Visual Concealment for Games using JavaScript

function Player() {
	Body.call(this);
	this.standardForce = 20000;
	this.fireLossFactor = 0.01;	
}

Player.prototype = new Body();
Player.prototype.constructor = Player;

Player.prototype.processInput = function(totalElapsed, elapsed, level, entities, keyboard) {
	
	if (keyboard.pressed.forward)
		this.forces.push(Vector2D.mul(this.lookDirection, this.standardForce / (1 + this.size)));

	if (keyboard.pressed.backward)
		this.forces.push(Vector2D.mul(this.lookDirection, -(this.standardForce / 2) / (1 + this.size)));
	
	if (keyboard.pressed.left || keyboard.pressed.right) {
		var perpendicular = Vector2D.cross(this.lookDirection);
		if (keyboard.pressed.left)
			this.forces.push(Vector2D.mul(perpendicular, 0.25 * this.standardForce / (1 + this.size)));
		else
			this.forces.push(Vector2D.mul(perpendicular, -0.25 * this.standardForce / (1 + this.size)));
	}

	if (keyboard.pressed.turnleft)
		this.lookDirection = Vector2D.rotate(this.lookDirection, -(32 * elapsed / (1 + this.size)));
	
	if (keyboard.pressed.turnright)
		this.lookDirection = Vector2D.rotate(this.lookDirection,  (32 * elapsed / (1 + this.size)));
	
	if (keyboard.pressed.fire) {
	    var bullet = new Bullet(this.size * this.fireLossFactor);
	    this.size *= 1 - this.fireLossFactor;
	    bullet.lookDirection = new Vector2D(this.lookDirection.x, this.lookDirection.y);
	    bullet.position = Vector2D.add(Vector2D.mul(bullet.lookDirection, this.size), new Vector2D(this.position.x, this.position.y));
	    bullet.forces.push(Vector2D.mul(bullet.lookDirection, 50000));
	    this.additionalEntities.push(bullet);
	}
	
	if (this.size < 5) {
        for(var j = 0; j < 200; ++j) {
            var fragment = new ExplosionFragment(3 + Math.random() * 4);
            fragment.position = this.position;
            fragment.velocity = Vector2D.rotate(new Vector2D(Math.random() * 1000, 0), Math.random() * TWO_PI);
            this.additionalEntities.push(fragment);
            this.isDead = true;
        }
	    
	}
	    
	    
};