GitHub - xatuke/screenshader

Real-time screen shader overlay for your desktop. Applies GLSL post-processing effects (CRT, glitch, thermal, VHS, etc.) to your entire display.

Platforms

• Linux/X11 — C + XComposite + OpenGL
• macOS — Swift + ScreenCaptureKit + Metal (auto GLSL→MSL conversion)
• Hyprland — native decoration:screen_shader integration

Shaders

20 built-in effects in shaders/:

crt amber green glitch vhs thermal matrix sketch dreamy oilpaint underwater anime nightlight neon halftone filmgrain pixelate marvel lcd tilt_shift rain minecraft

Build

make          # auto-detects platform
make macos    # macOS only
make x11      # Linux/X11 only

Dependencies:

• macOS: Xcode command line tools (swiftc)
• X11: libx11 libxcomposite libxdamage libxfixes libxrender libgl pkg-config gcc

Usage

./screenshader.sh                        # start with default CRT shader
./screenshader.sh amber                  # pick a shader by name
./screenshader.sh shaders/amber.frag     # or by file path
./screenshader.sh --list                 # list available shaders
./screenshader.sh --stop                 # stop the overlay
./screenshader.sh --reload               # hot-reload current shader
./screenshader.sh --set u_curvature 0.1  # tweak a shader parameter
./screenshader.sh --get                  # show current parameters

A GUI shader browser is also available:

Writing Custom Shaders

Drop a .frag file in shaders/. Available uniforms:

uniform sampler2D u_screen;    // captured screen texture
uniform vec2      u_resolution; // screen resolution
uniform float     u_time;       // elapsed time (for animation)

Input: vec2 v_texcoord — Output: vec4 frag_color

Notes

• macOS requires Screen Recording permission (System Settings → Privacy & Security)
• Shaders hot-reload on file save (macOS) or via --reload / SIGUSR1
• Runtime parameters are stored in /tmp/screenshader.params