text: /**
   * @author alteredq / http://alteredqualia.com/
   *
   * Sepia tone shader
   * based on glfx.js sepia shader
   * https://github.com/evanw/glfx.js
   */
  
  v3d.SepiaShader = {
  
      uniforms: {
  
          "tDiffuse": { value: null },
          "amount": { value: 1.0 }
  
      },
  
      vertexShader: [
  
          "varying vec2 vUv;",
  
          "void main() {",
  
          "    vUv = uv;",
          "    gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);",
  
          "}"
  
      ].join("\n"),
  
      fragmentShader: [
  
          "uniform float amount;",
  
          "uniform sampler2D tDiffuse;",
  
          "varying vec2 vUv;",
  
          "void main() {",
  
          "    vec4 color = texture2D(tDiffuse, vUv);",
          "    vec3 c = color.rgb;",
  
          "    color.r = dot(c, vec3(1.0 - 0.607 * amount, 0.769 * amount, 0.189 * amount));",
          "    color.g = dot(c, vec3(0.349 * amount, 1.0 - 0.314 * amount, 0.168 * amount));",
          "    color.b = dot(c, vec3(0.272 * amount, 0.534 * amount, 1.0 - 0.869 * amount));",
  
          "    gl_FragColor = vec4(min(vec3(1.0), color.rgb), color.a);",
  
          "}"
  
      ].join("\n")
  
  };
  