Mobs in 3D tutorial "Squash the creeps" don't move

EFrion

I'm following the 3D tutorial Squash the Creeps using Godot 4.1.2 on Ubuntu 22.04. At some point, the mobs are instantiated but they are not moving. I'm sure the mob scene is called from the main scene since the mobs appear. The player can move as intended too. I believe the _physics_process function from the mob script, and therefore its move_and_slide() function, is actually never called (print("Physics process in mob is called!") is not appearing using the code below, but the prints in initialize work).

The code I'm using comes from the tutorial. For the main scene, this is

extends Node

@export var mob_scene: PackedScene

func _on_mob_timer_timeout():
    var mob = mob_scene.instantiate()

    # Choose a random location on the SpawnPath.
    # We store the reference to the SpawnLocation node.
    var mob_spawn_location = get_node("SpawnPath/SpawnLocation")
    # And give it a random offset.
    mob_spawn_location.progress_ratio = randf()

    var player_position = $Player.position
    mob.initialize(mob_spawn_location.position, player_position)

    # Spawn the mob by adding it to the Main scene.
    add_child(mob)

and for the mob script

extends CharacterBody3D

@export var min_speed = 10
@export var max_speed = 18

func _physics_process(_delta):
    print("Physics process in mob is called!")
    print(is_on_floor()) #Just a test to see if the mob touches the floor
    move_and_slide()

func initialize(start_position, player_position):
    print("Start_position,player_position",start_position, player_position)
    look_at_from_position(start_position, player_position, Vector3.UP)

    # Rotate this mob randomly within range of -90 and +90 degrees,
    # so that it doesn't move directly towards the player.
    rotate_y(randf_range(-PI / 4, PI / 4))

    # We calculate a random speed (integer)
    var random_speed = randi_range(min_speed, max_speed)
    print("Random speed ",random_speed)

     # We calculate a forward velocity that represents the speed.
     velocity = Vector3.FORWARD * random_speed
     print("Velocity ",velocity)
     # We then rotate the velocity vector based on the mob's Y rotation
     # in order to move in the direction the mob is looking.
     velocity = velocity.rotated(Vector3.FORWARD, rotation.y)
     print("Velocity final ",velocity)
     print("Position of the mob ", position)

Toxe

EFrion Do you get any errors? Does your mob code look exactly like the one you posted? Because from the line # We calculate a forward velocity that represents the speed the code indentation is wrong and the code won't run like this.

Tomcat

EFrion I never use spaces when indenting

But it was the extra spaces in your code that I copied from here.

EFrion and for the mob script

Try copying my code — what will you get? I have a tab.

EFrion

Toxe There is no error, and the code is indeed the same (maybe the copy pasting was poorly done, sorry!).

Toxe

EFrion Looks all fine to me.

Toxe

EFrion Have you used the debugger before? You could add breakpoints to the first lines of _physics_process() and initialize() and then run the project (F5) and check if the debugger stops in your functions. If it doesn't then that means they don't get called.

EFrion

Toxe I never have, so I gave it a try, and indeed _physics_process() is never called, but initialize() is! I checked whether the argument was relevant by using _physics_process(_delta): with an underscore instead of _physics_process(delta): but it doesn't matter.

I'm not sure whether this is related to Godot's version. I first tried this project with 4.1.1 but I had to switch to 4.1.2 because of driver issues.

Tomcat

For begin, there are extra spaces in your code, starting with:

20	var random_speed = randi_range(min_speed, max_speed)

and to the end of the code.

If you have problems with the code from the tutorial, copy it from the tutorial itself and paste it. See where you went wrong in typing the code.

For some reason you use spaces instead of tabs for indentation — it's easier to make a mistake that way.

EFrion

Tomcat Hi, this is what I've done. I never use spaces when indenting, so I guess they come from writing my issue here!

EFrion

Tomcat The spaces don't change the behaviour, unfortunately. I tried copy/pasting your code, but that's not the issue.

In any case, I tried commenting the initialize() function and adding a mob directly onto the main scene but, even like this, the mob stays idle.

DaveTheCoder

Can you upload the project folder as a .zip, with the .godot subfolder excluded?

That tutorial has this note, so it's possible that it has mistakes:

Work in progress

The content of this page was not yet updated for Godot 4.1 and may be outdated. If you know how to improve this page or you can confirm that it's up to date, feel free to open a pull request.

https://docs.godotengine.org/en/4.1/getting_started/first_3d_game/index.html

Toxe

DaveTheCoder That tutorial has this note, so it's possible that it has mistakes:

A couple of months ago I did this tutorial without any issues. The sample source code on GitHub was outdated but the code in the manual was fine.

EFrion

DaveTheCoder

squashcreeps.zip

2MB

Here it is! I also ignored the .import folder when creating the zip file.

Toxe

EFrion You are mixing tab and spaces indentation. Pick either only using spaces or only using tabs but don't mix both.

Tomcat

EFrion Here it is!

You put the mob scene in the main scene for some reason. This is not in the tutorial.

I would suggest that you start doing the lesson from the beginning, following the tutorial exactly and with extra attention to detail.

EFrion

Toxe I don't, I only use tabs. I don't have this error popping out on my computer

Toxe

EFrion I don't, I only use tabs. I don't have this error popping out on my computer

You clearly don't use tabs on line 42 and 43.

EFrion

Toxe
I do. I've tried cleaning any possible space indent by doing ctrl+tab and ctrl+shift+tab everywhere in my scripts. The code runs, so I don't believe indentation is the issue here

Toxe

EFrion I do. I've tried cleaning any possible space indent by doing ctrl+tab and ctrl+shift+tab everywhere in my scripts.

Then you gave us old and outdated code to look at.

spaceyjase

In the scene tree, you have the visibiltiy screen notifier's visibility disabled, which prevents the mob from working. Enable it.

From the docs:

The VisibleOnScreenEnabler3D will disable RigidBody3D and AnimationPlayer nodes when they are not visible. It will only affect other nodes within the same scene as the VisibleOnScreenEnabler3D itself.

DaveTheCoder

spaceyjase visibiltiy screen notifier's visibility disabled

That's an odd and unexpected side effect. The documentation should mention that. Maybe there should be a warning in the editor as well, as there are for other situations such a missing shape. If I feel motivated, I'll submit that as an issue.
https://docs.godotengine.org/en/4.1/classes/class_visibleonscreenenabler3d.html

Actually, the tutorial says to use a VisibleOnScreenNotifier3D, not a VisibleOnScreenEnabler3D. That might have avoided the problem. But it's an easy mistake to make.
https://docs.godotengine.org/en/4.1/getting_started/first_3d_game/04.mob_scene.html#removing-monsters-off-screen

Tomcat

DaveTheCoder Actually, the tutorial says to use a VisibleOnScreenNotifier3D, not a VisibleOnScreenEnabler3D.

This is not in the originally submitted piece of code at all. I guess it didn't get to that point then.

EFrion

DaveTheCoder I opened an issue suggesting to implement this enhancement in the editor.