Chapter 14

Simulation, Graphics, Gaming and Other

Applications

Chapter Goals – THE BIG SLICES

•Models and Simulation•Computational Biology•(Complex) Computer Graphics•Computer Gaming

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Chapter Goals

•Models and Simulation• Complex Systems• Continuous and Discrete simulation• Object-oriented design and building models• Queuing systems• Weather and Seismic models

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Chapter Goals

•Computational Biology• Bioinformatics• Computational Biomodeling• Protein Modeling• Molecular Modeling

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Chapter Goals

•Computer Graphics• The CREATION of complex images• CAD• Fractal and Other Techniques• Light and Rendering• Movement

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Chapter Goals

•Computer Gaming• The LAYERS• Design and Development• Game Programming

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Complexity!

• Some real-world systems are complicated

• We want to model complex systems to:– better understand them– predict the future

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What is a Model?

• An Abstraction of a Real World System– A representation of the objects or quantities

within the system (Noun, the Data)

– and the rules that govern the interactions between them (Verb, the Code & Algorithms)

– Systems that are best suited to being simulated are dynamic, interactive, and complicated

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What Is Simulation?

• Simulation is RUNNING a model to PREDICT the results of experimental CHANGES in the system

• Doing “What If” analysis“What happens if I change this?“What happens if I don’t?”

Kinds of Models

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Kinds of Models• There are 2 Big Slices:

–Discrete Models–Continuous Models

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Kinds of Models

•Discrete event simulation•Made up of entities, attributes, and events

– Entity The representation of some object in the real system

– Attribute Some characteristic of a particular entity

– Event An interaction between entities

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Air Traffic – A Discrete Model

• Air Traffic in USA– Planes are

objects– Attributes

include speed– Events are

planes entering and leaving airspace

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Kinds of Models

• Continuous simulation

– Treats time as continuous

– Expresses changes in terms of a set of differential equations that reflect the relationships among the quantities in the model

– Meteorological models falls into this category

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Hurricanes – A Continuous Model

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A Continuous Models and FEA

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• Finite Element Analysis (FEA): Dividing a volume of space into small cubes, which contain our quantities of interest

• Many Continuous Models Use FEA

Queuing Systems

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Queuing Systems

Queuing system: A particular kind of discrete-event model

The system is made up of – Server objects– Clients objects– Queues of clients to be served

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Please Wait….

Queuing Systems

•Can you name at least three queuing systems that you interact with every day?

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Please wait!

Queuing Systems

• To construct a queuing model, we must know – The number of events and how they affect the system in

order to determine the rules of entity interaction

– The number of servers

– The distribution of arrival times in order to determine if an entity enters the system

– The expected service time in order to determine the duration of an event

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Queuing Systems

•Given a hypothetical service station, what are • the events?• the number of servers?•How can you determine• distribution of arrival time?• expected service time?

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Meteorological Models

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Weather – A Continuous Model

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Meteorological Models

Meteorological models •Models based on the time-dependent partial differential equations of fluid mechanics and thermodynamics•Initial values for the variables are entered from observation, and the equations are solved to define the values of the variables at some later time

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Meteorological Models

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How muchmath

does ittake tobe a

meteorologist?

Weather – A Continuous Model

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Hurricane Tracking

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Figure 14.2 Improvements in hurricane models

(GFDL) Geophysical and Fluid DynamicsLaboratory

Computational Biology

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Computational Biology

The application of computer science to problems in biology (or is it the other way around?? )

Encompasses:

• bioinformatics

• computational biomodeling

• molecular modeling

• protein structure prediction

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Computational Biology

•Bioinformatics• Discovering and Processing DNA sequences• Human Genome Project and Others

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Computational Biology

•Computational Biomodeling• The simulation of biological systems

Cell Wall Protein

Knees

Cell Metabolism

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Computational Biology

•Protein Structure Modeling• Simulating 3-Dimensional Structure and

Function of Protein Molecules

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Computational Biology

•Molecular Modeling• Simulating Structure and Function of Chemical

Molecules (usually drug discovery)

