CRT shaders

CRT-Geom-Flat, with default settings

These replicate aperture grille CRTs, which have sharp images and strong scanlines. If you find that this doesn't look a damn thing like your old TV, it's probably because you owned a shadow-mask style CRT, which has less noticeable scanlines (the easiest way to tell the difference is to feel the curve of the screen; aperture grilles only curve horizontally if at all). Unfortunately, shadow masks require resolutions of upwards of 3000x4000 to emulate accurately, so all we have for the time being are aperture grille shaders.

Use integer scaling. This means either using windowed mode (x2,x3,x4) or setting an integer scaling option in the video options. The reason is that non-integer scaled scanlines will result in uneven lines with artifacts.

Download

https://github.com/libretro/common-shaders/tree/master/crt

https://interpolation-shaders.googlecode.com/files/GTUv050_CG.zip

Types

CRT Geom

Main article: CRT Geom

Simulates an apperture grille. Very versatile and modable. One of the more popular CRT shaders. Visit the main article.

Shadowmask

Hypothetical shadowmask shaders are being developed. Due to the nature of the shadowmask screen, 4K resolution is likely needed.

GTU

A CRT shader that focuses more on simulating blur and blending effects and color levels of CRT screens rather than the physical attributes like phosphors and curvature. Highly configurable, can be really sharp, or really blurry or anywhere in between, with optional scanlines and contrast and gamma settings. Settings are stored in a separate "config.h" file for easy editing.