getting_started/first_2d_game/06.heads_up_display

[giscus[bot]]

getting_started/first_2d_game/06.heads_up_display

The final piece our game needs is a User Interface (UI) to display things like score, a "game over" message, and a restart button. Create a new scene, click the "Other Node" button and add a Canvas...

https://docs.godotengine.org/en/stable/getting_started/first_2d_game/06.heads_up_display.html

[MountainWizard]

In the last part about "removing old creeps" the newest version of Godot now supports global and scene groups.
Click the + to add a new group and give it the name mobs. You don't need to make it a global group since the group does only apply to the mobs node.

[ThomasCrane]

C# users must change the connections under the Node tab to C# nomenclature, not the default it provides you.

Change these:

_on_start_button_pressed
_on_message_timer_timeout

to:

OnStartButtonPressed
OnMessageTimerTimeout

or, if you've already created the script as guided, you can select the Pick button to the right of the text field when editing the connection, and then select the appropriate method.

[K-Princ]

why am i not able to connect start_game signal of HUD node to new_game() function of Main node?

[MountainWizard]

Make sure you have a signal start_game in your HUD script. The connect the start button pressed node to you script to create the func _on_start_button_pressed(): function. And in the function you need the start_game.emit() to send the signal.
Then in Main connect the start_game node to the script. Something that confused met at first was, that you need to run the game from the Main Scene. If you have the HUD scene selected and press F6 to run the Game it doesn't work.

[gerritnowald]

The main scene from which the game starts can be set under:
Project Settings --> Application --> Run --> Main Scene

[K-Princ]

when i am trying to connect start_game signal of HUD node to new_game() function of Main node , I can't find the function new_game() in the options in the pop?

[GoutteDooo]

Did you write signal start_game in top of hud.gd script ?

[BastardSeagull]

Make sure you're in the HUD node under Main, not accidentally looking at your HUD scene.
I made that mistake, and it took me a sec to realize it.

[Roedhip]

When I create a new group named "mobs" and use the code to clear all mobs, the Player and the HUD are also cleared. I assume the problem is that they are being included the in mobs group, but I have no idea how this group is supposed to know what is inside it anyway. How do I make sure the "mobs" group only contains instances of Mob?

[Roedhip]

I have now looked up groups in the Godot documentation and found commands for adding Nodes to a group. By adding the line:

mob.add_to_group("mobs")

to the end _on_mob_timer_timeout() function, I can be sure all mobs that are created are added to the "mobs" group. I then unselected the "mobs" group in Main node so that Main was not in the "mobs" group any more. This fixed my problem.

[rmondragon]

After reading some of the comments, what it worked for me was :

• Be sure that "mobs" groups was created only in Mob scene and not in any other scenes by mistake with the same name.

• Make the group 'mobs" type Scene (no Global) to the main node of the Mob scene. Just the main one, I didn't need to select all sub-nodes. If you make it GLOBAL , it will show up on Main scene, available for all sub scenes.

• Add GetTree().CallGroup("mobs", Node.MethodName.QueueFree); at the end of `Main.GameOver.

I don't think that you need to do call mob.addGroup("mobs") b/c any instance of Mob will be part of "mobs" group b/c it was checked in Mob scene.

[BastardSeagull]

Something breaking down between my _on_start_button_pressed and new_game, not sure what I'm missing.

Tried disconnecting and reconnecting, but no change. new_game triggers fine if I have _ready call it. I'm seeing the debug print I added for the start button press.

Best I can tell is the signal isn't being emitted.
Debugger is giving me "Standalone expression (the line may have no effect)." for my start_game.emit line, but it's identical to the finished project (pasting that in also doesn't resolve the bug).

Anyone have an idea what's breaking down?

Here's my _on_start_button_pressed:

func _on_start_button_pressed():
	print("Debug: Start Button pressed")
	$StartButton.hide()
	start_game.emit

Here's my new_game:

func new_game():
	print("Debug: new_game called")
	score = 0
	$Player.start($StartPosition.position)
	$StartTimer.start()
	$HUD.update_score(score)
	$HUD.show_message("Get Ready")

[Roedhip]

Have you connected the start_game() signal from your HUD node to the new_game() function in main.gd?

You can check if they are connected by selecting the HUD node in your main scene and looking at its signals in the right hand panel (in this panel, select "Node" from "Inspector"/"Node"/"History", and then make sure you are on "Signals" not "Groups"). At the top of the list of signals you should see the hud.gd category, and underneath it start_game(). In my scene, there is a green arrow underneath start_game() that points to new_game().

If this connection isn't there, here is the line from the tutorial above that explains how to make the connection:
In the Node tab, connect the HUD's start_game signal to the new_game() function of the Main node by clicking the "Pick" button in the "Connect a Signal" window and selecting the new_game() method or type "new_game" below "Receiver Method" in the window. Verify that the green connection icon now appears next to func new_game() in the script.

If the connection is there and is spelled correctly, I don't know what is going wrong.

[BastardSeagull]

Unfortunately I have; that's why I'm confused.

Looks like it's time to join the Discord!

[BastardSeagull]

I was just missing the () after emit. Whoops!

[sec-knight]

I was crashing with an error that it couldn't find "$HUD.update_score(score)" and I had to poke around for the solution. Mine was named #hud and not #HUD. Case matters apparently, because I fixed the case and the game works fine.

