Apparent issue with the XBR shaders

[mijofr]

I've been working on some of my own stuff using XBR shaders and have been using the libretro implementation as reference, and I've noticed what seems to be a common issue across the XBR implementations:

Take a look at the reference image:

And then upscaled in XBR-2x-noblend

If you look at the edges of the balls, there seems to be a lot of small sharp edges poking out around the corners. The same issue is visible in my personal rendering of the shader code, which lets me go in closer:

These spikes happen in all of the XBR shaders, but I've run a few tests on the reference using other XBR implementations and libraries around and the circles are rendered more like you'd expect:

Is it possible there's a common math issue across this repo's glsl implementations?

[Hyllian]

The problem is related to color difference math. In shader, the color diff math is very basic, because the speed is critical. It's more problematic with red shades, like in those balls. There's an implementation where I tried another approach and called the shader xbr-accuracy or something. There these problems are more rare. The drawback is on speed, though. Feel free to try other color diff implementations. But beware that it takes a good hit on shader speed. Em qua., 14 de abr. de 2021 às 08:51, mijofr ***@***.***> escreveu:

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I've been working on some of my own stuff using XBR shaders and have been using the libretro implementation as reference, and I've noticed what seems to be a common issue across the XBR implementations: Take a look at the reference image: [image: contra] <https://user-images.githubusercontent.com/20412792/114705344-f9ebb380-9d6a-11eb-8518-65d65c529537.png> And then upscaled in XBR-2x-noblend [image: vWb9vKP] <https://user-images.githubusercontent.com/20412792/114705396-0c65ed00-9d6b-11eb-957b-0e533556742c.png> If you look at the edges of the balls, there seems to be a lot of small sharp edges poking out around the corners. The same issue is visible in my personal rendering of the shader code, which lets me go in closer: [image: hkgRgcy] <https://user-images.githubusercontent.com/20412792/114705575-37504100-9d6b-11eb-8d13-75921c98ab5a.png> These spikes happen in all of the XBR shaders, but I've run a few tests on the reference using other XBR implementations and libraries around and the circles are rendered more like you'd expect: [image: image] <https://user-images.githubusercontent.com/20412792/114705786-78485580-9d6b-11eb-9fd6-d73656b13c52.png> Is it possible there's a common math issue across this repo's glsl implementations? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#164>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAGJS3F2CP4J23PNN3ZADM3TIV6UZANCNFSM425HQO3Q> .