text: /**
   * @author takahirox / http://github.com/takahirox/
   *
   * Reference: https://en.wikipedia.org/wiki/Cel_shading
   *
   * API
   *
   * 1. Traditional
   *
   * var effect = new OutlineEffect( renderer );
   *
   * function render() {
   *
   * 	effect.render( scene, camera );
   *
   * }
   *
   * 2. VR compatible
   *
   * var effect = new OutlineEffect( renderer );
   * var renderingOutline = false;
   *
   * scene.onAfterRender = function () {
   *
   * 	if ( renderingOutline ) return;
   *
   * 	renderingOutline = true;
   *
   * 	effect.renderOutline( scene, camera );
   *
   * 	renderingOutline = false;
   *
   * };
   *
   * function render() {
   *
   * 	renderer.render( scene, camera );
   *
   * }
   *
   * // How to set default outline parameters
   * new OutlineEffect( renderer, {
   * 	defaultThickness: 0.01,
   * 	defaultColor: [ 0, 0, 0 ],
   * 	defaultAlpha: 0.8,
   * 	defaultKeepAlive: true // keeps outline material in cache even if material is removed from scene
   * } );
   *
   * // How to set outline parameters for each material
   * material.userData.outlineParameters = {
   * 	thickness: 0.01,
   * 	color: [ 0, 0, 0 ]
   * 	alpha: 0.8,
   * 	visible: true,
   * 	keepAlive: true
   * };
   */
  
  import {
  	BackSide,
  	Color,
  	ShaderMaterial,
  	UniformsLib,
  	UniformsUtils
  } from "../../../build/three.module.js";
  
  var OutlineEffect = function ( renderer, parameters ) {
  
  	parameters = parameters || {};
  
  	this.enabled = true;
  
  	var defaultThickness = parameters.defaultThickness !== undefined ? parameters.defaultThickness : 0.003;
  	var defaultColor = new Color().fromArray( parameters.defaultColor !== undefined ? parameters.defaultColor : [ 0, 0, 0 ] );
  	var defaultAlpha = parameters.defaultAlpha !== undefined ? parameters.defaultAlpha : 1.0;
  	var defaultKeepAlive = parameters.defaultKeepAlive !== undefined ? parameters.defaultKeepAlive : false;
  
  	// object.material.uuid -> outlineMaterial or
  	// object.material[ n ].uuid -> outlineMaterial
  	// save at the outline material creation and release
  	// if it's unused removeThresholdCount frames
  	// unless keepAlive is true.
  	var cache = {};
  
  	var removeThresholdCount = 60;
  
  	// outlineMaterial.uuid -> object.material or
  	// outlineMaterial.uuid -> object.material[ n ]
  	// save before render and release after render.
  	var originalMaterials = {};
  
  	// object.uuid -> originalOnBeforeRender
  	// save before render and release after render.
  	var originalOnBeforeRenders = {};
  
  	//this.cache = cache;  // for debug
  
  	var uniformsOutline = {
  		outlineThickness: { value: defaultThickness },
  		outlineColor: { value: defaultColor },
  		outlineAlpha: { value: defaultAlpha }
  	};
  
  	var vertexShader = [
  		"#include <common>",
  		"#include <uv_pars_vertex>",
  		"#include <displacementmap_pars_vertex>",
  		"#include <fog_pars_vertex>",
  		"#include <morphtarget_pars_vertex>",
  		"#include <skinning_pars_vertex>",
  		"#include <logdepthbuf_pars_vertex>",
  		"#include <clipping_planes_pars_vertex>",
  
  		"uniform float outlineThickness;",
  
  		"vec4 calculateOutline( vec4 pos, vec3 normal, vec4 skinned ) {",
  		"	float thickness = outlineThickness;",
  		"	const float ratio = 1.0;", // TODO: support outline thickness ratio for each vertex
  		"	vec4 pos2 = projectionMatrix * modelViewMatrix * vec4( skinned.xyz + normal, 1.0 );",
  		// NOTE: subtract pos2 from pos because BackSide objectNormal is negative
  		"	vec4 norm = normalize( pos - pos2 );",
  		"	return pos + norm * thickness * pos.w * ratio;",
  		"}",
  
