Collision Detection of Sprites in Actionscript 3.0 Flash

Question

I am making an achtung die kurve-like game in AS3.0. So far I\'ve done the movements of the 4 different players, and it works alright.

I am now to make collision de

Answer 1

Try this function if you want a Pixel Perfect Collision Detection with efficient CPU usage:

trace("Collided: " + (areaOfCollision(mc1, mc2) != null));
trace("Where: " + areaOfCollision(mc1, mc2));

function areaOfCollision(object1:DisplayObject, object2:DisplayObject, tolerance:int = 255):Rectangle {
    if (object1.hitTestObject(object2)) {
        var limits1:Rectangle = object1.getBounds(object1.parent);
        var limits2:Rectangle = object2.getBounds(object2.parent);
        var limits:Rectangle = limits1.intersection(limits2);
        limits.x = Math.floor(limits.x);
        limits.y = Math.floor(limits.y);
        limits.width = Math.ceil(limits.width);
        limits.height = Math.ceil(limits.height);
        if (limits.width < 1 || limits.height < 1) return null;

        var image:BitmapData = new BitmapData(limits.width, limits.height, false);
        var matrix:Matrix = object1.transform.concatenatedMatrix;
        matrix.translate(-limits.left, -limits.top);
        image.draw(object1, matrix, new ColorTransform(1, 1, 1, 1, 255, -255, -255, tolerance));
        matrix = object2.transform.concatenatedMatrix;
        matrix.translate(-limits.left, -limits.top);
        image.draw(object2, matrix, new ColorTransform(1, 1, 1, 1, 255, 255, 255, tolerance), BlendMode.DIFFERENCE);

        var intersection:Rectangle = image.getColorBoundsRect(0xFFFFFFFF, 0xFF00FFFF);
        if (intersection.width == 0) return null;
        intersection.offset(limits.left, limits.top);
        return intersection;
    }
    return null;
}

After a successful preliminary hitTestObject(), this function backgroundly takes a snapshot from the shapes of both objects painted with different colors each, then overlays them intersecting the colors on a new one, returning the Rectangle of the resulting shape. So cool.

To learn more about Pixel Perfect Collision Detection you can google Collision Detection followed by one of these names: "The ActionScript Man", "Troy Gilbert", "Boulevart (wim)", "Grant Skinner (gSkinner)" or "Senocular". Those guys are awesome AS3 references by the way.