📦 Bundle size

Full ESM build, minified and gzipped.

🌳 Bundle size after tree-shaking

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

Would you be okay if we target r181 with this PR? The current dev version is quite stable and I would prefer to not apply deeper refactorings shortly for release.

The additional MSAA for the single full-screen quad should be no huge performance waste.

Did some integration testing today for r181 and noticed a regression when dynamically switching from PostProcessing.render() to WebGPURenderer.render(). The regression is introduced with this PR since reverting fixes the issue. Below example can be used for reproduction by toggling the effect with the GUI:

https://rawcdn.githack.com/mrdoob/three.js/dev/examples/webgpu_postprocessing_sobel.html

The screen becomes black and the following WebGPU warnings are logged:

190Cannot set [TextureView of Texture "IOSurface(RasterRead|DisplayRead|Scanout|WebgpuRead|WebgpuSwapChainTexture|WebgpuWrite)"] as a resolve target when the color attachment [TextureView of Texture "IOSurface(RasterRead|DisplayRead|Scanout|WebgpuRead|WebgpuSwapChainTexture|WebgpuWrite)"] has a sample count of 1.
While validating colorAttachments[0].
While encoding [CommandEncoder "renderContext_16"].BeginRenderPass([RenderPassDescriptor]).
While finishing [CommandEncoder "renderContext_16"].

It seems, it does not happen with the WebGL backend.