added rotation point parameter to Body.rotate, closes #410

liabru · May 3, 2017 · 749ed50 · 749ed50
1 parent ab0283b
commit 749ed50
Showing 1 changed file with 17 additions and 2 deletions.
diff --git a/src/body/Body.js b/src/body/Body.js
@@ -492,9 +492,24 @@ var Axes = require('../geometry/Axes');
  * @method rotate
  * @param {body} body
  * @param {number} rotation
+ * @param {vector} [point]
  */
- Body.rotate = function(body, rotation) {
- Body.setAngle(body, body.angle + rotation);
+ Body.rotate = function(body, rotation, point) {
+ if (!point) {
+ Body.setAngle(body, body.angle + rotation);
+ } else {
+ var cos = Math.cos(rotation),
+ sin = Math.sin(rotation),
+ dx = body.position.x - point.x,
+ dy = body.position.y - point.y;
+
+ Body.setPosition(body, {
+ x: point.x + (dx * cos - dy * sin),
+ y: point.y + (dx * sin + dy * cos)
+ });
+
+ Body.setAngle(body, body.angle + rotation);
+ }
  };
 
  /**