Tired of GZDoom's sterile smoothness? So am I. There's just something aesthetically pleasing about low colour and low resolution graphics, and this shader does just that.
Spoiler: ScreenshotsDownload Instructions:
This replaces the Lens Distortion shader in the recent GZDoom dev builds, so enable Lens Distortion under Display Options -> OpenGL Options -> Preferences. While you're there, set Sector Light Mode to Software. To make lights extra pronounced you can go to OpenGL Options -> Dynamic Light Options and set the Light Size to 2.
Open up the PK3 in Slade and open lensdistortion.fp, you'll now see a neat list of variables you can change. Enable or disable effects with a simple 1 or 0, no more copy and pasting shaders in and out of files.
To get PlayStation vertex jiggles in GZDoom, open gzdoom.pk3, navigate to shaders/glsl/main.vp, and in a new line after "gl_Position = ProjectionMatrix * eyeCoordPos;" add "gl_Position.xy = floor(gl_Position.xy/gl_Position.w*(1./0.015))*0.015*gl_Position.w;//The Vertex Jiggler" Setting 0.015 lower will lower the jiggle, setting is higher will increase the jiggle. This affects sprites, HUDs, menus, and HUD messages as well.