Cross the pits, grab every coin, and make three lives last. Assembles Platformer Movement, Collect Coins, and Lives System.
Loading the game engine. This takes a moment the first time.
This is a project, not a lesson: nothing in this folder is new. Cross the pits, collect every coin, and make three lives last the whole way.
The signal chain from the Lives System lesson runs unchanged: kill zone emits life_lost, this file subtracts and emits lives_updated, the HUD redraws. All this file adds is a second way for the round to end, collecting every coin, and a flag so the two endings cannot overlap.
■ UI node · ■ 2D node · % unique name · .tscn instanced scene
game_events.gd
Switch it on once, under Project > Project Settings, on the Globals tab. Not made yet? Press Create Script to make it right there. Already made it? Press Select Script/Scene, pick it, and press Add. Its Name column should say GameEvents, which Godot fills in for you. That's the name your code uses.
extends Node2D
## How many lives the player begins with.
@export var starting_lives: int = 3
## How many coins are in the scene. Change this if you add coins!
@export var total_coins: int = 6
var lives: int
var collected: int = 0
var round_over: bool = false
@onready var player: Player = $Player
func _ready() -> void:
lives = starting_lives
# kill_zone.gd emits "life_lost", the exact chain from Lives System.
GameEvents.life_lost.connect(_on_life_lost)
GameEvents.coin_collected.connect(_on_coin_collected)
func _on_life_lost() -> void:
if round_over:
return
lives -= 1
# hud.gd connects to "lives_updated" and redraws the number.
GameEvents.lives_updated.emit(lives)
if lives <= 0:
round_over = true
player.set_physics_process(false)
# hud.gd shows Game Over.
GameEvents.player_died.emit()
_restart_soon()
func _on_coin_collected(_value: int) -> void:
if round_over:
return
collected += 1
if collected >= total_coins:
round_over = true
player.set_physics_process(false)
# hud.gd shows the win message.
GameEvents.goal_reached.emit()
_restart_soon()
func _restart_soon() -> void:
var timer: SceneTreeTimer = get_tree().create_timer(2.0)
timer.timeout.connect(_on_restart_timeout)
func _on_restart_timeout() -> void:
get_tree().reload_current_scene()extends Area2D
## How many points this coin is worth.
@export var value: int = 1
func _ready() -> void:
body_entered.connect(_on_body_entered)
func _on_body_entered(body: Node2D) -> void:
# "Player" is the class_name at the top of player.gd.
if body is Player:
# Emit first, erase second: erased nodes cannot send messages.
GameEvents.coin_collected.emit(value)
queue_free()extends CanvasLayer
## Keep these in step with the level's exports.
@export var starting_lives: int = 3
@export var total_coins: int = 6
var _collected: int = 0
@onready var lives_label: Label = %LivesLabel
@onready var score_label: Label = %ScoreLabel
@onready var result_label: Label = %ResultLabel
@onready var home_button: Button = %HomeButton
func _ready() -> void:
GameEvents.lives_updated.connect(_on_lives_updated)
GameEvents.coin_collected.connect(_on_coin_collected)
GameEvents.player_died.connect(_on_player_died)
GameEvents.goal_reached.connect(_on_goal_reached)
home_button.pressed.connect(_on_home_pressed)
lives_label.text = "Lives: %d" % starting_lives
_update_score()
func _on_lives_updated(remaining: int) -> void:
lives_label.text = "Lives: %d" % remaining
func _on_coin_collected(value: int) -> void:
_collected += value
_update_score()
func _on_player_died() -> void:
result_label.text = "Game over!"
func _on_goal_reached() -> void:
result_label.text = "You win!"
func _update_score() -> void:
score_label.text = "Coins: %d / %d" % [_collected, total_coins]
# Loads the lesson list screen, which replaces this whole scene.
func _on_home_pressed() -> void:
get_tree().change_scene_to_file("res://shared/ui/lesson_select.tscn")extends Area2D
func _ready() -> void:
body_entered.connect(_on_body_entered)
func _on_body_entered(body: Node2D) -> void:
if body is Player:
# Two different ways of talking, side by side, on purpose:
# the zone cannot reach the HUD, so it emits on the bus...
GameEvents.life_lost.emit()
# ...but "body_entered" already handed us the player, so we just
# call a function on it. No signal needed.
body.respawn()class_name Player
extends CharacterBody2D
## How fast the player runs left and right.
@export var speed: float = 200.0
## How hard the player jumps. Negative because up is negative in Godot.
@export var jump_velocity: float = -650.0
## How hard gravity pulls down.
@export var gravity: float = 1800.0
# Where the run began. respawn() sends us back here after a fall.
var _start_position: Vector2
@onready var sprite: Sprite2D = $Sprite2D
func _ready() -> void:
_start_position = global_position
func _physics_process(delta: float) -> void:
# FALL: gravity only pulls when our feet are off the ground.
if not is_on_floor():
velocity.y += gravity * delta
# JUMP: only on the frame the key goes down, only from the floor.
if Input.is_action_just_pressed("jump") and is_on_floor():
velocity.y = jump_velocity
# RUN: -1 for left, 1 for right, 0 for neither.
var direction: float = Input.get_axis("move_left", "move_right")
velocity.x = direction * speed
move_and_slide()
# The warrior picture only faces right. Walking left mirrors it.
if direction != 0.0:
sprite.flip_h = direction < 0.0
## Called BY kill_zone.gd when we fall in a pit.
func respawn() -> void:
global_position = _start_position
# Falling speed does not come back with us. Otherwise we would arrive
# at the start already plummeting.
velocity = Vector2.ZEROextends Node
# All of the game's signals are declared below, grouped by the lesson
# that uses them. A signal with brackets, like coin_collected(value: int),
# passes that value to every function connected to it.
# This shows only the signals this lesson uses. The full file declares
# every lesson's signals.
# Coin Pickup lesson
signal coin_collected(value: int)
# Platformer Movement lesson
signal goal_reached
# Health and Damage lesson
signal player_died
# Lives System lesson
signal life_lost
signal lives_updated(remaining: int)