AtrousDenoiser

The edge-avoiding à-trous filter on the GPU, the viewport's denoiser (rendering-revamp §RVR-7).

In the namespace construct::denoise. Declared in src/libs/libconstruct/construct/denoise/AtrousDenoiser.hpp.

Detailed description

One fullscreen fragment pass per filter pass (`atrous.frag`), each into an RGBA16F target: two targets in turn, and the output for the last. Fragment passes, not compute, so the filter runs on every backend and every device that draws a frame, compute or not. The filter itself, and its CPU reference, are in AtrousFilter.hpp.