One texture, four worlds.

A native WebGL2 study of the advanced postprocessing example: render one scene texture, then route it through four independent composer chains with blur and stencil-mask ownership.

This route preserves the source-backed multi-composer, TexturePass, blur, and MaskPass contracts with local fixtures. Official Lee Perry-Smith/HDR assets, exact four-quadrant pixels, Stats/gui presentation, device/compiler coverage, and whole-example fidelity remain unverified.