Move with time and bounds

Move with time and bounds — guided practice

Explain input direction, elapsed time and a bounded position.

Install the free Godot 4 editor suitable for your computer. Extract project.godot, main.tscn and main.gd into one new folder, keeping the names unchanged. In Godot Project Manager choose Import, select project.godot, then Import & Edit. Open main.tscn; use Run Project (F6 runs the current scene, while F5 runs the configured project). The game is a 640×480 top-down collection activity with no external assets. Arrow keys move; Space pauses; R restarts. Finish each changed case, then restore the supplied baseline before the next lesson.

1. 1. Trace the movement

   Find Input.get_vector and player += direction * SPEED * delta. Hold Right in the running game.

   You should see: The circle moves right; SPEED is 180 pixels per second.

   Multiplying by elapsed time avoids making speed depend directly on update count.

2. 2. Work one update

   For direction (1,0), speed 180 and delta 0.5, calculate the displacement before bounds.

   You should see: Horizontal displacement is 90 pixels.

   A simple numeric case checks the meaning of speed and time.

3. 3. Test the boundaries

   Hold Right until the circle stops, then hold Down. Read both clampf statements.

   You should see: The center stops at x620 and y460 inside the play area.

   Clamping keeps the position in the stated allowed interval.

4. 4. Change one parameter

   Stop, change SPEED from 180.0 to 120.0, save and rerun. Compare travel time between the same two points, then restore 180.0.

   You should see: The circle moves more slowly; a half-second rightward displacement would be 60 pixels.

   One parameter change is easier to attribute than several simultaneous edits.