ProgrammingPatterns

Programming Patterns

Introduction

References

• Nys14 - Game programming patterns

Vocabulary

• speed - how fast you are traveling

• velocity - speed in a given direction

• keep variable scope as narrow as possible, to have fewer places to keep in the head, while working with the code(Nys14, 114)

Singleton

When to use: Seemingly never?

Replacement for the Singleton:

• Requiring a single instance - (Nys14, 112)
• To provide convenient access to an instance
  • Pass it in (Nys14, 114)
  • Get it from the base class (Nys14, 114)
    • Maybe also see: ServiceLocator pattern(Nys14, 116)
  • Get it from something already global(Nys14, 116)
  • Get it from a service locator(Nys14, 117)

When the class interacts with an external system that maintains its own global state(Nys14, 99).

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When deriving a class, it is a good idea for it to model the "is a" relationship. This means that the derived class should also be of the same type as the parent class. For example, deriving a Player2 class from Player would fit the model, as Player2 "is a" Player . But let's say, for example, we have a Jetpack class and we derive Player from this class to give it access to all the functionality that a Jetpack class has. This would not model the "is a" relationship, as a Player class is not a Jetpack class. It makes a lot more sense to say a Player class has a Jetpack class, and therefore, a Player class should have a member variable of type Jetpack with no inheritance; this is known as containment p61

• If your core loop involves calling a virtual function many times per second, the performance penalties can add up.