53425-计算机科学概论原书chapter

1、Chapter 14Simulation, Graphics and Other Applications2Chapter GoalsDefine simulationGive examples of complex systemsDistinguish between continuous and discrete event simulationExplain how object-oriented design principles can be used in building models3Chapter GoalsName and discuss the four parts of

2、 a queuing systemExplain the complexity of weather and seismic modelsDescribe the important issues in graphics image generation4Chapter GoalsExplain the additional concerns for animation versus single imagesDescribe the important issues in computer gaming5What Is Simulation?Simulation A model of a c

3、omplex system and the experimental manipulation of the model to observe the resultsSystems that are best suited to being simulated are dynamic, interactive, and complicatedModel An abstraction of a real systemIt is a representation of the objects within the system and the rules that govern the inter

4、actions of the objects6Constructing ModelsContinuous simulation Treats time as continuous Expresses changes in terms of a set of differential equations that reflect the relationships among the set of characteristicsMeteorological models fall into this category7Constructing ModelsDiscrete event simul

5、ationMade up of entities, attributes, and eventsEntity The representation of some object in the real system that must be explicitly definedAttribute Some characteristic of a particular entityEvent An interaction between entities8Queuing SystemsQueuing system A discrete-event model that uses random n

6、umbers to represent the arrival and duration of eventsThe system is made up of servers queues of objects to be servedPlease wait!9Queuing SystemsCan you name at least three queuing systems that you interact with every day?Please wait!10Queuing SystemsTo construct a queuing model, we must know The nu

7、mber of events and how they affect the system in order to determine the rules of entity interactionThe number of serversThe distribution of arrival times in order to determine if an entity enters the systemThe expected service time in order to determine the duration of an event11Queuing SystemsGiven

8、 a hypothetical service station, what are the events?the number of servers?How can you determinedistribution of arrival time?expected service time?12Meteorological ModelsMeteorological models Models based on the time-dependent partial differential equations of fluid mechanics and thermodynamicsIniti

9、al values for the variables are entered from observation, and the equations are solved to define the values of the variables at some later time13Meteorological ModelsHow muchmathdoes ittake tobe a meteorologist?14Meteorological ModelsComputer models are designed to aid the weathercaster, not replace

10、 him or herThe outputs from the computer models are predictions of the values of variables in the futureIt is up to the weathercaster to determine what the values mean15Meteorological ModelsRelocatable modelsModels applied to a moving targetCan you think of an example?What is special about weather m

11、odels?16Hurricane TrackingFigure 14.2 Improvements in hurricane models(GFDL) Geophysical and Fluid DynamicsLaboratory17Computational BiologyAn interdisciplinary field that applies techniques of computer science, applied mathematics, and statistics to problems in biology passes bioinformatics, comput

12、ational biomodeling, computational genomics, molecular modeling, and protein structure prediction.Can you think of some recent successes?18GraphicsGraphics Originally the language of communications for engineers, designers, and architectsComputer-aided design (CAD) A system that uses computers with

13、advanced graphics hardware and software to create precision drawings or technical illustrations What does the term pass today?19Graphics Figure 14.3 Geometric modeling techniquesA. ArtyFree/ShutterStock, Inc.; B. Stephen Sweet/ShutterStock, Inc.;20GraphicsHow does light work?Figure 14.4 The normal (

14、N), light (L), and Reflection (R) vectors21GraphicsShape and surface influence an objectsappearanceEquations used to describe planes, spheres,and cylindersReal world surfaces are rough, which scatter light differently, requiring texture mappingtechniques22GraphicsIllumination modelSimulation of ligh

15、t interaction at one pointon an objectShading model (shading)Process of using an illumination model to determine the appearance of an entire objectRenderingThe process of creating an entire imageWhat istheproblemwiththismodel?23Modeling Complex ObjectsWhatgraphicschallengesare inherentin naturalland

16、scapes?Figure 14.5 A natural computer generated landscapeReproduced from Oliver Deussen, et al., “Realistic Modeling and Rendering of Plant Ecosystems.” SIGGRAPH (1998): 275-286. 1998 AMC, Inc. Reprinted by permission. 24Modeling Complex ObjectsFigure 14.6 Midpoint subdivisionfor creating fractal te

