Three.JS VRAM memory leak when adding removing THREE.Geometry to scene

Question

I have encountered a VRAM memory leak in my app. The app adds and removes THREE.Geometry very often to create a volumetric animation. If instead of a THREE.Geometry with it's own populated vertices, I used instead THREE.SphereBufferGeometry, the memory leak doesn't happen.

I have created a minimal app to prove this memory leak is real. The memory leak increase VRAM memory very slowly, but it does fill up in the end. I think that pools won't help, since it's VRAM and not managed memory. I do use dispose.

If you can make this sample work and not have memory leak, that might solve my issue:

https://jsfiddle.net/4a7ksryd/16/

Edit: I am adding here the code of the app:

var camera, scene, renderer;
var geometry, material, mesh;
var lastSphere;
var lastGeo;

init();
animate();

function init() {

    camera = new THREE.PerspectiveCamera( 70, window.innerWidth / window.innerHeight, 0.01, 10 );
    camera.position.z = 1;

    scene = new THREE.Scene();


    renderer = new THREE.WebGLRenderer( { antialias: true } );
    renderer.setSize( window.innerWidth, window.innerHeight );
    renderer.shadowMap.enabled = true;
renderer.shadowMap.type = THREE.PCFSoftShadowMap; // default THREE.PCFShadowMap

    var light = new THREE.DirectionalLight( 0xffffff, 1, 100 );
light.position.set( 0, 4, 0 );          //default; light shining from top
light.castShadow = true;            // default false
//Set up shadow properties for the light
light.shadow.mapSize.width = 1024;  // default
light.shadow.mapSize.height = 1024; // default
light.shadow.camera.near = 1;    // default
light.shadow.camera.far = 20;     // default

scene.add( light );


    //Create a sphere that cast shadows (but does not receive them)

geometry = new THREE.SphereBufferGeometry( 0.1, 32, 32 );
material = new THREE.MeshStandardMaterial( { color: 0xff0000 } );
//    geometry = new THREE.BoxGeometry( 0.2, 0.2, 0.2 );
//    material = new THREE.MeshNormalMaterial();

    mesh = new THREE.Mesh( geometry, material );
    mesh.position.y = 0.1;
    mesh.castShadows = true;
    mesh.receiveShadow = false;
    scene.add( mesh );

    var planeGeometry = new THREE.PlaneBufferGeometry( 15, 15, 1, 1 );
var planeMaterial = new THREE.MeshStandardMaterial( { color: 0xffffff, emissive:0x111111 } )
var plane = new THREE.Mesh( planeGeometry, planeMaterial );
plane.position.y = -0.2;
plane.rotation.x = -Math.PI / 2;
plane.receiveShadow = true;
scene.add( plane );


    document.body.appendChild( renderer.domElement );

}

function animate() {

    requestAnimationFrame( animate );

    mesh.rotation.x += 0.01;
    mesh.rotation.y += 0.02;

        var dim = 32;
        var geo1 = new THREE.Geometry();
    const numVertices = dim*dim;
    var vertices = new Array(numVertices);
    for (var i=0; i<vertices.length; i++)
    {
        const x = i%dim;
        const y = (Math.floor(i/dim))%dim;    
      vertices[i] = new THREE.Vector3(x*0.1, y*0.1, 0);
    }
    const numFaces = (dim-1)*(dim-1)*2;
    var faces = new Array(numFaces);

    for (var i=0; i<(faces.length/2); i++)
    {
        const x = i%(dim-1);
        const y = Math.floor(i/(dim-1))%(dim-1);
        faces[2*i] = new THREE.Face3(x+y*dim, x+1+y*dim, x+(y+1)*dim);
        faces[2*i+1] = new THREE.Face3(x+1+y*dim, x+1+(y+1)*dim, x+(y+1)*dim);
    }
    var uv = new Array(numFaces);
    for (var i=0; i<uv.length; i++)    
        uv[i] = [new THREE.Vector2(0, 0), new THREE.Vector2(0, 0), new THREE.Vector2(0, 0)];
    geo1.faces = faces;
    geo1.vertices = vertices;
    geo1.faceVertexUvs[0] = uv;
        geo1.uvsNeedUpdate = true;
        geo1.verticesNeedUpdate = true;
        geo1.elementsNeedUpdate = true;
//    var sphereGeometry = new THREE.SphereBufferGeometry( 0.1, 256, 256 );
    var sphereGeometry = geo1;
    var sphereMaterial = new THREE.MeshBasicMaterial( { color: 0xff0000 } );
    var sphere = new THREE.Mesh( sphereGeometry, sphereMaterial );
    sphere.position.y = 0.1+Math.sin(mesh.rotation.x)*0.1;
    sphere.position.x = 0.5;
    sphere.castShadow = true; //default is false
    sphere.receiveShadow = false; //default
    if (lastGeo!=null)
        lastGeo.dispose();
    if (lastSphere!=null)
        scene.remove(lastSphere);
    scene.add( sphere );
    lastSphere = sphere;
    lastGeo = sphereGeometry;
//    geo1.dispose();

    renderer.render( scene, camera );

}

Answer 1

This is actually a bug in three.js. I've filed a PR to fix the issue:

https://github.com/mrdoob/three.js/pull/20479