  		"void main() {",
  
  		"	#include <uv_vertex>",
  
  		"	#include <beginnormal_vertex>",
  		"	#include <morphnormal_vertex>",
  		"	#include <skinbase_vertex>",
  		"	#include <skinnormal_vertex>",
  
  		"	#include <begin_vertex>",
  		"	#include <morphtarget_vertex>",
  		"	#include <skinning_vertex>",
  		"	#include <displacementmap_vertex>",
  		"	#include <project_vertex>",
  
  		"	vec3 outlineNormal = - objectNormal;", // the outline material is always rendered with BackSide
  
  		"	gl_Position = calculateOutline( gl_Position, outlineNormal, vec4( transformed, 1.0 ) );",
  
  		"	#include <logdepthbuf_vertex>",
  		"	#include <clipping_planes_vertex>",
  		"	#include <fog_vertex>",
  
  		"}",
  
  	].join( "\n" );
  
  	var fragmentShader = [
  
  		"#include <common>",
  		"#include <fog_pars_fragment>",
  		"#include <logdepthbuf_pars_fragment>",
  		"#include <clipping_planes_pars_fragment>",
  
  		"uniform vec3 outlineColor;",
  		"uniform float outlineAlpha;",
  
  		"void main() {",
  
  		"	#include <clipping_planes_fragment>",
  		"	#include <logdepthbuf_fragment>",
  
  		"	gl_FragColor = vec4( outlineColor, outlineAlpha );",
  
  		"	#include <premultiplied_alpha_fragment>",
  		"	#include <tonemapping_fragment>",
  		"	#include <encodings_fragment>",
  		"	#include <fog_fragment>",
  
  		"}"
  
  	].join( "\n" );
  
  	function createMaterial() {
  
  		return new ShaderMaterial( {
  			type: 'OutlineEffect',
  			uniforms: UniformsUtils.merge( [
  				UniformsLib[ 'fog' ],
  				UniformsLib[ 'displacementmap' ],
  				uniformsOutline
  			] ),
  			vertexShader: vertexShader,
  			fragmentShader: fragmentShader,
  			side: BackSide
  		} );
  
  	}
  
  	function getOutlineMaterialFromCache( originalMaterial ) {
  
  		var data = cache[ originalMaterial.uuid ];
  
  		if ( data === undefined ) {
  
  			data = {
  				material: createMaterial(),
  				used: true,
  				keepAlive: defaultKeepAlive,
  				count: 0
  			};
  
  			cache[ originalMaterial.uuid ] = data;
  
  		}
  
  		data.used = true;
  
  		return data.material;
  
  	}
  
  	function getOutlineMaterial( originalMaterial ) {
  
  		var outlineMaterial = getOutlineMaterialFromCache( originalMaterial );
  
  		originalMaterials[ outlineMaterial.uuid ] = originalMaterial;
  
  		updateOutlineMaterial( outlineMaterial, originalMaterial );
  
  		return outlineMaterial;
  
  	}
  
  	function isCompatible( object ) {
  
  		var geometry = object.geometry;
  		var hasNormals = false;
  
  		if ( object.geometry !== undefined ) {
  
  			if ( geometry.isBufferGeometry ) {
  
  				hasNormals = geometry.attributes.normal !== undefined;
  
  			} else {
  
  				hasNormals = true; // the renderer always produces a normal attribute for Geometry
  
  			}
  
  		}
  
  		return ( object.isMesh === true && object.material !== undefined && hasNormals === true );
  
  	}
  
  	function setOutlineMaterial( object ) {
  
  		if ( isCompatible( object ) === false ) return;
  
  		if ( Array.isArray( object.material ) ) {
  
  			for ( var i = 0, il = object.material.length; i < il; i ++ ) {
  
  				object.material[ i ] = getOutlineMaterial( object.material[ i ] );
  
  			}
  
  		} else {
  
  			object.material = getOutlineMaterial( object.material );
  
  		}
  
  		originalOnBeforeRenders[ object.uuid ] = object.onBeforeRender;
  		object.onBeforeRender = onBeforeRender;
  
  	}
  
  	function restoreOriginalMaterial( object ) {
  
  		if ( isCompatible( object ) === false ) return;
  
  		if ( Array.isArray( object.material ) ) {
  
  			for ( var i = 0, il = object.material.length; i < il; i ++ ) {
  
  				object.material[ i ] = originalMaterials[ object.material[ i ].uuid ];
  
