Revision Difference
EventSystem#543969
<cat>Code.Misc</cat>
<title>Event System</title>
The event system is like the Hook system in Garry's Mod. It allows you to register functions on classes to receive a callback on certain global events.
## Registering a callback
# Registering a callback
Adding an `[Event]` attribute will add it to the list to be called.
```
[Event( "server.tick" )]
public void MyCallback()
{
// will get called every server tick
}
```
# Current Engine Events
## Engine events
The various events called from the engine currently:
* `client.disconnect` - called from `GameLoop.ClientDisconnected`
* `frame` - called from `GameLoop.PreRender`
* `client.tick` `server.tick` `tick` - tick is always called, client/server are appropriate to their state
* `physics.step` - called from `GameLoop.PostPhysicsStep`
* `client.hotloaded` - called from `HotloadManager.DoSwap`
### client.disconnect
Called when a client disconnects.
```csharp
[Event( "client.disconnected" )]
```
Called from `GameLoop.ClientDisconnected`
### frame
Called just before the beginning of a rendering frame.
```csharp
[Event( "frame" )]
```
Called from `GameLoop.PreRender`
### tick
Called every <page text="server or client tick">GameLoop#everytick</page> (60 times a second by default).
```csharp
[Event( "tick" )]
[Event( "server.tick" )]
[Event( "client.tick" )]
```
Called from `GameLoop.ServerFrame_Think` and `GameLoop.ClientFrame_Think`.
### physics.step
Called after each physics step, this is usually every tick but can be more depending on <page text="Global.PhysicsSubSteps">Sandbox.Global.PhysicsSubSteps</page>.
```csharp
[Event( "physics.step" )]
```
Called from `GameLoop.PostPhysicsStep`.
### hotloaded
Called each time your C# is hotloaded after successful recompile.
```csharp
[Event( "hotloaded" )]
```
Called from `HotloadManager.DoSwap`.
## Custom Events
You can register your own custom event callbacks and call them.
```csharp
[Event( "mygame.gameover" )]
public void OnGameOver()
{
}
public void DoGameOver()
{
Event.Run( "mygame.gameover" )
}
```
# Custom Events
You can call your own events.
```
Event.Run( "gameover" )
```### Event arguments
Events can pass any amount of arguments too.
```csharp
[Event( "mygame.gameover" )]
public void OnGameOver( Player winner )
{
}
public void DoGameOver( Player winner )
{
Event.Run( "mygame.gameover", winner )
}
```