add lights effect

lights_frag.glsl

@@ -0,0 +1,27 @@
+#ifdef GL_ES
+precision mediump float;
+#endif
+
+uniform float time;
+uniform vec3 resolution;
+
+#define PI 3.1415926
+
+void main(){
+    vec2 p = (gl_FragCoord.xy - 0.5 * resolution.xy) / min(resolution.x, resolution.y);
+    vec2 t = vec2(gl_FragCoord.xy / resolution.xy);
+
+    vec3 c = vec3(0);
+
+    for(int i = 0; i < 10; i++) {
+            float t = 0.4 * PI * float(i) / 30.0 * time * 0.5;
+            float x = cos(3.0*t);
+            float y = sin(4.0*t);
+            vec2 o = 0.5 * vec2(x, y);
+            float r = fract(x);
+            float g = 0.5 - r;
+            c += 0.02 / (length(p-o)) * vec3(r, g, 0.9);
+        }
+
+    gl_FragColor = vec4(c, 1);
+}