three.js/examples/js/materials/nodes/NodeGL.js

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

THREE.NodeGL = function( type ) {
	
	this.uuid = THREE.Math.generateUUID();
	
	this.allow = {};
	this.requestUpdate = false;
	
	this.type = type;
	
};

THREE.NodeGL.prototype.verify = function( builder ) {
	
	builder.isVerify = true;
	
	var material = builder.material;
	
	this.build( builder, 'v4' );
	
	material.clearVertexNode();
	material.clearFragmentNode();
	
	builder.setCache(); // reset cache
	
	builder.isVerify = false;

};

THREE.NodeGL.prototype.verifyAndBuildCode = function( builder, output, cache ) {
	
	this.verify( builder.setCache(cache) );
	
	return this.buildCode( builder.setCache(cache), output );
	
};

THREE.NodeGL.prototype.buildCode = function( builder, output, uuid ) {
	
	var material = builder.material;
	var data = { result : this.build( builder, output, uuid ) };
	
	if (builder.isShader('vertex')) data.code = material.clearVertexNode();
	else data.code = material.clearFragmentNode();
	
	builder.setCache(); // reset cache
	
	return data;

};

THREE.NodeGL.prototype.verifyNodeDeps = function( builder, data, output ) {
	
	data.deps = (data.deps || 0) + 1;
	
	var outputLen = builder.getFormatLength( output );
	
	if (outputLen > data.outputMax || this.getType( builder )) {
		
		data.outputMax = outputLen;
		data.output = output;
		
	}

};

THREE.NodeGL.prototype.build = function( builder, output, uuid ) {

	var material = builder.material;
	var data = material.getNodeData( uuid || this.uuid );
	
	if (builder.isShader('verify')) this.verifyNodeDeps( builder, data, output );
	
	if (this.allow[builder.shader] === false) {
		throw new Error( 'Shader ' + shader + ' is not compatible with this node.' );
	}
	
	if (this.requestUpdate && !data.requestUpdate) {
		material.requestUpdate.push( this );
		data.requestUpdate = true;
	}
	
	return this.generate( builder, output, uuid );
	
};

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

	return this.type;
	
};