text: /**
   * @author sunag / http://www.sunag.com.br/
   */
  
  import { TempNode } from '../core/TempNode.js';
  import { FunctionNode } from '../core/FunctionNode.js';
  import { MaxMIPLevelNode } from '../utils/MaxMIPLevelNode.js';
  import { BlinnShininessExponentNode } from './BlinnShininessExponentNode.js';
  
  function RoughnessToBlinnExponentNode( texture ) {
  
  	TempNode.call( this, 'f' );
  
  	this.texture = texture;
  
  	this.maxMIPLevel = new MaxMIPLevelNode( texture );
  	this.blinnShininessExponent = new BlinnShininessExponentNode();
  
  }
  
  RoughnessToBlinnExponentNode.Nodes = ( function () {
  
  	var getSpecularMIPLevel = new FunctionNode( [
  		// taken from here: http://casual-effects.blogspot.ca/2011/08/plausible-environment-lighting-in-two.html
  		"float getSpecularMIPLevel( const in float blinnShininessExponent, const in float maxMIPLevelScalar ) {",
  
  		//	float envMapWidth = pow( 2.0, maxMIPLevelScalar );
  		//	float desiredMIPLevel = log2( envMapWidth * sqrt( 3.0 ) ) - 0.5 * log2( pow2( blinnShininessExponent ) + 1.0 );
  
  		"	float desiredMIPLevel = maxMIPLevelScalar + 0.79248 - 0.5 * log2( pow2( blinnShininessExponent ) + 1.0 );",
  
  		// clamp to allowable LOD ranges.
  		"	return clamp( desiredMIPLevel, 0.0, maxMIPLevelScalar );",
  
  		"}"
  	].join( "\n" ) );
  
  	return {
  		getSpecularMIPLevel: getSpecularMIPLevel
  	};
  
  } )();
  
  RoughnessToBlinnExponentNode.prototype = Object.create( TempNode.prototype );
  RoughnessToBlinnExponentNode.prototype.constructor = RoughnessToBlinnExponentNode;
  RoughnessToBlinnExponentNode.prototype.nodeType = "RoughnessToBlinnExponent";
  
  RoughnessToBlinnExponentNode.prototype.generate = function ( builder, output ) {
  
  	if ( builder.isShader( 'fragment' ) ) {
  
  		this.maxMIPLevel.texture = this.texture;
  
  		var getSpecularMIPLevel = builder.include( RoughnessToBlinnExponentNode.Nodes.getSpecularMIPLevel );
  
  		return builder.format( getSpecularMIPLevel + '( ' + this.blinnShininessExponent.build( builder, 'f' ) + ', ' + this.maxMIPLevel.build( builder, 'f' ) + ' )', this.type, output );
  
  	} else {
  
  		console.warn( "THREE.RoughnessToBlinnExponentNode is not compatible with " + builder.shader + " shader." );
  
  		return builder.format( '0.0', this.type, output );
  
  	}
  
  };
  
  RoughnessToBlinnExponentNode.prototype.copy = function ( source ) {
  
  	TempNode.prototype.copy.call( this, source );
  
  	this.texture = source.texture;
  
  	return this;
  
  };
  
  RoughnessToBlinnExponentNode.prototype.toJSON = function ( meta ) {
  
  	var data = this.getJSONNode( meta );
  
  	if ( ! data ) {
  
  		data = this.createJSONNode( meta );
  
  		data.texture = this.texture;
  
  	}
  
  	return data;
  
  };
  
  export { RoughnessToBlinnExponentNode };
  