Strictly Confidential. Copyright © 2017 Electronic Arts DATA ORIENTED DESIGN IN GAMES Christian Dahlberg, Gameplay Engineer Strictly Confidential. Copyright © 2017 Electronic Arts GHOST GAMES > EA studio based in Gothenburg > Ghost made the three Last Need for Speed games > Worked on Far Cry 3, NFS and NFS Payback > Worked as a teacher at The Game Assembly Strictly Confidential. Copyright © 2017 Electronic Arts OBJECT ORIENTED DESIGN PROBLEMS > Started simple > Years has taught us the issues > Not scalable > Grows in complexity exponentially Rendering Physics IO Animations Objects Art Logic Game Scene Gameplay Strictly Confidential. Copyright © 2017 Electronic Arts REAL LIFE IS A BAD EXAMPLE > What are we taught in schools? > Create objects based on reality > Everything in an object in all functions of that object > To share functionality use inheritance > Interdependency between objects is synchronous > This is bad for games Strictly Confidential. Copyright © 2017 Electronic Arts DATA ORIENTED DESIGN > Create objects based on the data access of your systems > This stops the data complexity problem from growing as fast > Mike Acton – The purpose of all programs, and all parts of those programs, is to transform data from one form to another. > If you don’t understand the data you don’t understand the problem > The more data you have the more complex your problem is Strictly Confidential. Copyright © 2017 Electronic Arts ALL DATA AVAILABLE ALWAYS > When all data is available you can solve any problem in any function or object > This will scale poorly with team size Rendering Rendering Physics IO Physics IO Animations Objects System process Animations Objects Scene Gameplay Scene Gameplay Strictly Confidential. Copyright © 2017 Electronic Arts RACE CONDITIONS > When complexity is high you create race condition by accident all the time > Thread issues are hard to reproduce > Knowing the dependecy between threads is really difficult > Race conditions are very hard to find > We shipped with a lot of them(we can implement them in scripts) Strictly Confidential. Copyright © 2017 Electronic Arts REAL LIFE OBJECTS IN DATA ORIENTATION > All objects consist of of components > Every component is a class > The real life object only exists in data and not in your code Strictly Confidential. Copyright © 2017 Electronic Arts COMPONENT SYSTEMS IN GAMES > Components are sub-objects attached to Entities > Dependencies between components in the same game object is the tricky part > Memory traversal is harder to solve > Linear memory traversal Communication across coponents? Code objects aka classes Physics component Mesh Component Referenced by Id, Component to entity Entity Strictly Confidential. Copyright © 2017 Electronic Arts DOD NOT OOD > Start thinking about the data that is your first problem not what objects > Think about the following things: > What data do you need for your system to work? > What data do you want to be shared between systems? > How many objects are you operating on? > Is there any interdependency between objects? Strictly Confidential. Copyright © 2017 Electronic Arts SCRIPTING LANGUAGES > Be scared! in many scripting languages! > Creates race conditions if run on mutliple threads or across network Strictly Confidential. Copyright © 2017 Electronic Arts WHAT IS THE GAME INDUSTRY DOING? > Components as objects > Real world objects are only a data construct > Create scripts that can run in parallel Strictly Confidential. Copyright © 2017 Electronic Arts SMALL BESPOKE SYSTEMS > Small bespoke makes it flexible > Clearer interface > More effective > What can be done is more well defined > Dependencies are what a game have to implement > Ideally only data will be different between games > Keeps divergence with the base systems low Strictly Confidential. Copyright © 2017 Electronic Arts CONCLUSION > Don’t base your system on real life > What data is shared and which is not > How does your system traverse memory Strictly Confidential. Copyright © 2017 Electronic Arts WANT TO LEARN MORE? > https://www.youtube.com/watch?v=rX0ItVEVjHc - CppCon 2014: Mike Acton "Data-Oriented Design and C++“ > https://www.youtube.com/watch?v=p65Yt20pw0g - Unity at GDC - A Data Oriented Approach to Using Component Systems > https://www.youtube.com/watch?v=fHNmRkzxHWs CppCon 2014: Chandler Carruth "Efficiency with Algorithms, Performance with Data Structures" > https://www.youtube.com/watch?v=ZHqFrNyLlpA Hands on example from Jonathan Blow > http://www.dice.se/wp-content/uploads/2014/12/Introduction_to_Data- Oriented_Design.pdf Strictly Confidential. Copyright © 2017 Electronic Arts THANK YOU!.