CRTty is an innovative post-processing shader framework designed specifically for the kitty terminal, utilizing the LD_PRELOAD technique. This project enables users to seamlessly inject custom fragment shaders into kitty or any EGL/GLX application without needing to modify the application code or use specialized drivers.

Features

• Built-in Effects: Comes equipped with various effects such as crt, greyscale, and invert to enhance visual output.
• Live Hot-Reloading: Custom .glsl shaders can be added or modified on-the-fly, allowing real-time updates without restarting kitty.
• Auto Uniforms for Animation: Automatically provides uniforms like u_time and u_resolution for dynamic visual effects.
• No App Patching Required: Functions solely through LD_PRELOAD, making it easy to deploy.

Usage Examples

Launch the kitty terminal with the CRT effect:

crtty

List all available effects:

crtty --list

Use a predefined effect or a custom shader:

crtty -s greyscale
crtty -s ./my_shader.glsl
crtty -s examples/retro.glsl

Custom GLSL shaders are straightforward to create. For instance, an animated RGB wave effect can be implemented as follows:

#version 330 core
in vec2 v_uv;
out vec4 o_color;
uniform sampler2D u_input;
uniform float u_time;
uniform vec2 u_resolution;

void main() {
    float wave = sin(v_uv.y * 40.0 + u_time * 3.0) * 0.003;
    vec3 c;
    c.r = texture(u_input, v_uv + vec2(wave, 0.0)).r;
    c.g = texture(u_input, v_uv).g;
    c.b = texture(u_input, v_uv - vec2(wave, 0.0)).b;
    float scan = 0.95 + 0.05 * sin(v_uv.y * u_resolution.y * 3.14 + u_time * 2.0);
    o_color = vec4(c * scan, 1.0);
}

Write Your Own Shader

To create a custom effect, you can develop a new Rust library crate:

cargo new --lib my-shader && cd my-shader

In Cargo.toml, specify the crtty dependency and implement your effect according to the provided Effect trait.

Effect Configuration

Users can configure various CRT effect parameters by editing the ~/.config/crtty.conf file:

enabled=1
scanline_intensity=0.75
phosphor_strength=1.1
curvature=0.04
vignette=0.35
aberration=0.003

Parameters Explained

With CRTty, enhancing the aesthetic quality of your terminal experience is both flexible and convenient.