Video Game Design and Coding · PLECK lesson

PLECK lesson 37 · suggested week 8, day 2

Model explicit phases

Objective. Use an enum to prevent contradictory behavior.

Godot Engine Standard desktop editor 4.7.2-stable, GDScript (Godot 4), Compatibility renderer. Headless Godot 4.7.2.stable.official.ed1daf0bf passed 106 assertions on the supplied scaffolds, including malformed JSON saves. Audio used the Dummy driver and a synthetic WAV, not a speaker. The visual editor, browser export, and signed-in submission were not tested. The desk still does not run a student's own upload.

About 55 minutes. The due date is chosen by a parent.

Lives, time, state transitions and replay

Suggested pace: Recall and predict 5 min; Read instruction and scaffold 12 min; Build or design the assigned artifact 25 min; Run acceptance tests 8 min; Explain and checkpoint 5 min.

Materials: Godot Standard 4.7.2 desktop editor (GDScript, Compatibility renderer), Local course folder and prior checkpoint, No paid assets or public account required.

Comes after VGC-L036.

An enum names a finite set of states. C-STATES demonstrates Title, Play, Win and Lose. In the real game, one manager owns phase and exposes functions for transitions. Start initializes score, lives and time before enabling player and spawner. End changes phase once, disables movement and stops spawning. A Boolean called playing can handle two states, but an enum makes several screens easier to distinguish. Keep state names independent from the wording shown in a label.

Worked example

If phase is TITLE, a scoring event returns immediately. After start_round sets phase PLAY, the same event may add points. One exclusive phase prevents simultaneous WIN and LOSE flags. 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] ```

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

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.

Model explicit phases — evidence task

  1. 1. Adapt C-STATES into Meteor Mail’s manager.
  2. 2. Write an event/state table and test scoring on Title, Play and Lose.

Deliverable. Four-state manager and state-event test table.

Acceptance checks

Understanding question. Why is one phase variable safer than separate won and lost flags?

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. Print lives and phase in one Label before adding effects. Restrict every gameplay handler to the Play state. Start with the first assigned task and re-run its acceptance test before adding the remaining feature.

Optional extra. Test simultaneous end conditions and write a deliberate tie policy. Document one changed parameter, your prediction, and the observed effect; optional, not required for completion.

Name ____________________ Date ____________________