sphere.js

// From:  https://www.khronos.org/registry/webgl/sdk/demos/webkit/resources/J3DI.js
//
// makeSphere
//
// Create a sphere with the passed number of latitude and longitude bands and the passed radius.
// Sphere has vertices, normals and texCoords. Create VBOs for each as well as the index array.
// Return an object with the following properties:
//
//  normalObject        WebGLBuffer object for normals
//  texCoordObject      WebGLBuffer object for texCoords
//  vertexObject        WebGLBuffer object for vertices
//  indexObject         WebGLBuffer object for indices
//  numIndices          The number of indices in the indexObject
//
function makeSphere(radius, lats, longs)
{
    var geometryData = [ ];
    var normalData = [ ];
    var texCoordData = [ ];
    var indexData = [ ];

    for (var latNumber = 0; latNumber <= lats; ++latNumber) {
        for (var longNumber = 0; longNumber <= longs; ++longNumber) {
            var theta = latNumber * Math.PI / lats;
            var phi = longNumber * 2 * Math.PI / longs;
            var sinTheta = Math.sin(theta);
            var sinPhi = Math.sin(phi);
            var cosTheta = Math.cos(theta);
            var cosPhi = Math.cos(phi);

            var x = cosPhi * sinTheta;
            var y = cosTheta;
            var z = sinPhi * sinTheta;
            var u = 1-(longNumber/longs);
            var v = latNumber/lats;

            normalData.push(x);
            normalData.push(y);
            normalData.push(z);
            texCoordData.push(u);
            texCoordData.push(v);
            geometryData.push(radius * x);
            geometryData.push(radius * y);
            geometryData.push(radius * z);
        }
    }

    for (var latNumber = 0; latNumber < lats; ++latNumber) {
        for (var longNumber = 0; longNumber < longs; ++longNumber) {
            var first = (latNumber * (longs+1)) + longNumber;
            var second = first + longs + 1;
            indexData.push(first);
            indexData.push(second);
            indexData.push(first+1);

            indexData.push(second);
            indexData.push(second+1);
            indexData.push(first+1);
        }
    }

    var retval = {
	vertices : geometryData,
	normals : normalData,
	faces : indexData,
	uv    : texCoordData
    };

    return retval;
}