////  uniformTest.fs//  examples/tests/rapidProceduralChange////  Created by Eric Levin on 3/9/16.//  Copyright 2016 High Fidelity, Inc.////  This fragment shader is designed to test the rapid changing of a uniform.////  Distributed under the Apache License, Version 2.0.//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html  uniform float red; void mainImage(out vec4 fragColor, in vec2 fragCoord) {    fragColor = vec4(red, 0.0, 1.0, 1.0);} vec4 getProceduralColor() {    vec4 result;    vec2 position = _position.xz;    position += 0.5;    mainImage(result, position * iWorldScale.xz);    return result;}