Term
| Understand what a snapshot is in gaming terms. |
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Definition
| how often we send the game state to the clients
"snapshot is a complete state that reflects the most current aspects of the game. includes:
Player and/ or unit positions
Player / unit health or other statistics"
Currently occuring player/unit actions
projectiles and inanimate ocjects
changes the game world |
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Term
| Be ready to explain what a tick is and what occurs during one. |
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Definition
| a time unit - how often we update the game in the game server
measured in milliseconds
"the server updates the entire game state. A tick occurs every fixed amount of time delta time...... more to this" |
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Term
| What are the advantages / disadvantages of a higher tick rate? High snapshot rate? |
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Definition
higher tick rate increase the precision of the simulation
more cpu load
higher snapshot rates increase the smoothness of clients perception
more bandwidth |
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Term
| Understand the concept of broadcast and how it applies to games. |
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Definition
| a way to send a message to all hosts in your network
Discovery of Servers by Clients
Discovery of Peers by Peer-to-Peer Applications
If you use broadcast for anything you deserve to be hung upside down by your toenails until they slide uncomfortably from your toes.
You can only broadcast with UDP |
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Term
| What is “client-side prediction”, and why is it a useful technique? |
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Definition
| client predicts the result of user input before the server has issued an update"
take user input, prediction, (action would happen on client side - even before it reaches the server)
sends information back
client hopefully wont see anything out of wack |
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Term
| How is client side prediction implemented (i.e., how does it work)? |
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Definition
Receive updates from server
Fix Prediction Errors
Render Scene
Sample User Input
Send commands to server
Render input
Repeat |
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Term
| What is delta compression, what can it do, and how does it work? |
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Definition
a technique that can be applied to network data to reduce it in size
send only changes in game state, rather than the full game state
requires a baseline state (recent caseline for UDP)
Trade-off between bandwidth and memory (for storing previous full-states as potential baselines) when using UDP.
take a gamestate, only send what changes |
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Term
| What is sequencing, what can it do, and how does it work? |
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Definition
use to determine ordering of messages
also, timestamps can be used to determine age of a snapshot
id number, put timestamp, know what order its in, can see if its out of order if missed
see last slide |
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Term
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Definition
| the time it takes a packet to travel from the source to the destination (lag) |
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Term
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Definition
| the variation in latency from one packet to the next. (Take the highs and lows of ping and find the difference) |
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