text: /**
   * @author alteredq / http://alteredqualia.com/
   *
   */
  
  THREE.ShaderTerrain = {
  
  	/* -------------------------------------------------------------------------
  	//	Dynamic terrain shader
  	//		- Blinn-Phong
  	//		- height + normal + diffuse1 + diffuse2 + specular + detail maps
  	//		- point, directional and hemisphere lights (use with "lights: true" material option)
  	//		- shadow maps receiving
  	 ------------------------------------------------------------------------- */
  
  	'terrain' : {
  
  		uniforms: THREE.UniformsUtils.merge( [
  
  			THREE.UniformsLib[ "fog" ],
  			THREE.UniformsLib[ "lights" ],
  			THREE.UniformsLib[ "shadowmap" ],
  
  			{
  
  			"enableDiffuse1"  : { type: "i", value: 0 },
  			"enableDiffuse2"  : { type: "i", value: 0 },
  			"enableSpecular"  : { type: "i", value: 0 },
  			"enableReflection": { type: "i", value: 0 },
  
  			"tDiffuse1"	   : { type: "t", value: null },
  			"tDiffuse2"	   : { type: "t", value: null },
  			"tDetail"	   : { type: "t", value: null },
  			"tNormal"	   : { type: "t", value: null },
  			"tSpecular"	   : { type: "t", value: null },
  			"tDisplacement": { type: "t", value: null },
  
  			"uNormalScale": { type: "f", value: 1.0 },
  
  			"uDisplacementBias": { type: "f", value: 0.0 },
  			"uDisplacementScale": { type: "f", value: 1.0 },
  
  			"diffuse": { type: "c", value: new THREE.Color( 0xeeeeee ) },
  			"specular": { type: "c", value: new THREE.Color( 0x111111 ) },
  			"shininess": { type: "f", value: 30 },
  			"opacity": { type: "f", value: 1 },
  
  			"uRepeatBase"    : { type: "v2", value: new THREE.Vector2( 1, 1 ) },
  			"uRepeatOverlay" : { type: "v2", value: new THREE.Vector2( 1, 1 ) },
  
  			"uOffset" : { type: "v2", value: new THREE.Vector2( 0, 0 ) }
  
  			}
  
  		] ),
  
  		fragmentShader: [
  
  			"uniform vec3 diffuse;",
  			"uniform vec3 specular;",
  			"uniform float shininess;",
  			"uniform float opacity;",
  
  			"uniform bool enableDiffuse1;",
  			"uniform bool enableDiffuse2;",
  			"uniform bool enableSpecular;",
  
  			"uniform sampler2D tDiffuse1;",
  			"uniform sampler2D tDiffuse2;",
  			"uniform sampler2D tDetail;",
  			"uniform sampler2D tNormal;",
  			"uniform sampler2D tSpecular;",
  			"uniform sampler2D tDisplacement;",
  
  			"uniform float uNormalScale;",
  
  			"uniform vec2 uRepeatOverlay;",
  			"uniform vec2 uRepeatBase;",
  
  			"uniform vec2 uOffset;",
  
  			"varying vec3 vTangent;",
  			"varying vec3 vBinormal;",
  			"varying vec3 vNormal;",
  			"varying vec2 vUv;",
  
  			"uniform vec3 ambientLightColor;",
  
  			"#if MAX_DIR_LIGHTS > 0",
  
  				"uniform vec3 directionalLightColor[ MAX_DIR_LIGHTS ];",
  				"uniform vec3 directionalLightDirection[ MAX_DIR_LIGHTS ];",
  
  			"#endif",
  
  			"#if MAX_HEMI_LIGHTS > 0",
  
  				"uniform vec3 hemisphereLightSkyColor[ MAX_HEMI_LIGHTS ];",
  				"uniform vec3 hemisphereLightGroundColor[ MAX_HEMI_LIGHTS ];",
  				"uniform vec3 hemisphereLightDirection[ MAX_HEMI_LIGHTS ];",
  
  			"#endif",
  
  			"#if MAX_POINT_LIGHTS > 0",
  
  				"uniform vec3 pointLightColor[ MAX_POINT_LIGHTS ];",
  				"uniform vec3 pointLightPosition[ MAX_POINT_LIGHTS ];",
  				"uniform float pointLightDistance[ MAX_POINT_LIGHTS ];",
  				"uniform float pointLightDecay[ MAX_POINT_LIGHTS ];",
  
  			"#endif",
  
  			"varying vec3 vViewPosition;",
  
  			THREE.ShaderChunk[ "common" ],
  			THREE.ShaderChunk[ "shadowmap_pars_fragment" ],
  			THREE.ShaderChunk[ "fog_pars_fragment" ],
  
