Reconcile restart and persistence policies

Worked example

A richer-system table can pair valid values with safe fallback behavior. Unknown checkpoint IDs map to a known start marker rather than a path loaded from input. Scaffold C-STATE-SAVE — Validated inventory and checkpoint data Setup: Attach to a Node named SaveData. This is a separate file from C-SAVE and only reads fixed known scalar fields. get_checkpoint_data returns plain data, not live node references. When applying a loaded checkpoint, the assignment maps checkpoint ID to a teacher-approved safe Marker2D, never to a filename supplied by the save. ```gdscript extends Node const PATH: String = "user://seed_station_v1.json" func defaults() -> Dictionary: return {"version": 1, "seed": 0, "water": 0, "checkpoint": "start"} func _bounded_count(value: Variant) -> int: if value is int or value is float: return clampi(int(value), 0, 99) return 0 func validate(raw: Variant) -> Dictionary: var clean := defaults() if not raw is Dictionary: return clean var data: Dictionary = raw if data.get("version", 0) != 1: return clean clean["seed"] = _bounded_count(data.get("seed", 0)) clean["water"] = _bounded_count(data.get("water", 0)) var checkpoint: Variant = data.get("checkpoint", "start") if checkpoint is String and checkpoint in ["start", "greenhouse"]: clean["checkpoint"] = checkpoint return clean func save_data(raw: Dictionary) -> bool: var file := FileAccess.open(PATH, FileAccess.WRITE) if file == null: return false file.store_string(JSON.stringify(validate(raw))) file.close() return true func load_data() -> Dictionary: if not FileAccess.file_exists(PATH): return defaults() var file := FileAccess.open(PATH, FileAccess.READ) if file == null: return defaults() var text: String = file.get_as_text() file.close() var parser := JSON.new() if parser.parse(text) != OK: return defaults() return validate(parser.data) ``` Scaffold C-GRID — A deterministic grid with a guaranteed clear route Setup: Attach to Node2D GridLab. This example draws, not physics, so the assignment adds matching wall collision only after validation. Grid is 8 columns by 6 rows at 40 pixels per cell. Row 0 and column 7 are a guaranteed clear route from (0,0) to (7,5). RNG seed is a nonpersonal integer. ```gdscript extends Node2D const COLS: int = 8 const ROWS: int = 6 const CELL: int = 40 var cells: Array = [] func _ready() -> void: var rng := RandomNumberGenerator.new() rng.seed = 2468 for y in range(ROWS): var row: Array[int] = [] for x in range(COLS): var blocked: bool = y != 0 and x != COLS - 1 and rng.randf() < 0.25 row.append(1 if blocked else 0) cells.append(row) queue_redraw() func _draw() -> void: for y in range(cells.size()): for x in range(cells[y].size()): var color := Color.DIM_GRAY if cells[y][x] == 1 else Color.BEIGE draw_rect(Rect2(x * CELL, y * CELL, CELL - 2, CELL - 2), color) ``` 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] ```

Validated inventory and checkpoint data

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

Scene and node setup

Attach to a Node named SaveData. This is a separate file from C-SAVE and only reads fixed known scalar fields. get_checkpoint_data returns plain data, not live node references. When applying a loaded checkpoint, the assignment maps checkpoint ID to a teacher-approved safe Marker2D, never to a filename supplied by the save.

extends Node
const PATH: String = "user://seed_station_v1.json"
func defaults() -> Dictionary:
    return {"version": 1, "seed": 0, "water": 0, "checkpoint": "start"}
func _bounded_count(value: Variant) -> int:
    if value is int or value is float:
        return clampi(int(value), 0, 99)
    return 0
func validate(raw: Variant) -> Dictionary:
    var clean := defaults()
    if not raw is Dictionary:
        return clean
    var data: Dictionary = raw
    if data.get("version", 0) != 1:
        return clean
    clean["seed"] = _bounded_count(data.get("seed", 0))
    clean["water"] = _bounded_count(data.get("water", 0))
    var checkpoint: Variant = data.get("checkpoint", "start")
    if checkpoint is String and checkpoint in ["start", "greenhouse"]:
        clean["checkpoint"] = checkpoint
    return clean
func save_data(raw: Dictionary) -> bool:
    var file := FileAccess.open(PATH, FileAccess.WRITE)
    if file == null:
        return false
    file.store_string(JSON.stringify(validate(raw)))
    file.close()
    return true
func load_data() -> Dictionary:
    if not FileAccess.file_exists(PATH):
        return defaults()
    var file := FileAccess.open(PATH, FileAccess.READ)
    if file == null:
        return defaults()
    var text: String = file.get_as_text()
    file.close()
    var parser := JSON.new()
    if parser.parse(text) != OK:
        return defaults()
    return validate(parser.data)

Checks to run in the editor

• Missing file returns defaults.
• Negative count becomes zero; count 1000 becomes 99.
• Unknown checkpoint becomes start.
• Malformed JSON, arrays and unsupported versions return safe defaults.

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.

A deterministic grid with a guaranteed clear route

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

Scene and node setup

Attach to Node2D GridLab. This example draws, not physics, so the assignment adds matching wall collision only after validation. Grid is 8 columns by 6 rows at 40 pixels per cell. Row 0 and column 7 are a guaranteed clear route from (0,0) to (7,5). RNG seed is a nonpersonal integer.

extends Node2D
const COLS: int = 8
const ROWS: int = 6
const CELL: int = 40
var cells: Array = []
func _ready() -> void:
    var rng := RandomNumberGenerator.new()
    rng.seed = 2468
    for y in range(ROWS):
        var row: Array[int] = []
        for x in range(COLS):
            var blocked: bool = y != 0 and x != COLS - 1 and rng.randf() < 0.25
            row.append(1 if blocked else 0)
        cells.append(row)
    queue_redraw()
func _draw() -> void:
    for y in range(cells.size()):
        for x in range(cells[y].size()):
            var color := Color.DIM_GRAY if cells[y][x] == 1 else Color.BEIGE
            draw_rect(Rect2(x * CELL, y * CELL, CELL - 2, CELL - 2), color)

Checks to run in the editor

• Same seed and version produce same grid.
• All cells on top row and rightmost column are empty.

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.

Reconcile restart and persistence policies — evidence task

1. 1. Write the reset/persistence matrix.
2. 2. Test two consecutive restarts, loads or regenerations as appropriate.

Deliverable. Reset-policy matrix and two-cycle integration log.

Acceptance checks

• VGC-L159-T1. State follows the matrix after both cycles.
• VGC-L159-T2. No duplicated object, reward or stale target remains.

Understanding question. Why separate transient state from persistent progress?

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. Use the focused test scene from week 30 to compare isolated behavior with the main game. Keep one explicit state owner. Start with the first assigned task and re-run its acceptance test before adding the remaining feature.

Optional extra. Add one validated field, AI cue or generation constraint only after existing tests pass. Document one changed parameter, your prediction, and the observed effect; optional, not required for completion.

Turn in typed notes and a JPEG, PNG, or WebP screenshot. One https address is stored as text and is not opened, extracted, or run. An MP3, WAV, M4A, MP4, or WebM file up to 4 MB can show a demo. The demo does not replace editable source. Zip and code files are refused. If there is no private link, keep the project on the family computer and review the code in person.

• 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.