  			}
  
  		} else {
  
  			object.material = originalMaterials[ object.material.uuid ];
  
  		}
  
  		object.onBeforeRender = originalOnBeforeRenders[ object.uuid ];
  
  	}
  
  	function onBeforeRender( renderer, scene, camera, geometry, material ) {
  
  		var originalMaterial = originalMaterials[ material.uuid ];
  
  		// just in case
  		if ( originalMaterial === undefined ) return;
  
  		updateUniforms( material, originalMaterial );
  
  	}
  
  	function updateUniforms( material, originalMaterial ) {
  
  		var outlineParameters = originalMaterial.userData.outlineParameters;
  
  		material.uniforms.outlineAlpha.value = originalMaterial.opacity;
  
  		if ( outlineParameters !== undefined ) {
  
  			if ( outlineParameters.thickness !== undefined ) material.uniforms.outlineThickness.value = outlineParameters.thickness;
  			if ( outlineParameters.color !== undefined ) material.uniforms.outlineColor.value.fromArray( outlineParameters.color );
  			if ( outlineParameters.alpha !== undefined ) material.uniforms.outlineAlpha.value = outlineParameters.alpha;
  
  		}
  
  		if ( originalMaterial.displacementMap ) {
  
  			material.uniforms.displacementMap.value = originalMaterial.displacementMap;
  			material.uniforms.displacementScale.value = originalMaterial.displacementScale;
  			material.uniforms.displacementBias.value = originalMaterial.displacementBias;
  
  		}
  
  	}
  
  	function updateOutlineMaterial( material, originalMaterial ) {
  
  		if ( material.name === 'invisible' ) return;
  
  		var outlineParameters = originalMaterial.userData.outlineParameters;
  
  		material.skinning = originalMaterial.skinning;
  		material.morphTargets = originalMaterial.morphTargets;
  		material.morphNormals = originalMaterial.morphNormals;
  		material.fog = originalMaterial.fog;
  		material.toneMapped = originalMaterial.toneMapped;
  		material.premultipliedAlpha = originalMaterial.premultipliedAlpha;
  		material.displacementMap = originalMaterial.displacementMap;
  
  		if ( outlineParameters !== undefined ) {
  
  			if ( originalMaterial.visible === false ) {
  
  				material.visible = false;
  
  			} else {
  
  				material.visible = ( outlineParameters.visible !== undefined ) ? outlineParameters.visible : true;
  
  			}
  
  			material.transparent = ( outlineParameters.alpha !== undefined && outlineParameters.alpha < 1.0 ) ? true : originalMaterial.transparent;
  
  			if ( outlineParameters.keepAlive !== undefined ) cache[ originalMaterial.uuid ].keepAlive = outlineParameters.keepAlive;
  
  		} else {
  
  			material.transparent = originalMaterial.transparent;
  			material.visible = originalMaterial.visible;
  
  		}
  
  		if ( originalMaterial.wireframe === true || originalMaterial.depthTest === false ) material.visible = false;
  
  		if ( originalMaterial.clippingPlanes ) {
  
  			material.clipping = true;
  
  			material.clippingPlanes = originalMaterial.clippingPlanes;
  			material.clipIntersection = originalMaterial.clipIntersection;
  			material.clipShadows = originalMaterial.clipShadows;
  
  		}
  
  		material.version = originalMaterial.version; // update outline material if necessary
  
  	}
  
  	function cleanupCache() {
  
  		var keys;
  
  		// clear originialMaterials
  		keys = Object.keys( originalMaterials );
  
  		for ( var i = 0, il = keys.length; i < il; i ++ ) {
  
  			originalMaterials[ keys[ i ] ] = undefined;
  
  		}
  
  		// clear originalOnBeforeRenders
  		keys = Object.keys( originalOnBeforeRenders );
  
  		for ( var i = 0, il = keys.length; i < il; i ++ ) {
  
  			originalOnBeforeRenders[ keys[ i ] ] = undefined;
  
