P5.js Starter

Curran Kelleher

Last edited Jan 31, 2024
Created on Jan 31, 2024

Unlocking P5.js with hot reloading!

This example is copied from the P5: Functions example. Several modifications were required to make it work in VizHub with hot reloading:

  • Since VizHub uses ES modules, we can't rely on the P5 globals (like setup and draw), and we can't rely on the way P5 usually runs and interprets those.
  • Therefore in index.js, some setup is required to import P5 and manually execute the Sketch.
  • To support hot reloading, we store the sketch instance on the container DOM element, and remove the old one if it's present.
  • The sketch is defined in sketch.js as an ES module that exports a function that accepts the container element. This was required so that we can call use the P5 parent function to tell it to attach the canvas to our container element.
  • Within the sketch, we can't reference functions like createCanvas and background because we are using ES modules and not globals. However, we can "simulate" globals by extracting those functions from the p5 instance p! Since those internally reference this, we need to use bind to make sure that they work properly. If you need more p5 functions, you can follow the same pattern used here.
  • Finally, we need to attach our setup and draw functions to the p5 instance.

I've tried to make this setup mimic regular P5 in the internals as much as possible. It should, in theory, be possible to copy the code from any P5 example straight into this template. Just make sure to:

  • Set up .parent on the canvas
  • Extract the p5 instance functions you need
  • Attach your setup and draw functions

Magically, this all works pretty well with VizHub's hot reloading, so you can use Alt+drag to edit numbers and see the rendered graphic update instantly.


MIT Licensed