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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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