CRT-easymode

[PatrickM]

This shader is freaking awesome. I think it looks better than the scanlines produced by a $400 Framemeister. However, an acquaintance of mine thinks that it “doesn’t look right”- he thinks the vertical space between pixels doesn’t look like a CRT.

I would like to discuss this shader in detail. What does it do and what is the rationale for what it does. I think it looks better than simple scanlines but I don’t know how to explain why.

[EasyMode]

Thanks for the compliment Patrick.

I believe your friend is referring to the RGB mask that, by default, mimics an aperture grille pattern running vertically along the screen. The mask in this shader is fixed pixel, so the density of the pattern will vary depending on your display’s resolution. On a lower res screen it may appear more like an LCD grid, whereas on a 4K display it will appear very fine and perhaps closer to a real CRT with an aperture grille. I use a 1080p monitor and I wouldn’t call the mask realistic at that resolution, but I just happen to like the way it looks.

Your friend may also be more accustomed to CRTs with shadow masks. You can see the differnce here:

Crt-easymode can be configured in a Lottes style shadow mask (a la crt-lottes) by setting the following parameters like so: MASK_SUBPIXEL_WIDTH 2.0, MASK_SUBPIXEL_HEIGHT 1.0, MASK_STAGGER 3.0.

You can see a preview here (second pic):

viewtopic.php?f=6&t=2360

If someone prefers having no mask, they can set MASK_STRENGTH to 0.0 – and if they do that I recommend also lowering BRIGHT_BOOST to 1.0 as that parameter is meant to make up for the brightness loss caused by the mask.

Also, in case you’re still using RetroArch 1.0.0.2, lord ashram has a dropbox where he posts test builds. These newer builds have a parameter menu that lets you adjust shader parameters from within RetroArch.

https://www.dropbox.com/sh/91sakv0qdyxj … lyXea?dl=0

1.0.0.3 Beta is apparently coming soon too.

[PatrickM]

Thanks for the compliment Patrick.

I believe your friend is referring to the RGB mask that, by default, mimics an aperture grille pattern running vertically along the screen. The mask in this shader is fixed pixel, so the density of the pattern will vary depending on your display’s resolution. On a lower res screen it may appear more like an LCD grid, whereas on a 4K display it will appear very fine and perhaps closer to a real CRT with an aperture grille. I use a 1080p monitor and I wouldn’t call the mask realistic at that resolution, but I just happen to like the way it looks.

Your friend may also be more accustomed to CRTs with shadow masks. You can see the differnce here:

Crt-easymode can be configured in a Lottes style shadow mask (a la crt-lottes) by setting the following parameters like so: MASK_SUBPIXEL_WIDTH 2.0, MASK_SUBPIXEL_HEIGHT 1.0, MASK_STAGGER 3.0.

You can see a preview here (second pic):

viewtopic.php?f=6&t=2360

If someone prefers having no mask, they can set MASK_STRENGTH to 0.0 – and if they do that I recommend also lowering BRIGHT_BOOST to 1.0 as that parameter is meant to make up for the brightness loss caused by the mask.

Also, in case you’re still using RetroArch 1.0.0.2, lord ashram has a dropbox where he posts test builds. These newer builds have a parameter menu that lets you adjust shader parameters from within RetroArch.

https://www.dropbox.com/sh/91sakv0qdyxj … lyXea?dl=0

1.0.0.3 Beta is apparently coming soon too.

Awesome reply! I suspected that the vertical lines were meant to emulate an aperture grille. I’m going to post a link to this reply because there’s a lot of good info here.