Video Game Design and Coding · PLECK lesson

PLECK lesson 27 · suggested week 6, day 2

Balance speed with a controlled experiment

Objective. Measure a parameter change using a comparable test route.

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.

Functions, parameter experiments, original challenges and evidence

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-L026.

A parameter is a value you can tune without rewriting the algorithm. C-BODY exposes speed in the Inspector. Compare speeds 120, 160 and 200 on the same route, starting from the same position. Record approximate completion time and wall collisions for two runs per speed. More speed is not automatically better: a tight route may become hard to steer. Your recommendation should refer to evidence and the intended beginner player, not simply the fastest result.

Worked example

Two parameter trials can use the same start and route while changing only speed. Record an observation such as two wall contacts rather than an unsupported claim such as more fun. Scaffold C-BODY — Reusable top-down player with collision Setup: Create CharacterBody2D root Player at (80,180); add CollisionShape2D with CircleShape2D radius 14. Attach this script to Player and save Player.tscn. Use C-FREE-MOVE input actions. Root collision layer 1, mask 2. Create a separate StaticBody2D Wall on layer 2 mask 1 with RectangleShape2D collision and a Polygon2D rectangle as visible child. Instance both under an unscaled Node2D World. Do not put a body inside another physics body. ```gdscript extends CharacterBody2D @export var speed: float = 160.0 func _draw() -> void: draw_circle(Vector2.ZERO, 14.0, Color.CORNFLOWER_BLUE) draw_line(Vector2(-8, 0), Vector2(8, 0), Color.WHITE, 3.0) func _physics_process(_delta: float) -> void: velocity = Input.get_vector("move_left", "move_right", "move_up", "move_down") * speed move_and_slide() ```

Reusable top-down player with collision

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

Scene and node setup

Create CharacterBody2D root Player at (80,180); add CollisionShape2D with CircleShape2D radius 14. Attach this script to Player and save Player.tscn. Use C-FREE-MOVE input actions. Root collision layer 1, mask 2. Create a separate StaticBody2D Wall on layer 2 mask 1 with RectangleShape2D collision and a Polygon2D rectangle as visible child. Instance both under an unscaled Node2D World. Do not put a body inside another physics body.

extends CharacterBody2D
@export var speed: float = 160.0
func _draw() -> void:
    draw_circle(Vector2.ZERO, 14.0, Color.CORNFLOWER_BLUE)
    draw_line(Vector2(-8, 0), Vector2(8, 0), Color.WHITE, 3.0)
func _physics_process(_delta: float) -> void:
    velocity = Input.get_vector("move_left", "move_right", "move_up", "move_down") * speed
    move_and_slide()

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.

Pocket Orchard starter, as text files. Open the files in Godot on the family computer. This page does not download a zip or run the project.

Balance speed with a controlled experiment — evidence task

  1. 1. Run the same route twice at each of three speeds.
  2. 2. Choose one speed and justify it with time and steering observations.

Deliverable. Speed experiment table and chosen-speed project.

Acceptance checks

Understanding question. What must stay constant for a useful speed comparison?

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. Keep the three-coin version working. Duplicate the project folder before experimenting with one parameter at a time. Start with the first assigned task and re-run its acceptance test before adding the remaining feature.

Optional extra. Make one alternate layout with the same rules and compare route clarity. Document one changed parameter, your prediction, and the observed effect; optional, not required for completion.

Name ____________________ Date ____________________