Event-based spawning


This is really an architecture / pattern issue… don’t know where it belongs. I hope it’s not misplaced or a “what kind of ice cream do you like”-type question. If so, please feel free to ignore me =)

I’m trying to set up an event-based spawning of various objects, and I’m looking for a clean way to do it. I have a class (non-MonoBehaviour) that holds the ‘blueprint’ for the object to be spawned. I have lots of instances of that class, so I like that it is NOT a MonoBehaviour, 'cause it keeps it clean (should use a struct, maybe…). Then I want the game engine to fire events, carrying the game state (an int called ‘height’), triggering callbacks to instantiate based on the blueprint.

My challenge is to do this in a clean way. Right now I’m nestling the classes in a kind of ugly way, which I would like to avoid if possible.

So: can I do this in a way that keeps the ObstacleSpec (‘blueprint’) class free from any logic, thus separating creation from blueprint? Or is this code actually fine, I’m I just whining?

The code works, it’s just that I feel it could be done alot better. I do kind of understand events and delegates and that stuff, but I’m hardly a pro… Any thoughts greatly appreciated!

My code is (basically):

public delegate void EntryEventHandler(int height);

public class LevelBehaviour : MonoBehaviour {


	public event EntryEventHandler Entry;
	protected virtual void OnEntry(int height) {
		if (Entry != null) {

	//This is called from a game engine singleton, at the appropriate occasions... No trouble here
	public void performLevelActions(int currentHeight) {

	public void Spawn(ObstacleSpec os) {
		Instantiate... etc, i.e. MonoBehaviour-based operations, and set stuff based on information in blueprint


public class ObstacleSpec {

	LevelBehaviour levelBehaviour;
	int entryHeight;

	//various other properties

	public ObstacleSpec(LevelBehaviour levelBehaviour, int entryHeight, ...) {
		this.levelBehaviour = levelBehaviour;
		this.entryHeight = entryHeight;
		this. ... = ...;

		//Subscribe to the listener, REALLY want to avoid referencing LevelBehaviour from inside ObstacleSpec!
		levelBehaviour.Entry += new EntryEventHandler(PerformEntry);


	//REALLY want to avoid referencing LevelBehaviour from inside ObstacleSpec! Can I move this outside, somehow?
	void PerformEntry(int height) {
		if(height == entryHeight) {

You could try this method to send a message to LevelBehaviour without referencing it, or else use a singleton for LevelBehaviour.