Added some more example shaders

shaders/gradient.frag

@@ -0,0 +1,10 @@
+// https://www.shadertoy.com/new
+
+void mainImage( out vec4 fragColor, in vec2 fragCoord )
+{
+    vec2 uv = fragCoord/iResolution.xy;
+
+    vec3 col = 0.5 + 0.5*cos(iTime+uv.xyx+vec3(0,2,4));
+
+    fragColor = vec4(col,1.0);
+}