<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <canvas id="canvas"></canvas>
    <script id="vertexShader" type="x-shader/x-vertex">
        attribute vec4 a_Position;
        void main(){
            gl_Position = a_Position;
            gl_PointSize = 50.0;
        }
    </script>
