“We’ve Got Game!” Teaching and Researching Computer Games at WPI

1. “We’ve Got Game!”Teaching and Researching Computer Games at WPI Mark Claypool Assistant Professor Computer Science Department Worcester Polytechnic Institute Worcester, MA, USA http://www.cs.wpi.edu/~claypool

2. Outline • Interactive Media and Game Development • Aspects of Networking • Latency and Warcraft III Gamestock, WPI, Worcester, MA, USA

3. A Proposal for a New Major Interactive Media and Game Development David Finkel, Computer Science Frederick Bianchi, Humanities and Arts Mark Claypool, Computer Science Michael Gennert, Computer Science Patrick Quinn, Humanities and Arts

4. Opportunity • Games are growing • In 2000, U.S. economy grew by 7% while computer game industry grew by 15% (International Digital Software Association, 2001) • 60% of Americans age 6+ play computer games (International Digital Software Association, 2001) • 221+ million computer games sold in 2002 • 2 games for every household in America • Exact labor statistics are difficult to obtain • But indicators are that game companies are hiring • Recent ad by Electronic Arts say “triple digits” • Not many 4-year technical degree programs Gamestock, WPI, Worcester, MA, USA

5. Related Programs • Over 60 different academic programs (Game Developer’s Magazine, Game Career Guide 2003) • Many at art schools (no technical component) • Many certificate or 2-year programs • CMU offers MA in Entertainment Technology • SMU offers 18-month certificate (Guildhall) • USC announced minor in game development • Few full undergraduate majors at 4-year universities Gamestock, WPI, Worcester, MA, USA

6. A Proposal for a New Major • A Proposal • Offered with many existing courses • Some new, core courses • Offered with many existing resources • Some new dedicated faculty • Some new gaming labs • Benefits of • Attracting new students • Solidifying education of game developers • Future extension to minor and graduate programs Gamestock, WPI, Worcester, MA, USA

7. The Undergraduate Major • Based on: • IGDA Curriculum Framework (Feb 2003) • Examination of other programs • Consultation with GDC, other academics, administration, marketing … • Core courses with fundamental ideas for game development • Two tracks: • Technical • Artistic • Emphasize well-rounded B.S. with game development strength Gamestock, WPI, Worcester, MA, USA

8. Core Courses • Critical Game Studies • Non-technical study of use, history, and industry of games. Develop vocabulary, analyze merits and tools and why some games are successful. • Game Development Process • Discuss roles of participants, artistic and technical. Importance of testing and play testing. Students will develop games or parts of games. • Social Issues in Game Development • Human need for play, philosophy of games, social interactions in multiplayer games, role of violence and ethical and legal issues for games Gamestock, WPI, Worcester, MA, USA

9. Technical Track • 3 core courses • 5 math (Lin Alg, Prob and Stats) • 3 science (Physics and Bio) • 11 computer science (HCI, Soft Eng, Arch, Networks, Graphics, Animation, AI) • 2 advanced technical • 3 humanities (Writing, Studio Art) • Sufficiency, IQP, MQP Gamestock, WPI, Worcester, MA, USA

10. Artistic Track • 3 core courses • 2 science (Physics and Bio) • 1 math • 3 writing • 3 studio art • 2 computer art • 2 drama or music • Sufficiency, IQP, MQP Gamestock, WPI, Worcester, MA, USA

11. Advanced Courses • Two Technical • Programming of games, 2d and 3d game engines, sound and music implementations, networking, latency compensation… • Artistic • Visual arts, music, sound and writing for game play, aspects of interactivity… Gamestock, WPI, Worcester, MA, USA

12. Resources Required • Directors for technical an artistic tracks • Could be appointed from WPI faculty • Three (new) dedicated faculty • 2 in Humanities • 1 in Computer Science • Game development environment • Software (develop some in-house) • Equipment (general and special purpose) • Space Gamestock, WPI, Worcester, MA, USA

13. Spring 2004 Approval by administration and faculty If successful … Summer 2004 Prepare core courses Academic year2004-2005 Core course offerings (experimental) Marketing Development of game laboratory Summer 2005 Advance course preparation Academic year 2005-2006 All new courses in place New major in place New tenure-track faculty hired Academic year 2007+ Minor, grad program, additional faculty … When Might This All Happen? Gamestock, WPI, Worcester, MA, USA

