Game Production: game development

Transcription

1 Game Production: game development Fabiano Dalpiaz 1

2 Outline Lecture contents 1. Development team and tasks 2. Game dev vs. Software dev 3. Tooling 4. Game engines 5. Sub-disciplines 2

3 1. Development team and tasks Software development team Main roles Technical director Lead engineer Engineers (developers) Network (multiplayer) Sound Graphics Tools (for scripting, localization, game engine) Artificial Intelligence Developers are typically specialized At least in large projects Some generalists act as a glue For each subdiscipline, a lead developer may be defined The one that talks with the producer 3

4 1. Development team and tasks Team size Team size depends on the genre Action/adventure/online games require large teams AAA games require a massive amount of people Mobile and casual games need less people Indie games: very few and hard-working people Programming is often a smaller part of a project than the art/audio/model content creation Contractors may be included See lecture on planning and risk The size may vary over time 4

5 1. Development team and tasks Development teams: late 80s 1988, Sublogic s JET (an early flight simulator): 5 people Sublogic later made scenery for Microsoft's flight simulator 3 Programmers 1 Part-Time Artist 1 Tester 1989, Prince of Persia: 1 person Jordan Mechner You may want to read his book 5

6 1. Development team and tasks Development teams: Nineties 1995, Interplay's Descent: 11 people Used 3D polygon engine instead of 2D sprites 6 Programmers 1 Artist 2 Level Designers 1 Sound Designer Off-site Musicians 1996, Tomb Raider: 6 people It took 18 months to develop it Off-site musicians 6

7 1. Development team and tasks THQ s AlterEcho (2002): 19+ people 1 Executive Producer 1 Producer 4 Programmers 2 Game Designers 1 Writer 3 Level Designers 1 2D and Texture Artist 1 Audio Designer 3 Character Modelers and Animators 1 Cinematic Animator 1 QA Lead and Testers 7

8 1. Development team and tasks 2K s Bioshock, 90 developers, 30 contract Boston team Programmer: 1 Artists and Animators: 15, plus 2 borrowed from Firaxis Designers: 6 in-house, 1 contract Audio Developers: 2 in-house, 7 contract Producers: 3 in-house, 2 contract Testers: 13 contract, plus 8 on-site testers Australia team Programmers: 12, Artists And Animators: 10 Designers: 5, Audio Developer: 1, Producers: 2 Testers: 1 in-house, 7 contract Shanghai team Artists And Animators: 12 Designers: 3 8

9 1. Development team and tasks Recent games GTA V (2013) In total: 1000 people Only in Edinburgh: 360 Budget: $200M Sales (3 days): $1B FarmVille (2009) Developed in 5 weeks Core team size: 10 people Experienced people in the team Budget unknown Revenue (approx): $113M/year w-social-games-make-money-lessons-from-farmville.html 9

10 1. Development team and tasks Side-by-side comparison: tell the difference Assassin s Creed Revelation (2011) Fez (2012) 10

11 1. Development team and tasks Task 1: system design What is game development all about? Input: the requirements in the game design document Output: the actual game Don t dive into programming upfront Design the system first (e.g., via UML or others) Use cases Interaction diagrams Activity or state diagrams Class diagrams The design defines the architecture of the system Promotes modularity Fosters reuse 11

12 1. Development team and tasks Task 1: system design exemplified (static) 12

13 1. Development team and tasks Task 2: programming game code What to program? The game itself Camera behavior Score keeping AI for bots Often in scripting language Produce faster iterations that C++ or the alike Allow technical designers/artists to change behaviors More appropriate language for domain E.g., different languages for graphics and AI 13

14 1. Development team and tasks Task 2: programming game code Some events from a scripting language: COG 14

15 1. Development team and tasks Task 2: programming game code Some events from a scripting language: COG Used in the game Jedi Knight: Dark Forces 2 15

16 1. Development team and tasks Task 3: programming the game engine Support code that is not game specific More than just drawing 3D graphics That is actually the graphics engine, part of the game engine Isolate game code from hardware E.g., controller, graphics, sound Allows designers to concentrate on the game Common functionality needed across game Serialization Network communication Pathfinding Collision detection 16

17 1. Development team and tasks Task 4: programming support tools Many tools involve content creation Level editors Particle effect editors Sound editors Some automate repetitive tasks Convert content to game format Usually have no GUI Sometimes written as plug-ins for off-the-shelf tools Maya, 3dStudio, or Photoshop If no such extension is available, build from scratch 17

