Add fft

src/shaders/fragment.frag

@@ -3,6 +3,7 @@ precision mediump float;
 out vec4 o;
 const float PI = 22./7.;
 layout(location = 0) uniform float syncs[7];
+layout(location = 8) uniform float fft_output[512]; // FFT_SIZE / 4
 float u_time = syncs[0];
 
 vec3 render(vec2 uv, float time) {
@@ -23,5 +24,18 @@ vec3 render(vec2 uv, float time) {
 void main() {
   	vec2 uv = gl_FragCoord.xy * 2. / vec2(1920,1080);
     vec3 col = render(uv, u_time);
-    o = vec4(col,1.0);
+    
+    // Determine FFT bin index for current x position
+    int index = int(floor(uv.x*128.0));
+    index = clamp(index, 0, 255);
+
+    // Get the FFT energy (clamped to avoid NaNs or overflow)
+    float energy = clamp(fft_output[index], .0, 1.0);
+
+    float bar_height = energy;
+    float fade = smoothstep(bar_height, bar_height + 0.02, 1.0 - uv.y);
+
+    vec3 color = vec3(fade);
+
+    o = vec4(color, 1.0);
 }