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.
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The main game scene¶
Now it's time to bring everything we did together into a playable game scene.
Create a new scene and add a Node named Main
.
(The reason we are using Node instead of Node2D is because this node will
be a container for handling game logic. It does not require 2D functionality itself.)
Click the Instance button (represented by a chain link icon) and select your saved
player.tscn
.
Ora, aggiungi i seguenti nodi come figli di Main
, e rinominali come mostrato (i valori sono in secondi):
Timer (chiamato
MobTimer
) - per controllare la frequenza con cui i mob si generanoTimer (chiamato
ScoreTimer
) - per incrementare il punteggio ogni secondoTimer (chiamato
StartTimer
) - per dare un ritardo prima di iniziareMarker2D (named
StartPosition
) - to indicate the player's start position
Imposta la proprietà Wait Time
di ciascuno dei nodi Timer
come segue:
MobTimer
:0.5
ScoreTimer
:1
StartTimer
:2
In addition, set the One Shot
property of StartTimer
to "On" and set
Position
of the StartPosition
node to (240, 450)
.
Generazione dei Mostri¶
Il nodo Main genererà nuovi mob, e vogliamo che appaiano in una posizione casuale sul bordo dello schermo. Aggiungi un nodo Path2D chiamato MobPath
come figlio di Main
. Quando selezioni Path2D
, vedrai alcuni nuovi pulsanti nella parte superiore dell'editor:
Select the middle one ("Add Point") and draw the path by clicking to add the points at the corners shown. To have the points snap to the grid, make sure "Use Grid Snap" and "Use Smart Snap" are both selected. These options can be found to the left of the "Lock" button, appearing as a magnet next to some dots and intersecting lines, respectively.
Importante
Disegna il percorso in ordine orario, o i tuoi nemici verranno generati verso l'esterno invece che verso l'interno!
Dopo aver posizionato il punto 4
nell'immagine, fare clic sul pulsante "Chiudi curva" e la curva sarà completa.
Ora che il percorso è definito, aggiungere un nodo :ref:'PathFollow2D <class_PathFollow2D>' come figlio di ''MobPath'' e denominarlo ''MobSpawnLocation''. Questo nodo ruoterà automaticamente e seguirà il percorso mentre si muove, quindi possiamo usarlo per selezionare una posizione e una direzione casuali lungo il percorso.
La tua scena dovrebbe assomigliare a questa:
Script principale¶
Add a script to Main
. At the top of the script, we use
@export var mob_scene: PackedScene
to allow us to choose the Mob scene we want
to instance.
extends Node
@export var mob_scene: PackedScene
var score
using Godot;
public partial class Main : Node
{
// Don't forget to rebuild the project so the editor knows about the new export variable.
[Export]
public PackedScene MobScene { get; set; }
private int _score;
}
Click the Main
node and you will see the Mob Scene
property in the Inspector
under "Script Variables".
Puoi assegnare il valore di questa proprietà in due modi:
Drag
mob.tscn
from the "FileSystem" dock and drop it in the Mob Scene property.Click the down arrow next to "[empty]" and choose "Load". Select
mob.tscn
.
Next, select the instance of the Player
scene under Main
node in the Scene dock,
and access the Node dock on the sidebar. Make sure to have the Signals tab selected
in the Node dock.
You should see a list of the signals for the Player
node. Find and
double-click the hit
signal in the list (or right-click it and select
"Connect..."). This will open the signal connection dialog. We want to make a
new function named game_over
, which will handle what needs to happen when a
game ends. Type "game_over" in the "Receiver Method" box at the bottom of the
signal connection dialog and click "Connect". You are aiming to have the hit
signal
emitted from Player
and handled in the Main
script. Add the following code
to the new function, as well as a new_game
function that will set
everything up for a new game:
func game_over():
$ScoreTimer.stop()
$MobTimer.stop()
func new_game():
score = 0
$Player.start($StartPosition.position)
$StartTimer.start()
public void GameOver()
{
GetNode<Timer>("MobTimer").Stop();
GetNode<Timer>("ScoreTimer").Stop();
}
public void NewGame()
{
_score = 0;
var player = GetNode<Player>("Player");
var startPosition = GetNode<Marker2D>("StartPosition");
player.Start(startPosition.Position);
GetNode<Timer>("StartTimer").Start();
}
Now connect the timeout()
signal of each of the Timer nodes (StartTimer
,
ScoreTimer
, and MobTimer
) to the main script. StartTimer
will start
the other two timers. ScoreTimer
will increment the score by 1.