14. Outline • Interactive Media and Game Development • Aspects of Networking • Network Resource Limitations • Compensation Techniques • Security and Cheating • Latency and Warcraft III Gamestock, WPI, Worcester, MA, USA

15. Network Resource Limitations • Distributed simulations face three resource limitations • Network bandwidth • Network latency • Host processing power (to handle network) • Physical restrictions that the system cannot overcome • Must be considered in the design of the application (More on each, next) Gamestock, WPI, Worcester, MA, USA

16. Capacity • Data sent/received per time • LAN – 10 Mbps to 10 Gbps • Limited size and scope • WANs – tens of kbps from modems, to 1.5 Mbps (T1, broadband), to 55 Mbps (T3) • Potentially enormous, Global in scope • Number of users, size and frequency of messages determines capacity • As does transmission technique • Multicast, Unicast, Broadcast Gamestock, WPI, Worcester, MA, USA

17. Latency • Delay when message sent until received • Variation (jitter) also matters • Cannot be totally eliminated • Speed of light propagation yields 25-30 ms across Atlantic • With routing and queuing, usually 80 ms • Application tolerances: • File download – minutes • Web page download – up to 10 seconds • Interactive audio – 100s of ms • MCG latencies tolerance depends upon game • First-Person Shooters – 100s of ms • Real-Time Strategy – up to 1 second • Other games Gamestock, WPI, Worcester, MA, USA

18. Computational Power • Processing to send/receive packets • Most devices powerful enough for raw sending • Can saturate LAN • Rather, application must process state in each packet • Especially critical on resource-constrained devices • i.e.- hand-held console, cell phone, PDA, Gamestock, WPI, Worcester, MA, USA

19. Outline • Interactive Media and Game Development • Aspects of Networking • Network Resource Limitations • Compensation Techniques • Security and Cheating • Latency and Warcraft III Gamestock, WPI, Worcester, MA, USA

20. Data and Control Architectures • Want consistency • Same state on each node • Needs tightly coupled, low latency, small nodes • Want responsiveness • More computation locally to reduce network • Loosely coupled • In general, cannot do both. Tradeoffs. Gamestock, WPI, Worcester, MA, USA

21. Networked Multiplayer Game Architectures • Centralized • Use only two-way relay (no short-circuit) • One node holds data so view is consistent at all times • Lacks responsiveness • Distributed and Replicated • Allow short-circuit relay • Replicated has copies, used when predictable (ie- non-player characters) • Distributed has local node only, used when unpredictable (ie- players) • May be inconsistent Gamestock, WPI, Worcester, MA, USA

22. Interest Management – Auras • Nodes express area of interest to them • Do not get messages for outside areas • - Only circle sent even if • world is larger. • Can implement with • square to make simpler Gamestock, WPI, Worcester, MA, USA

23. Interest Management- Focus and Nimbus • nimbus must intersect with focus to receive • Example: Hider has smaller nimbus, so Seeker • cannot see, while Hider can see Seeker since • Seeker’s nimbus intersects Hider’s focus Gamestock, WPI, Worcester, MA, USA

24. (predicted position) (“warp”) (actual position) Dead Reckoning • Based on ocean navigation techniques • Predict position based on last known position plus direction • Can also only send updates when deviates past a threshold • When prediction differs, get “warping” or “rubber-banding” effect Gamestock, WPI, Worcester, MA, USA

25. Security and Cheating • Unique to games • Other multi-person applications typically don’t have same type of cheating problems • Cheaters want: • Vandalism – create havoc (relatively few) • Dominance – gain advantage (more) Gamestock, WPI, Worcester, MA, USA

26. Packet and Traffic Tampering • Reflex augmentation - enhance cheater’s reactions • Example: aiming proxy monitors opponents movement packets, when cheater fires, improve aim • Packet interception – prevent some packets from reaching cheater • Example: suppress damage packets, so cheater is invulnerable • Packet replay – repeat event over for added advantage • Example: multiple bullets or rockets if otherwise limited Gamestock, WPI, Worcester, MA, USA

