how do we implement explosions in Godot 2d that do stuff(eg. damage)

[austere mesa]

just use an Area2D/3D where the explosion is happening and deal damage to any overlapping objects

[iron steppe]

no but i cant do that

because then you would be able to do damage through walls and stuff

thats what i thought of too actually

[violet wadi]

what i usually do is add a raycast at the center thats the same length as the radius of the explosion, and have it loop through every overlapping body and check if the raycast result is that body, if it is apply damage. if its not, do nothing

[reef remnant]

basically what I was about to say

[iron steppe]

ahh thats pretty smart, i was thinking of just doing raycasts in 8 directions and seeing if they hit anything 💀

ty

[violet wadi]

yea its a useful thing to learn, good for not letting players pick up objects through walls, and for vision cones not seeing thru stuff

[reef remnant]

trust me, I went down a path like that for a game I made (for light detection not explosions) and it's far better to just do a raycast per target

(I stuck with the alternative because it provided better results for light detection, but it's heavy on performance)

[violet wadi]

you can create a new raycast per target, or reuse the same raycast and call force_raycast_update() every time it gets_collider()

before it gets_collider(), rather

[iron steppe]

im not too familiar with ray casts (i havent used them yet), but how would this matter if we qeue free the explosion at the end anyway

btw do we use autoloads for functions we want to use through the code, so say i want to use the explosion function, i would pass in coords and radius and i want to use it anywhere in the code

i would use globals right

[violet wadi]

i dont think it would matter, its just different ways of doing the same thing. i think reusing the raycast might be a little more performant, though its probably not too big a deal

[iron steppe]

fair

[violet wadi]

yeah

so its like Global.create_explosion(radius, position) which can be called from anywhere

[iron steppe]

the actual script name doesent matter when we use globals right

[violet wadi]

yeah you can set it to be anything

[normal badge]

you could also store the explosion in the player itself, as a child of a Node so it doesn't inherit the player's transform

reduces the messiness of needing to do lots of things through an external node

[iron steppe]

but wouldnt i have to re write the code every time i wanted an explosion then

like say i made a grenade

also how do we make global nodes for the area2d and ray casts required

[iron steppe]

plus i might qufree it after i explode it, so its prolly better to have it externally

[normal badge]

if you're queue freeing it, then you'd still need to instantiate it, and can do so in the player
get_tree().current_scene.add_child()
is how you'd put it in the scene

then that also puts the preload in the player, which is pretty sensible

or you could even export a packed scene

can't do that with an autoload

[reef remnant]

I think the idea is that several things may want to do explosions, so they want to implement it in an autoload to make life as easy as possible

[iron steppe]

yes exactly

but i still need to add it as a child of something for it to work right

i added it as a child of the autoload but that doesent work

[reef remnant]

What's the issue?

[iron steppe]

i made an explosion class and am testing it rn
func explode():
print("called explode")
get_node("Explosion area").get_node("explosion radius").get_node("Shape2D").radius = radius
var bodies = get_node("Explosion Area").get_overlapping_bodies()
print(str(bodies))

i put the explosion radius really high (50 pixels), the game is pixel art so that should be enough. i make a new explosion every time a player dies

so i killed on of the players, but it doesent print anything

[reef remnant]

Oh, a quick tip. Often a better way to get child nodes like that is with an @onready variable:

[iron steppe]

oh nvm, it seems the method isnt getting called at all

[reef remnant]

@onready explosion_shape = $Explosion area/explosion radius/Shape2D

[iron steppe]

oh yeah, that makes sense

[reef remnant]

Then you can just refer to explosion_shape instead of the big string of .get_node() calls

[iron steppe]

i forgot about that 💀

[reef remnant]

But anyway, onto the actual problem, what's the code that the player uses to create the explosion

[iron steppe]

func die():
print(name + " died")
Global.explosion(position, 30)

[reef remnant]

And you're seeing it print the died message?

[iron steppe]

i can see the died in the output

yes

[reef remnant]

Okay, so let's look at the function in the Global autoload

[iron steppe]

@onready var explosion_class = preload("res://explosion.tscn")
func explosion(position: Vector2, radius: float):
var explosion = explosion_class.instantiate()
explosion.radius = radius
explosion.position = position

[reef remnant]

Mhm. So, does the explosion script call the explode() function at any point?

Or does that need to be called from outside?

[iron steppe]

oh lol

wait i added it lemme see if it works

atleast it calls it now

explosion_shape.radius = radius

its claiming that the object is of type nil

[reef remnant]

What's the tree structure of the explosion scene?

[reef remnant]

Ah, right

[flint lily]

You can use a shapecast that does not change its position and checks for anything, if found then it damages the enemy

[reef remnant]

Knowing that, you actually want to do the following:
@onready explosion_shape = $Explosion Area/explosion radius
And then:
explosion_shape.shape.radius = radius

[flint lily]

I'm not really good at explaining

[reef remnant]

Why use a shapecast instead of an area?

[flint lily]

personally an area did not work for me

[iron steppe]

oh thats how it works

[reef remnant]

What issue did you encounter?

[flint lily]

brain issues, i have low intelligence stat when i was born (obvious skill issue) so i had to do what i could

[iron steppe]

you dont need the string marks?

it gives me an error if i dont use quotation marks

[reef remnant]

Mhm! Notice how the Radius property is inside the Shape property, so that's how it has to be accessed

[reef remnant]

Ah, right, yes, you do need quotes in your case. That's because your node names contain spaces.

