From d3813fc611aaf54363313c9b39f06140614d705b Mon Sep 17 00:00:00 2001
From: Gustavo Canedo <gustavo.canedo@betrybe.com>
Date: Mon, 1 Nov 2021 12:48:14 -0300
Subject: [PATCH] add relativeForce

---
 src/body/Body.js | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/src/body/Body.js b/src/body/Body.js
index 3bdc75c..9407d23 100644
--- a/src/body/Body.js
+++ b/src/body/Body.js
@@ -694,6 +694,28 @@ var Axes = require('../geometry/Axes');
         body.torque += offset.x * force.y - offset.y * force.x;
     };
 
+    /**
+     * Applies a relative force to a body from a given relative position, including resulting torque.
+     * @method applyForce
+     * @param {body} body
+     * @param {vector} relativePosition
+     * @param {vector} relativeForce
+     */
+    Body.applyRelativeForce = function(body, relativePosition, relativeForce) {
+        var sin = Math.sin(body.angle);
+        var cos = Math.cos(body.angle);
+        
+        Body.applyForce(
+            body, {
+                x: body.position.x + cos * relativePosition.x - sin * relativePosition.y,
+                y: body.position.y + sin * relativePosition.x + cos * relativePosition.y,
+            }, {
+                x: cos * relativeForce.x - sin * relativeForce.y,
+                y: sin * relativeForce.x + cos * relativeForce.y,
+            }
+        );
+    };
+
     /**
      * Returns the sums of the properties of all compound parts of the parent body.
      * @method _totalProperties