afegit flicker a postfx

data/shaders/postfx.frag

@@ -23,9 +23,9 @@ layout(set = 3, binding = 0) uniform PostFXUniforms {
     float curvature;
     float bleeding;
     float pixel_scale;   // physical pixels per logical pixel (vh / tex_height_)
-    float time;          // seconds since SDL init (for future animated effects)
+    float time;          // seconds since SDL init
     float oversample;    // supersampling factor (1.0 = off, 3.0 = 3×SS)
-    float pad1;          // padding — 48 bytes total (3 × 16)
+    float flicker;       // 0 = off, 1 = phosphor flicker ~50 Hz — 48 bytes total (3 × 16)
 } u;
 
 // YCbCr helpers for NTSC bleeding
@@ -85,8 +85,8 @@ void main() {
         colour = base;
     }
 
-    // Aberración cromática
-    float ca = u.chroma_strength * 0.005;
+    // Aberración cromática (drift animado con time para efecto NTSC real)
+    float ca = u.chroma_strength * 0.005 * (1.0 + 0.15 * sin(u.time * 7.3));
     colour.r = texture(scene, uv + vec2(ca, 0.0)).r;
     colour.b = texture(scene, uv - vec2(ca, 0.0)).b;
 
@@ -134,5 +134,11 @@ void main() {
         colour = mix(colour, colour * mask, u.mask_strength);
     }
 
+    // Parpadeo de fósforo CRT (~50 Hz)
+    if (u.flicker > 0.0) {
+        float flicker_wave = sin(u.time * 100.0) * 0.5 + 0.5;
+        colour *= 1.0 - u.flicker * 0.04 * flicker_wave;
+    }
+
     out_color = vec4(colour, 1.0);
 }