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ghostty-shaders/bettercrt.glsl

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+// Original shader collected from: https://www.shadertoy.com/view/WsVSzV
+// Licensed under Shadertoy's default since the original creator didn't provide any license. (CC BY NC SA 3.0)
+// Slight modifications were made to give a green-ish effect.
+
+// This shader was modified by April Hall (arithefirst)
+// Sourced from https://github.com/m-ahdal/ghostty-shaders/blob/main/retro-terminal.glsl
+// Changes made:
+// - Removed tint
+// - Made the boundaries match ghostty's background color
+
+float warp = 0.25; // simulate curvature of CRT monitor
+float scan = 0.50; // simulate darkness between scanlines
+
+void mainImage(out vec4 fragColor, in vec2 fragCoord)
+{
+    // squared distance from center
+    vec2 uv = fragCoord / iResolution.xy;
+    vec2 dc = abs(0.5 - uv);
+    dc *= dc;
+    
+    // warp the fragment coordinates
+    uv.x -= 0.5; uv.x *= 1.0 + (dc.y * (0.3 * warp)); uv.x += 0.5;
+    uv.y -= 0.5; uv.y *= 1.0 + (dc.x * (0.4 * warp)); uv.y += 0.5;
+
+    // determine if we are drawing in a scanline
+    float apply = abs(sin(fragCoord.y) * 0.25 * scan);
+        
+    // sample the texture
+    vec3 color = texture(iChannel0, uv).rgb;
+
+    // mix the sampled color with the scanline intensity
+    fragColor = vec4(mix(color, vec3(0.0), apply), 1.0);
+}