Removed preCalc

src/Body.java

@@ -4,7 +4,7 @@ import codedraw.CodeDraw;
  * This class represents celestial bodies like stars, planets, asteroids, etc...
  */
 public class Body {
-    private final double mass;
+    private double mass;
     private Vector massCenter; // position of the mass center.
     private Vector currentMovement;
 
@@ -83,6 +83,12 @@ public class Body {
         return massCenter;
     }
 
+    public void update(Body b) {
+        double combinedMass = this.mass + b.mass;
+        this.massCenter = this.massCenter.times(this.mass / combinedMass).plus(b.massCenter.times(b.mass / combinedMass));
+        this.mass = combinedMass;
+    }
+
     public boolean collidesWith(Body body) {
         return this.distanceTo(body) < this.radius() + body.radius();
     }