lientX, touch.clientY); 	
			leftTouchPos.copyFrom(leftTouchStartPos); 
			leftVector.reset(0,0); 
		}
		else{
			rightTouchID = touch.identifier; 
			rightTouchStartPos.reset(touch.clientX, touch.clientY); 	
			rightTouchPos.copyFrom(rightTouchStartPos); 
			rightVector.reset(0,0); 
		}
		continue;
	}
	touches = e.touches; 
}

function onMouseDown(event) {
	if(event.offsetX <= halfWidth){
		leftTouchStartPos.reset(event.offsetX, event.offsetY); 	
		leftTouchPos.copyFrom(leftTouchStartPos); 
		leftVector.re