17、rrains 25Modeling Complex ObjectsFigure 14.7 Water pouring into a glassReproduced from Douglas Enright, et al., “Animation and Rendering of Complex Water Surfaces.” SIGGRAPH 21 (2002): 275-286. 2002 AMC, Inc. Reprinted by permission. 26Modeling Complex ObjectsFigure 14.8 Cellular automata-based clou

18、dsWhatmathematicaltechniqueis usedinmodelingcloudformation?Reproduced from Yoshinori Dobashi, et al., “A Simple, Efficient Method for Realistic Animation of Clouds.” SIGGRAPH (2000): 19-28. 2000 AMC, Inc. Reprinted by permission. 27Modeling Complex ObjectsWhat do smoke andfire have in common?Reprodu

19、ced from Duc Quang Nguye, et al., “Physically Based Modeling and Animation of Fire.” SIGGRAPH (2002): 721-728. 2002 AMC, Inc. Reprinted by permission. Reproduced from Ronald Fedkiw, et al., “Visual Simulation of Smoke.” SIGGRAPH (2001): 15-22. 2001 AMC, Inc. Reprinted by permission. 28Modeling Compl

20、ex ObjectsFigure 14.11 A simulation of cloth showing ending and drapingCourtesy of Robert Bridson. 2004 Robert Bridson.29Modeling Complex ObjectsWhat is the most difficult object to model?What is the next step up in complexity?Computer GamingComputer gaming is a simulation of a virtual worldGame des

21、igners must have knowledge of the following to make people, objects, and environments behave realistically in a virtual world:Computer graphicsArtificial intelligence puter interactions and simulationSoftware engineeringComputer securityFundamentals of mathematicsLaws of physics relating to gravity,

22、 elasticity, light, and sound30GameplayGameplay: The type of interactions and experiences a player has during the gameGame genres, based on gameplay, include:Action gamesShooter gamesAction-adventure gamesLife-simulation gamesRole-playing gamesStrategy games31Creating the Virtual WorldGame engine-a

23、software system within which games can be created Following functionality provided by tools of a game engine: A rendering engine for graphics A physics engine to provide a collision detection system and dynamics simulation A sound-generating component32Creating the Virtual WorldAdditional functional

24、ity resulting from tools of a game engine:A scripting language apart from the code driving the gameAnimationArtificial intelligence algorithms (e.g., path-finding algorithms)A scene graph that holds the spatial representation in a graphical sense33Soft SkillsHigh Quality Game Design and Development

25、Requires Effective Use of “Soft Skills”: Effective collaboration with designers, programmers, and artists on various technical ideas throughout the entire game design and development process Flexibility and adaptability as the game design constantly evolves and changes throughout the development and

26、 production process 34Soft SkillsWillingness to abandon much of the completed design work when the games story line, mechanics, art, programming, audio, video, and/or scripting requires significant changes 35Game ProgrammingAfter all the design decisions have been finalized, programmers produce the

27、code to create the virtual world of the gamePopular languages include: C+, Java, and C Some well-established game engineers have created custom languages based on their games, e.g., Epic Games UnrealScript for the Unreal Game36Game Programming A variety of application programming interfaces (APIs) a

28、nd libraries are available to help developers with key programming tasksThe choice of API determines which vocabulary and calling conventions the programmer should employ to use the servicesThe target game platform determines which service the programmer will use; some libraries permit efficient cro

29、ss-platform development37Game ProgrammingCoding process begins with the creation of “the game loop”Game loop is responsible for managing the game world, regardless of any input from the userFor example, the game loop might update enemy movement in the game or check for victory/loss conditionsBasical

30、ly, the game loop manages the simulation38Game ProgrammingLarge design teams have different programmers focus on different aspects of the gameThus, you might find yourself working as: A Junior Engine programmer writing and maintaining code for the game loopA 3D Software Programmer designing and implementing the 3D graphics component A User-Interface Programmer working on the APIs in the game engine39Game ProgrammingCollab