Shared screen local co-op game

Help
1

Godot Version

v4.7.1-stable

Question

I want to make a 2D Co-op Bullet-Hell Boss Rush game.

And I want the game to share the camera with all the four players. As everyone is going to be on a small ship.

And have all their controls.

But I’m struggling to make godot know what index controls to use for each players.

class_name PlayerControls extends Resource

@export var player_index := 0
@export var move_left := "p" + str(player_index) + "_move_left"
@export var move_right := "p" + str(player_index) + "_move_right"
@export var jump := "p" + str(player_index) + "_jump"
var assigned_player = "player" + str(player_index)


# Called when the node enters the scene tree for the first time.
func _ready():
	if assigned_player == 0:
		print("you")


# Called every frame. 'delta' is the elapsed time since the previous frame.
func _process(delta):
	if assigned_player == 0:
		print("you")

image
image306×457 9.78 KB

image
image1195×578 32.8 KB

image
image1189×615 38.3 KB

extends CharacterBody2D

const SPEED = 100.0
const JUMP_VELOCITY = -200.0

func _enter_tree():
	set_multiplayer_authority(int(str(name)))

func _ready():
	if !is_multiplayer_authority():
		$CharacterBase.modulate = Color.RED

func _physics_process(delta):
	if !is_multiplayer_authority():
		return
	
	# Add the gravity.
	if not is_on_floor():
		velocity += get_gravity() * delta

	# Handle jump.
	if Input.is_action_just_pressed("jump") and is_on_floor():
		velocity.y = JUMP_VELOCITY

	# Get the input direction and handle the movement/deceleration.
	# As good practice, you should replace UI actions with custom gameplay actions.
	var direction = Input.get_axis("left", "right")
	if direction:
		velocity.x = direction * SPEED
	else:
		velocity.x = move_toward(velocity.x, 0, SPEED)

	move_and_slide()
2

Let’s break this down:

  • Right now you don’t have distinct input actions for your players. `p2_move_left` and `p3_move_left` accept the same input. See where it says “All Devices”? You need to change that to only accept input from one device, a different one for each player.
  • `PlayerControls` is a `Resource`, not a `Node`. That means that `_ready` and `_process` never get called. You could turn it into a node, or you could dump those functions (which aren’t doing anything interesting anyway). Or you could inline that functionality into your player script.
  • Your initialization of `move_left`, `move_right` and `jump` happens once, before exported variables are loaded, when `player_index` still has its initial value of 0. You will have to set these variables manually. If `PlayerControls` were a node, you could change these @export variables into an @onready variable, which would update them automatically.
  • Your player script doesn’t use `PlayerControls`, so none of the changes to `PlayerControls` matter. You can add an @export variable of type `PlayerControls`, set it in the inspector (different values for different players), and use it.
3 
class_name PlayerControls extends Node

@export var player_index := 0
@onready var move_left := "p" + str(player_index) + "_move_left"
@onready var move_right := "p" + str(player_index) + "_move_right"
@onready var jump := "p" + str(player_index) + "_jump"
var assigned_player = "player" + str(player_index)


# Called when the node enters the scene tree for the first time.
func _ready():
	if assigned_player == 0:
		print("you")


# Called every frame. 'delta' is the elapsed time since the previous frame.
func _process(delta):
	if assigned_player == 0:
		print("you")

I changed the script to a Node.

And added a node to all the players.

image
image1919×708 112 KB

But when I play the game, only the first player is able to move.

I can send you the godot game if you want.

4

Post the input/movement code.

5

extends CharacterBody2D

const SPEED = 100.0
const JUMP_VELOCITY = -200.0

func _enter_tree():
set_multiplayer_authority(int(str(name)))

func _ready():
if !is_multiplayer_authority():
$CharacterBase.modulate = Color.RED

func _physics_process(delta):
if !is_multiplayer_authority():
return

# Add the gravity.
if not is_on_floor():
	velocity += get_gravity() * delta

# Handle jump.
if Input.is_action_just_pressed("p1_jump") and is_on_floor():
	velocity.y = JUMP_VELOCITY

# Get the input direction and handle the movement/deceleration.
# As good practice, you should replace UI actions with custom gameplay actions.
var direction = Input.get_axis("p1_move_left", "p1_move_right")
if direction:
	velocity.x = direction * SPEED
else:
	velocity.x = move_toward(velocity.x, 0, SPEED)

move_and_slide()
6

According to this, you’re always getting the input vector for p1_* actions.

Shouldn’t that be Input.get_axis(move_left, move_right) since you assign the corresponding action names to those variables here:

@onready var move_left := "p" + str(player_index) + "_move_left"
@onready var move_right := "p" + str(player_index) + "_move_right"
7

In the game, when I click on Join, on the second game screen, the second player doesn’t show up.

And doesn’t move.

But it does appear in the host’s screen. the First screen.

image
image1828×479 2.36 KB

8

Do you have a multiplayer synchronizer in the player node? You would synchronize the position and it would update all the peers