WebGLRenderer: Only clear when bit mask is set.

[Philipp-M]

Firefox outputs this warning:

WebGL warning: clear: Calling gl.clear(0) has no effect.

Chrome this:

Performance warning: clear() called with no buffers in bitmask

When gl.clear is called with 0

This can happen, e.g. when using integer buffers and only clearing the color buffer, as then gl.clearBuffer(u)iv is called instead.

To prevent this, just don't call gl.clear when no mask is set...

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	359.14 85.24	359.15 85.24	+7 B +2 B
WebGPU	623.31 173.4	623.31 173.4	+0 B +0 B
WebGPU Nodes	621.89 173.15	621.89 173.15	+0 B +0 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

	Before	After	Diff
WebGL	490.87 119.65	490.88 119.65	+7 B +4 B
WebGPU	696.88 188.4	696.88 188.4	+0 B +0 B
WebGPU Nodes	646.08 175.79	646.08 175.79	+0 B +0 B