  			"void main() {",
  
  				"vec3 outgoingLight = vec3( 0.0 );",	// outgoing light does not have an alpha, the surface does
  				"vec4 diffuseColor = vec4( diffuse, opacity );",
  
  				"vec3 specularTex = vec3( 1.0 );",
  
  				"vec2 uvOverlay = uRepeatOverlay * vUv + uOffset;",
  				"vec2 uvBase = uRepeatBase * vUv;",
  
  				"vec3 normalTex = texture2D( tDetail, uvOverlay ).xyz * 2.0 - 1.0;",
  				"normalTex.xy *= uNormalScale;",
  				"normalTex = normalize( normalTex );",
  
  				"if( enableDiffuse1 && enableDiffuse2 ) {",
  
  					"vec4 colDiffuse1 = texture2D( tDiffuse1, uvOverlay );",
  					"vec4 colDiffuse2 = texture2D( tDiffuse2, uvOverlay );",
  
  					"colDiffuse1.xyz = inputToLinear( colDiffuse1.xyz );",
  					"colDiffuse2.xyz = inputToLinear( colDiffuse2.xyz );",
  
  					"diffuseColor *= mix ( colDiffuse1, colDiffuse2, 1.0 - texture2D( tDisplacement, uvBase ) );",
  
  				" } else if( enableDiffuse1 ) {",
  
  					"diffuseColor *= texture2D( tDiffuse1, uvOverlay );",
  
  				"} else if( enableDiffuse2 ) {",
  
  					"diffuseColor *= texture2D( tDiffuse2, uvOverlay );",
  
  				"}",
  
  				"if( enableSpecular )",
  					"specularTex = texture2D( tSpecular, uvOverlay ).xyz;",
  
  				"mat3 tsb = mat3( vTangent, vBinormal, vNormal );",
  				"vec3 finalNormal = tsb * normalTex;",
  
  				"vec3 normal = normalize( finalNormal );",
  				"vec3 viewPosition = normalize( vViewPosition );",
  
  				"vec3 totalDiffuseLight = vec3( 0.0 );",
  				"vec3 totalSpecularLight = vec3( 0.0 );",
  
  				// point lights
  
  				"#if MAX_POINT_LIGHTS > 0",
  
  					"for ( int i = 0; i < MAX_POINT_LIGHTS; i ++ ) {",
  
  						"vec4 lPosition = viewMatrix * vec4( pointLightPosition[ i ], 1.0 );",
  						"vec3 lVector = lPosition.xyz + vViewPosition.xyz;",
  
  						"float attenuation = calcLightAttenuation( length( lVector ), pointLightDistance[ i ], pointLightDecay[i] );",
  
  						"lVector = normalize( lVector );",
  
  						"vec3 pointHalfVector = normalize( lVector + viewPosition );",
  
  						"float pointDotNormalHalf = max( dot( normal, pointHalfVector ), 0.0 );",
  						"float pointDiffuseWeight = max( dot( normal, lVector ), 0.0 );",
  
  						"float pointSpecularWeight = specularTex.r * max( pow( pointDotNormalHalf, shininess ), 0.0 );",
  
  						"totalDiffuseLight += attenuation * pointLightColor[ i ] * pointDiffuseWeight;",
  						"totalSpecularLight += attenuation * pointLightColor[ i ] * specular * pointSpecularWeight * pointDiffuseWeight;",
  
  					"}",
  
  				"#endif",
  
  				// directional lights
  
  				"#if MAX_DIR_LIGHTS > 0",
  
  					"vec3 dirDiffuse = vec3( 0.0 );",
  					"vec3 dirSpecular = vec3( 0.0 );",
  
  					"for( int i = 0; i < MAX_DIR_LIGHTS; i++ ) {",
  
  						"vec3 dirVector = transformDirection( directionalLightDirection[ i ], viewMatrix );",
  						"vec3 dirHalfVector = normalize( dirVector + viewPosition );",
  
  						"float dirDotNormalHalf = max( dot( normal, dirHalfVector ), 0.0 );",
  						"float dirDiffuseWeight = max( dot( normal, dirVector ), 0.0 );",
  
  						"float dirSpecularWeight = specularTex.r * max( pow( dirDotNormalHalf, shininess ), 0.0 );",
  
  						"totalDiffuseLight += directionalLightColor[ i ] * dirDiffuseWeight;",
  						"totalSpecularLight += directionalLightColor[ i ] * specular * dirSpecularWeight * dirDiffuseWeight;",
  
