text: /**
   * @author felixturner / http://airtight.cc/
   *
   * RGB Shift Shader
   * Shifts red and blue channels from center in opposite directions
   * Ported from http://kriss.cx/tom/2009/05/rgb-shift/
   * by Tom Butterworth / http://kriss.cx/tom/
   *
   * amount: shift distance (1 is width of input)
   * angle: shift angle in radians
   */
  
  THREE.DigitalGlitch = {
  
  	uniforms: {
  
  		"tDiffuse":		{ value: null },//diffuse texture
  		"tDisp":		{ value: null },//displacement texture for digital glitch squares
  		"byp":			{ value: 0 },//apply the glitch ?
  		"amount":		{ value: 0.08 },
  		"angle":		{ value: 0.02 },
  		"seed":			{ value: 0.02 },
  		"seed_x":		{ value: 0.02 },//-1,1
  		"seed_y":		{ value: 0.02 },//-1,1
  		"distortion_x":	{ value: 0.5 },
  		"distortion_y":	{ value: 0.6 },
  		"col_s":		{ value: 0.05 }
  	},
  
  	vertexShader: [
  
  		"varying vec2 vUv;",
  		"void main() {",
  			"vUv = uv;",
  			"gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );",
  		"}"
  	].join( "\n" ),
  
  	fragmentShader: [
  		"uniform int byp;",//should we apply the glitch ?
  		
  		"uniform sampler2D tDiffuse;",
  		"uniform sampler2D tDisp;",
  		
  		"uniform float amount;",
  		"uniform float angle;",
  		"uniform float seed;",
  		"uniform float seed_x;",
  		"uniform float seed_y;",
  		"uniform float distortion_x;",
  		"uniform float distortion_y;",
  		"uniform float col_s;",
  			
  		"varying vec2 vUv;",
  		
  		
  		"float rand(vec2 co){",
  			"return fract(sin(dot(co.xy ,vec2(12.9898,78.233))) * 43758.5453);",
  		"}",
  				
  		"void main() {",
  			"if(byp<1) {",
  				"vec2 p = vUv;",
  				"float xs = floor(gl_FragCoord.x / 0.5);",
  				"float ys = floor(gl_FragCoord.y / 0.5);",
  				//based on staffantans glitch shader for unity https://github.com/staffantan/unityglitch
  				"vec4 normal = texture2D (tDisp, p*seed*seed);",
  				"if(p.y<distortion_x+col_s && p.y>distortion_x-col_s*seed) {",
  					"if(seed_x>0.){",
  						"p.y = 1. - (p.y + distortion_y);",
  					"}",
  					"else {",
  						"p.y = distortion_y;",
  					"}",
  				"}",
  				"if(p.x<distortion_y+col_s && p.x>distortion_y-col_s*seed) {",
  					"if(seed_y>0.){",
  						"p.x=distortion_x;",
  					"}",
  					"else {",
  						"p.x = 1. - (p.x + distortion_x);",
  					"}",
  				"}",
  				"p.x+=normal.x*seed_x*(seed/5.);",
  				"p.y+=normal.y*seed_y*(seed/5.);",
  				//base from RGB shift shader
  				"vec2 offset = amount * vec2( cos(angle), sin(angle));",
  				"vec4 cr = texture2D(tDiffuse, p + offset);",
  				"vec4 cga = texture2D(tDiffuse, p);",
  				"vec4 cb = texture2D(tDiffuse, p - offset);",
  				"gl_FragColor = vec4(cr.r, cga.g, cb.b, cga.a);",
  				//add noise
  				"vec4 snow = 200.*amount*vec4(rand(vec2(xs * seed,ys * seed*50.))*0.2);",
  				"gl_FragColor = gl_FragColor+ snow;",
  			"}",
  			"else {",
  				"gl_FragColor=texture2D (tDiffuse, vUv);",
  			"}",
  		"}"
  
  	].join( "\n" )
  
  };
  