18 1. Development team and tasks Task 5: quality assurance Code reviews: examine code by other programmer(s) Asserts: force program to crash to help debugging Example: Check condition is true at top of code, say pointer not NULL before following Unit tests: a single unit of the game, often automated Acceptance tests: does high-level functionality work? Do levels load correctly? Bug tracking Document bugs, track their status, classify severity Helps see the game progress 18

19 2. Game dev vs. Software dev Results from a survey at Microsoft Survey with 300+ people at Microsoft working on games, MS Office, other products 1. Being able to communicate with non-engineers is highly valuable in my job Much more in games than office & other 2. My software is well tested by unit tests Much more in other 3. When I tell people outside of my company about the software I work on, they are impressed. More in games than office & other 19

20 2. Game dev vs. Software dev Results from a survey at Microsoft 4. My team uses a waterfall process, rather than an agile process. More in office and other than in games 5. Creativity is highly valued on my team More in games than in office and other 6. Creating my software requires a team of people, each with different skills More in games than in office and other 7. It's difficult to write thorough automated tests for my software because it's so complex. More in games than in other 20

21 2. Game dev vs. Software dev Results from a survey at Microsoft 8. My software has clear functional requirements More in office and other than in games 9. Most of the code I write is reviewed by other people. More in office than in games 10. My software creates value for society More in office than in games 11.My team adheres strictly to a process (for example, scrum or waterfall). More in office than in games 21

22 3. Tooling Game development is a socio-technical effort Social aspects Developers engage in a coordinated activity Proper interaction is needed to succeed Technical aspects Proper tooling is essential to deliver the game Tooling facilitates interaction, reuse, and quick development We have mentioned content creation tooling Music Graphics Level editing More tools are needed though! Any examples in mind? 22

23 3. Tooling Version control Enables managing changes to documents, programs, websites, etc. Every file has a revision number Support sharing and access control Enable concurrent work The shared version is kept on a server Developers keep local versions on their computer Basic operations Checkout: retrieve a project from the server Commit: upload files to server Update: get the latest version of a project Well-known tools CVS, Subversion (SVN), GIT, Mercurial 23

24 3. Tooling Centralized vs distributed version control 24

25 3. Tooling Bug tracking, a la Bugzilla 25

26 3. Tooling Bugzilla for Eclipse 26

27 3. Tooling Project management Keep track of the status of the project Are developers doing their task? What is the effect of late delivery? Suppose programmer A needs a module from programmer B Programmer B is 5 days late Programmer A may be stuck and waiting Task-based vs. issue-based Tasks come from the project plan Issues come from assigned bugs Most often, bug tracking is integrated with project mgmt See, e.g., Jira 27

28 3. Tooling Project management: Jira 28

29 3. Tooling Integrated development environment (IDE) Developer s productivity can be boosted by using an integrated development environment Main features Code Auto-completion Project management Support to code versioning Automated generation of documentations Code refactoring Graphical design of user interfaces Interactive debugger Plugins 29

30 3. Tooling IDE: Visual Studio in action 30

31 3. Tooling Which IDE? It depends on the programming language(s) Personal preference Development team constraints Some options Microsoft Visual Studio: C++, C# Eclipse: Java Different IDEs for different activities E.g., Eclipse for a conversion tool, Visual Studio for the game code, etc. BTW, some hardcore game programmers use less graphical IDEs, e.g., emacs 31

32 4. Game engines Don t build games from scratch! Different games share a lot of commonality Consist of objects Have AI, graphics, sound, Since the 80s (but more prominently in the 90s), game studios have been using game engines A system for the creation of a videogame Basic functionalities are embedded 2D/3D rendering Physics engine Sound Scripting Animation AI Networking Localization 32

33 4. Game engines Illustration 33

34 4. Game engines How a game engine works 34

35 4. Game engines Scripting languages Game engines do often make use of scripts Created using a scripting language Not compiled, interpreted Pros Ease of development (less technical programming) Low-level things taken care of (fewer errors) Faster iteration time (no full re-compile needed) Cons Worse debuggers Performance Interface with rest of the game (no export primitive) 35

36 4. Game engines Well-known game engines Game Maker: Studio Initially developed by a former colleague, Mark Overmars Widely used to develop 2D games Targets entry-level programmers Unity3D Fast-growing Very complete for 3D Unreal Engine (Perhaps) the best for 3D Gaining popularity due to a 2013 change in its business model 36

37 4. Game engines Unity in a open-source / freeware pipeline 37

38 4. Game engines What s in Unity? Integrated visual editor Graphics in DirectX or OpenGL Asset import Shaders Physics Terrain modeling + vegetation Audio + video Scripting Networking support Database connectivity Shadow & Light + particle emitters 38

