SENG 454
Game Design Patterns
Assoc.Prof.Dr. Tansel Dökeroğlu
Books
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Books
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Syllabus of the lecture
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Definition of a design pattern
• A general, reusable solution to a commonly occurring
problem within a given context in software design.
• A description or template for how to solve a problem that
can be used in many different situations.
• Formalized best practices that the programmer can use to
solve common problems when designing an application or
system.
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Definition of a design pattern
• Not a finished design that can be transformed directly into
source or machine code.
• Design patterns show relationships and interactions between
classes or objects, without specifying the final application
classes or objects that are involved.
• Only suitable for object-oriented languages.
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Applications of design patterns
• Speed up the development process by providing tested,
proven development paradigms.
• Improves code readability for coders and architects familiar
with the patterns.
• Design patterns provide general solutions, not specific to
some problems.
• Allows developers to communicate using well-known, well
understood names for software interactions.
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Good for solving software structural problems
• Abstraction
• Encapsulation
• Information hiding
• Separation of concerns
• Coupling and cohesion
• Separation of interface and implementation
• Single point of reference
• Divide and conquer
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Solving non-functional software problems
• Changeability
• Interoperability
• Efficiency
• Reliability
• Testability
• Reusability
• Maintenance
• Flexibility
Patterns, Architectures & Frameworks
Frameworks are partially completed software systems that
may be targeted at a particular type of application.
These are tailored by completing the unfinished components.
Architectures model software structure at the highest
possible level, and give the overall system view.
An architecture can use many different patterns in different
components
Software Design Patterns are more like small-scale or local
architectures for architectural components or sub-components
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Categorization of Classical Design Patterns
• Creational: Creating an object in a flexible way.
Separate creation from operation/use.
• Structural: Compose objects to obtain new functionality.
• Behavioral: Related with communication between
objects.
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Creational Design Patterns
Factory : providing an interface for creating objects in a superclass,
but allows subclasses to alter the type of objects that will be
created.
Builder: constructing complex objects step by step.
The pattern allows you to produce different types and
representations of an object using the same construction code.
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Creational Design Patterns
Prototype: copying existing objects without making your code
dependent on their classes. Some of the object’s fields may be
private and not visible from outside of the object itself.
Singleton: Ensuring that a class has only one instance, while
providing a global access point to this instance. some of the object’s
fields may be private and not visible from outside of the object itself.
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Structural Design Patterns
Adapter: allows objects with incompatible interfaces to collaborate.
Bridge: splitting a large class or a set of closely related classes into
two separate hierarchies—abstraction and implementation—which
can be developed independently of each other.
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Structural Design Patterns
Decorator: attaching new behaviors to objects by placing these
objects inside special wrapper objects that contain the behaviors.
Facade: providing a simplified interface to a library, a framework, or
any other complex set of classes.
Flyweight: fitting more objects into the available amount of RAM by
sharing common parts of state between multiple objects instead of
keeping all of the data in each object.
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Behavioral Design Patterns
Command: turning a request into a stand-alone object that contains
all information about the request. This transformation lets you
parameterize methods with different requests, delay or queue a
request’s execution, and support undoable operations.
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Behavioral Design Patterns
Iterator: traversing elements of a collection without exposing its
underlying representation (list, stack, tree, etc.).
Mediator: reducing chaotic dependencies between objects.
The pattern restricts direct communications between the objects
and forces them to collaborate only via a mediator object.
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Behavioral Design Patterns
Observer: defining a subscription mechanism to notify multiple
objects about any events that happen to the object
they’re observing.
Template: defining the skeleton of an algorithm in the superclass
but lets subclasses override specific steps of the algorithm without
changing its structure.
Visitor: separating algorithms from the objects on which
they operate.
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Behavioral Design Patterns
State: letting an object alter its behavior when its internal state
changes. It appears as if the object changed its class. This pattern can
be observed in a vending machine. Vending machines have states
based on the inventory, amount of currency deposited, the ability to
make change, the item selected, etc.
Strategy: defining a family of algorithms, put each of them into a
separate class, and make their objects interchangeable.
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Game Design Patterns
• Sequencing Patterns: time — the artificial world lives and
breathes at its own rthyme. We must invent time and craft the
gears that drive our clock of the game.
• Behavioral (game): quickly define and refine a large quantity of
maintainable behavior.
• Decoupling Patterns : we mean a change in one usually doesn’t
require a change in the other. When you change some feature in
your game, the fewer places in code you have to touch, the easier
it is.
• Optimization Patterns: Optimizing for performance is a deep art
that touches all aspects of software.
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Sequencing Patterns
• Double Buffer
• Game Loop
• Update Method
Behavioral Patterns
• Bytecode
• Subclass Sandbox
• Type Object
Decoupling Patterns
• Component
• Event Queue
• Service Locator
Optimization Patterns
• Data Locality
• Dirty Flag
• Object Pool
• Spatial Partition
