text: /**
   * @author sunag / http://www.sunag.com.br/
   */
  
  import {
  	UniformsLib,
  	UniformsUtils
  } from '../../../../../build/three.module.js';
  
  import { Node } from '../../core/Node.js';
  import { ColorNode } from '../../inputs/ColorNode.js';
  
  function SpriteNode() {
  
  	Node.call( this );
  
  	this.color = new ColorNode( 0xEEEEEE );
  	this.spherical = true;
  
  }
  
  SpriteNode.prototype = Object.create( Node.prototype );
  SpriteNode.prototype.constructor = SpriteNode;
  SpriteNode.prototype.nodeType = "Sprite";
  
  SpriteNode.prototype.build = function ( builder ) {
  
  	var output;
  
  	builder.define( 'SPRITE' );
  
  	builder.requires.lights = false;
  	builder.requires.transparent = this.alpha !== undefined;
  
  	if ( builder.isShader( 'vertex' ) ) {
  
  		var position = this.position ? this.position.analyzeAndFlow( builder, 'v3', { cache: 'position' } ) : undefined;
  
  		builder.mergeUniform( UniformsUtils.merge( [
  			UniformsLib.fog
  		] ) );
  
  		builder.addParsCode( [
  			"#include <fog_pars_vertex>",
  			"#include <logdepthbuf_pars_vertex>",
  			"#include <clipping_planes_pars_vertex>"
  		].join( "\n" ) );
  
  		output = [
  			"#include <clipping_planes_fragment>",
  			"#include <begin_vertex>"
  		];
  
  		if ( position ) {
  
  			output.push(
  				position.code,
  				position.result ? "transformed = " + position.result + ";" : ''
  			);
  
  		}
  
  		output.push(
  			"#include <project_vertex>",
  			"#include <fog_vertex>",
  
  			'mat4 modelViewMtx = modelViewMatrix;',
  			'mat4 modelMtx = modelMatrix;',
  
  			// ignore position from modelMatrix (use vary position)
  			'modelMtx[3][0] = 0.0;',
  			'modelMtx[3][1] = 0.0;',
  			'modelMtx[3][2] = 0.0;'
  		);
  
  		if ( ! this.spherical ) {
  
  			output.push(
  				'modelMtx[1][1] = 1.0;'
  			);
  
  		}
  
  		output.push(
  			// http://www.geeks3d.com/20140807/billboarding-vertex-shader-glsl/
  			// First colunm.
  			'modelViewMtx[0][0] = 1.0;',
  			'modelViewMtx[0][1] = 0.0;',
  			'modelViewMtx[0][2] = 0.0;'
  		);
  
  		if ( this.spherical ) {
  
  			output.push(
  				// Second colunm.
  				'modelViewMtx[1][0] = 0.0;',
  				'modelViewMtx[1][1] = 1.0;',
  				'modelViewMtx[1][2] = 0.0;'
  			);
  
  		}
  
  		output.push(
  			// Thrid colunm.
  			'modelViewMtx[2][0] = 0.0;',
  			'modelViewMtx[2][1] = 0.0;',
  			'modelViewMtx[2][2] = 1.0;',
  
  			"gl_Position = projectionMatrix * modelViewMtx * modelMtx * vec4( transformed, 1.0 );",
  
  			"#include <logdepthbuf_vertex>",
  			"#include <clipping_planes_vertex>",
  			"#include <fog_vertex>"
  		);
  
  	} else {
  
  		builder.addParsCode( [
  			"#include <fog_pars_fragment>",
  			"#include <logdepthbuf_pars_fragment>",
  			"#include <clipping_planes_pars_fragment>"
  		].join( "\n" ) );
  
  		builder.addCode( [
  			"#include <clipping_planes_fragment>",
  			"#include <logdepthbuf_fragment>"
  		].join( "\n" ) );
  
  		// analyze all nodes to reuse generate codes
  
  		if ( this.mask ) this.mask.analyze( builder );
  
  		if ( this.alpha ) this.alpha.analyze( builder );
  
  		this.color.analyze( builder, { slot: 'color' } );
  
  		// build code
  
  		var mask = this.mask ? this.mask.flow( builder, 'b' ) : undefined,
  			alpha = this.alpha ? this.alpha.flow( builder, 'f' ) : undefined,
  			color = this.color.flow( builder, 'c', { slot: 'color' } ),
  			output = [];
  
  		if ( mask ) {
  
  			output.push(
  				mask.code,
  				'if ( ! ' + mask.result + ' ) discard;'
  			);
  
  		}
  
  		if ( alpha ) {
  
  			output.push(
  				alpha.code,
  				'#ifdef ALPHATEST',
  
  				'if ( ' + alpha.result + ' <= ALPHATEST ) discard;',
  
  				'#endif',
  				color.code,
  				"gl_FragColor = vec4( " + color.result + ", " + alpha.result + " );"
  			);
  
  		} else {
  
  			output.push(
  				color.code,
  				"gl_FragColor = vec4( " + color.result + ", 1.0 );"
  			);
  
  		}
  
  		output.push(
  			"#include <tonemapping_fragment>",
  			"#include <encodings_fragment>",
  			"#include <fog_fragment>"
  		);
  
  	}
  
  	return output.join( "\n" );
  
  };
  
  SpriteNode.prototype.copy = function ( source ) {
  
  	Node.prototype.copy.call( this, source );
  
  	// vertex
  
  	if ( source.position ) this.position = source.position;
  
  	// fragment
  
  	this.color = source.color;
  
  	if ( source.spherical !== undefined ) this.spherical = source.spherical;
  
  	if ( source.mask ) this.mask = source.mask;
  
  	if ( source.alpha ) this.alpha = source.alpha;
  
  	return this;
  
  };
  
  SpriteNode.prototype.toJSON = function ( meta ) {
  
  	var data = this.getJSONNode( meta );
  
  	if ( ! data ) {
  
  		data = this.createJSONNode( meta );
  
  		// vertex
  
  		if ( this.position ) data.position = this.position.toJSON( meta ).uuid;
  
  		// fragment
  
  		data.color = this.color.toJSON( meta ).uuid;
  
  		if ( this.spherical === false ) data.spherical = false;
  
  		if ( this.mask ) data.mask = this.mask.toJSON( meta ).uuid;
  
  		if ( this.alpha ) data.alpha = this.alpha.toJSON( meta ).uuid;
  
  	}
  
  	return data;
  
  };
  
  export { SpriteNode };
  