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48 lines
1.2 KiB
Markdown
48 lines
1.2 KiB
Markdown
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# Clock Synchronization
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For many algorithms you need the clock to be synchronized between the client and
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the server. Mirror does that automatically for you.
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To get the current time use this code:
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```cs
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double now = NetworkTime.time;
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```
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It will return the same value in the client and the servers. It starts at 0 when
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the server starts. Note the time is a double and should never be casted to a
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float. Casting this down to a float means the clock will lose precision after
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some time:
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- after 1 day, accuracy goes down to 8 ms
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- after 10 days, accuracy is 62 ms
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- after 30 days , accuracy is 250 ms
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- after 60 days, accuracy is 500 ms
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Mirror will also calculate the RTT time as seen by the application:
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```cs
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double rtt = NetworkTime.rtt;
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```
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You can measure accuracy.
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```cs
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double time_standard_deviation = NetworkTime.timeSd;
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```
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for example, if this returns 0.2, it means the time measurements swing up and
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down roughly 0.2 s
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Network hickups are compensated against by smoothing out the values using EMA.
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You can configure how often you want the the ping to be sent:
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```cs
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NetworkTime.PingFrequency = 2.0f;
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```
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You can also configure how many ping results are used in the calculation:
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```cs
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NetworkTime.PingWindowSize = 10;
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```
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