publish: make room for future sketches

generated from commit 68a08e1763f1028c9229b91f7886406715c44475

shaders/white-noise.frag

@@ -1,17 +1,21 @@
 precision mediump float;
 
 uniform vec2 u_resolution;
+uniform float u_alpha;
 
-float random (vec2 st) {
-  return fract(sin(dot(st.xy,
-             vec2(12.9898,78.233)))*
-    43758.5453123);
+highp float random(vec2 co) {
+  highp float a = 12.9898;
+  highp float b = 78.233;
+  highp float c = 43758.5453;
+  highp float dt= dot(co.xy, vec2(a, b));
+  highp float sn= mod(dt, 3.14);
+  return fract(sin(sn) * c);
 }
 
 void main() {
   vec2 st = gl_FragCoord.xy/u_resolution.xy;
 
-  float rnd = random( st );
+  float rnd = random(st);
 
-  gl_FragColor = vec4(vec3(rnd),0.05);
+  gl_FragColor = vec4(vec3(rnd), u_alpha);
 }