Picking and dragging bodies – mouse joints

Hard things first; we are going to start with one of the most difficult joints. Sad but necessary, as it will allow us to create and test other joints easily.

A mouse joint allows a player to move bodies with the mouse, and we will create it with the following features:

• Pick a body by clicking on it

• Move a body following the mouse as long as the button is pressed

• Release a body once the button is released

Some quiet before the storm; the beginning of this process does not differ to other scripts you have already mastered through the book.

1. So, we are importing the required classes:

   import flash.display.Sprite;
   import flash.events.Event;
   import flash.events.MouseEvent;
   import Box2D.Dynamics.*;
   import Box2D.Collision.*;
   import Box2D.Collision.Shapes.*;
   import Box2D.Common.Math.*;

2. Then we need the class-level variables for the world itself, and the conversion from pixels to meters:

   private var world:b2World;
   private var worldScale:Number=30;

   And even the Main...