Explain and assess the arcade game

Worked example

An incoming three-lane wave blocks left and center but leaves right clear. Randomly choosing among valid two-lane combinations creates variation while preserving an escape route. Scaffold C-TIMER — Timer-based spawning with a hard cap Setup: World Node2D root contains Node2D Hazards and Timer SpawnTimer: wait_time 1.2, autostart On, one_shot Off. Hazard scene root Area2D has a CircleShape2D radius 12 and C-HAZARD. Attach script to World and drag Hazard.tscn into hazard_scene Inspector field. Set viewport 640x360. Name Hazards group not needed. This script is a separate lab; merge its _ready into an existing manager rather than declaring a second _ready. ```gdscript extends Node2D @export var hazard_scene: PackedScene @export var spawn_limit: int = 12 func _ready() -> void: $SpawnTimer.timeout.connect(_spawn) func _spawn() -> void: if hazard_scene == null or $Hazards.get_child_count() >= spawn_limit: return var hazard := hazard_scene.instantiate() as Area2D $Hazards.add_child(hazard) hazard.position = Vector2(randf_range(20.0, 620.0), -20.0) ``` Scaffold C-HAZARD — Falling hazard with player notification and cleanup Setup: Area2D Hazard root on layer 4 (bit 8), mask layer 1 only, child CollisionShape2D circle radius 12. Attach this script. Player in group player. A Player damage method is deliberately not hardcoded: connect hit_player to a manager’s damage handler when instantiating. Parent Hazards must be unscaled and unrotated. ```gdscript extends Area2D signal hit_player @export var fall_speed: float = 110.0 var hit: bool = false func _ready() -> void: body_entered.connect(_on_body_entered) func _draw() -> void: draw_rect(Rect2(-12, -12, 24, 24), Color.TOMATO) draw_line(Vector2(-8,-8),Vector2(8,8),Color.BLACK,2.0) func _physics_process(delta: float) -> void: position.y += fall_speed * delta if position.y > 390.0: queue_free() func _on_body_entered(body: Node2D) -> void: if hit or not body.is_in_group("player"): return hit = true hit_player.emit() queue_free() ``` Scaffold C-STATES — Explicit game states and gated scoring Setup: Attach to Node root StateLab with child Label Status. This is a standalone demonstrator; call start_round, add_points, finish_round from buttons or Remote Inspector. In a real game the manager owns this state. Additional Player and spawner scripts must also honor the manager’s state, or be disabled when finishing. ```gdscript extends Node enum Phase { TITLE, PLAY, WIN, LOSE } var phase: Phase = Phase.TITLE var score: int = 0 func _ready() -> void: _show() func start_round() -> void: score = 0 phase = Phase.PLAY _show() func add_points(amount: int) -> void: if phase != Phase.PLAY: return score += maxi(amount, 0) _show() func finish_round(won: bool) -> void: if phase != Phase.PLAY: return phase = Phase.WIN if won else Phase.LOSE _show() func _show() -> void: $Status.text = "State: %s | Score: %d" % [Phase.keys()[phase], score] ```

Timer-based spawning with a hard cap

GDScript (Godot 4, not Scratch, Python, JavaScript or C#). Scaffold C-TIMER. Copy starts from this text. The desk does not run it.

Scene and node setup

World Node2D root contains Node2D Hazards and Timer SpawnTimer: wait_time 1.2, autostart On, one_shot Off. Hazard scene root Area2D has a CircleShape2D radius 12 and C-HAZARD. Attach script to World and drag Hazard.tscn into hazard_scene Inspector field. Set viewport 640x360. Name Hazards group not needed. This script is a separate lab; merge its _ready into an existing manager rather than declaring a second _ready.

extends Node2D
@export var hazard_scene: PackedScene
@export var spawn_limit: int = 12
func _ready() -> void:
    $SpawnTimer.timeout.connect(_spawn)
func _spawn() -> void:
    if hazard_scene == null or $Hazards.get_child_count() >= spawn_limit:
        return
    var hazard := hazard_scene.instantiate() as Area2D
    $Hazards.add_child(hazard)
    hazard.position = Vector2(randf_range(20.0, 620.0), -20.0)

Checks to run in the editor

• One object appears about each 1.2 seconds.
• At most 12 hazards exist, even during a long run.

