Instanced projectile firing toward mouse position is slight offset. 2D TOPDOWN

[left dagger]

Hello,

I have successfully made this eye shoot bullets, but they are slight offset, ChatGDP summarized the issue pretty well.

The slight offset you're experiencing might be due to the difference between the gun's rotation and the direction of the mouse cursor. When you set the rotation of the bullet instance to match the gun's rotation, it doesn't necessarily mean the bullet will move in the same direction as the mouse cursor.

Sadly, most of the help it gives is Godot 3.X and not fully up to date.
Here is the code from the player :

    if Input.is_action_just_pressed("fire"):
        shoot()
        
        
func shoot():
    
    var mousepos = get_viewport().get_mouse_position()
    var bullet_instance = bullet.instantiate()
    
    gun.look_at(mousepos)
    owner.add_child(bullet_instance)
    
    bullet_instance.global_position = gun.global_position
    bullet_instance.global_rotation = gun.global_rotation```

BULLET CODE :

```extends Area2D
var speed = 150
var direction = 0
# Called when the node enters the scene tree for the first time.
func _physics_process(delta):
    position += Vector2.from_angle(direction) * speed * delta    

S```

Find attached, a GIF of the issue.
Thanks !

[vast knoll]

chatgpt is pretty much useless for learning godot 4. free chatgpt 3.5, at least
it produces a lot of correct lines but makes way too much errors in between for a beginner to realize

we have great tutorial videos on youtube for almost any genre, i recommend checking those out since you can not only see some good code but also how to set it all up correctly in the editor

[left dagger]

oh yes, i am aware, it seems to run on a jan. 2022 database

i use it to ask wide questions, but never or rarely code itself since the syntax is outdated

i follow courses and tutorials on the side

[vast knoll]

alright, thats a good approach!

so theres a direction var in your bullet code but it isnt set anywhere, as far as i can tell. and you dont need it really.
the direction it should travel is already stored in its transform, since you assigned its rotation to the gun rotation.
position+= global_transform.x * speed * delta
would be the easier way to do this

adding the bullet to the owner might also be the wrong idea here, depending on who the owner is

i think its generally safer to add the bullet as a child to the root scene node get_tree().current_scene.add_child()

because if the owner of the bullet was the player, for example, it would still move and rotate with the player

[left dagger]

thank you for the answer! here is the Scene tree in live testing. Bullets are independent from the player.

[left dagger]

sadly this causes a similar problem

[left dagger]

thank you for the explanation though, i though owner and get_tree().current_scene.add_child() behaved the same, safe code is cool!

[fresh flint]

you want it to keep firing in a straight line ?

and not have any offset

[left dagger]

yes!

[fresh flint]

the reason for the offset is your transform is changing constatly

[left dagger]

by rotating the gun, it changes it's transform ?

[fresh flint]

yes

you are rotating it

ik a fix

try set the velocity of the bullet at the moment of instantiation

[left dagger]

ah, so i guess using look_at toward the mouse cursor wasn't a safe thing to do

[fresh flint]

i am just shooting out there but try

func shoot():
    var mousepos = get_viewport().get_mouse_position()
    var bullet_instance = bullet.instantiate()
    
    gun.look_at(mousepos)
    owner.add_child(bullet_instance)
    
    bullet_instance.global_position = gun.global_position
    bullet_instance.velocity = (mousepos -gun.global_position).normalized() * speed

bullet code in physics process

position += velocity * speed * delta

[left dagger]

trying

[vast knoll]

owner will refer to the most immediate scene parent. since your player is a scene, in this case if the script runs from the player node or any of its children it will refer to the player scene root node
btw, its common practice to have the physics body be the root node of your scene. so the player scene should have the CharacterBody as root

godot expects the default rotation to be facing right in 2d. if your gun sprite faces to the right look_at() should work in theory

[left dagger]

i haven't been able to apply your logic right now, i think there was an issue that my bullet tree has a parent on top of it, and right now that parent being a Node2D is receiving the logic and it doesn't like it. (Invalid set index 'velocity' (on base: 'Node2D (bulletmain.gd)') with value of type 'Vector2'.)
working on fixing that.

[left dagger]

