Three.js, moving a partical along an EllipseCurve - three.js

Question

I know questions related to my problem have been asked and answered before but three.js changed a lot in the last couple years and I'm having trouble finding what I need in the currently available examples.
I have an elliptical curve that I'd like to run particles along. My code runs without error but it doesn't actually move the particle anywhere. What am I missing?
var t = 0;
var curve = new THREE.EllipseCurve( .37, .15, .35, .25, 150, 450, false, 0 );
var points = curve.getPoints( 50 );
var curveGeometry = new THREE.BufferGeometry().setFromPoints( points );
var particleGeometry = new THREE.Geometry();
var particleMap = new THREE.TextureLoader().load( "/img/spark.png" );
var vertex = new THREE.Vector3();
vertex.x = points[0].x;
vertex.y = points[0].y;
vertex.z = 0;
particleGeometry.vertices.push(vertex);
particleMaterial = new THREE.PointsMaterial({
size: .05,
map: particleMap,
blending: THREE.AdditiveBlending,
depthTest: false,
transparent : true
});
particles = new THREE.Points( particleGeometry, particleMaterial );
scene.add(particles);
animate();
function animate() {
if (t <= 1) {
particles.position = curveGeometry.getPointAt(t)
t += 0.005
} else {
t = 0;
}
requestAnimationFrame( animate );
render();
}
function render() {
renderer.render( scene, camera );
}

Answer 1

Just a rough concept of how you can do it, using THREE.Geometry():
var scene = new THREE.Scene();
var camera = new THREE.PerspectiveCamera(60, window.innerWidth / window.innerHeight, 1, 1000);
camera.position.set(0, 0, 50);
var renderer = new THREE.WebGLRenderer({
antialias: true
});
renderer.setClearColor(0x404040);
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);
var controls = new THREE.OrbitControls(camera, renderer.domElement);
var grid = new THREE.GridHelper(40, 40, "white", "gray");
grid.rotation.x = Math.PI * -0.5;
scene.add(grid);
var curve = new THREE.EllipseCurve(0, 0, 20, 20, 0, Math.PI * 2, false, 0);
// using of .getPoints(division) will give you a set of points of division + 1
// so, let's get the points manually :)
var count = 10;
var inc = 1 / count;
var pointAt = 0;
var points = [];
for (let i = 0; i < count; i++) {
let point = curve.getPoint(pointAt); // get a point of THREE.Vector2()
point.z = 0; // geometry needs points of x, y, z; so add z
point.pointAt = pointAt; // save position along the curve in a custom property
points.push(point);
pointAt += inc; // increment position along the curve for next point
}
var pointsGeom = new THREE.Geometry();
pointsGeom.vertices = points;
console.log(points);
var pointsObj = new THREE.Points(pointsGeom, new THREE.PointsMaterial({
size: 1,
color: "aqua"
}));
scene.add(pointsObj);
var clock = new THREE.Clock();
var time = 0;
render();
function render() {
requestAnimationFrame(render);
time = clock.getDelta();
points.forEach(p => {
p.pointAt = (p.pointAt + time * 0.1) % 1; // it always will be from 0 to 1
curve.getPoint(p.pointAt, p); //re-using of the current point
});
pointsGeom.verticesNeedUpdate = true;
renderer.render(scene, camera);
}
body {
overflow: hidden;
margin: 0;
}
<script src="https://threejs.org/build/three.min.js"></script>
<script src="https://threejs.org/examples/js/controls/OrbitControls.js"></script>