Graphics

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“Traditional” Graphics

•Technical or Engineering Graphics •Originally a language of communication for engineers, designers, and architects•Computer-Aided Design (CAD) •A system that uses computers with advanced graphics hardware and software to create precision drawings or technical illustrations

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Graphics for Computer Aided Design

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Figure 14.3 Geometric modeling techniques

Simulating Light

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Ray TracingThe projection of a 3-Dimensional model onto a 2-Dimensional computer screen

Simulating Light

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Illumination modelUsed to simulate the interaction of light with objects

Objects areShadedRendered

Fractal Techniques

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Modeling Complex Objects

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Whatgraphics

challengesare

inherentin

naturallandscapes

?

Figure 14.5 A natural computer generated landscape

Fractal Terrain

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Fractal terrains viaMidpoint subdivision(Fractal Mountains)

“Cell” Models

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Earth, Wind, Fire and Water

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•Cell-Based Models• Like continuous FEA models• Uses quantities and laws from physics• “How is a hurricane like a glass of water?”• Or a Cloud?• Or Fire?• Or Smoke?

Cell Models

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Figure 14.7 Water pouring into a glass

Cell Models

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Figure 14.8 Cellular automata-based clouds

Modeling Complex Objects

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Figure 14.9 A campfire

What do clouds, smoke andfire have in common?

Cell Models

Gaming

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Computer Gaming• A simulation of a virtual world• Usually based on the rules of our real world• Some rules can be bent• Some rules can be broken•

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Computer Gaming•Game designers need to know the LAYERS:

– Computer graphics– Artificial intelligence– Human-computer interactions and simulation– Software engineering (management of large complex

projects)– Computer security– Laws of physics relating to gravity, elasticity, light & sound

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Creating the Virtual World

•Game engine: •A software system within which games can be created (A tool to create games)

•Analogous to a compiler (A tool to create programs)

•(Similarly, some people write engines, some people write games)50

A Game Engine Provides

•A rendering engine for graphics•A physics engine for collision detection and dynamics•A sound-generating component•A scripting language apart from the code driving the game•Character Animations•Algorithms (e.g., path-finding algorithms)•Artificial intelligence algorithms (NonPlayerCharacters)

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Game Engine Scene Graphs• Where is your toothbrush?• Where did you park your car?• You use a Scene Graph to find these things in your

brain first

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• A way to store object locations and other data in memory

Soft Skills Needed

•High Quality Game Design and Development Requires Effective Use of “Soft Skills”:

• Effective collaboration with designers, programmers, and artists on various technical ideas throughout entire game design and development process

• Flexibility and adaptability as the game design constantly evolves and changes throughout the development and production process

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Game Programming

•After all the design decisions have been finalized, programmers produce the code to create the virtual world of the game

•Popular languages include: C++, Java, and C

•Some well-established game engineers have created custom languages based on their games, e.g., Epic Game’s UnrealScript for the Unreal Game

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Game Programming API’s and Platforms

•Application Programmers Interface (API): A set of commands used in a programming language to interface with another piece of software

•Game Engines provide APIs to help developers with key programming tasks

•Game Engines usually target a particular platform such as PC or Xbox or PlayStation, etc

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Game ProgrammingThe “Game Loop”

•Coding process begins with the creation of the “game loop”•Game loop is responsible for managing the game world, regardless of any input from the user•For example, the game loop might update enemy movement in the game or check for victory/loss conditions•Basically, the game loop manages the simulation

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Game ProgrammingTeams and Roles

•Large design teams have different programmers focus on different aspects of the game•Thus, you might find yourself working as: – A Junior Engine programmer writing and

maintaining code for the game loop or a– A 3D Software Programmer designing and

implementing the 3D graphics component or a– A User-Interface Programmer working on the APIs

in the game engine– Etc…

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