2D Shoot Mechanics: Top down, mouse aim?

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:bust_in_silhouette: Asked By jim

Hello! Im quite new to Godot engine, and even with a few tutorials and the manual, I still need help understanding what im doing wrong here…

In essence: I have a character with its own movement script. How can i shoot a bullet from my character towards my mouse position in a 2D game, while using an area2D node?

I’ve tried to implement the following code, but the trajectory of the projectile makes little sense to me…

Gun Script

extends Area2D
var shoot

export (PackedScene) var laser
onready var Laser_container = get_node("Laser_container")

func _shoot():
    var pew = laser.instance()
    Laser_container.add_child(pew)

    pew._start_at(get_angle_to(get_global_mouse_position()), get_position())

Laser shot

extends Area2D
var velocity = Vector2()
export var speed = 1000

func _start_at(dir, pos):
    set_rotation(dir)
    set_position(pos)

    velocity = Vector2(speed, 0).rotated(dir + PI/2)


func _process(delta):
    set_position(get_position() + velocity * delta)

It just sorta…goes all over the place. I’ve seen a few instances of people using rigidbodies or kinematics to do it, but i wanted to keep the project simple, with the option of returning and altering it at a later time.

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:bust_in_silhouette: Reply From: Bartosz

Ok fast course on shooting lasers in desire direction (my personal flavor)

Lets split shooting in steps
Inside gun script:

  1. Instantiate laser var pew = laser.instance()
  2. Make laser adjust itself to your design: laser.shot(global_position,get_global_mouse_position())

Inside laser script in shoot method:

  1. set it in the right place global_position = gun_position
  2. find in what direction laser is shoot var direction = (aim_position - global_position).normalized()
  3. make laser point in that direction rotation = direction.angle()
  4. make laser moving rotation = direction.angle()

Inside laser script in _process method:

  1. make it fly in desired direction `position += direction * speed * delta

code would look like this:

Gun script:

extends Area2D
var shoot

export (PackedScene) var laser
onready var Laser_container = get_node("Laser_container")

func _shoot():
    var pew = laser.instance()
    Laser_container.add_child(pew)

    pew.shoot(get_global_mouse_position(), global_position)

Laser script

extends Area2D
var direction = Vector2()
export var speed = 1000

func shoot(aim_position, gun_position):
    global_position = gun_position
    direction = (aim_position - gun_position).normalized()
    rotation = direction.angle()

func _process(delta):
    position += direction * speed * delta

Awesome Bartosz! Just one small detail: My laser shot ends up going sideways in the direction of the click (its kindda like a bolt or capsule instead of round bullet, so its sideways)…any tips?

Thanks again!

jim | 2018-03-25 03:56

If I understand you correctly you’re saying that lase sprite is rotated 90 degrees of what it suppose to be. To correct that just apply adjustment rotation. Because 90degrees == 0.5*PI radians you need to modify this rotation = direction.angle() to that rotation = direction.angle() + 0.5 *PI

Bartosz | 2018-03-25 13:31

That did the trick! Thanks again Bartosz!

jim | 2018-03-26 05:00

Thanks, that helped me!

Goathier | 2020-02-04 03:59