  		}
  
  		// remove unused outlineMaterial from cache
  		keys = Object.keys( cache );
  
  		for ( var i = 0, il = keys.length; i < il; i ++ ) {
  
  			var key = keys[ i ];
  
  			if ( cache[ key ].used === false ) {
  
  				cache[ key ].count ++;
  
  				if ( cache[ key ].keepAlive === false && cache[ key ].count > removeThresholdCount ) {
  
  					delete cache[ key ];
  
  				}
  
  			} else {
  
  				cache[ key ].used = false;
  				cache[ key ].count = 0;
  
  			}
  
  		}
  
  	}
  
  	this.render = function ( scene, camera ) {
  
  		var renderTarget;
  		var forceClear = false;
  
  		if ( arguments[ 2 ] !== undefined ) {
  
  			console.warn( 'THREE.OutlineEffect.render(): the renderTarget argument has been removed. Use .setRenderTarget() instead.' );
  			renderTarget = arguments[ 2 ];
  
  		}
  
  		if ( arguments[ 3 ] !== undefined ) {
  
  			console.warn( 'THREE.OutlineEffect.render(): the forceClear argument has been removed. Use .clear() instead.' );
  			forceClear = arguments[ 3 ];
  
  		}
  
  		if ( renderTarget !== undefined ) renderer.setRenderTarget( renderTarget );
  
  		if ( forceClear ) renderer.clear();
  
  		if ( this.enabled === false ) {
  
  			renderer.render( scene, camera );
  			return;
  
  		}
  
  		var currentAutoClear = renderer.autoClear;
  		renderer.autoClear = this.autoClear;
  
  		renderer.render( scene, camera );
  
  		renderer.autoClear = currentAutoClear;
  
  		this.renderOutline( scene, camera );
  
  	};
  
  	this.renderOutline = function ( scene, camera ) {
  
  		var currentAutoClear = renderer.autoClear;
  		var currentSceneAutoUpdate = scene.autoUpdate;
  		var currentSceneBackground = scene.background;
  		var currentShadowMapEnabled = renderer.shadowMap.enabled;
  
  		scene.autoUpdate = false;
  		scene.background = null;
  		renderer.autoClear = false;
  		renderer.shadowMap.enabled = false;
  
  		scene.traverse( setOutlineMaterial );
  
  		renderer.render( scene, camera );
  
  		scene.traverse( restoreOriginalMaterial );
  
  		cleanupCache();
  
  		scene.autoUpdate = currentSceneAutoUpdate;
  		scene.background = currentSceneBackground;
  		renderer.autoClear = currentAutoClear;
  		renderer.shadowMap.enabled = currentShadowMapEnabled;
  
  	};
  
  	/*
  	 * See #9918
  	 *
  	 * The following property copies and wrapper methods enable
  	 * OutlineEffect to be called from other *Effect, like
  	 *
  	 * effect = new StereoEffect( new OutlineEffect( renderer ) );
  	 *
  	 * function render () {
  	 *
   	 * 	effect.render( scene, camera );
  	 *
  	 * }
  	 */
  	this.autoClear = renderer.autoClear;
  	this.domElement = renderer.domElement;
  	this.shadowMap = renderer.shadowMap;
  
  	this.clear = function ( color, depth, stencil ) {
  
  		renderer.clear( color, depth, stencil );
  
  	};
  
  	this.getPixelRatio = function () {
  
  		return renderer.getPixelRatio();
  
  	};
  
  	this.setPixelRatio = function ( value ) {
  
  		renderer.setPixelRatio( value );
  
  	};
  
  	this.getSize = function ( target ) {
  
  		return renderer.getSize( target );
  
  	};
  
  	this.setSize = function ( width, height, updateStyle ) {
  
  		renderer.setSize( width, height, updateStyle );
  
  	};
  
  	this.setViewport = function ( x, y, width, height ) {
  
  		renderer.setViewport( x, y, width, height );
  
  	};
  
  	this.setScissor = function ( x, y, width, height ) {
  
  		renderer.setScissor( x, y, width, height );
  
  	};
  
  	this.setScissorTest = function ( boolean ) {
  
  		renderer.setScissorTest( boolean );
  
  	};
  
  	this.setRenderTarget = function ( renderTarget ) {
  
  		renderer.setRenderTarget( renderTarget );
  
  	};
  
  };
  
  export { OutlineEffect };
  