Along — Preposition Programming

Fig. 1 Path following — position sampled along connected waypoints

Try it — drag, click, or tap inside the figure.

Open in p5 Web Editor Fork and experiment with this sketch

Concept

ALONG means following the length, edge, or course of something—not crossing it.

Translation strategy

Ways to express along in a sketch:

Waypoints: Store an ordered list of path points
Progress index: Move between consecutive points over time
Curves: Use vertices, Bézier points, or parametric math for smooth paths

Key p5.js methods

Key methods

Path
• Arrays of points; lerp() between them
• beginShape(), vertex() — draw the route

Pointer input
• mousePressed() — start motion or set a target
• mouseX, mouseY — click position

Code pattern

Code pattern

1. Define the path
let path = [{x:50,y:150},{x:150,y:100},{x:250,y:200},{x:350,y:150}];

2. Track progress along segments
let progress = 0; // 0 … path.length - 1

3. Interpolate between two points
let a = path[floor(progress)];
let b = path[ceil(progress)];
let t = progress - floor(progress);
let x = lerp(a.x, b.x, t);

4. Advance each frame
if (isMoving) progress += speed;