Creating a Node

• Overview
• Initializing the Node Class
• Defining the Constructor
• Implementing Actions
• Creating a Property Node
• Creating a Shape Node
• Creating a Group Node
• Using New Node Classes
• Creating an Abstract Node Class
• The copy() Method
• The affectsState() Method
• Uncacheable Nodes
• Creating an Alternate Representation
• Generating Default Normals

This chapter explains how you can create new subclasses of SoNode. It discusses enabling elements in the state, constructing a node, and implementing actions for it. Key Concepts provides important background material on these concepts, and this chapter assumes you are familiar with the material presented there.

The first part of this chapter offers an overview of the steps required to create a new node. When necessary, additional sections explain key concepts in further detail and list the relevant macros. Next, the chapter examples show how to create four new node classes:

• A property node class called Glow
• A shape node class called Pyramid
• A more complex shape node class called Torus
• A group node class called Alternate Sections at the end of the chapter discuss the following:
• Using new node classes
• Creating abstract classes
• The copy() method
• The affectsState() method
• Creating nodes that cannot be cached
• Creating an alternate representation for a new node class