3.3 programming fundamentals
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The document discusses several common data structures and design patterns used in programming. It describes arrays, linked lists, dictionaries, stacks, and queues as basic data structures. It then covers object oriented programming concepts like classes, inheritance, and polymorphism. Component-based design patterns are introduced as an alternative to inheritance. Finally, common design patterns like singleton, factory, observer, and composite are explained at a high level.
3.3 programming fundamentals
- 2. 2 Data Structures Arrays Elements are adjacent in memory (great cache consistency) They never grow or get reallocated In C++ there's no check for going out of bounds Inserting and deleting elements in the middle is expensive
- 3. 3 Data Structures Linked lists Very cheap to add/remove elements. Available in the STL (std::list) Every element is allocated separately Lots of little allocations Not placed contiguously in memory
- 4. 4 Data Structures Dictionaries Maps a set of keys to some data. std::map, std::hash, etc Very fast access to data Perfect for mapping IDs to pointers, or resource handles to objects
- 5. 5 Data Structures Stacks First in, last out std::stack adaptor in STL Queues First in, first out std::deque
- 6. 6 Data Structures Bit packing Fold all necessary data into a smaller number of bits Very useful for storing boolean flags (pack 32 in a double word) Possible to apply to numerical values if we can give up range or accuracy Very low level trick Only use when absolutely necessary
- 7. 7 Object Oriented Design Concepts Class Abstract specification of a data type Instance A region of memory with associated semantics to store all the data members of a class Object Another name for an instance of a class
- 8. 8 Object Oriented Design Inheritance Models “is-a” relationship Extends behavior of existing classes by making minor changes
- 9. 9 Object Oriented Design Inheritance UML diagram representing inheritance E n e m y B o s s S u p e r D u p e r B o s s
- 10. 10 Object Oriented Design Polymorphism The ability to refer to an object through a reference (or pointer) of the type of a parent class Key concept of object oriented design
- 11. 11 Object Oriented Design Multiple Inheritance Allows a class to have more than one base class Derived class adopts characteristics of all parent classes Huge potential for problems (clashes, casting, etc) Multiple inheritance of abstract interfaces is much less error prone
- 12. 12 Component Systems Limitations of inheritance Tight coupling Unclear flow of control Not flexible enough Static hierarchy
- 13. 13 Component Systems Component system organization Use aggregation (composition) instead of inheritance A game entity can “own” multiple components that determine its behavior Each component can execute whenever the entity is updated Messages can be passed between components and to other entities
- 14. 14 Component Systems Component system organization G a m e E n t i t y N a m e = s w o r d R e n d e r C o m p C o l l i s i o n C o m p D a m a g e C o m p P i c k u p C o m p W i e l d C o m p
- 15. 15 Component Systems Data-Driven Composition The structure of the game entities can be specified in data Components are created and loaded at runtime Very easy to change (which is very important in game development)
- 16. 16 Component Systems Analysis Very hard to debug Performance can be a bottleneck Keeping code and data synchronized can be a challenge Extremely flexible Great for experimentation and varied gameplay Not very useful if problem/game is very well known ahead of time
- 17. 17 Design Patterns Singleton Implements a single instance of a class with global point of creation and access Don't overuse it!!! S i n g l e t o n s t a t ic S in g le t o n & G e t I n s t a n c e ( ) ; / / R e g u la r m e m b e r f u n c t io n s . . . s t a t ic S in g le t o n u n iq u e I n s t a n c e ;
- 18. 18 Design Patterns Object Factory Creates objects by name Pluggable factory allows for new object types to be registered at runtime Extremely useful in game development for creating new objects, loading games, or instantiating new content after game ships
- 19. 19 Design Patterns Object factory O b j e c t F a c t o r y P r o d u c t * C r e a t e O b je c t ( P r o d u c t T y p e t y p e ) ; C r e a t e P r o d u c t P r o d u c t
- 20. 20 Design Patterns Observer Allows objects to be notified of specific events with minimal coupling to the source of the event Two parts subject and observer
- 21. 21 Design Patterns Observer S u b j e c t A t t a c h ( O b s e r v e r * ) ; D e t a c h ( O b s e r v e r * ) ; N o t if y ( ) ; O b s e r v e r U p d a t e ( ) ; C o n c r e t e O b s e r v e r U p d a t e ( ) ; C o n c r e t e S u b j e c t
- 22. 22 Design Patterns Composite Allow a group of objects to be treated as a single object Very useful for GUI elements, hierarchical objects, inventory systems, etc
- 23. 23 Design Patterns Composite C o m p o s i t e O p e r a t io n ( ) ; lis t < C o m p o n e n t * > c h ild r e n S p e c i f i c C o m p o n e n t O p e r a t io n ( ) ; C o m p o n e n t O p e r a t io n ( ) ;