feat: incrementally add elements to sketch in draw

lib/loadp5.js

@@ -1,4 +1,5 @@
 export var p5;
+export var p5vector;
 export var p5loaded = new Promise(async function(resolve, reject) {
     var success = false;
     try {
@@ -13,5 +14,6 @@ export var p5loaded = new Promise(async function(resolve, reject) {
 	catch {}
 	console.log('Used local fallback for p5'); }
     p5 = window.p5;
+    p5vector = window.p5.Vector
     delete window.p5;
     if (success) { resolve(); } else { reject(); }});

polytree.coffee

@@ -1,13 +1,25 @@
 # PolyTree, intended to be loaded as a module
 
-import {p5, p5loaded} from './lib/loadp5.js'
+import {p5, p5loaded, p5vector} from './lib/loadp5.js'
 
 sketch = (p) ->
+   pos = null
+   vel = null
+   abs = Math.abs  # For convenience
+
    p.setup = =>
       p.createCanvas window.innerWidth, 575, p.WEBGL
       p.background 224
-      p.ellipse 0, 0, 100, 50
+      p.frameRate 5
-      p.ellipse p.width/4, -p.height/4, 50, 100
+      pos = p.createVector p.width, p.height
+
+   p.draw = =>
+      if abs(pos.x) > p.width/2 or abs(pos.y) > p.height/2
+         pos = p.createVector 0
+         vel = p5vector.random2D().mult 32
+      else
+         pos.add vel
+      p.point pos
 
 show = () ->
    P5 = new p5 sketch