Flexible code architecture

[wintry rampart]

Game Dev (Unity).

I noticed that GTA San Andreas systems are so flexible that you're easily able to swap the playable character and it worked perfectly, even using each character proper animations when moving, running, etc. Even tho throughout the game you only play with one character only. San Andreas Multiplayer used this feature to allow you to change this skin. But this left me wondering why'd they design it like this in the first place if the game is only intended to be one character. In GTA 5 it would make sense but why the old ones with just 1 character.

So as a result, I've been looking about how game studios develop their games and their architecture and stuff like that, and how they opt for data driven architecture where new weapons, cars, characters are simply data files containing different info like which model to use, how many seats a car has and where each seat is, etc. and the engine automatically handles all of that. And they open interfaces that they use to build the game progession using a higher-level DSL, using methods like give_player_weapon or something similiar. Alongside that, they have self-initializing systems that require little to no manual setup. You just drag the player and it automatically sets up the character, camera, wires everything up and you're on your way to go, something that I struggle with.

I'd like to apply these principles in my game. I have good understanding of how Unity works but I suck in creating flexible code architecture. Most of my game systems are not self-initializing, meaning creating a new scene requires whole lot of wiring up even if the code is there. And alot of my stuff is hardcoded, pretty much nothing is data driven.

The question is, how do I learn the skill to create flexible architecture that can expand easily. This is not like web dev where they follow the same(or similar) patterns. Each game is fundamentally different, depending on the feature, some stuff can be data driven only while others have to have custom code.

I’m mainly struggling to find something that works across multiple systems that HAVE to talk to each other. I can’t seem to find something that works, and it’s not about you telling me what to do, but rather how to DESIGN something like that based on my game demands. I’ve been struggling for a few days trying to figure out how to structure it cuz my older project (even tho was an amazing one) was hell to work with.

P.S I'm not a beginner programmer, I have experience in other fields.

Mention me please <3

[tame mica]

It's not just studios. Many indie games have good architecture. In fact, many big games have pretty bad architecture.

You can try looking up projects on github to see how people implement different systems/features.

Learning different oop programming patterns and principles, like SOLID could also be useful.
Other than that it's just experience and trial and error.

[wintry rampart]

I do understand such patterns and principles but that alone isn't enough. It's not like web dev where you can use already existing architecture that's well documented like onion based or layered or mvc or whatever. Each game is fundamentally different and what works in one game wouldn't work on another

[sullen mural]

You can take "good" programming and architecture principles to any project regardless of the context. You can definitely go too far with them as well and code 100 interfaces instead of your actual game. Principles only stand to make your code easier to maintain, extend, test, and debug.

You can find 1000 different ways people will recommend you structure your game but it usually all goes back to the same few principles.

[tame mica]

In the end it's up to what your project needs, and there's no single right answer.
Also it's very hard to give a good advice without any context. If you ask about specific feature you want to implement, we might be able to give some advices.

[wintry rampart]

yeah but principles isnt architectures, or how to name and split files.

[wintry rampart]

Okay so heres a full breakdown.

Usually I had a PlayerController.cs and CameraController.cs and they have to talk to each other (shake when the player attacks or something).

What I'm trying to do is this:

• First, have self initializing systems where I can drag like a simple object inside the scene and it will automatically be setup to play directly, no dragging references across the scene. This includes initializing the player controller, the camera controller, the UI for the game.

• My player has magic spells that he can select from and then fire, each of them have their own different code (an example is launching a fireball, another is freezing surrounding entities). And each enemy has its own attacking mechanics, a gremlin is slow and attacks when ur near, a floating soul sucks ur soul from a further distance (with a ray appearing when u get close).

[sullen mural]

how to name and split files is not consequential on your architecture at all, but I'm curious where you're going with this

[wintry rampart]

• A story progression script. In GTA games they use their own DSL scripting language for the missions with bindings for stuff like give_player_money or spawn_npc. Altho Im not gonna use a different language, I want an easy and flexible way/interface to do this.

Usually i do a normal script and i store a missionStage and i check every frame if the player stage is X and he's near specific point then set missionstage to X + 1 to avoid the frame check and do whatever supposed to do.

I want an easy way to script mission progression, showing instruction, when some parts being sequential (u have to reach A before trigging the next objective) and other being in paralell, (like go to A but also the npcs move while u go there, or having a conversation with an NPC)

• A cutscene system. a good and flexible way to create cutscenes that, have multiple camera animations ( i do this using cinemachine), triggerable by the mission script i've said above.
  including a dialogue, a skip feature that allows me to set everything if the player skipped (like where the player should be or the npcs should be or how much health he has, etc).

[wintry rampart]

To me it does.

I thought...
Ok lets make a Character.cs class, but for my player i have PlayerController.cs, but a controller is not a character so it shouldnt inherit from it.

ok then PlayerCharacter.cs right? ok but should that character file include logic for taking input and moving the player, or should it only hold values like health and stuff and another PlayerController.cs should deal with that.

