Lazer.pde

class Lazer extends GameObject
{
  float aliveFor = 0;
  float toLive;
  
  Lazer()
  {
    w = 5.0f;
    h = 5.0f;
    mass = 0.2f;
    speed = 300.0f;
    toLive = 3.0f;
  }
  
  void update()
  {
   
    aliveFor += timeDelta;    
    if (aliveFor > toLive)
    {
      alive = false;
    }
    integrate();
    wrap();    
    
    theta = velocity.heading() + HALF_PI;
    force.setMag(0);
    look.x = sin(theta);
    look.y = -cos(theta);
  }
  
  void draw()
  {
    pushMatrix();
    translate(position.x, position.y);
    rotate(theta);
    scale(scaleF);
    float alpha = (1.0f - aliveFor / toLive) * 2000.0f;
    stroke(red(colour), green(colour), blue(colour), (int)alpha); 
    line(0, - h / 2.0f, 0, h / 2.0f);
      
    popMatrix();        
  }
}