Shake, punch and tilt on any CameraComponent. Effects stack, run out on their own, and don't touch the player's aim, they only move what's rendered.
// rumble the screen for a second
Scene.Camera.AddShake( amplitude: 5f, frequency: 40f, duration: 1f );
// kick the view up and let it bounce back, like recoil
Scene.Camera.AddPunch( new Angles( -2f, 0, 0 ) );
AddShake is a sustained rumble, a duration of zero shakes until you call Stop() on the returned effect. AddPunch is a single kick that springs back, either along a direction or in view angles, with an optional FOV punch for impact. AddTilt eases the camera to a lean and back, good for damage indication or peeking.
These are local. Call them on whichever client should feel them, from a damage callback for example.
EnvShake
EnvShake is the map component version, for earthquakes and explosions. Place it in a scene or Hammer map and it shakes every player within Radius, falling off toward the edge, or everywhere with GlobalShake. It can also kick nearby physics objects with ShakePhysics, and Rumble game controllers.
StartShake() and StopShake() control it, and they broadcast so every player gets the shake.
Custom effects
For a custom effect, implement ICameraModifier on a component and reshape the view in ModifyCamera. It runs once per camera per frame while the component is enabled, and CameraOrder decides who goes first. This is the same hook the player controller, vehicles and weapons use to drive the camera.
public class DrunkCamera : Component, ICameraModifier
{
public void ModifyCamera( CameraComponent camera, ref CameraView view )
{
var sway = MathF.Sin( Time.Now * 2f ) * 5f;
view.Rotation *= Rotation.FromRoll( sway );
view.FieldOfView += sway;
}
}
The view has the position, rotation, field of view and clip planes. Change whatever you like, the next modifier gets your result.