text: /// <reference types="./VerticalBlurShader.d.ts" />
  /// <reference lib="dom" />
  
  /**
   * Two pass Gaussian blur filter (horizontal and vertical blur shaders)
   * - described in http://www.gamerendering.com/2008/10/11/gaussian-blur-filter-shader/
   *   and used in http://www.cake23.de/traveling-wavefronts-lit-up.html
   *
   * - 9 samples per pass
   * - standard deviation 2.7
   * - "h" and "v" parameters should be set to "1 / width" and "1 / height"
   */
  
  var VerticalBlurShader = {
    uniforms: {
      "tDiffuse": { value: null },
      "v": { value: 1.0 / 512.0 },
    },
  
    vertexShader: [
      "varying vec2 vUv;",
  
      "void main() {",
  
      "	vUv = uv;",
      "	gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );",
  
      "}",
    ].join("\n"),
  
    fragmentShader: [
      "uniform sampler2D tDiffuse;",
      "uniform float v;",
  
      "varying vec2 vUv;",
  
      "void main() {",
  
      "	vec4 sum = vec4( 0.0 );",
  
      "	sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y - 4.0 * v ) ) * 0.051;",
      "	sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y - 3.0 * v ) ) * 0.0918;",
      "	sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y - 2.0 * v ) ) * 0.12245;",
      "	sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y - 1.0 * v ) ) * 0.1531;",
      "	sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y ) ) * 0.1633;",
      "	sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y + 1.0 * v ) ) * 0.1531;",
      "	sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y + 2.0 * v ) ) * 0.12245;",
      "	sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y + 3.0 * v ) ) * 0.0918;",
      "	sum += texture2D( tDiffuse, vec2( vUv.x, vUv.y + 4.0 * v ) ) * 0.051;",
  
      "	gl_FragColor = sum;",
  
      "}",
    ].join("\n"),
  };
  
  export { VerticalBlurShader };
  