Game Events - Power & Simplicity in Unity3D 

'ScriptableObject-Architecture' - free Asset on Unity store implementing all this for you. There is only one major flaw with this pattern, which is never talked about. I learned the hard way, after implementing this in my project. That is, that you lose any reference-tracking with implementing this ScriptableObject event (or any other type) system. What do I mean with that? If you take a look again into your IDE (Visual Studio), you will notice that there is no helper for WHICH class is calling/using this ScriptableObject. It is a interface into the void. You are fine with 1-5 ScriptableObjects like that. But in a more bigger project, you will effectively have 100's of those, to manage your game mechanics. And will suddenly wake up in a nightmare. "Can I safely delete or modify this SO, is anything still using it?", "which systems are actually using this SO?" those will be your main concerns each day. I found it to be very frustrating and removed the system completely at the end. Just a heads up.

Very interesting. I work with designers a lot, but never thought of exposing events to them like this. Thanks for sharing.

I use a similar pattern with C# Action delegates for blistering fast performance and ease of communicating across scripts in my project.

This is great stuff Jason. Your specific tutorials such as this one always help me out a lot. Your channel is great!

Really interesting. I like how well it is explained and is not only for advanced users (explaining quickly each concept). Thanks!

Incredible timing! I started learning about the observer pattern and C# delegates yesterday!

This is a great technique; thank you for sharing it! I appreciate the way you frame explanations of a system with potential use cases and intent. It makes things very clear and straightforward.

Jason, i just wanted to report back and say I used game events/Scriptable objects for the first time today after watching your vids, and also I read the article you mentioned and wow, very powerful stuff! I'm glad it totally clicked with me because the biggest thing that always seems to be holding me back when i tried any game engine, is getting all the parts to communicate properly without errors or bugs, to the point where it actually overwhelmed me more than anything.. and finally i feel i've found a way to build my games that really suits me and won't have me pulling my hair out thanks to your videos! I just got up and legit cheered when I just had an event easily do everything i wanted it to do, felt so good! Multiple features in my game just got added within 20 minutes because the only solution i needed was a way for the parts to communicate as some were not. That article is fantastic too the way it breaks down the sword data and what not, thats a great example to refer to. I think a lot of people are like me where even though they may be somewhat new to programming/Unity, they can actually code stuff they need to make or always find a way but they just suffer with the fundamentals like how to get parts of the game to communicate easily without running into walls, more people need to see these videos and be aware of Scriptable Objects and Events and how they can tie together. I feel more free now to make my game.

This is cool. Another chunk tip/trick to throw in my bag of goodies! Thanks for all of these videos. It makes a big difference for us.

Appreciate the fact that you explained every little thing that you were doing. Good job!

I have a playlist with game dev tutorials for when I get deeper into a project and i bump into problems / want to improve performance and so far your channel totally dominates said playlist. Literally the best programming channel for game makers! Sincerely thank you man.

Clever Code. It takes little effort to understand and it takes you to another level. Awesome.

OG Jason is back!!! Love this kind of content

0:23 Getting fancy with the editing there!

This is amazing. Definitely upload more amazing programming practices

Thanks a lot for all your videos. I'm in a 2 week isolation and binging the hell out of your content to fill by goopy brain with knowledge.

This is a great way to implement the observer pattern. Thanks for sharing !

Man I love your videos. Thanks for existing

Thank you for this video. It really simplifies triggering actions between scripts a ton.

Good timing! I had this exact problem moments before this video was uploaded : )

Awesome video and awesome trick for decoupling relationships. Thank you 🙏

This is very helpful. thank you. I am new to Unity (came from UE4) and I did not even know that there was a "Unity Event" variable I could use like that. I will be using that in my game for sure.

You make a huge difference in my life as a developer. When I finish some games and start making money with it I'll definitely become a Patreon. Thanks for the videos!

Really looking forward to the other things you will suggest doing with scriptable objects :)

I didn't appreciate the events until I had to turn my 3d game into d2. Swapping scenes, collisions etc. I was downright shocked at how easy it was for me. Most of the logic was based on them. And this is just lvl 2 of this :D It's great.

Looks great, thank you Jason !

This is a really useful system. I first seen it used from a Unite talk on scriptable objects.

Big thanks for this implementation. I was curious about the event scriptable object to use it as an architecture for the game 😁

I like editing in this video, all you need is sound effects and your done!

Thanks for the lesson, Jason!

This is awesome - thanks for the great video!

You have saved me from tons of problems. Thanks!!

More excellence! Thank you!

Thank you very much. Your videos always useful and there is always to learn.

awesome video once again :)

Hey Jason, your videos are awesome. Using dark mode will make our eyes healthier!

Brilliant having moved back to Unity from UE recently. This technique will keep me working my core game mechanics rather than working on say dissolve mesh effects before the core game is done :)

Agree 100%! I've built my game using Scriptable Objects with events extensively and it saves you so many headaches! Everything is much better separated and can still tightly work together.

