predictive movement in multiplayer games
TRANSCRIPT
Predictive Movement in Multiplayer Games
Jobe [email protected]
@jobemakar
http://www.electrotank.com/lab/FATC/Files.zip
THANK YOU FATC COMMUNITY!!!
Predictive Movement in Multiplayer Games
• Real-time movement• Multiplayer concepts• Smoothing / latency Hiding• Clock synchronization• Predictive movement• How this affects game design
…and what we won’t cover
Tank Game
Wireless network: Electrotank_demo
No password
http://192.168.1.106/
Tank Game
• Prediction and smoothing in this game• Tank movement• Shots• Collisions
• Things not predicted or smoothed• Powerup collecting• Exploding tank
Multiplayer Games and Socket Servers
• Multiplayer game refresher• Persistent connection• Rooms• Extensions
Real-time movement
• Avatar in a virtual world• Character in FPS• Vehicle in a driving game• Bullet
Making it multiplayer
• Here I am• Way points• Heading• Role of client vs server
Blob Bros
• Real-time coop game• Uses ‘Here I am’ technique
Elysium
• Virtual world• Uses way points
Smoothing & latency hiding
• Examples of why it is needed• Smoothing types
Smoothing & latency hiding
• Here I am example – no diagram
Smoothing & latency hiding
• Bullet example
Smoothing & latency hiding
• Car example
Smoothing & latency hiding
• Its all about good user experience• Smoothing types
• Easing – frame-based• Convergence – time-based
Synchronizing clocks
• Ping = round trip time• Latency = Ping / 2• Syncrhonizing clocks means finding the latency
Synchronizing clocks
• Take 5-10 data points• Throw out values > 1.5 the median value• Average what remains
Synchronizing clocks
• Clock class• _clock.time
Predictive movement
• Prediction is the easy part• Using heading• Scheduled events
Predictive movement
• Heading• Starting position• Starting velocity• Acceleration information
v = v0 + ½*a*t^2x = x0 + vx*ty = y0 + vy*t
Predictive movement
• Scheduled events• Door opening• Explosion due to grenade• Gun shot if there is lead up animation
Smoothing and latency hiding revisited
• Convergence – more on this in a moment• Lead up animation• Some combination• Sometimes nothing needed: customizing avatar
Smoothing and latency hiding revisited
• Convergence• Uses heading for prediction• Choose an algorithm for smoothing
Smoothing and latency hiding revisited
Smoothing and latency hiding revisited
• Converger class• Uses Heading class• Uses linear accel / decel algorithm for smoothing• Show example usage
Converger class limitations
• Acceleration locking• Rotation smoothing• Smoothing is linear
Game design knowing technical limitations
• Making a good game choice• Car – accel/decel• Make character-character interactions indirect
