在Pycharm中运行官网上的fractal.py例子时，只显示窗口，并没有显示分形Julia set图案，这是为啥？
60fps… maybe the render function is not called at all?
@k-ye Metal bug? Does ti.init(arch=ti.cpu) solve the problem?
Also note that 0.6.8 is out of date, does upgrading to latest version solve the problem?