Holy smokes this is going to make everything much quicker. Thanks Jason.

I use UnityEvents or standard C# events frequently. It took me a moment to understand what you’re doing here moved the editor configuration to the listening object rather than the sender, which makes a lot of sense from the design side.

Thank you so much, my code is so much more flexible now. God bless.

Cool. I don't see how I can apply to my game now, but I've learned more about the SO and the UnityEvents.

Seems like a great tool for updating my ui panels on certain events like updating currency display.

Very clever, love it

Game programming is truly overwhelming, I'm currently trying to learn patterns like factories, observers, commands, adapters, etc. and there's always something new popping up. Just learned about abstract classes and invokes and now here comes game events, and I know it's just the beginning! Does it ever end? I find most of this stuff really hard to learn without real examples of how to implement them, and it gets even harder when you try it yourself on more complex features. All this knowledge is insanely fragmented into hundreds of courses, books and youtube tutorials. How do most people learn about all of this?

Thanks for the video ^^

Hey, thanks for the hashset tip, will change that, I actually use the same workflow for my game architecture, it is insanely modular, quick to develop and a bit of a pain to debug sometimes, I just recently put all the events in a singleton class, so they can be easily invoked from any script, and a bit easier to find references and debug, and you avoid extra work for classes that have to invoke event, no inspector references( granted, that has drawbacks, if changing scenes, but is easily worked around ) Also naming convention must be respected here, when it comes to events and methods that are calling them. As an extra, I made the editor script dropdown that lets you choose what type of an event you want the newly created event to be( empty, vector3, int... whatever, it just lists game event methods ) So each listener, will display only calls that assigned event has. Also added to this is a default event to call, just an empty event, in case of gamesuccess, and gamefailed, there is an default event game completed, that always triggers in both cases. very useful. Delay is the same with coroutine, but each event call method has a condition if delay is > 0 start coroutine and fire the event after the delay, don't have delayed event and regular. Drawbacks to all this, bit harder debugging, a lot of references in inspector, but if you put on each event listeners list, it also becomes a bit easier. Pros: insane modularity, flexibility, development speed, and development agility, keeping things very orthogonal. that GDC was mindblowing, I am also using all the time those reference fields, that accept either scriptable object value, or just regular value, pure gold this all is. I wouldn't want to develop in any other way honestly... Thanks for the tutorial.

I approve of the tutorial reference :]

awesome stuff thanks

Hey, super video. I actually already implemented this system into my game but I have problem when it comes to connecting other systems and monobehaviours together. As a solo developer I can't really tell where the line between design and programming is. What I mean is that I don't know what to connect through code and what to connect via an event system. Because I code since 9 years and I got into game development only last year, my immediate intention is to hook everything up through code but this obviously leads to said problems and I would need to do a rewrite every time I would like something to get changed. On the other hand, if I connect all those system together with an event system, it's not written down, can be forgotten, etc., like the other Jason said in the last game dev talk of yours. It would be incredibly helpful if you could make a followup video where you name some guidelines and tell us about your experiences with connecting systems. I think many solo devs and small teams would learn a lot about how to structure their game robustly while keeping the needed work low to change and / or add something new to their project.

Thanks for the tutorial

Thank you! Can you make tutorial about sending through this game events parameters to listeners?

My heavily interconnected character selection screen with unlocks using some questionable parenting of objects thanks you in advance. Time to refactor and unlink that rats nest!

Would you consider making a series where you play a game (finished or not) find bugs and go through how you would fix them?

Great video thank you very much! Id like to ask what happens when you need to pass some parameters for the unity event?

Saying no is easier option and work perfectly fine XD

Nice trick. I do not like to use events, but maybe I try it one day.

I love the beginning of your videos when you're explaining the concepts, but the second you open the text editor with the code I'm like 😵‍💫. Guess that's why I'm an artist and I'll never be able to program. It's like hieroglyphics to me.

Thank you Jason, I like this and use these a fair bit, they are very handy when you want to step back a bit from the code and think like a designer. But is there a way to inject the event name into the title bar of the component (in the Unity Inspector)? that way when I have many collapsed components listening to different game events, they'd be easy to tell apart. Currently I just see "Game Event Listener" for each of them. Thanks!

The only issue with this is whenever the referenced script is removed or moved from the Gameobject. The Unity event loses the reference and will just show an empty slot. If we take the same example as in the video, if someone decides to recreate the text object by deleting it for some reason. It gets hard in the bigger project to realize what the Unity event was holding the reference of.

Awesome video! I love using this! How do you approach finding all the references in code when you run into trouble?

