Design Patterns

Lecture Material

• Introduction to software design patterns

Reference Material

• Code examples of design patterns in C# and .NET
• Game Programming Patterns - examples tailored to game development in C++
• Q&A with some good specific (but high level) examples

Handling Input: command pattern + events

• Some starter code ideas for command based keyboard controls and a command to change the current sprite to dead mario
• Command design pattern example
• Event driven programming and the Command design pattern - wikipedia
• Events in C#
• C# events tutorial
• On the difference between events and commands - 1 - 2

Management of objects: factories, factory methods, singletons, and static classes

• Factory - wikipedia
• Factory method pattern - wikipedia
• Singleton pattern - wikipedia
• C# singleton example with "lazy initialization" - use this version if you need to load content in the singleton's constructor
• Static classes
• Some starter code ideas: a Enemy sprite factory as a singleton (using eager initialization and a Game1 singleton)
• Some starter code ideas: a static class to store Texture2Ds

Object behavior: state and strategy patterns

• Old example - enum based C# code for game and enemy state machines in XNA
• Game state machine diagram example
• Limited player character state machine diagram example
• State design pattern - wikipedia
• Some starter code ideas: Goomba class using state pattern and Goomba class using state machine
• Finite state machine tutorial in C++
  FYI, another way to handle state transition logic Table-driven Approach and Table-based State Machine and Literate Programming for the Adventure Game
• Consider splitting up state logic by rarely made state changes being an element of the player: IPlayer implemented by BigMario (Partial state diagram - BigMario), SmallMario (Partial state diagram - SmallMario), etc.
• Strategy design pattern example
• Strategy design pattern - wikipedia

More on object behavior: decorator pattern

• Decorator design pattern example
• Decorator design pattern - wikipedia
• Star Mario decorator
• Damaged Link decorator

More on objects: null object pattern

• Null object design pattern - wikipedia

Since you can only master a topic when you understand both sides of it, here are articles against the use of design patterns

• Design patterns are from hell! and the better followup Design patterns are from hell^2!. In particular, note that design patterns generally only apply to object oriented programming and some pattern-like behaviors are included in the core syntax of some programming languages (for example, events in C# compared to the observer pattern).