Random, tiles

src/psychadelic-graphics/psychadelicColors.frag.glsl

@@ -9,6 +9,11 @@ uniform float u_canvasHeight;
 
 out vec4 fragColor;
 
+// See https://thebookofshaders.com/10/
+float random (vec2 st) {
+    return fract(sin(dot(st.xy, vec2(12.9898,78.233)))* 43758.5453123);
+}
+
 void main() {
     vec2 uv = gl_FragCoord.xy/vec2(u_canvasWidth, u_canvasHeight);
 
@@ -16,12 +21,19 @@ void main() {
     vec3 green = vec3(0.0, 1.0, 0.0);
     vec3 blue = vec3(0.0, 0.0, 1.0);
 
-    if (uv.x < 0.33) {
-        fragColor = vec4(red, 1.0);
-    } else if (uv.x < 0.66) {
-        fragColor = vec4(green, 1.0);
-    } else {
-        fragColor = vec4(blue, 1.0);
-    }
+    float size = 0.05;
+
+    uv.x = floor(uv.x / size) * size;
+    uv.y = floor(uv.y / size) * size;
+
+    float rand = random(uv);
+
+    float period = 5.0;
+    float mask = mod(u_time / period, 1.0);
+
+    float x = rand < mask ? uv.x : 0.0;
+    float y = rand < mask ? uv.y : 0.0;
+
+    fragColor = vec4(x, 0.0, y, 1.0);
  
 }