p

fragment.glsl

@@ -1,6 +1,5 @@
 #version 330 core
 out vec4 FragColor;
-in vec2 uv;
 uniform vec2 WindowSize;
 uniform float time;
 
@@ -8,7 +7,28 @@ float rand(vec2 co){
     return fract(sin(dot(co, vec2(12.9898, 78.233))) * 43758.5453);
 }
 
+float cell_size = 0.1;
+
 void main() {
-    float glob = rand(gl_FragCoord.xy / WindowSize + time);
-    FragColor = vec4(glob * (sin(time)/2 + 0.5), glob, 1.0, 1.0); //vec4(gl_FragCoord.xy / WindowSize, 0.0, 1.0);
+    // We'll make origin in the top-left.
+    vec2 uv = gl_FragCoord.xy / WindowSize;
+    uv.y = 1.0 - uv.y;
+    vec2 grid_edge_offset = mod(uv, cell_size);
+    // c: corner
+    vec2 c_tl = uv - grid_edge_offset;
+    vec2 c_tr = uv - grid_edge_offset + vec2(cell_size, 0);
+    vec2 c_bl = uv - grid_edge_offset + vec2(0,         cell_size);
+    vec2 c_br = uv - grid_edge_offset + vec2(cell_size, cell_size);
+    // random vectors
+    vec2 c_tl_ran = rand(c_tl);
+    vec2 c_tr_ran = rand(c_tr);
+    vec2 c_bl_ran = rand(c_bl);
+    vec2 c_br_ran = rand(c_br);
+    // offset vectors
+    vec2 c_tl_off = c_tl - uv;
+    vec2 c_tr_off = c_tr - uv;
+    vec2 c_bl_off = c_bl - uv;
+    vec2 c_br_off = c_br - uv;
+
+    FragColor = 
 }