implement CRT shader effects

[nippur72]

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I've found a comment in the source code mentioning CRT effects so I would like to point you to this very cool shader effect... it has scanlines, rgbmask and pincushion:

https://www.shadertoy.com/view/XsjSzR

It doesn't need to be included in the C source code, it can be simply applied to the HTML canvas.

[floooh]

Yep I know that effect, and I even had it implemented in a previous emulator.

See here and click on the little "CRT" button in the bottom left corner:

http://floooh.github.io/virtualkc/

In this older emulator I had to make the effect optional because performance on mobile devices was very poor, so I tried to come up with cheaper effects in the new emulators, but this ended up in lots of tinkering without satisfying results, so I switched it off again to maybe do it "properly" later.

[nippur72]

WOW that is absolutely amazing, it looks like a true CRT display! I wonder if there's a simple way to apply it to a HTML canvas, because I don't know much about shaders & c.

[chrisbward]

+1 would love to see some shaders in the mix!