Shphere in webgl

buildSphere.js

// based on text book 2.4 https://inspirit.net.in/books/academic/Interactive%20Computer%20Graphics.pdf
function buildSpherePoints(){
  const  DegreesToRadians = Math.PI / 180.0; // Math.PI = 3.14159...
  let quad_data = [];   // 8 rows of 18 quads
  let k = 0;
  for(let phi = -80.0; phi <= 80.0; phi += 20.0)
  {
    let phir = phi*DegreesToRadians;
      let phir20 = (phi + 20.0)*DegreesToRadians;
      for(let theta = -180.0; theta <= 180.0; theta += 20.0)
      {
          let thetar = theta*DegreesToRadians;
          shapes.sphere.points[k] = vec4(
            Math.sin(thetar)*Math.cos(phir),
            Math.cos(thetar)*Math.cos(phir), 
            Math.sin(phir),
            1);
            shapes.sphere.colors.push(lightblue)
            k++;
            shapes.sphere.points[k] = vec4(
              Math.sin(thetar)*Math.cos(phir20),
              Math.cos(thetar)*Math.cos(phir20), 
              Math.sin(phir20),
              1
              );
            shapes.sphere.colors.push(lightblue)
          k++;
    }
  }
}