[reef remnant]

I'm, uh.. Sorry for your loss?

[iron steppe]

is godot case sensitive?

anyway its still showing nil

[reef remnant]

Yes.

What thing is it saying is nil?

[reef remnant]

Hm. Could be an issue with order? What does your explosion() function inside the autoload look like now?

[iron steppe]

func explosion(position: Vector2, radius: float):
var explosion = explosion_class.instantiate()
explosion.radius = radius
explosion.position = position
explosion.explode()

[reef remnant]

Oh, you haven't actually added it to the tree

You'll need to use add_child somewhere to do that

If you don't add it to the tree, then it never actually readies itself

[iron steppe]

so do i explode it after using add_child or before

[reef remnant]

After

[iron steppe]

but since its an autoload, what will it be a child of

[reef remnant]

The explosion could be a child of the autoload itself (that's totally fine, since an autoload is just a node)

There are other options, but for now that should work

I think the ideal is probably adding it as a child of the current level, so that it'd be removed when the level is unloaded

You can get the current scene using get_tree().current_scene

[iron steppe]

its going to be removed by itself anyway after i add the particle effects ( since i can only remove it after the particles are over )

but it still doesent add my tank in the bodies hit

P2 died
bodies hit []

[reef remnant]

Check the collision layers?

[iron steppe]

all are on 1

[reef remnant]

You can tick "Visible Collision Shapes" so you can see the area's shape appear

That might help with debugging?

[iron steppe]

ohh, i didnt know that was an option

ill go ahead and do that

yep its quite big

bigger than the screen infact

[reef remnant]

As an alternative to using .get_overlapping_bodies(), you could use the body_entered signal?

It might be the case that you're asking the area for overlapping bodies before it's gotten a chance to check for them

[iron steppe]

is that even possible?

[reef remnant]

Yeah, that kind of thing can happen in some cases

[iron steppe]

how would i impliment it with the body entered signal, have an array and append it for every time the signal is called?

[reef remnant]

You could, or you could just apply the effect inside the on_body_entered implementation

[iron steppe]

oh right

[reef remnant]

No need to maintain a list in most cases

[iron steppe]

oh ok nice it lists the bodies now

[reef remnant]

:D

[iron steppe]

wierd, i implimented the damage function in it

func _on_explosion_area_body_entered(body: Node2D) -> void:
print(str(body))
if(body is TANK):
body.damage()

and it just drains all the hp and destroys the game

like literally hangs it

ahh

i got it

since i do damage but dont delete the tanks when they die

they just keep killing each other using explosions

[reef remnant]

Oop

[iron steppe]

nice the explosion finally works

tysm

[reef remnant]

Glad to hear!

I remember you wanted to make it not hit things behind walls?

[iron steppe]

oh yeah, i havent implimented that yet, since i dont really have any objects in my game, im implimenting explosion particles first. but that should be easy enough (famous last words)

tbh i feel like i should have started with either using unity or godot with C#, since i aldready knew java and C# is apparently just microsoft flavor java

[reef remnant]

mm..

Godot does support C#

But not fully, to a degree

[iron steppe]

yeah i think now that ive started with GDscript im just going to continue

[reef remnant]

I know there's issues with web builds when using C#, for instance

[iron steppe]

oof, still godot better than unity cuz open source

[reef remnant]

Which, for me, was an instant massive issue.

GDScript is a perfectly good language

And not hard to learn

I think it fits Godot well

[iron steppe]

true

[reef remnant]

For me, until Godot C# has support for web builds, I can't even consider using it. Web builds are just too important for the things I do (almost entirely game jams)

[iron steppe]

i think over time GD script might get some of the features of C#

[reef remnant]

That and, I've become really comfortable with GDScript at this point

[iron steppe]

so it might be worth holding out

seriously though interfaces are like quite a common thing

weird that they arent in godot

[reef remnant]

I get what you mean, but they're kind of unnecessary because of the philosophy of the language.

[iron steppe]

wdym

[reef remnant]

Kind of. They'd still have uses, of course.

In GDScript, the idea is that you don't care so much whether a certain object implements an interface or is of a certain class, you care about what it can do. If you want to damage it, just check if it can be damaged, no need to check if it's a player or an enemy or what have you. That's why you have stuff like the has_method() function

Of course, that's not the entirety of the language's philosophy.

[iron steppe]

oh nice

[iron steppe]

tbh thats kinda janky

cuz you might name it slightly different accidentally in some classes

or might forget to impliment the function

but ig it works

[reef remnant]

Godot really isn't meant for huge games

Stuff like that becomes more important as scale increases

But with smaller games and smaller teams, stuff like that is much easier to just go in and fix

[iron steppe]

fair ig, but you shouldnt be needing to fix it in the first place

[reef remnant]

With an interface, you can still forget to implement the interface, or one of the functions

If the argument is "you could forget to do something", then that can always happen

I'm not saying it's a perfect system. Interfaces would have uses.

But you honestly get used to it

[iron steppe]

fair

[normal badge]

the problem now is how to set the explosion's targets and stuff like collision layers. which could be solved by simply having different packed scenes

[reef remnant]

Or including them as parameters (probably with default values)

[iron steppe]

ig i could, just have an explosion scene and duplicate it and put the explosion function in the scene itself

but atp idc, i aldready implimented the global so i might as well use it

im new to godot so some of my structuring decisions do end up a bit weird

but we improve with time

👍

[normal badge]

just wanted to share some ideas, but yea, anything works if it works

[normal badge]

this is the main advantage