three.js/examples/js/nodes/math/OperatorNode.js

/**
 * @author sunag / http://www.sunag.com.br/
 */

THREE.OperatorNode = function ( a, b, op ) {

	THREE.TempNode.call( this );

	this.a = a;
	this.b = b;
	this.op = op || THREE.OperatorNode.ADD;

};

THREE.OperatorNode.ADD = '+';
THREE.OperatorNode.SUB = '-';
THREE.OperatorNode.MUL = '*';
THREE.OperatorNode.DIV = '/';

THREE.OperatorNode.prototype = Object.create( THREE.TempNode.prototype );
THREE.OperatorNode.prototype.constructor = THREE.OperatorNode;
THREE.OperatorNode.prototype.nodeType = "Operator";

THREE.OperatorNode.prototype.getType = function ( builder ) {

	var a = this.a.getType( builder );
	var b = this.b.getType( builder );

	if ( builder.isFormatMatrix( a ) ) {

		return 'v4';

	} else if ( builder.getFormatLength( b ) > builder.getFormatLength( a ) ) {

		// use the greater length vector

		return b;

	}

	return a;

};

THREE.OperatorNode.prototype.generate = function ( builder, output ) {

	var material = builder.material,
		data = material.getDataNode( this.uuid );

	var type = this.getType( builder );

	var a = this.a.build( builder, type );
	var b = this.b.build( builder, type );

	return builder.format( '( ' + a + ' ' +  this.op + ' '+ b + ' )', type, output );

};

THREE.OperatorNode.prototype.copy = function ( source ) {
			
	THREE.GLNode.prototype.copy.call( this, source );
	
	this.a = source.a;
	this.b = source.b;
	this.op = source.op;
	
};

THREE.OperatorNode.prototype.toJSON = function ( meta ) {

	var data = this.getJSONNode( meta );

	if ( ! data ) {

		data = this.createJSONNode( meta );

		data.a = this.a.toJSON( meta ).uuid;
		data.b = this.b.toJSON( meta ).uuid;
		data.op = this.op;

	}

	return data;

};