func _on_score_timer_timeout():
score += 1
func _on_start_timer_timeout():
$MobTimer.start()
$ScoreTimer.start()
private void OnScoreTimerTimeout()
{
_score++;
}
private void OnStartTimerTimeout()
{
GetNode<Timer>("MobTimer").Start();
GetNode<Timer>("ScoreTimer").Start();
}
In _on_mob_timer_timeout()
, we will create a mob instance, pick a random
starting location along the Path2D
, and set the mob in motion. The
PathFollow2D
node will automatically rotate as it follows the path, so we
will use that to select the mob's direction as well as its position.
When we spawn a mob, we'll pick a random value between 150.0
and
250.0
for how fast each mob will move (it would be boring if they were
all moving at the same speed).
Nota che una nuova istanza deve essere aggiunta alla scena usando add_child()
.
func _on_mob_timer_timeout():
# Create a new instance of the Mob scene.
var mob = mob_scene.instantiate()
# Choose a random location on Path2D.
var mob_spawn_location = get_node("MobPath/MobSpawnLocation")
mob_spawn_location.progress_ratio = randf()
# Set the mob's direction perpendicular to the path direction.
var direction = mob_spawn_location.rotation + PI / 2
# Set the mob's position to a random location.
mob.position = mob_spawn_location.position
# Add some randomness to the direction.
direction += randf_range(-PI / 4, PI / 4)
mob.rotation = direction
# Choose the velocity for the mob.
var velocity = Vector2(randf_range(150.0, 250.0), 0.0)
mob.linear_velocity = velocity.rotated(direction)
# Spawn the mob by adding it to the Main scene.
add_child(mob)
private void OnMobTimerTimeout()
{
// Note: Normally it is best to use explicit types rather than the `var`
// keyword. However, var is acceptable to use here because the types are
// obviously Mob and PathFollow2D, since they appear later on the line.
// Create a new instance of the Mob scene.
Mob mob = MobScene.Instantiate<Mob>();
// Choose a random location on Path2D.
var mobSpawnLocation = GetNode<PathFollow2D>("MobPath/MobSpawnLocation");
mobSpawnLocation.ProgressRatio = GD.Randf();
// Set the mob's direction perpendicular to the path direction.
float direction = mobSpawnLocation.Rotation + Mathf.Pi / 2;
// Set the mob's position to a random location.
mob.Position = mobSpawnLocation.Position;
// Add some randomness to the direction.
direction += (float)GD.RandRange(-Mathf.Pi / 4, Mathf.Pi / 4);
mob.Rotation = direction;
// Choose the velocity.
var velocity = new Vector2((float)GD.RandRange(150.0, 250.0), 0);
mob.LinearVelocity = velocity.Rotated(direction);
// Spawn the mob by adding it to the Main scene.
AddChild(mob);
}
Importante
Why PI
? In functions requiring angles, Godot uses radians,
not degrees. Pi represents a half turn in radians, about
3.1415
(there is also TAU
which is equal to 2 * PI
).
If you're more comfortable working with degrees, you'll need to
use the deg_to_rad()
and rad_to_deg()
functions to
convert between the two.
Testare la scena¶
Let's test the scene to make sure everything is working. Add this new_game
call to _ready()
:
func _ready():
new_game()
public override void _Ready()
{
NewGame();
}
Let's also assign Main
as our "Main Scene" - the one that runs automatically
when the game launches. Press the "Play" button and select main.tscn
when
prompted.
Suggerimento
If you had already set another scene as the "Main Scene", you can right
click main.tscn
in the FileSystem dock and select "Set As Main Scene".
Dovresti essere in grado di muovere il giocatore, vedere i nemici che vengono generati e vedere il giocatore scomparire quando viene colpito da uno di essi.
Quando sei sicuro che tutto funzioni, rimuovi la chiamata a new_game()
da _ready()
.
What's our game lacking? Some user interface. In the next lesson, we'll add a title screen and display the player's score.