Collision Detection

1

Hi there, I was wondering if there was a more accurate way to detect collisions using actionscript3. I’ve made a simple helicopter-like side-scroller, and the collision detection isn’t working very well. Basically, the red rectangle (the helicopter) will detect a collision when it travels downward to hit an obstacle. If it’s traveling upward or sideways, the collision detection gets a bit funky. Right now I’m using the hitTestPoint command, if anyone else knows a better way to do it, I’d be very appreciative. I’ll attach the .fla and its source code.

package
{
    import flash.display.MovieClip
    import flash.events.Event
    import flash.events.KeyboardEvent
    
    public class DocumentMain extends MovieClip
    {
        public var _startMarker:StartMarker;
        public var _player:Player;
        public var _boundaries:Boundaries;
        
        private var _vx:Number;
        private var _vy:Number;
        
        public function DocumentMain():void
        {
            // assign default values
            _vx = 0;
            _vy = 0;
            _startMarker.visible = false;
            
            // set focus for keyboard input
            stage.focus = stage;
            
            // add event listeners
            this.addEventListener(Event.ENTER_FRAME, enterFrameHandler);
            stage.addEventListener(KeyboardEvent.KEY_DOWN, keyDownHandler);
            stage.addEventListener(KeyboardEvent.KEY_UP, keyUpHandler);
        }
        
        private function enterFrameHandler(e:Event):void
        {
            // gravitate the player
            _vy += 1;
            
            // move the player
            _player.x += _vx;
            _player.y += _vy;
            
            // process collisions
            processCollisions();
            
            // scroll the stage
            scrollStage();
        }
        
        private function keyDownHandler(e:KeyboardEvent):void
        {
            switch (e.keyCode)
            {
                case 37:
                _vx = -7;
                break;
                
                case 38:
                _vy = -10;
                break;
                
                case 39:
                _vx = 7;
                break;
                
                default:
            }
        }
        
        private function keyUpHandler(e:KeyboardEvent):void
        {
            switch (e.keyCode)
            {
                case 37:
                case 39:
                _vx = 7;
                break;
                
                default:
            }
        }
        
        private function processCollisions():void
        {
            // when player is falling
            if (_vy > 0)
            {
                // respawn if player fell off the stage
                if (_player.y > stage.stageHeight)
                {
                    _player.x = _startMarker.x;
                    _player.y = _startMarker.y;
                    _boundaries.x = 0;
                    _boundaries.y = 0;
                    _vy = 0;
                }
                if (_boundaries.hitTestPoint(_player.x, _player.y, true))
                {
                    _player.x = _startMarker.x;
                    _player.y = _startMarker.y;
                    _boundaries.x = 0;
                    _boundaries.y = 0;
                    _vy = 0;
                }
                // otherwise, process collisions with boundaries
            }
        }
        
        private function scrollStage():void
        {
            _boundaries.x += (stage.stageWidth * 0.5) - _player.x;
            _player.x = stage.stageWidth * 0.5;
        }
    }
}