Ok if we go with the former, then why does a Character take input while other characters (NPCs) don't? shouldnt all subclasses deal within same scope? And if I do that, should camera movement be part of it or a separate CameraController.cs, if its a separate file then why is there CameraController.cs and not PlayerController.cs

[sullen mural]

Naming and splitting files is different than how you structure classes, inheritance and data ownership. But yes you're right to be focusing on this.

I'd look into interfaces if I were you. A player character can be a Character but also have an IControllable interface that allows for the player to control them and an ICameraFollow interface that allows you to attach the camera to them.

These are examples, not actual advice on how to structure the code exactly.

[wintry rampart]

yeah but the entire issue is that i cant decide on which to use or how to structure.

IControllable will be an interface to be used only once, so is it really worth having?

in the player script i mean

[sullen mural]

what if you want to have two separate characters to control at the same time? Or you want to have two characters that you want to switch between?

As for the rest of the systems, focus on refining and challenging your assumptions. For example, if you're keeping just an int for changing the 'stage' what happens when the player goes out of sequence?

[wintry rampart]

i understand but in my game there isn't, so is it worth having a separate interface? etc

its driving me crazy the past few days

[wintry rampart]

thats not the issue, the issue is that the script is too spaghetti for such a simple script

[sullen mural]

Perfect is the enemy of good. make a decision that works with your current context and move on.

You can always try to forsee potential extensions but if you're also fighting the idea of the extensions then what's the point

[sullen mural]

Also, you're never gonna write perfect code the first time. Rarely happens. So experiment with it and design it multiple times to see the tradeoffs.

Eventually you'll have a mental library of 'solved problems' and you'll know how to generalize past experience to new tasks/problems.

[placid bronze]

the character thing is basically just a model swap in unity while still using the same animationcontroller. ofc the models have to be similiar enough and for example humanoid (defined bone hierarchy)
probably gta has a similar thing

for example a parent player object that spawn/holds a model in a child gameobject and gets a reference to the animator to play the current one

[storm coral]

Correction: you are never gonna write perfect code the first time, you could go back a hundred times and improve things

Striving for the "perfect" architecture is a major reason people procrastinate their projects, caught between feeling like they want to do it perfect and they want to progress ending in progress paralysis cause they neither want to progress unless its perfect, nor work on scaffoling that doesnt feel like progress 😄

[prime dock]

I usually have a Character.cs a Brain.cs, an AIBrain.cs and a PlayerBrain.cs. The brain controls a character. You could also have a PlayerAgent and AIAgent if you wanted to have something more standard.

[wintry rampart]

yeah but each character has its own animation controller

[wintry rampart]

So, each character has a Brain componetn and a Character component or does Character have a property called Brain

or is it the opposite

or how is it structure

and also how would i have self initialziing systems without having to drag and drop each single thing

[prime dock]

Each Character has a Brain Component.

[wintry rampart]

and a property for the character

that seems like something id use

thanks

[prime dock]

You can have a default brain in the character and simply override it when instancing with a player brain

Obviously, the Brain is 1<->1 with the Character.

[wintry rampart]

how would u even set a default value for a monobehavior class? dont i have to drag and drop

and also for the AIBrain how do u structure it so that they can either wander around like a normal npc, follow a specific path when called, attack a certain enemy or just automatically pick an enemy surrounding it and shit

[prime dock]

private void Reset()
{
...
}

[prime dock]

You can use the Strategy Pattern inside the AI brain

Or make multiple brain type

[prime dock]

You can also use a SerializeReference instead of working with component if you prefer

[wintry rampart]

what i mean is that the those are drag-and-drop components, so i have to reference it in the inspector either way, is there a way to reference the default one without dragging it in inspector

[storm coral]

yes in OnValidate you can look for a reference you want to use as default via code

[wintry rampart]

how

[storm coral]

private void OnValidate() {
  _rigidbody ??= GetComponent<Rigidbody>();
}

for example like that

[wintry rampart]

thats not what i meant

public class Character : MonoBehavior {

    public Brain brain;

    
}

and Brain could be scriptable object

i have to drag it

[storm coral]

yes you can also search for that in OnValidate

[wintry rampart]

how would i search it

[storm coral]

You can query the AssetDatabase

[wintry rampart]

isnt that bad tho

[storm coral]

if you do it in editor runtime no

it will basically do the drag & drop for you

[wintry rampart]

yeah but it has to search it

[quick wind]

is there a problem with having to drag it in? yes you're going to have to setup objects in a specific way if you want them setup a specific way

[storm coral]

yes, once while you attach the script, never again afterwards

[wintry rampart]

the problem is that i have to manually do that in each single new scene i create, and i dont have just 1 simple thing, i have TONS of shit

[quick wind]

who said you have to do it per scene? this would be a character and you use prefabs.

