Creating the Bullet Scene

1. Scene Setup & Node Structure

Click the + icon next to your open scene tabs to create a New Scene.

-Click Other Node, search for Area2D, and select it as the root node.

-Rename the root Area2D node to bullet.

-With bullet selected, add two child nodes:

-Sprite2D

-CollisionShape2D

Scene Tree Structure

-bullet (Area2D)

-Sprite2D

-CollisionShape2D

2. Node Settings & Adjustments

-Sprite2D Setup:

-Select Sprite2D.

-Drag your (res://assets/kenney_space-shooter-remastered/PNG/Lasers/laserGreen11.png) texture file into the Texture property in the Inspector.

-Expand Transform and set Scale to x: 0.5, y: 0.5.

-CollisionShape2D Setup:

-Select CollisionShape2D.

-In the Inspector, set Shape to New RectangleShape2D.

-Under Size, set x: 4.0 px and y: 10.0 px.

-Expand Node2D Transform and set Position to x: 0.0 px, y: -8.0 px.

3. Save the Scene

-Press Ctrl + S (or Cmd + S on macOS).

-Save the scene file inside your scenes folder as res://scenes/bullet.tscn.

let's add a script to the bullet

-Select Root node bullet Create a script call it "bullet.gd"

-copy the code on your right and paste it to bullet.gd script

let's add signal to bullet script.

- Collision Signals

-Select the root bullet (Area2D) node in your Scene panel.

-Open the Node tab next to the Inspector panel on the right.

-Under Signals, double-click area_entered(area: Area2D)

-In the window that appears, select the bullet node and click Connect.

-Repeat the same steps for body_entered(body: Node2D): double-click it and hit Connect.

Code Breakdown

-extends Area2D: Inherits built-in 2D area detection for handling collisions.

-bullet_speed: Variables defining travel speed

-Bullet_life_time: lifetime duration.

-position -= transform.y * bullet_speed: Moves the bullet straight upward along its local Y-axis every frame.

-Bullet_life_time -= delta: Decreases the remaining lifespan value by frame time (delta).

-if bullet_speed < 1: queue_free(): Destroys the bullet (queue_free()) if speed drops below 1. (Note: Typically set to check Bullet_life_time <= 0).

-_on_area_entered(area): Triggered when hitting another Area2D node; destroys the bullet if the target belongs to the "enemy" group.

-_on_body_entered(body): Triggered when hitting a physics body (like StaticBody2D or CharacterBody2D); destroys the bullet if the target belongs to the "obstacle" group.

let's Make a player to shoot

-copy and add the code on your right to your player script (player.gd)

-find bullet_path variable on top and remove null and set it to var bullet_path = preload("res://scenes/bullet.tscn") or a path of a scene of a bullet we created

- call function shoot() in _physics_process(delta: float)

Let's extra node to player node

-Add Node2D as child of player nodes and rename it to spawn_position set it position:y to -25.0

-Add Timer nodes as a child of player nodes. connect signal (timeout) to player nodes script.

- select Time nodes go to the inspector and set wait time to 0.5

- Find a variable var time: Timer = $Timer replace it with (@onready var time: Timer = $Timer)

Code Breakdown (Shooting Mechanics)

-var bullet_path = preload("res://scenes/bullet.tscn"): Preloads the bullet scene into memory so it is ready to spawn instantly without lag.

-@onready var time: Timer = $Timer: Grabs a reference to the child Timer node as soon as the player enters the scene tree.

-var can_shoot: bool = true: A true/false toggle flag used to prevent firing when the weapon is on cooldown.

-shoot(): Called inside _physics_process(); checks if the player presses the accept/fire button (ui_accept) while can_shoot is true.

-can_shoot = false & time.start(): Locks shooting ability immediately upon firing and starts the cooldown timer.

-bullet_path.instantiate(): Creates a live clone/instance of the preloaded bullet scene.

-get_parent().add_child(bullet): Adds the spawned bullet to the parent scene (e.g., main), allowing it to move independently of the player.

-bullet.global_position = spawn_position.global_position: Moves the newly spawned bullet directly to the location of the player's firing muzzle (spawn_position).

-_on_timer_timeout(): Signal callback connected to the Timer node; unlocks shooting (can_shoot = true) when the timer reaches zero.

Space Invaders Player Movement

Space Invaders Create Enemies