The page stuck when using Safari browser

The product we developed based on playcanvas became stuck when you open it on Safari browser.
We debugged the other browser, such as chrome and firefox, all is fine.
And the reason why it has bug on safari browser, according to our investigation, is about it’s CPU when the project on work rather than GPU. While using other browsers, it’s GPU working rather CPU.
We assume there is a code on other browsers(qq, chrome, and firefox) so that it can make GPU working, while there is no such code on Safari.

Our question is: How to fix the stuck problem on Safari when you open the product?

Link to product:

Which platform(s) and versions do you see this on? Windows, MacOS, mobile, etc?

Windows hasn’t Safari at all, mobile hasn’t GPU, so it is related to MacOS.

So, which version of Safari do you use?

My computer system version is 10. 13. 5, safari version 11. 11, there is this problem, debugging found that GPUs do not work, only CPUs work

Have a similar problem.
Page works with all browsers on Desktop and on Android mobile, but renders black on Safari for iOS.

Here is a link to the page…

So the issue was with the fxaa/bloom and the height map. After disabling all three the scene has started loading… but now I have another problem.

The scene loads, It also goes to the next scene, but when I come back to the first scene, only UI elements are loaded and the rest of the scene is not. Both the scene changes are by the same script.

The issue with the scene not loading correctly while going back to scene 1 from scene 2 was becasue in scene 2 I had enabled FSAA and Bloom and in Scene 1 I had not. Once I switched off both in scene 2 everything is fine.