39 4. Game engines Unity, conceptually 39

40 5. Sub-disciplines Specific disciplines within game development Game Physics Programmer AI Programmer Graphics Programmer Sound Programmer UI Programmer Input Programmer Network Programmer Game Tools Programmer Porting Programmer 40

41 5. Sub-disciplines Game physics Developers need good understanding of physics Processor cycles are at a premium Efficiency is key FPS games typically demand large teams of physics programmers Typically embodied in the game engine Newtonian physics Collision detection Particle systems (explosion, smoke, flowing water) 41

42 5. Sub-disciplines Artificial Intelligence Game behavior that is not player-controlled (NPCs) Strategy and tactics Pathfinding AI research is very advanced But AI techniques are typically customized in games Why? AI has to be adaptive Increasing difficulty with game progress (in arcades) adapt to the player 42

43 5. Sub-disciplines Artificial Intelligence: pathfinding The problem of pathfinding Given a graph G, an initial node I in G, and a goal/target node T in G Find the best path from I to T Best typically mean: minimize the number of traversed arcs The most prominent and used algorithm is A* Best-first search 43

44 5. Sub-disciplines Artificial Intelligence: behavior How to systematically make characters decide? And to define the game logics Hard-coded If-then-else Finite state machines Decision trees Rule-based systems Why not using if-then-else? Reuse Formal verification! 44

45 5. Sub-disciplines Graphics Programmers who specialize in developing and modifying complex 3D graphics 2D graphics abilities are still useful though Casual games Scarce in industry Demand high salaries Required knowledge in math Vectors and matrices Linear algebra 45

46 5. Sub-disciplines Sound Sound in games evolved considerably Very basic sounds (Pong) Background music BG + Foreground music Soundtracks 3D positional sound Required skill: digital signal processing The different sound streams have to be well-orchestrated 46

47 5. Sub-disciplines User interface User interfaces are crucial for playability Graphics knowledge 2D, 3D, transparency, animation, particle effects Usability Engineering knowledge Where are items best positioned? How to be non-intrusive? Bad example: Oblivion s inventory (see next slide) what s wrong here? 47

48 5. Sub-disciplines User interface: Oblivion 48

49 5. Sub-disciplines User interface: Oblivion Oblivion was ported to PC, but remained a controller-focused UI Wasted space (21% of the screen only is for the inventory, with 1920x1080) Windows are not adjustable Only six items a time No shortcuts 49

50 5. Sub-disciplines Input The code that determines how the player will use the input devices Traditional input devices Controller Joystick Keyboard & Mouse Advanced input devices Wii controller Kinect Processing data is harder Adhere to standards! Don t use W to indicate reverse 50

51 5. Sub-disciplines Network The code that allows players to play the game on a LAN and or on the internet Very important in Massively Multiplayer Online (MMO) Latency control is especially important Slower connections shall be supported too Must be efficient The challenge of time synchronization Which architecture? 51

52 5. Sub-disciplines Game tools Code to handle auxiliary tasks Scripting Converting art Batches Modifying the game and levels They significantly boost development efficiency Or slow it down, if poorly engineered Typically, many of these tools are within a game engine Game-specific tools are to be programmed Required experience depends on the tool type 52

53 5. Sub-disciplines Porting These days, you want most games to be available on all (or as many as possible) platforms Exception: exclusive agreement You don t want to rebuild the game How hard is it? It depends on the game type Game engines do support porting but what if you customize a game engine? Easier for 2D casual games 53

54 5. Sub-disciplines Lead programmer Keeps the programmers focused, and on track Quite often a middle man between the client and programmers Should have a general base knowledge of all aspects of the game Sound Graphics Networking Etc. 54

55 References Mandatory 1. Murphy-Hill, Emerson, Thomas Zimmermann, and Nachiappan Nagappan. "Cowboys, ankle sprains, and keepers of quality: how is video game development different from software development?." Proceedings of the 36th International Conference on Software Engineering. ACM, Kasurinen, Jussi, Andrey Maglyas, and Kari Smolander. "Is requirements engineering useless in game development?." Requirements Engineering: Foundation for Software Quality. Springer International Publishing,

56 References Other This material is based on The game development process course held at Worcester Polytechnic Institute in 2006: df Animation and Games Development course held at Prince of Songkla University in 2012 V.M. Larios, F. Gonzales, K. Sung. Open source and freeware tools for 3D games development courses. CIGCSE 2011 Workshop 5 Holistic Game Development with Unity by Penny Byl, Focal Press,