Adding bodies to the space

We already have the addBody function with all required arguments, so it's time to define it:

addBody: function(posX,posY,width,height,isDynamic,spriteImage,type){
  if(isDynamic){
    var body = new cp.Body(1,cp.momentForBox(1,width,height));
  }
  else{
    var body = new cp.Body(Infinity,Infinity);
  }
  body.setPos(cp.v(posX,posY));
  if(isDynamic){
    world.addBody(body);
  }
  var shape = new cp.BoxShape(body, width, height);
  shape.setFriction(1);
  shape.setElasticity(0);
  shape.name=type;
  world.addShape(shape);
}

This is where big differences between Box2D and Chipmunk2D start to show. Thus, we will explain the addBody function line-by-line:

if(isDynamic) {
  var body = new cp.Body(1,cp.momentForBox(1,width,height));
}
else{
  var body = new cp.Body(Infinity,Infinity);
}

We have two ways to create a body, irrespective of whether it's static or dynamic. Both use the cp.Body method, whose arguments are the mass and the moment of inertia. The moment of inertia...