Native Godot 4.7.2.stable.official.ed1daf0bf headless compile and representative node-tree/runtime tests passed; see native-qa-results.json. Visual UI, audible output, exports and website submission still need separate checks.

Falling hazard with player notification and cleanup

GDScript (Godot 4, not Scratch, Python, JavaScript or C#). Scaffold C-HAZARD. Copy starts from this text. The desk does not run it.

Scene and node setup

Area2D Hazard root on layer 4 (bit 8), mask layer 1 only, child CollisionShape2D circle radius 12. Attach this script. Player in group player. A Player damage method is deliberately not hardcoded: connect hit_player to a manager’s damage handler when instantiating. Parent Hazards must be unscaled and unrotated.

extends Area2D
signal hit_player
@export var fall_speed: float = 110.0
var hit: bool = false
func _ready() -> void:
    body_entered.connect(_on_body_entered)
func _draw() -> void:
    draw_rect(Rect2(-12, -12, 24, 24), Color.TOMATO)
    draw_line(Vector2(-8,-8),Vector2(8,8),Color.BLACK,2.0)
func _physics_process(delta: float) -> void:
    position.y += fall_speed * delta
    if position.y > 390.0:
        queue_free()
func _on_body_entered(body: Node2D) -> void:
    if hit or not body.is_in_group("player"):
        return
    hit = true
    hit_player.emit()
    queue_free()

Checks to run in the editor

• Hazard moves downward and disappears beyond y390.
• One overlap emits one damage event.

Native Godot 4.7.2.stable.official.ed1daf0bf headless compile and representative node-tree/runtime tests passed; see native-qa-results.json. Visual UI, audible output, exports and website submission still need separate checks.

Explicit game states and gated scoring

GDScript (Godot 4, not Scratch, Python, JavaScript or C#). Scaffold C-STATES. Copy starts from this text. The desk does not run it.

Scene and node setup

Attach to Node root StateLab with child Label Status. This is a standalone demonstrator; call start_round, add_points, finish_round from buttons or Remote Inspector. In a real game the manager owns this state. Additional Player and spawner scripts must also honor the manager’s state, or be disabled when finishing.

extends Node
enum Phase { TITLE, PLAY, WIN, LOSE }
var phase: Phase = Phase.TITLE
var score: int = 0
func _ready() -> void:
    _show()
func start_round() -> void:
    score = 0
    phase = Phase.PLAY
    _show()
func add_points(amount: int) -> void:
    if phase != Phase.PLAY:
        return
    score += maxi(amount, 0)
    _show()
func finish_round(won: bool) -> void:
    if phase != Phase.PLAY:
        return
    phase = Phase.WIN if won else Phase.LOSE
    _show()
func _show() -> void:
    $Status.text = "State: %s | Score: %d" % [Phase.keys()[phase], score]

Checks to run in the editor

• Calling add_points before start does not change score.
• After finish_round, extra score events do nothing.

Native Godot 4.7.2.stable.official.ed1daf0bf headless compile and representative node-tree/runtime tests passed; see native-qa-results.json. Visual UI, audible output, exports and website submission still need separate checks.

Explain and assess the arcade game — evidence task

1. 1. Submit the arcade source, readme and state/cooldown test log.
2. 2. Explain signal flow and predict the three damage cases before testing.

Deliverable. Meteor Mail assessment ZIP or private downloadable ZIP link, explanations and test log.

Acceptance checks

• VGC-L045-T1. Predictions are compared with actual results.
• VGC-L045-T2. Teacher can locate manager, spawner and hazard scripts in the artifact.

Understanding question. What is the signal path for a runtime hazard hit?

Include a downloadable project ZIP with project.godot, .tscn, .gd and original asset files when code changes. A private, teacher-accessible download link to that ZIP is equivalent. Screenshots or a playthrough do not replace editable source.

If this is still shaky. Tune just hazard speed and spawn interval on a copied project. Use fixed test runs before adding more mechanics. Start with the first assigned task and re-run its acceptance test before adding the remaining feature.

Optional extra. Offer an optional challenge mode while retaining a gentle default. Document one changed parameter, your prediction, and the observed effect; optional, not required for completion.

• Your first 2D game

  Free public tutorial; no account; external asset download is optional, not used by this course.

  · Opening this link does not submit the lesson.