Some classes in the HTML 3D Library inherit the methods of others. These classes are called subclasses. To make a class a subclass of another, place the following code after the subclass's constructor:
SUBCLASS.prototype = Object.create(BASECLASS.prototype); SUBCLASS.prototype.constructor = SUBCLASS;
SUBCLASS is the name of the subclass, and BASECLASS is the name
of the class whose methods the subclass will inherit.