move a displayobject based on another objects rotation

Question

Ive probably ran into some code like this before. just cant remember where. I have 2 display objects on my stage. One is rotating and the other is positioned 90 degrees from the rotating object. As the object rotates, the other object adjusts its x and y positioning from the rotating object..

If this doesnt make sense, then let me explain what I am trying to do. I have a spaceship in my flash game. this ship has 2 torrets siting on the left and right wing. as the ship turns, the torrets need to remain on the wings. Does anyone know how I would go about doing this.

Answer 1

why don't you just nest them inside the wings? if the wing rotates they will remain on top of the wing.

Answer 2

If you insist on keeping the DisplayObjects non-nested, use the power of trigonometry.

Assuming that at rotation = 0, your turret object is a distance, r, directly to the right of the ship center.

private function degreesToRadians(degrees:Number):Number {
    return degrees * Math.PI / 180;
}

turret.x = shipCenter.x + r*Math.cos(degreesToRadians(ship.rotation));
turret.y = shipCenter.y + r*Math.sin(degreesToRadians(ship.rotation));

However, learning how to use a proper transformation matrix or nesting your display objects will ultimately lead to a cleaner solution