1. Invitation to Computer Science 5th Edition
Chapter 16
Computer Graphics and Entertainment: Movies, Games, and Virtual Communities

2. Objectives In this chapter, you will learn about:
Computer-generated imagery (CGI)
Video gaming
Multiplayer games and virtual communities
Invitation to Computer Science, 5th Edition

3. Introduction Computer-based entertainment
A $15–20 billion industry
By the start of the twenty-first century:
Entertainment had become an application that stands alongside traditionally “important” uses of computers
Invitation to Computer Science, 5th Edition 3

4. Computer-Generated Imagery (CGI)
Advantages
Can produce extremely high-quality, lifelike images, called photorealistic animation
Can generate images that are prohibitively expensive to produce manually
Without it, directors would either have to:
Hire thousands of extras
Animate the scenes by hand, or
Produce thousands of miniature models
Invitation to Computer Science, 5th Edition 4

5. How It’s Done: The Graphics Pipeline
Sequence of operations that must be completed successfully to produce a realistic three-dimensional image
Invitation to Computer Science, 5th Edition

6. Figure 16.2 A Simplified Three-Stage Graphics Pipeline
Invitation to Computer Science, 5th Edition

7. Object Modeling First step in generating a three-dimensional image
Creation of a mathematical or computational model of a three-dimensional object that:
Can be stored in memory and manipulated algorithmically
Invitation to Computer Science, 5th Edition

8. Figure 16.3 Wireframe Model of a Dolphin (based on image in Wikipedia entry on polygon meshes)
Invitation to Computer Science, 5th Edition

9. Figure 16.4(a) Tesselation Producing Three Triangles and Five Vertices
Invitation to Computer Science, 5th Edition

10. Figure 16. 4(b) Vertex List Representation of the Model in Figure 16
Figure 16.4(b) Vertex List Representation of the Model in Figure 16.4(a)
Invitation to Computer Science, 5th Edition

11. Object Motion Rigid motion Transformation matrix Advantage of CGI
Motion that does not bend or deform an object
Types: translation, rotation, and reflection
Transformation matrix
Mathematical structure used to implement motions
Advantage of CGI
Computer can perform many of the required operations without the assistance of a human designer
Invitation to Computer Science, 5th Edition

12. Figure 16.5 The Three Types of Rigid Motion
Invitation to Computer Science, 5th Edition

13. Figure 16.6 Using Matrix Multiplication to Implement Object Translation
Invitation to Computer Science, 5th Edition

14. Object Motion (continued)
Keyframing
Human animator only needs to produce:
The first frame, containing the starting location of the object
The last frame, containing the final location of the object
The elapsed time
Control point
Point or axis used to control the motion of an object
Invitation to Computer Science, 5th Edition

15. Figure 16.7 Example of a Translation Performed on the Object Shown in Figure 16.4(a)
Invitation to Computer Science, 5th Edition

16. Figure 16.8 Figure-8 Object
Invitation to Computer Science, 5th Edition

17. Rendering and Display Rendering
Taking an object stored as a mathematical model and converting it into a fully formed, visually pleasing three-dimensional image
Often consumes the vast majority of computer time required to produce an image
Invitation to Computer Science, 5th Edition

18. Rendering and Display (continued)
Issues addressed during the rendering process
Lighting
Color shading
Shadows
Texture mapping
Blur
Algorithms for carrying out rendering operations
Ray tracing, rasterization, and radiosity
Invitation to Computer Science, 5th Edition

19. Figure 16.10 Three Light Sources Illuminating Triangle T
Invitation to Computer Science, 5th Edition

20. Figure 16.11 Converting an Image to a Two-Dimensional Representation
Invitation to Computer Science, 5th Edition

21. The Future of CGI Parallel and multicore computers Computer scientists
Are becoming more common
Allow computers to overcome Moore’s law and continue to gain in speed
Computer scientists
Are discovering newer and better algorithms for such common CGI operations as modeling, animation, and rendering
Invitation to Computer Science, 5th Edition

22. Video Gaming
A movie is a static environment that is created once and shown as often as desired
A video game is a highly interactive environment
Real-time graphics
Branch of computer graphics that studies methods for creating images at a rate matching that of the real world
Graphics Processing Unit
Common technique for increasing imaging speed
Invitation to Computer Science, 5th Edition

23. Figure 16.12 Typical Architecture of a GPU and Video Memory
Invitation to Computer Science, 5th Edition

24. Video Gaming (continued)
To achieve speedup in real-time graphics:
Avoid the use of algorithms that simply take too much time
Culling
Used to speed up rendering and display
Cut-ins
Fully modeled and fully rendered objects stored in a video library in video memory
Invitation to Computer Science, 5th Edition

25. Multiplayer Games and Virtual Communities
Massively multiplayer on-line games (MMOG)
Allow a large number of players to interact, form groups, and compete against one another within a simulated virtual world
Game servers
Special computers used to manage simulated virtual world
In an MMOG:
The virtual world in which the game is played is persistent
Invitation to Computer Science, 5th Edition

26. Multiplayer Games and Virtual Communities (continued)
Client software
Users log on to the game server
MMOG must address and solve the following technical problems
Registration management
Client/server protocols
Security
Database design
Invitation to Computer Science, 5th Edition

27. Figure 16.13 Architecture of an MMOG
Invitation to Computer Science, 5th Edition

28. Multiplayer Games and Virtual Communities (continued)
Noncompetitive MMOG
Simulated virtual world where the goal is not to destroy your opponent or get the highest score
Purpose of entering this metaverse is to:
Explore the virtual world
Interact with other people in the world
Form communities of residents with similar interests
Create new economic entities that have (virtual) value
Invitation to Computer Science, 5th Edition

29. Summary Computer-based entertainment Object modeling Rigid motion
A $15–20 billion industry
Object modeling
First step in generating a three-dimensional image
Rigid motion
Motion that does not bend or deform an object
Rendering
Often consumes the vast majority of computer time required to produce an image
Invitation to Computer Science, 5th Edition

30. Summary (continued) Graphics Processing Unit Noncompetitive MMOG
Common technique for increasing imaging speed
Noncompetitive MMOG
Simulated virtual world where the goal is not to destroy your opponent or get the highest score
Invitation to Computer Science, 5th Edition