Hope that makes sense and helps someone.

[InfieldTriple]

So I worked through this over a couple of days and I was a bit confused at the end because I realized that I never added my mob scene to the Main tree. So I was left wondering "how the f is this even connected?" Of course it was a bit simple to solve by simply going backwards. But I wonder if it would be useful to show the mob scene in the tree somehow. Basically to show its being used by Mobpath. Maybe this would be good for a small game like this, and would be problematic in a complicated scene.

[jsonjunkie]

it isn't that the MobPath is using the mob scene, it is the other way around.

the mob scene uses MobPath to give an instantiated mob its positioning and related values like direction and velocity.

all this happens in the _on_mob_timer_timeout() function (in the script attached to the main scene) including the instantiation of a mob into the main scene:

var mob = mob_scene.instantiate()

[just1and0s]

Hi all, I have having an issue after pressing Start button. Error message: Attempt to call function 'start' in base 'null instance' on a null instance. There seems to be an issue with the message timer activation. 3 things were called onto the stack frames and the corresponding code below:

0. hud.gd at function: show_message

func show_message(text):
	$Message.text = text
	$Message.show()
	$MessageTimer.start()

1. main.gd at function: new_game

func new_game():
	score = 0
	$Player.start($StartPosition.position)
	$StartTimer.start()
	$HUD.update_score(score)
	$HUD.show_message("Get Ready")
	get_tree().call_group("mobs", "queue_free")

2. hud.gd at function:_on_start_button_pressed

func _on_start_button_pressed():
	$StartButton.hide()
	start_game.emit()

Can anyone share where I went wrong?

[just1and0s]

1 extra S in the $MessageTimer.start() haha

[ItzTK]

Did you figure out the issue? Because just1and0s is just lying?

[MatthewWinchester0]

The instructions say to extend HUD from CanvasLayer. But if I do I get this error:

script inherits from native type ‘area2d’ so it cannot be instanced in object of type node

Changing it to "extends Node" works - I found a similar question posed online too so I was surprised not to see a similar comment here.

[BraveVN]

which version of Godot are you using?

[MatthewWinchester0]

v4.3.stable.official [77dcf97d8]

However, when I used the project files downloaded from the site, and fixed a couple of things because they didn't support 4.3, it works using "extends Canvas Layer". So I'm going to assume I did something wrong earlier and that is the real error.

[vncafecode]

strange, I used the same version and the same assets and everything in the tutorial worked fine

[LFAdams]

Hello I am having some issues with my scripts breaking at the

start_game.emit()

portion of the code. I have added

signal start_game

to the top of the HUD.gd script, under extends CanvasLayer, and linked the start game signal from later in the hud.gd script

func _on_start_button_pressed():
	$StartButton.hide()
	start_game.emit()

to the new_game() function in the main.gd script

func new_game():
	score = 0
	$Player.start($StartPosition.position)
	$StartTimer.start()
	$HUD.update_score(score)
	$HUD.show_message("Get Ready")
	get_tree().call_group("mobs", "queue_free")

Despite seemingly following the instructions, when I press the start button the game crashes, and the debugger identifies the line with start_game.emit() as the point where the code breaks. Can anyone tell me what I am doing wrong?

[LFAdams]

I deleted the line containing

start_game.emit()

and replaced it with

start_game.emit()

and it seems to work now, despite looking exactly the same to my eyes. I think there was some kind of hidden character messing it up or something.

[wuliwong]

I also had to start the ScoreTimer in the new_game function. I added the MobTimer.start() to it on the last tutorial section, it was also left out. I feel like I'm missing something but I can't seem to make it work without starting the timers when a new game starts. It also makes logical sense to start these timers when a new game starts. :shrugs:

	$ScoreTimer.start()
	$MobTimer.start()

[wuliwong]

Eesh, sorry, I should have previewed that before I sent it. Can't seem to edit it now. So anyway, here's my new_game function:

func new_game():
	get_tree().call_group("mobs", "queue_free")
	score = 0
	$Player.start($StartPosition.position)
	$HUD.update_score(score)
	$HUD.show_message("Get Ready")
	$StartTimer.start()
	$ScoreTimer.start()
	$MobTimer.start()

And this is connected the the HUD start_game method.

[jsonjunkie]

did you have your StartTimer node (with wait time set and one shot set to true) as a child of the root node of the main scene?

from there you have to connect that timer's timeout signal to the main scene and have it call _on_start_timer_timeout where the mob and score timers are set to start

func _on_start_timer_timeout():
	$MobTimer.start()
	$ScoreTimer.start()

after the set wait time passes for StartTimer, the function above should get called which in turn starts the mob and score timers

[ElectricZax]

Thanks to Calinou,
You can edit/delete comments from GitHub Discussions directly.
Login to GitHub and from #69 you can find your comment, then use drop-down menu to Edit or Delete your post.

https://ibb.co/7KZs9Xt

[freakyfrogboy24531]

I'm pretty sure I followed all the instructions but for some reason the score wont update. It merely stays at zero

[aniran96]

I am having the same issue.

[aniran96]

nvm. i got it. i was having issues with the timeout function.

[MuJame]

The groups tab is not giving me the option create a new group. godot 4btw

[GoutteDooo]

Can you show a screenshot ?

[MuJame]

deleted the project out of frustration sorry.