# Objective
TAA, FXAA, and some other post processing effects can cause the image to
become blurry. Sharpening helps to counteract that.
## Solution
~~This is a port of AMD's Contrast Adaptive Sharpening (I ported it from
the
[SweetFX](https://github.com/CeeJayDK/SweetFX/blob/master/Shaders/CAS.fx)
version, which is still MIT licensed). CAS is a good sharpening
algorithm that is better at avoiding the full screen oversharpening
artifacts that simpler algorithms tend to create.~~
This is a port of AMD's Robust Contrast Adaptive Sharpening (RCAS) which
they developed for FSR 1 ([and continue to use in FSR
2](149cf26e12/src/ffx-fsr2-api/shaders/ffx_fsr1.h (L599))).
RCAS is a good sharpening algorithm that is better at avoiding the full
screen oversharpening artifacts that simpler algorithms tend to create.
---
## Future Work
- Consider porting this to a compute shader for potentially better
performance. (In my testing it is currently ridiculously cheap (0.01ms
in Bistro at 1440p where I'm GPU bound), so this wasn't a priority,
especially since it would increase complexity due to still needing the
non-compute version for webgl2 support).
---
## Changelog
- Added Contrast Adaptive Sharpening.
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Co-authored-by: JMS55 <47158642+JMS55@users.noreply.github.com>
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