Bouncing Rotating Ball Mask Problem

programming flash
1

I have this rubberband ball that I’ve made interactive, when it bounces it also rotates to try and give a more realistic feel to it. When it’s rolling across the “table” it seems to rotate from the center, but it’s rolling like a square, as if it’s a square. I masked the image I’m using, but it still rotates like a square. I’m not sure if it’s my gravity code or what the problem is.


import flash.filters.BlurFilter;
var blurShadow:BlurFilter;

init();

function init() {
    dragging = false;
    friction = 0.96;
    bounce = -0.7;
    gravity = 2;
    top = 0;
    left = 100;
    bottom = Stage.height - 200;
    right = Stage.width + 120;
    ball._x = Stage.width / 2
    ball._y = Stage.height / 2;
    vx = Math.random() * 10 - 5;
    vy = Math.random() * 10 - 5;
}
ball.onPress = function() {
    oldX = ball._x;
    oldY = ball._y;
    dragging = true;
    ball.startDrag();
}
ball.onRelease = function() {
    dragging = false;
    ball.stopDrag();
}
ball.onReleaseOutside = function() {
    dragging = false;
    ball.stopDrag();
}
function onEnterFrame(Void):Void {
    trace(Math.round(vy*1000)/1000);
    if (vy >= -0.806 && vy <= -0.7) {
        gravity = 0;
    }
    else {
        gravity = 2;
    }
    mcShadow._x = ball._x;
    mcShadow._width = (mcShadow._y - ball._y) / 1.2;
    blurAmt = mcShadow._width / 8;
    mcShadow.filters = [new flash.filters.BlurFilter(blurAmt, blurAmt, 3)];
    if (!dragging) {
        vy += gravity;
        vx *= friction;
        vy *= friction;
        if (vx < .001 && vx > -.001) {
            vx = 0;
        }
        if (vy < .001 && vy > -.001) {
            vy = 0;
        }
        ball._x += vx;
        ball._y += vy;
        ball._rotation += vx;
        if (ball._x + ball._width / 2 > right) {
            ball._x = right - ball._width / 2;
            vx *= bounce;
        }
        else if (ball._x - ball._width / 2 < left) {
            ball._x = left + ball._width / 2;
            vx *= bounce;
        }
        if (ball._y + ball._height / 2 > bottom) {
            ball._y = bottom - ball._height / 2;
            vy *= bounce;
        }
        else if (ball._y - ball._height / 2 < top) {
            ball._y = top + ball._height / 2;
            vy *= bounce;
        }
    }
    else {
        vx = ball._x - oldX;
        vy = ball._y - oldY;
        oldX = ball._x;
        oldY = ball._y;
    }
}