Re-initilizing instance of p5.js

I’m working on a special use of p5.js, for hot-swapping sketches – this involves dynamically embedding a script with a new setup()/draw() which overrides the initial one. It’s working quite well, however I run into two main issues:

  • some settings are blending from one sketch to another, ie. rectMode() + WEBGL
  • if there’s a bug, p5 fails on render and have to refresh page.

Of course I should be using the instance mode of p5.js, then could probably destroy and re-create it… however I’m set on the friendliness and ease of coding in global mode so one doesn’t need a p.function() throughout code.

Does anyone know if/how one can re-initialize the global instance of p5.js??
Tried things like var p5 = new p5(); – but no luck.

This is exactly the kind of thing instance mode was meant for. Anything else is going to be pretty hacky.

Sure, totally get that the instance mode solves this – but what speaks for hacky, is not requiring the scope prefix… there’s gotta be a way. Essentially, should also be fine removing the global instance of p5.js and reloading it with the updated setup() + draw() in place. How might one go about doing that?? Was surprised I couldn’t find an init() function to the global kick things off on demand.

Once upon a time, there was this “Random p5.js Loader” sketch: :mage:

However, since when URL CodiceInutile.GitHub.io/website-dev/homepage.json ceased to exist, that sketch is no more. :cry:

Here’s a sample of what that “homepage.json” file used to be: :scream_cat:

[
  {
    "title": "Should display squares",
    "author": "Name of author",
    "description": "Lorem Ipsum",
    "kind": "javascript",
    "href": "https://codiceinutile.github.io/website-dev/js/hero/federico.js",
    "includes": [
      "https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.5.5/p5.min.js",
      "https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.5.5/addons/p5.dom.min.js"
    ]
  },
  {
    "title": "Should display circles",
    "author": "Name of author",
    "description": "Lorem ipsum",
    "kind": "javascript",
    "includes": [
      "https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.5.5/p5.min.js",
      "https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.5.5/addons/p5.dom.min.js"
    ],
   "href": "https://codiceinutile.github.io/website-dev/js/hero/alka.js"
  },
  {
    "title": "PixelDawn",
    "author": "Matteo Testa",
    "description": "Processing",
    "kind": "javascript",
    "includes": [
      "https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.5.4/p5.min.js",
      "https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.5.4/addons/p5.dom.min.js"
    ],
   "href": "https://codiceinutile.github.io/website-dev/js/hero/matteo.js"
  },
   {
     "title"        : "Hypnotic lines",
     "author"       : "Federico Pepe",
     "description"  : "Un progetto di Federico Pepe",
     "url"         : "/project/2016/12/30/esempio_project.html",
     "href"         : "https://codiceinutile.github.io/website-dev//js/projects/test_1.js",
     "includes"     : [
       "https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.5.5/p5.min.js",
       "https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.5.5/addons/p5.dom.min.js"
     ]
   },
   {
     "title"        : "Retini",
     "author"       : "cybermarinella",
     "description"  : "p5",
     "url"         : "/project/2016/01/01/esempio_project_mari.html",
     "href"         : "https://codiceinutile.github.io/website-dev//js/projects/retini.js",
     "includes"     : [
       "https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.5.5/p5.min.js",
       "https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.5.5/addons/p5.dom.min.js"
     ]
   }
]
1 Like

@GoToLoop thankyouverymuch!

That properly named p5RemoveHack() did the trick to remove all traces of the P5 instance and seeing your technique for re-loading the files, specifically re-linking p5.min + p5.dom = what I was missing (as I was only replacing the actual sketch script).

Here’s my hacky snippet which is working perfect for live-switching between a sketch with WEBGL and one without (testing by using text(), which unfortunately still doesn’t work in WEBGL mode):

function updateP5(){
    if(validCode){
        p5RemoveHack();
        document.getElementById("holdscript").innerHTML = "";

        var ps = document.createElement("script");
        ps.type = "text/javascript";
        ps.src = "includes/p5/p5.min.js";
        document.getElementById("holdscript").appendChild(ps);

        var ps2 = document.createElement("script");
        ps.type = "text/javascript";
        ps.src = "includes/p5/addons/p5.dom.min.js";
        document.getElementById("holdscript").appendChild(ps2);

        var s = document.createElement("script");
        s.type = "text/javascript";
        s.innerHTML = editor.getValue();
        document.getElementById("holdscript").appendChild(s);
        }
    }

// GoToLoop » https://codepen.io/GoSubRoutine/pen/ZBPjdP
function p5RemoveHack() {
    if (window.p5 && p5.instance) {
        p5.instance.remove();
        p5.instance = window.setup = window.draw = null;
    } else {
        const canv = document.querySelector('canvas');
        canv && canv.remove();
    }
}