/*
* Implement SVGF style denoising as bgfx example. Goal is to explore various
* options and parameters, not produce an optimized, efficient denoiser.
*
* Starts with deferred rendering scene with very basic lighting. Lighting is
* masked out with a noise pattern to provide something to denoise. There are
* two options for the noise pattern. One is a fixed 2x2 dither pattern to
* stand-in for lighting at quarter resolution. The other is the common
* shadertoy random pattern as a stand-in for some fancier lighting without
* enough samples per pixel, like ray tracing.
*
* First a temporal denoising filter is applied. The temporal filter is only
* using normals to reject previous samples. The SVGF paper also describes using
* depth comparison to reject samples but that is not implemented here.
*
* Followed by some number of spatial filters. These are implemented like in the
* SVGF paper. As an alternative to the 5x5 Edge-Avoiding A-Trous filter, can
* select a 3x3 filter instead. The 3x3 filter takes fewer samples and covers a
* smaller area, but takes less time to compute. From a loosely eyeballed
* comparison, N 5x5 passes looks similar to N+1 3x3 passes. The wider spatial
* filters take a fair chunk of time to compute. I wonder if it would be a good
* idea to interleave the input texture before computing, after the first pass
* which skips zero pixels.
*
* I have not implemetened the variance guided part.
*
* There's also an optional TXAA pass to be applied after. I am not happy with
* its implementation yet, so it defaults to off here.
*/
/*
* References:
* Spatiotemporal Variance-Guided Filtering: Real-Time Reconstruction for
* Path-Traced Global Illumination. by Christoph Schied and more.
* - SVGF denoising algorithm
*
* Streaming G-Buffer Compression for Multi-Sample Anti-Aliasing.
* by E. Kerzner and M. Salvi.
* - details about history comparison for temporal denoising filter
*
* Edge-Avoiding À-Trous Wavelet Transform for Fast Global Illumination
* Filtering. by Holger Dammertz and more.
* - details about a-trous algorithm for spatial denoising filter
*/
* Implement SDF font outlines, drop shadows, and image glyphs
* Update 11-fontsdf to showcase the SDF outlines, drop shadows, and image glyphs
Co-authored-by: Josh Jensen <josh@everrush.com>
