gl.POINTS

index.css

html, body { margin: 0; height: 100%; }
canvas { width: 100%; height: 100%; display: block; }
#info {
  position: absolute;
  left: 0;
  top: 0;
  background: rgba(0,0,0,0.8);
  color: white;
  padding: 0.5em;
  font-family: monospace;
}
#info a {
  color: orange;
}

index.html

<canvas></canvas>
<div id="info">See <a target="_blank" href="https://jsgist.org/?src=535da7687726e14dc26884e085de7629">here</a> for <i>better</i> emulated POINTS</div>

index.js

import * as twgl from 'https://twgljs.org/dist/4.x/twgl-full.module.js';

const gl = document.querySelector('canvas').getContext('webgl');

const pointsVS = `
attribute vec4 position;
void main() { 
  gl_PointSize = 64.0;
  gl_Position = position;
}
`;

const pointsFS = `
precision mediump float;
void main() {
  gl_FragColor = vec4(gl_PointCoord, 0, 1);
}
`;

const prg = twgl.createProgram(gl, [pointsVS, pointsFS]);
gl.useProgram(prg);

const posLoc = gl.getAttribLocation(prg, "position");

const rand = (min, max) => Math.random() * (max - min) + min;

const numPoints = 100;
const pointPositions = new Float32Array(numPoints * 2);
const pointVelocities = new Float32Array(numPoints * 2);
for (let i = 0; i < numPoints; ++i) {
  const offset = i * 2;
  pointPositions[offset    ]  = rand(-2, 2);
  pointPositions[offset + 1]  = rand(-2, 2);
  pointVelocities[offset    ] = rand(-1, 1);
  pointVelocities[offset + 1] = rand(-1, 1);
}

const pointsBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, pointsBuffer);
gl.bufferData(gl.ARRAY_BUFFER, pointPositions.byteLength, gl.DYNAMIC_DRAW);

let then = 0;
function render(now) {
  now *= 0.001;  // convert to seconds
  
  const elapsedTime = Math.min(now - then, 0.5);
  then = now;

  twgl.resizeCanvasToDisplaySize(gl.canvas);
  
  gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);

  // I'd update this positions on the GPU if I can but 
  // just for the sake of an example we're doing it on the CPU
  for (let i = 0; i < numPoints * 2; ++i) {
    pointPositions[i] = (pointPositions[i] + pointVelocities[i] * elapsedTime + 6) % 4 - 2;
  }

  gl.bindBuffer(gl.ARRAY_BUFFER, pointsBuffer);
  gl.bufferSubData(gl.ARRAY_BUFFER, 0, pointPositions);
  
  gl.enableVertexAttribArray(posLoc);
  gl.vertexAttribPointer(posLoc, 2, gl.FLOAT, false, 0, 0);
  
  gl.drawArrays(gl.POINTS, 0, numPoints);
  
  requestAnimationFrame(render);
}
requestAnimationFrame(render);

jsGist.json

{"name":"gl.POINTS","settings":{},"filenames":["index.html","index.css","index.js"]}