I am making a space-themed shooter game, and I need to render many "lasers" at the same time. I am using the library Slick2D, a wrapper around lwjgl. Unfortunately, when there are a lot of these "lasers" on the screen at one time, the game drops from its usual 60 FPS to around 30 or even 20.

Things I've noticed:

• Not calling drawSelf = no lag
• Not calling .fill = no lag
• As is = lag as stated in title

public void drawSelf(Graphics g){
    int[] pos = tr.toSlick(blast.getPosition());
    g.setColor(Color.green);
    Circle circle = new Circle(pos[0], pos[1], tr.xscale/2);
    g.fill(circle);
}

public int[] toSlick(float x, float y){
    int [] output = new int[2];
    output[0] = (int)(x*xscale+width/2);
    output[1] = (int)(-1*y*yscale+height/2);
    return output;
}

tr is the coordinate transformer object (I'm using jbox2d physics, but that's not impacting anything), and blast is the "Body".

Can I have some suggestions on making this code faster or am I stuck because of Slick's internals?