animate method
Implementation
void animate(num time) {
int now = DateTime.now().millisecondsSinceEpoch;
unprocessedFrames+=(now-lastTime)*60.0/1000.0;
if(unprocessedFrames>10.0) unprocessedFrames = 10.0;
while(unprocessedFrames > 1.0) {
tick();
unprocessedFrames -=1.0;
}
render();
window.requestAnimationFrame(animate);
}