1. Mafia II Bringing city to life Martin Brandstätter Jan Kratochvíl

2. Content Ideas for creating living city Filling city with elements Basics of artificial intelligence Specific examples: –Pedestrians –Traffic cars

3. Living city Full of life Variability No restrictions for player Seamless streaming

4. Filling city with elements Static geometry Grass, garbage, etc Translocated objects Pedestrians Cars

5. Empty street

6. Translocated objects Translocator Many types of objects –Lamps, chairs, benches –Billboards, neons, traffic signs, semaphores –Trees, shrubs –Action points, and more

7. Translocator Multiple grids Storing only GUID, position, rotation & scale High & Low range Spawn is not optional

8. Street with translocated objects

9. Pedestrian spawning Where to spawn? –Position –Visibility –Usability Spawn points –Kynapse nodes

10. Kynapse visualization

11. Pedestrian despawn When to despawn a Pedestrian? –Is too far away –Is not visible for too long –Is not in any action Line of death

12. Car Spawn Little bit more complicated Data from roadmap Three types –“Translocated” –Parked –Moving

13. Spawn in black area Annulus P

14. Egg P

15. Advanced Egg P

16. Spawn points example

17. Car despawn Reasons to get despawned: –Not visible and not moving towards player –Be too far away and out of sight Visible cars are never despawned Police has special rules

18. Empty street

19. Street with translocated objects

20. Final Street

21. ActionPoints Sidewalk graph with crossings Actionpoints Destructible Objects with ActionPoints

22. Basics of artificial intelligence Brain Hierarchy Black Board Messaging Basic Behaviours Behaviour tree Ai and Script Comunication

23. Brain Hierarchy Small Brain Base Brain Single Brain Human Brain Car Brain Boat Brain Train Brain Team Brain

24. Basic Behaviours brain object small parallel selector composite team behaviour

25. More Behaviours Desire Desire Commander Desire Composite Slave and mapping factory

26. selector commander Composite commander commander commander Parallel Slave Action 0 Action 1

27. Ai and Script Communication Designers demands –script running in parallel with AI –script running without AI –script running with some parts of AI

28. Script Configuration Alive Parallel ScriptParallel Action 0 Action 1 Main Selector Desire Script AI Desire 0 AI Desire 1

29. Script commands Lua Script Message New Command Move,Turn,Anim,.. Desire Script Parallel Script

30. Script wants Exclusive Control Lua Script Message Script Control TRUE Desire Script Parallel Script

31. Script Gains Exclusive Control Lua Script Message Script Control TRUE Desire Script

32. Script Returns Control to AI Lua Script Message Script Control FALSE Desire Script Parallel Script

33. AI Gains Exclusive Control Lua Script Message Script Control FALSE Desire Script

34. AI wants Exclusive Control Lua Script Message AI Control - Reason Selector Script

35. Civilian Archetype Archetype configuration Behavior sub-tree wander Action-Point scripts

37. Wander Configuration Wander Parallel Wander Selector Crossing AP Scan Get In car Special Desire Wander Around Wander Slave Wander Style

38. Driving Roadmap Wandering driver Hunter – police, gangster, … Escaper – taxi, gangster, mission car

39. Roadmap Catmull-Rom splines Whole city roadmap is about 400Kb –Including all necessary meta information No 3 rd party library Crossroads are defined using splines as well

40. Catmull-Rom spline Special case of cubic Hermit spline Relatively easy to compute Spline is going through its interpolation points Tangents are continuous over multiple segments

41. Roadmap

42. Basic driving 1.Interpolate some position before you 2.Set wheels to point at this position 3.Set speed to something 4.You are done

43. Speed Desired speed is influenced by –Behavior – traffic lights, crossings, follower, … –Obstacle –Curve Every “desire” can only lower the desired speed

44. Curve speed Iterative algorithm Input –Preferred deceleration –Centripetal acceleration –Expected braking distance –Max speed

45. Curve speed ca – centripetal acceleration cr – curve radius L – segment length

46. Behavior speed Example: stop before crossing d – distance to crossing a – preferred deceleration of car

47. Obstacle speed Obstacle detection –Subdivision queries – no static scene Detection ahead on desired path Avoid obstacle if possible and desirable Adjust speed to obstacle speed Aggressiveness playing its role

48. Navigation point Interpolation on spline Shift to fit correct lane Random shift Obstacle shift

49. Navigation points

50. Crossroad Team AI Priority for each car Main roads Traffic lights Aggression & green wave

51. Crossroad

52. Hunter Police & gangsters Need to go off roadmap Player drops info behind him Need of collision scene tests

53. Escaper Special case of wandering car May be aggressive Crossroad trespassing is not random Has to ensure that he will reach its destination

54. Special behaviors Avoiding special cars Jam detector Collision detector Horn reaction …

55. Q&A