Game Development Patterns and Best Practices

The Static Factory

The simplest way to implement a factory method the way we want is with either a global function or a static class function. We could define a function called MakeStage outside of StateMananger that is responsible for instantiating the correct derived type based on a parameter. In this case, we will use an enum called StageType to help us choose our correct type:

//MakeStage.cpp Stage* MakeStage(StageType type) {   switch(type)   {     case ST_Level1:       return new Level1;     case ST_LEVEL2:       return new Level2;     case ST_MainMenu:       return new MainMenu;     default:       //Throw exception or assert   } } 

If we use this style of factory, our StageManager::Update function will look like this:

void StageManager::Update() {  Stage* pStage = ...