sbox-public/engine/Sandbox.Engine/Scene/GameObjectSystems/SceneSoundscapeSystem.cs

namespace Sandbox;

/// <summary>
/// Implements logic for the SoundScape system
/// </summary>
[Expose]
sealed class SceneSoundscapeSystem : GameObjectSystem<SceneSoundscapeSystem>
{
	public SceneSoundscapeSystem( Scene scene ) : base( scene )
	{
		Listen( Stage.UpdateBones, 0, Update, "TickSoundScapes" );
	}

	SoundscapeTrigger active;
	RealTimeSince timeSinceUpdate;

	void Update()
	{
		if ( Scene.IsEditor )
			return;

		if ( timeSinceUpdate < 0.2f )
			return;

		timeSinceUpdate = 0;

		var head = Sound.Listener;

		// Find the closest soundscape, sphere and box take priority over point.
		var best = Scene.GetAllComponents<SoundscapeTrigger>()
								.Where( x => x.TestListenerPosition( head.Position ) )
								.MinBy( x => (x.Type == SoundscapeTrigger.TriggerType.Point ? 1 : 0, x.WorldPosition.DistanceSquared( head.Position )) );

		if ( best == active )
			return;

		if ( best == null && active.StayActiveOnExit )
			return;

		if ( active is not null )
			active.Playing = false;

		active = best;

		if ( active is not null )
			active.Playing = true;


	}
}