Regarding the p5.Vector functions random2D() and random3D() using Math.random()

Topic

The p5.Vector functions random2D() and random3D() now use Math.random() to get random numbers.

random3D

static random3D() {
  const angle = Math.random() * constants.TWO_PI;
  const vz = Math.random() * 2 - 1;
  const vzBase = Math.sqrt(1 - vz * vz);
  const vx = vzBase * Math.cos(angle);
  const vy = vzBase * Math.sin(angle);
  return new p5.Vector(vx, vy, vz);
}

But for example, the p5.js functions shuffle() and randomGaussian() use p5.js random().

shuffle

p5.prototype.shuffle = function(arr, bool) {
  const isView = ArrayBuffer && ArrayBuffer.isView && ArrayBuffer.isView(arr);
  arr = bool || isView ? arr : arr.slice();

  let rnd,
    tmp,
    idx = arr.length;
  while (idx > 1) {
    rnd = (this.random(0, 1) * idx) | 0;

    tmp = arr[--idx];
    arr[idx] = arr[rnd];
    arr[rnd] = tmp;
  }

  return arr;
};

The difference between random() and Math.random() is whether they are affected by randomSeed(). With random(), you can get the same set of values ​​if you use the same seed value.
For example, with the following sketch, if you get random3D() values ​​every frame, Math.random() won't work because the values ​​will be different each time.

(latest version)

function setup() {
  createCanvas(400, 400, WEBGL);
  noStroke();
}

function draw() {
  orbitControl();

  background(0);
  randomSeed(999);
  lights();
  fill("red");
  ambientMaterial("red");
  specularMaterial(64);

  for(let i=0; i<300; i++){
    const v = p5.Vector.random3D();
    translate(v.mult(100));
    sphere(4);
    translate(-v.x,-v.y,-v.z);
  }
}

In the following video, the modified random3D() is used in the second half. The same vector can be obtained because it is affected by randomSeed().

https://github.com/processing/p5.js/assets/39549290/f5d70911-80af-4545-a36c-d830d9af2a8f

There is a way to prefetch and use the same set of values, but it is more convenient to have it affected by randomSeed(). I think there is no problem because both methods can be used.

However, I am not very familiar with how to rewrite it, so I would appreciate it if someone could tell me...

static random3D() {

  const angle = p5.prototype.random() * constants.TWO_PI;
  const vz = p5.prototype.random() * 2 - 1;

  const vzBase = Math.sqrt(1 - vz * vz);
  const vx = vzBase * Math.cos(angle);
  const vy = vzBase * Math.sin(angle);
  return new p5.Vector(vx, vy, vz);
}

How should I rewrite Math.random()? random()? p5.random()? p5.prototype.random()? something else...

Start in src/math/p5.Vector.js at random2D() and random3D(), then compare their use of Math.random() with shuffle() and randomGaussian(). Verify whether randomSeed(999) should make repeated vector generation deterministic, using the sketch in the issue; done means the intended random-source behavior is consistent and documented by the relevant checks.