  					"}",
  
  				"#endif",
  
  				// hemisphere lights
  
  				"#if MAX_HEMI_LIGHTS > 0",
  
  					"vec3 hemiDiffuse  = vec3( 0.0 );",
  					"vec3 hemiSpecular = vec3( 0.0 );",
  
  					"for( int i = 0; i < MAX_HEMI_LIGHTS; i ++ ) {",
  
  						"vec3 lVector = transformDirection( hemisphereLightDirection[ i ], viewMatrix );",
  
  						// diffuse
  
  						"float dotProduct = dot( normal, lVector );",
  						"float hemiDiffuseWeight = 0.5 * dotProduct + 0.5;",
  
  						"totalDiffuseLight += mix( hemisphereLightGroundColor[ i ], hemisphereLightSkyColor[ i ], hemiDiffuseWeight );",
  
  						// specular (sky light)
  
  						"float hemiSpecularWeight = 0.0;",
  
  						"vec3 hemiHalfVectorSky = normalize( lVector + viewPosition );",
  						"float hemiDotNormalHalfSky = 0.5 * dot( normal, hemiHalfVectorSky ) + 0.5;",
  						"hemiSpecularWeight += specularTex.r * max( pow( hemiDotNormalHalfSky, shininess ), 0.0 );",
  
  						// specular (ground light)
  
  						"vec3 lVectorGround = -lVector;",
  
  						"vec3 hemiHalfVectorGround = normalize( lVectorGround + viewPosition );",
  						"float hemiDotNormalHalfGround = 0.5 * dot( normal, hemiHalfVectorGround ) + 0.5;",
  						"hemiSpecularWeight += specularTex.r * max( pow( hemiDotNormalHalfGround, shininess ), 0.0 );",
  
  						"totalSpecularLight += specular * mix( hemisphereLightGroundColor[ i ], hemisphereLightSkyColor[ i ], hemiDiffuseWeight ) * hemiSpecularWeight * hemiDiffuseWeight;",
  
  					"}",
  
  				"#endif",
  
  				"outgoingLight += diffuseColor.xyz * ( totalDiffuseLight + ambientLightColor + totalSpecularLight );",
  
  				THREE.ShaderChunk[ "shadowmap_fragment" ],
  				THREE.ShaderChunk[ "linear_to_gamma_fragment" ],
  				THREE.ShaderChunk[ "fog_fragment" ],
  
  				"gl_FragColor = vec4( outgoingLight, diffuseColor.a );",	// TODO, this should be pre-multiplied to allow for bright highlights on very transparent objects
  
  			"}"
  
  		].join("\n"),
  
  		vertexShader: [
  
  			"attribute vec4 tangent;",
  
  			"uniform vec2 uRepeatBase;",
  
  			"uniform sampler2D tNormal;",
  
  			"#ifdef VERTEX_TEXTURES",
  
  				"uniform sampler2D tDisplacement;",
  				"uniform float uDisplacementScale;",
  				"uniform float uDisplacementBias;",
  
  			"#endif",
  
  			"varying vec3 vTangent;",
  			"varying vec3 vBinormal;",
  			"varying vec3 vNormal;",
  			"varying vec2 vUv;",
  
  			"varying vec3 vViewPosition;",
  
  			THREE.ShaderChunk[ "shadowmap_pars_vertex" ],
  
  			"void main() {",
  
  				"vNormal = normalize( normalMatrix * normal );",
  
  				// tangent and binormal vectors
  
  				"vTangent = normalize( normalMatrix * tangent.xyz );",
  
  				"vBinormal = cross( vNormal, vTangent ) * tangent.w;",
  				"vBinormal = normalize( vBinormal );",
  
  				// texture coordinates
  
  				"vUv = uv;",
  
  				"vec2 uvBase = uv * uRepeatBase;",
  
  				// displacement mapping
  
  				"#ifdef VERTEX_TEXTURES",
  
  					"vec3 dv = texture2D( tDisplacement, uvBase ).xyz;",
  					"float df = uDisplacementScale * dv.x + uDisplacementBias;",
  					"vec3 displacedPosition = normal * df + position;",
  
  					"vec4 worldPosition = modelMatrix * vec4( displacedPosition, 1.0 );",
  					"vec4 mvPosition = modelViewMatrix * vec4( displacedPosition, 1.0 );",
  
  				"#else",
  
  					"vec4 worldPosition = modelMatrix * vec4( position, 1.0 );",
  					"vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );",
  
  				"#endif",
  
  				"gl_Position = projectionMatrix * mvPosition;",
  
  				"vViewPosition = -mvPosition.xyz;",
  
  				"vec3 normalTex = texture2D( tNormal, uvBase ).xyz * 2.0 - 1.0;",
  				"vNormal = normalMatrix * normalTex;",
  
  				THREE.ShaderChunk[ "shadowmap_vertex" ],
  
  			"}"
  
  		].join("\n")
  
  	}
  
  };
  