27. Preventing Packet Tampering • Cheaters figure out by changing bytes and observing effects • Prevent by MD5 checksums (fast, public) • Still cheaters can: • Reverse engineer checksums • Attack with packet replay • So: • Encrypt packets • Add sequence numbers (or encoded sequence numbers) to prevent replay Gamestock, WPI, Worcester, MA, USA

28. Information Exposure • Allows cheater to gain access to replicated, hidden game data (i.e. status of other players) • Passive, since does not alter traffic • Example: defeat “fog of war” in RTS, see through walls in FPS • Cannot be defeated by network alone • Instead: • Sensitive data should be encoded • Kept in hard-to-detect memory location • Centralized server may detect cheating (example: attack enemy could not have seen) • Harder in replicated system, but can still share Gamestock, WPI, Worcester, MA, USA

29. Outline • Interactive Media and Game Development • Aspects of Networking • Latency and Warcraft III Gamestock, WPI, Worcester, MA, USA

30. The Effects of Latencyon User Performance in Warcraft III Nathan Sheldon, Eric Gerard, Seth Borg, Mark Claypool, Emmanuel Agu ACM NetGames Workshop Redwood City, CA, USA May 2003 http://www.cs.wpi.edu/~claypool/papers/war3/

31. Why Study Warcraft III? • Top selling computer game genres • Strategy (27.4%) • Children’s (15.9%) • Shooter (11.5%) • Family Entertainment (9.6%) • Warcraft III set sales record • Fastest to sell 1 million copies “Top Ten Industry Facts”, Interactive Digital Software Association, May 2003. “Warcraft III - Shatters Sales Records Worldwide...”, Blizzard Press Release, October 2002 Gamestock, WPI, Worcester, MA, USA

32. Network Games and Latency • Latency degrades performance of interactive applications • Web-browsing – seconds • Internet phone – 100’s of milliseconds • First Person Shooters (FPS) – 100’s of milliseconds • Real-Time Strategy (RTS)? • Knowing effects of latency useful for • Building better network games • Building better networks to support games (QoS)  Effects of Latency on Warcraft III (RTS) Gamestock, WPI, Worcester, MA, USA

33. Outline • Introduction  • Experiments  • Analysis • Conclusions Gamestock, WPI, Worcester, MA, USA

34. Warcraft III Overview • RTS User Interaction • Components: • Exploration • Building • Combat Gamestock, WPI, Worcester, MA, USA

35. Exploration Map • Performance? • Time • (to reach end) Gamestock, WPI, Worcester, MA, USA

36. Building Map • Performance? • Time • (to build tech- • nology tree) Gamestock, WPI, Worcester, MA, USA

37. Combat Map • Performance? • Games Won • Unit Scores Gamestock, WPI, Worcester, MA, USA

38. Controlling Latency • Warcraft III uses client-server • Set computer B as server (also a client) • Set computer C or D as client • NIST Net on computer A • Induce latency [0 ms to 3500 ms] Gamestock, WPI, Worcester, MA, USA

39. Outline • Introduction  • Experiments  • Analysis • Application Level • Network Level • User Level • Conclusions Gamestock, WPI, Worcester, MA, USA

40. Building and Latency Gamestock, WPI, Worcester, MA, USA

41. Exploration and Latency Gamestock, WPI, Worcester, MA, USA

42. Combat and Latency (1) Gamestock, WPI, Worcester, MA, USA

43. Combat and Latency (2) Gamestock, WPI, Worcester, MA, USA

44. Outline • Introduction  • Experiments  • Analysis • Application Level  • Network Level  • User Level • Conclusions Gamestock, WPI, Worcester, MA, USA

45. Bandwidth 3.8 Kbps 4.0 Kbps 6.8 Kbps Gamestock, WPI, Worcester, MA, USA

46. Inter-Packet Times Gamestock, WPI, Worcester, MA, USA

47. Payload Distributions Gamestock, WPI, Worcester, MA, USA

48. Payload Distributions and Latency Gamestock, WPI, Worcester, MA, USA

49. Commands and Latency • Pilot studies suggest 6 bytes of overhead per command • Remove 6 bytes from each packet payload • Add up remaining command payloads Gamestock, WPI, Worcester, MA, USA

50. Outline • Introduction  • Experiments  • Analysis • Application Level  • Network Level  • User Level  • Conclusions Gamestock, WPI, Worcester, MA, USA