AddictArts/three.js — comment on commit b3e90374600b088b48a1fa73d18b078ac945a0aa
File:  line 0
By ekitson:

I thought about that, but since `WebGLRenderer.clear()` is a publicly visible function, I figured putting `setDepthWrite` in there would mean it would always be able to clear the depth buffer. Since `setDepthWrite` isn't publicly visible, it would be possible for depth writing to be left disabled after the last render call and someone would call `WebGLRenderer.clear()` and not be able to actually clear the depth buffer.