Dynamic lighting test

package;

import flixel.FlxG;
import flixel.FlxSprite;
import flixel.FlxState;
import flixel.util.FlxPoint;
import flixel.util.FlxColor;
import flixel.util.FlxSpriteUtil;
import flixel.group.FlxGroup;
import flash.display.BlendMode;

class Darkness extends FlxSprite
{
    public var ambience:Int = 0x222222;

    public function new()
    {
        super(0, 0);

        makeGraphic(FlxG.width, FlxG.height, ambience);
        scrollFactor.x = 0;
        scrollFactor.y = 0;
        blend = BlendMode.MULTIPLY;
    }

    override public function update()
    {
        super.update();
    }
}

class Light extends FlxSprite
{
    private var darkness:Darkness;

    public function new(X:Float=0, Y:Float=0, Darkness:Darkness)
    {
        super(X, Y);

        blend = BlendMode.ADD;
        darkness = Darkness;
    }

    override public function draw()
    {
        if (isOnScreen() && visible) {
            var screenXY:FlxPoint = getScreenXY();
            darkness.stamp(this, Std.int(screenXY.x), Std.int(screenXY.y));
        }
    }
}

class TestState extends FlxState
{
    private var darkness:Darkness;
    private var lights:FlxGroup;

    override public function create():Void
    {
        super.create();

        var background = new FlxSprite(0, 0).loadGraphic(AssetPaths.background__png, false, 320, 240);
        add(background);

        darkness = new Darkness();
        lights = new FlxGroup();

        var redLight = new Light(75+25, 75+25, darkness);
        redLight.makeGraphic(100, 100, FlxColor.RED);
        lights.add(redLight);

        var greenLight = new Light(100+25, 50+25, darkness);
        greenLight.makeGraphic(100, 100, FlxColor.GREEN);
        lights.add(greenLight);

        var blueLight = new Light(50+25, 100+25, darkness);
        blueLight.makeGraphic(100, 100, FlxColor.BLUE);
        lights.add(blueLight);

        add(lights);
        add(darkness);
    }

    override public function destroy():Void
    {
        super.destroy();

        darkness = null;
        lights = null;
    }

    override public function update():Void
    {
        super.update();

        FlxSpriteUtil.drawRect(darkness, 0, 0, FlxG.width, FlxG.height, 0xff000000 | darkness.ambience);
    }
}