Creating manual events only if needed and most of the time use modified Unity Event editor. Instead of creating tons of Scriptable objects per event, create Scripable object per topic with list of events. Then refrence where you need it. Main problem with events after time you forget where they are and hard to test if you dont' have something visually like this ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-e_ygMVFhKWs.html

Habe you changed something with your camera setup? Looks much better! 👌🏻

I've been using game events for a while now, never thought of making a delayed listener, I used to code a monobehaviour that would do my action with delay and call this function on the listener

I have an issue in a build with that approach. Garbage collector cleans a HashSet in SO during loading a scene: Registering listener: PlayerPopupsUI to event: AnimationFinished_IntroScene; Total listeners: 3 Registering listener: SceneManager to event: AnimationFinished_IntroScene; Total listeners: 4 Unloading 1575 unused Assets to reduce memory usage. Loaded Objects now: 37889. Total: 17.566200 ms (FindLiveObjects: 1.458500 ms CreateObjectMapping: 0.920200 ms MarkObjects: 12.912100 ms DeleteObjects: 2.275000 ms) Registering listener: SALSA_Player to event: AnimationFinished_IntroScene; Total listeners: 1 Invoking event: AnimationFinished_IntroScene on listener: SALSA_Player So only instantiated objects work correctly. In the editor, there is no such issue

Oh wow. That's great. How do you set up multiples scenes in the hierarchy like this? Look great to disable in one click the whole UI to work on the scene.

Thanks for the video! BTW, @Jason Weimann - might be really random but what are those tile lights you are using? >

Nice video! I tried something like this before. But at some point, I lost the overview, which events fired/registered from which objects. Did you have a solution for it?

Works like a charm! But I want to challenge this system: what if I'm making a card game, and use this to make sure each card has its own unique event when dropping on the enemy. How do I make it pick the right game event each time and the right effect to call as well?

This is very helpful.If I need the same event to accept different parameters, what should I do?

In the EvenListener I've changed UnityEvent to UnityEvent and I pass a string on Invoke, so I can use it on whatever function UnityEvent calls. In the editor, when I add my desired function to the UnityEvent list on the Event Listener element, I can see that it shows as Unity Event (string) and the string field is available, but it doesn't receive the value I passed on Invoke and the function throws an error because the string is empty, even though it was correctly passed on Invoke. Help?

Why is it every video I watch about events.. it's totally different? What's the difference between this and using a monobehavior EventManager that uses public event Action onAction? Seems like people have so many different ways of using some Event System and they are all different.. unless using the UnityEvents system.

Can you do one with parameters?? I've solved that myself but would love to see your approach.

how would you pass a float from the object raising an event to the object receiving the event?

What would be a good way of extending this to allow the Invoke method to take arguments?

Now, how about creating swappable Sprites themes/Text/Colors etc. On Start it starts listening for a sprite with specific id/guid/alias etc from a data cache(scriptable object). And when some one(a button for instance) wants to change color palete or sprite theme it gives a new set of data(sprites or something) to this cache, cache updates existing aliases with new data set and invokes update on listeners. Thats it. Imagine complex UI or localized text acros different scenes that can be updated by a single button click without explicit references to monobehaviours or prefabs(it can be found by cache itself or use reference to singleton cache)! In simple words: Cache is observer, SpriteChanger is listener, and player clicked button is actual event invoker

@Jason Weimann Great video, The OnMouseDown() is not working for me, i have it on my player character and i have a 2D capsule collider.

Can you implement the similar concept but with actions that can pass int,string,bool?

Why would you use Hashmaps instead of UnityAction ?

how would you go about adding different parameters?

What about sending data when we invoke events? As far I as remember unity events with generic types can not be serialized (may be they changed in 2020 idk)

If we consider this method as a decentralized event system. How does it compare to a centralized one. For example, a central event system class owning all the events.

Is it an implementation of the observer pattern?

(14:19) we can use base.RaiseEvent() inside the override method, right? and the variable _unityEvent still in private

hey Jason, by the way... what is the font you are using in your editor?

It's just a roundabout way to end up doing the same thing. You still have to add the features they want.

2:55 video really starts here

Do you use this instead of regular C# event Actions?

It would be nice if registered methods to the game events could be IEnumerable and fire them off as coroutines.

How would you extend this to pass data through the .Raise(eventArgs) ?

Would have been nice to just add a link to that tutorial in the description

Question: In the GameEventListener class you have one SerializedField called _unityEvent that is just a UnityEvent, but in the inspector it looks like it is a list/array of events. Is that just how events are, that they can always be added as many instead of just one? Thanks Jason👍😊

Genuine question: Why would I want to use this method instead of just programming a singleton and casting to a specific function on it? It does the same thing and uses 1 less script.

wouldn't it be better to use an interface for the advanced usages instead of deriving from the base class?

What about the memory garbage generated by Unity Events in the architecture?

I'm a beginner and I'm trying to understand how shop system work I haven't found a good tutorial on it, please explain to me how shop system work like u but skins or items and it appears in game how do I integrate it in any game explain they key codes for shop system how it changes game objects please

The game event listener with delay is not working for me! Anyone else have that problem?

hmm I'm wondering, is there any way to modify this so that you can pass data with the event or is it really only for events without parameters?

i like your videos man but this one was really really fast. i think i may have to watch it about 100x. breath brother . stay off the gfuel .

Why this video not displayed on channel, and why i can watch it?) Great video btw