[storm coral]

then create a prefab of your object and assign the scriptable object in the prefab

then just drag the prefab into each scene

the prefab will retain the reference to the scriptable object

[quick wind]

i do find it somewhat weird though if you're using a Brain as a scriptable object. this would imply the brain has no mutable data at all

[storm coral]

well its perfectly ok not to tweak brain parameters at runtime anymore

[wintry rampart]

yeah but what about component that talk with each other, i have a canvas with UI that the player has to talk to and if i make a prefab for the player and prefab for the canvas i still have to wire them manually

[quick wind]

that depends entirely on what logic the brain is doing. we're talking hypotheticals here given theres no specific code. Even something like choosing a target to pathfind towards is considered mutable data

[storm coral]

you shouldnt create such a massive amount of scenes that this becomes a heavy workload

[quick wind]

use events on the player that the canvas subscribes to. the player doesnt need to know theres a canvas at all

this could still be done in a prefab anyways

it seems like you're overthinking a lot of the setup simply because its manual work. If you have tons of unique characters, all with different logic, then you have to set that up somehow. theres no magic solution where you can avoid defining what a character can do

you plan to have tons of stuff, thus you have tons of work to do

[wintry rampart]

i seen systems where they drag an object like a "player spawn location" and it spawns the player character ,the camera controller, the UI and everything is connected

u cant expect map designers to connect all these

[quick wind]

Nothing I said would prevent you from doing this either. That's still possible very easily through prefabs

I never stated a map designer would be doing it either. I'm specifically saying this is work for you to do. If you want many characters, you need to manually define the logic that each one can do. That's by dragging in references or adding components, then making that a prefab.
Whoever creates your map would only care about the prefabs or creating custom spawn locations, which at the end would be a script referencing a prefab

[prime dock]

And you do either by Code at Runtime or by Tool in edit mode. Almost everything can be automated. You could automate the creation of prefab. However, in most case, it is time lost. At least, in the context of a single developper game

[wintry rampart]

Yeah but some objects/prefabs need references to each other. Like I reference the health slider in the player object so it can work. If I make the canvas a prefab and the player a different prefab, then they still wouldn't have the references saved. Each time I drag the canvas prefab and the player prefab in a new scene. I still have to manually reference them

Or enemy for example. I need a reference to the player. Even if both are prefabs, since they're different game objects the references between them won't be saved

[tame mica]

These objects can find their own dependencies/references.

[wintry rampart]

So creating a script that automate the references

[wintry rampart]

How?

[tame mica]

There are many different find(gameobject/object/component) methods that unity provides, then you could have your own system that would provide easy access to various objects via singletons or static fields.

There are many different ways, depending on your specific use case.

[wintry rampart]

Yeah but those also require the objects existingm. Like finding a canvas if it doesn't exist is an issue. Meaning I have to manually drag and drop the canvas.

I was thinking something like putting a spawn point and everything initializes

[tame mica]

Obviously if there is no canvas, then there's no point finding one. You'd either have it in the scene at editing time, or create it at runtime. There's no going around it.

You don't have to drag and drop it. You can create it via code.

[tame mica]

Sure, you can do that

[wintry rampart]

And then set up the reference ?

[tame mica]

And set up the references via code, yes.

[wintry rampart]

Lovely

Another thing

Should the systems be decoupled? Like should I actually reference the UI slider for health in the player script or use some sort of event driven architecture broadcasting health change event? Or unity events maybe?

And then a UI controller would listen and set accordingly

[tame mica]

Ideally, you want to decouple things. Especially ui from game logic.
But it depends on your game complexity. Some simple games are fine with hard coded/manual assigned references. Implementing a complex system in this case would be a waste of time.
In more complex games, there are many different approaches. You can have model-view kind of system with events or callbacks and/or various components registering with the ui so that it listens to their value updates, etc...
Again, heavily depends on your project.

[wintry rampart]

Sounds good, thank you.

Are unity events slow?

[quick wind]

#1393159670646046821 message
Your player ideally shouldn't even be referencing any UI directly. But tbh i feel like a lot of the problems youre listing here are assumptions based on how you imagine a system to be. Once you actually implement things, you'll see its really trivial to reference things here

[tame mica]

Compared to what?

And it's probably not something you should worry about anyway.

[wintry rampart]

Ive run into those problems which is why I wanna fix those in the next game I'm making

The setup was so bad it was hell setting up a player In a new scene e

At one point it was easier to clone a map then delete the map objects and work from there just to avoid setting it up

[wintry rampart]

In general. I don't want it affecting performance

[tame mica]

Everything is affecting performance. The question is what alternatives you have and whether they are worth it.

[wintry rampart]

I usually update the UI each frame so I'm just saying like direct reference vs unity events

[tame mica]

So you're comparing to calling a method directly.
There might be a slight difference, but it's probably not worth worrying about. Unless you're calling tens of thousands of events every frame, at which point the amount of calls itself is the problem.

[quick wind]

Updating every frame compared to unity events or c# events is gonna be worse overall. Stuff like HP realistically isnt updating every frame, but something like a timer or movement speed might.

[tame mica]

Instead of worrying about certain api performance, worry about how much you're calling it an in out circumstances.

Ultimately, don't worry about performance, until you have an actual problem