read fragment shader from file

shaders/frag.glsl

@@ -0,0 +1,15 @@
+#version 330
+
+uniform float iTime;
+uniform vec2 iResolution;
+in vec2 vUV;
+out vec4 fragColor;
+
+void main() {
+    vec2 uv0 = vUV.st;
+    float ratio = iResolution.x / iResolution.y;
+    vec2 uv1 = (uv0 - .5) * vec2(ratio, 1);
+    vec3 color = vec3(vUV, sin(iTime * 0.5) * 0.5 + 0.5);
+    color *= 1 - step(cos(iTime) * 0.1 + 0.5,length(uv1));
+    fragColor = vec4(color, 1.0);
+}