i think it is a case of bad scene tree yes!

[vast knoll]

velocity isnt a built-in property, the comments above are a bit misleading

at least, for Areas it isnt

[left dagger]

even less for a base Node2D i assume

[vast knoll]

btw, the Area should be the root node of this scene here

[left dagger]

yes, changing

[fresh flint]

this i didnt knew

new info

but wait

area2d's dont have a velocity property either

[vast knoll]

only CharacterBody has a built-in velocityproperty

Rigidbodies have linear_velocity

[fresh flint]

yea

use linear velocity for that one

[left dagger]

tree is fixed, game isn't crashing, logic got applied on the bullet area2D node, bullet's aren't moving and despawning instantly (timer isn't the culprit)

[fresh flint]

yea show the code

for the bullet

[left dagger]

var speed = 150
var velocity = 200

## Called when the node enters the scene tree for the first time.
func _physics_process(delta):
    position += velocity * speed * delta


func _on_timer_2_timeout():
    queue_free()```

player logic below

    if Input.is_action_pressed("fire"):
        shoot()
        
        
func shoot():
    
    var mousepos = get_viewport().get_mouse_position()
    var bullet_instance = bullet.instantiate()
    
    gun.look_at(mousepos)
    owner.add_child(bullet_instance)
    
    bullet_instance.global_position = gun.global_position
    bullet_instance.velocity = (mousepos -gun.global_position).normalized() * speed```

[fresh flint]

hmm

what if you define velocity as a vector2

var velocity = Vector2()

or use your old code

but then that had angle in it

like

Here's how you can modify your shoot() function:

func shoot():
    var mousepos = get_viewport().get_mouse_position()
    var bullet_instance = bullet.instantiate()
    
    gun.look_at(mousepos)
    owner.add_child(bullet_instance)
    
    bullet_instance.global_position = gun.global_position + Vector2(bullet_instance.texture.get_width() / 2, 0).rotated(gun.rotation)
    bullet_instance.direction = (mousepos - gun.global_position).angle()

And here's how you can modify your _physics_process(delta) function:

func _physics_process(delta):
    position += Vector2.from_angle(direction) * speed * delta

look_at() is the culprit

i think

[left dagger]

testing

Invalid get index 'texture' (on base: 'Area2D (Bullet.gd)').

[fresh flint]

oh right wait

you need to get the texture size

save it in a variable

because

[left dagger]

22x22

[fresh flint]

yeah

try typing it in manually

22 / 2, 0

which is 11

so 11, 0

bullet_instance.global_position = gun.global_position + Vector2(11, 0).rotated(gun.rotation)

[left dagger]

good news

it's shooting

[fresh flint]

yay!

[left dagger]

bad news

[fresh flint]

its not straight ?

[left dagger]

yes

testing things

[fresh flint]

func shoot():
var mousepos = get_viewport().get_mouse_position()
var bullet_instance = bullet.instantiate()

bullet_instance.global_position = gun.global_position + Vector2(11, 0).rotated(gun.rotation)
bullet_instance.direction = (mousepos - gun.global_position).angle()
owner.add_child(bullet_instance)

[left dagger]

the weird thing, is that, even when it is centered (the gun / eye flies next to the player), it still has an offset

[fresh flint]

try that

[left dagger]

ok lol the spawnpoint changed but it's like, really really far away, also, sprite doesn't rotate anymore

[fresh flint]

lmao

func shoot():
var mousepos = get_viewport().get_mouse_position()
var bullet_instance = bullet.instantiate()

bullet_instance.global_position = gun.global_position + Vector2(11, 0).rotated(gun.rotation)
bullet_instance.rotation = gun.rotation
bullet_instance.direction = (mousepos - gun.global_position).angle()
owner.add_child(bullet_instance)

try this

[left dagger]

exact same issue

[fresh flint]

hmm

then idk lol

u can use your old code

[left dagger]

at least i fixed my tree issue

thank you for your time! i'll find a solution eventually

[left dagger]

Ok, found the culprit

var mousepos = get_viewport().get_mouse_position()

i just had to change it to : var mousepos = get_global_mouse_position()

final code for people that will travel through here :

BULLET

var speed = 150
# Called when the node enters the scene tree for the first time.
func _physics_process(delta):
    position+= global_transform.x * speed * delta```

PLAYER/GUN

    if Input.is_action_pressed("fire"):
        shoot()
        
func shoot():
    
    var mousepos = get_global_mouse_position()
    var bullet_instance = bullet.instantiate()
    
    gun.look_at(mousepos)
    owner.add_child(bullet_instance)
    
    bullet_instance.global_position = gun.global_position
    bullet_instance.global_rotation = gun.global_rotation```

@fresh flint FYI!