Game Development Patterns and Best Practices

The Factory method pattern

The Factory method pattern is exactly the design pattern we need to solve our problem. The purpose of this pattern is to have a way of creating the derived class that we want without needed to specify the concreate class in our high-level module. This is done by defining an interface for creating objects, but letting subclasses decide which class to instantiate.

In our case, we will create a StageFactory interface with a method called Build that will return a Stage*. We can then create subclasses such as Level2Factory to instantiate our derived classes. Our StageManager class now only needs to know about the Stage and StageFactory abstractions:

Creating a Stage Factory

//StageManager.cpp void StageManager::Update() ...