Three.js KeyframeTracks filtering

by Matt

HTML

<base href="https://rawcdn.githack.com/mrdoob/three.js/r152/examples/" />
<script async src="https://cdn.jsdelivr.net/npm/[email protected]/dist/es-module-shims.js"></script>
<script type="importmap">
	{
		"imports": {
			"three": "https://cdn.jsdelivr.net/npm/[email protected]/build/three.module.js",
			"three/addons/": "https://cdn.jsdelivr.net/npm/[email protected]/examples/jsm/",
			"lil-gui": "https://cdn.jsdelivr.net/npm/[email protected]/dist/lil-gui.esm.min.js"
		}
	}
</script>

CSS

canvas {
	position: fixed;
	inset: 0;
}

JavaScript

import * as THREE from 'three';

import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js';
import * as SkeletonUtils from 'three/addons/utils/SkeletonUtils.js';

let camera, scene, renderer;
let clock;

const mixers = [];

init();
animate();

function init() {

  camera = new THREE.PerspectiveCamera( 45, window.innerWidth / window.innerHeight, 1, 1000 );
  camera.position.set( 2, 3, - 6 );
  camera.lookAt( 0, 1, 0 );

  clock = new THREE.Clock();

  scene = new THREE.Scene();
  scene.background = new THREE.Color( 0xa0a0a0 );
  scene.fog = new THREE.Fog( 0xa0a0a0, 10, 50 );

  const hemiLight = new THREE.HemisphereLight( 0xffffff, 0x8d8d8d, 3 );
  hemiLight.position.set( 0, 20, 0 );
  scene.add( hemiLight );

  const dirLight = new THREE.DirectionalLight( 0xffffff, 3 );
  dirLight.position.set( - 3, 10, - 10 );
  dirLight.castShadow = true;
  dirLight.shadow.camera.top = 4;
  dirLight.shadow.camera.bottom = - 4;
  dirLight.shadow.camera.left = - 4;
  dirLight.shadow.camera.right = 4;
  dirLight.shadow.camera.near = 0.1;
  dirLight.shadow.camera.far = 40;
  scene.add( dirLight );

  // scene.add( new THREE.CameraHelper( dirLight.shadow.camera ) );

  // ground

  const mesh = new THREE.Mesh( new THREE.PlaneGeometry( 200, 200 ), new THREE.MeshPhongMaterial( { color: 0xcbcbcb, depthWrite: false } ) );
  mesh.rotation.x = - Math.PI / 2;
  mesh.receiveShadow = true;
  scene.add( mesh );

  const loader = new GLTFLoader();
  loader.load( 'models/gltf/Soldier.glb', function ( gltf ) {

    gltf.scene.traverse( function ( object ) {

      if ( object.isMesh ) object.castShadow = true;

    } );

    const model1 = SkeletonUtils.clone( gltf.scene );
    const model2 = SkeletonUtils.clone( gltf.scene );
    const model3 = SkeletonUtils.clone( gltf.scene );

    const mixer1 = new THREE.AnimationMixer( model1 );
    const mixer2 = new THREE.AnimationMixer( model2 );
    const mixer3 = new THREE.AnimationMixer( model3 );

    mixer1.clipAction( gltf.animations[ 0 ]...