Feature: 'A Real-Time Procedural Universe, Part Four: Dynamic Ground Textures and Objects'

Drawing from his experience on his ongoing project to create a real-time procedural universe, Sean O'Neil discusses how to implement dynamic ground textures and objects on a planetary object. Here O'Neil discusses how he created a planetary factory class to aid in planet creation: "To separate the node class from the code building the planet, I created a class called CPlanetaryFactory. Each class derived from CPlanetaryFactory adds something different to the planet, and factories can be combined in different ways to build different types of planets. The CPlanetaryMap class keeps a list of factories for each planet, and when a node in the quad-tree needs to be built, each factory's BuildNode() method is called. Just in case the factory creates something that needs to be cleaned up, each factory's DestroyNode() method is called when a node is destroyed. Each factory object is initialized with a CPropertySet object, which is a simple map of named properties. This property set is currently loaded from a configuration file called Planet_Quad.conf. A custom RTTI implementation is used to allow class names to be specified in the configuration file, and to keep CPlanetaryMap from having to know how to create and initialize each factory class. This should make it easy for you to create your own factory class, load its type class, and then change the config file to use it without having to change CPlanetaryMap or CPlanetaryMapNode. This is a very useful separation which can be extended to load factories from other DLLs using LoadLibrary. That would allow new factories to be added dynamically without changing or recompiling the main project." You can now read the full Gamasutra feature on the subject (no registration required, please feel free to link to the article from external websites).