# Guide to the Godot game engine/Signals and methods

Guide to the Godot game engine
<-- Resources and importing Signals and methods Your first game-->
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Many Godot users will say to you "signal up, call down" if you ask for tips with coding. Just what does this mean?

## Signals

Select a node from the Scene dock. Press the "Node" tab next to the inspector. A list will appear. These are signals.
Create a new scene. Press User Interface. Save it as Signal test.tscn. Add two nodes: a Button and a Label, both as children of the Control. Use the Layout button to center the Button to the screen. Set the Text property to Press Me in the inspector.
Now add a script to the Control root node (the first one). Select the Button. Open the Node dock, and double click "button_up". A popup will appear with your scene root (the Control node) selected. A text edit should say _on_Button_button_up. Press "Connect".
This will create the code
This function will be called when the signal button_up is emitted. Add the code print("You pressed me!") to the function. You may remove the pass # Replace with function body. if you wish.
Run the scene by pressing F6, and grant that button's wish!
You can make your own signals with signal <signal_name> <optional:(argument1: type, argument2: type, ect)> in GDScript. To emit it in a function: emit_signal(<"signal_name">, <argument1>,<argument2 ect.>).

## Calling

Just as important as signals, calling allows many things to happen. Add $Label.text = "You pressed me!" to the function. This is actually setting a variable, but it's still considered calling, as setting a variable uses a setter function. More on those in another chapter.
The $path is a short hand for the get_node(path) function. The Label is the path argument. This allows direct manipulation of the child node of that name.
These are called NodePaths. They work a bit like file paths, and this is a common example: $weapon/art.texture = preload("res://assets/weapons/upgraded_sword.png"), and can also be relative, like (called in res://game/player.gd) /weapons/upgraded_sword.tscn.
A global get_node looks like /root/game/player/weapon/art.
For more, please see GDScript: Manipulating the SceneTree.

## Signal up and call down

It means, if you are calling methods on another node, use signals for calling parents (to decrease code complexity) and use methods when calling children (to increase readability and freedom).

## What you have learned

* How to get a child node.
* How to connect a signal.
* How to set a property of another node (With the ".". You can use it to call their functions too!)

## Quiz
### Guide to the Godot game engine

    Getting started
       Installation
       What is a node?
       Programming
       Resources and importing
       Signals and methods
       Your first game
    Making it work
       Debugging
       Input
       Physics
       Saving and loading
       Multiplayer
    Making it look good
       UI skinning
       Animation
    Advanced help
       Servers (singletons)
       Platform specific
       Optimisation
       Encryption
       Exporting
       Plugins
    Miscellaneous
       Helpful links
       Authors and contributors
       Print version
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