code: function( renderer, n ) {
  
  			var r = arrayCacheI32[ n ];
  
  			if ( r === undefined ) {
  
  				r = new Int32Array( n );
  				arrayCacheI32[ n ] = r;
  
  			}
  
  			for ( var i = 0; i !== n; ++ i )
  				r[ i ] = renderer.allocTextureUnit();
  
  			return r;
  
  		}
docs: --- Base for inner nodes (including the root) ---