Why it seems draw twice when page load first time?

[rayliao]

Why it seems draw twice when page load first time, but save file to rerender, it looks good. Can't figure out it.

Here's the code example:

https://codesandbox.io/s/webgl-custom-attributes-points2-8flyc6?file=/src/App.js

[rayliao]

I found it's not draw twice, lineBasicMaterial with vertexColors Initialize render is different with rerender, but i still don't know how to solve it. 😂

[rayliao]

It's ok if I implement it directly with three.js