.x + startPoint.x) * 0.5,
+            rayY = (endPoint.y + startPoint.y) * 0.5,
+            ray = Bodies.rectangle(rayX, rayY, rayLength, rayWidth, { angle: rayAngle }),
+            collisions = Query.collides(ray, bodies);
+
+        for (var i = 0; i < collisions.length; i += 1) {
+            var collision = collisions[i];
+            collision.body = collision.bodyB = collision.bodyA;            
+        }
+
+        return collisions;
+    };
+
     /**
      * Returns all bodies whose bounds are inside (or outside if set) the given set of bounds, from the given set of bodies.
      * @method region