ntsc effect for real

1 files changed, 17 insertions, 19 deletions

diff --git a/src/shaders/render/scratch_lines.wgsl b/src/shaders/render/scratch_lines.wgsl
index 04ed6f8..6123486 100644
--- a/src/shaders/render/scratch_lines.wgsl
+++ b/src/shaders/render/scratch_lines.wgsl
@@ -12,24 +12,22 @@
 #include "math/noise"
 
 fn scratch_lines(uv: vec2f, resolution: vec2f, time: f32) -> f32 {
-    // Quantize to ~24fps to simulate film frame rate
-    let t = floor(time * 24.0);
+  // Quantize to ~24fps to simulate film frame rate
+  let t = floor(time * 24.0);
 
-    var intensity = 0.0;
-    for (var i = 0; i < 8; i++) {
-        let seed = f32(i) * 17.3 + t;
-        // ~25% chance this scratch is visible this frame
-        let visible = step(0.75, hash_1f(seed + 3.1));
-        // Random vertical position [0, 1]
-        let y = hash_1f(seed + 7.9);
-        // Thickness in pixels [1, 4]
-        let thickness = hash_1f(seed + 13.5) * 3.0 + 1.0;
-        // Brightness [0.5, 1.0]
-        let brightness = hash_1f(seed + 21.7) * 0.5 + 0.5;
-        // Soft linear falloff from line center
-        let dy = abs(uv.y - y) * resolution.y;
-        let line = clamp(1.0 - dy / thickness, 0.0, 1.0);
-        intensity += line * brightness * visible;
-    }
-    return clamp(intensity, 0.0, 1.0);
+  // Scanlines
+  let scan = abs(sin(uv.y * uniforms.resolution.y * 3.14159265));
+  var intensity = 0.2 * scan;
+
+  // Per-pixel temporal noise
+  let pixel = floor(uv * uniforms.resolution * .4);
+  let n = hash_2f(pixel + vec2f(time * 47.3, time * 31.7)) * 0.04 - 0.02;
+  intensity += n;
+
+  // Horizontal jitter line (random scanline rolling artifact)
+  let jitter_y = hash_1f(fract(t * 0.37));
+  let jitter_band = abs(uv.y - jitter_y);
+  let scratch = smoothstep(5. / uniforms.resolution.y, 0., jitter_band);
+  intensity += scratch * 0.11 * hash_1f(uv.x * 100.0 + t);
+  return clamp(intensity, 0.0, 1.0);
 }