1. Object Oriented Design

2. Goals  Feedback homework 8  Top Down Design: analyzing the requirements  Bottom Up Design: refactoring fundamental OpenGL functionality

3. The makings of the glutplane  Assumption: runtime environment is set up u Windows: GL4Java*.dlls installed u Mac: GL4Java*.zips installed in MRJClasses  Find file “glutplane.java” and “glutplane.html”  Install compile/link time environment u Windows: add GL4Java.jar to classpath u Mac: add GL4Java*.zips to project

4. Tools  Basic level tools u Javac (part of Sun’s JDK) u Jikes: http://www.research.ibm.com/jikes/http://www.research.ibm.com/jikes/  IDEs u Jbuilder (Windows, OS X) u CodeWarrior (Windows, OS X, OS 9, …)

5. Modify source  Edit “glutplane.java”  Replace 3 calls to add_plane(); with 20 calls u Hint: use a “for” loop instead of typing add_plane(); 20 times!  Compile/run/test  Upload binary files (.class) and.html file to Web server u glutplane.class u glutplane$planeobj.class u glutplane$glutplaneCanvas.class  Test applet on server  email URL referring to html file.

6. More information  Provided by the Game Engine builders  http://schenkc.freeshell.org/classes/csci4448 /contra/installation.html http://schenkc.freeshell.org/classes/csci4448 /contra/installation.html  Chris Schenk: schenkc@freeshell.orgschenkc@freeshell.org  Luke Swanson: swansonl@colorado.eduswansonl@colorado.edu

7. Top Down Requirement Analysis  Collect what the different applications/games need to have from the Game Engine  Danger: u Getting carried away u Creating specification that cannot be implemented (in time, within budget, …)

8. Requirement for Game engine  Camera aimed at character u Multiple cameras  Shapes  Aggregate shapes  Rotation of shapes and camera  Collision detection IIII  Clipping  Physics II u Particles  Text  Infinite backgrounds (repetitive textures, sky domes, …)  Foreground/messages/score keeping

9. Camera Control  Multiple cameras u Switching between cameras: no gui  Camera tracking (stay on object)  zoom  Multiple views at the same time  Independent control of camera

10. Shapes  Box, sphere, circle, rectangle, plane, line, point, cylinder, triangle strip,  Single / aggregate shapes  Rotation  Move in scene  Add textures to shape  Loading models u Load.obj files

11. Collision Detection iii  Detect collision of shapes and groups of shapes  Approximation with u spheres u Cubes

12. Clipping  no

13. Physics  Particles  Airplanes, skis, bikes  Simple gravity (would be nice)

14. Text  no

15. Backgrounds  Flat but repetitive  Sky domes, Sky boxes

16. Information panels  Score keeper  Output message  Dialogs (hard) u Use OpenGL, Swing or AWT?  Menus (hard) u Use OpenGL, Swing or AWT?

17. Bottom Up system design  Refactor existing functionality (the OpenGL mega blob) into service classes  Approach: look at instances of applications containing functionality that could be factored out of the application into a the middle ware layer => the Game Engine  Danger: u Feature oriented: contrast between cool and necessary functions

18. Refactoring textured square example  Basic structure of OpenGL application is give by init, display, and reshape  Look for code that, in generalized form could be pushed into game engine  => collect these operations and attributes in a class called glWindow

19. INIT  Collect a set of good initializations that make sense for most applications  Turn most features ON (lighting, texture mode)  In worst case application can overwrite or extend INIT

20. DISPLAY  Refactor display method into u preDisplay:  low level initializations that most applications would need anyway, e.g, clearing buffer.  Translating, rotating individual objects u mainDisplay: leave this to application to specialize u postDisplay:  Cleanup, error handling  Buffer swapping (to implement double buffering)

21. Factor out utility functions  Example: texture manager  Replace complex implementations of texture loading with single calls of texture managing functions located in middle ware (game engine)

22. Produce new application with middleware stuff removed

23. Homework  PROJECT: u Finish game proposal document u Email to Alex & Andri u Due: November 12  READING: u OpenGL Red book chapter 3; Viewing u http://fly.cc.fer.hr/~unreal/theredbook/ http://fly.cc.fer.hr/~unreal/theredbook/ u Due: November 12