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Old 14 April 2019, 11:38   #225
guest.r
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Join Date: May 2017
Location: EU
Posts: 283
It's quite simple, not too much to it.

Setting input gamma to 2.4 affects following:

- horizontal interpolation is done in gamma space, where brighter colors spread a bit more over darker ones. Should match interpolation of CRT's.
- scanlines are applied differently
- masks are better distributed over the spectrum

Ofc. we have to switch back to the normal colorspace, so there is the gamma out functionality. In some CRT shaders it's about 10% lower compared with the input gamma. Different input/output gamma values affect saturation and brightness.

Since there is an option to use neutral input/output gamma (1.0), you can observe the difference within the shader.

I think most importantly is that this part of the shader functions as intended and can be tweaked to personal preference.

I think the most catchy part here is that CRT's have this 2.2-2.25 gamma and i defaulted 2.4. It roots in sRGB a bit and i got used to it. You can set output gamma (often referred to as CRT gamma) to 2.25 np.

As i mentioned some crt shaders use different sets of gamma values, i like to use fast gamma of 2.0 in WinUAE, add some saturation and then use same or a bit higher output gamma.
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