GLTF Custom Animations

Video Lecture

Description

We don't need to download animations from other websites, we can create our own.

Using Blender, you can create a model and then adjust the positions, scales and rotations of its parts by creating key frames on the timeline editor.

Test your animation works by using the play options on the timeline editor in Blender, and then export your model as GLB(preferred) or GLTF with animation options selected for the export.

After exporting your model, you can drag the GLB/GLTF file from your filesystem, onto this example scene below. It will read the file and create a new checkbox for every animation clip that it finds. You can enable/disable each animation independently.

Lesson Scripts

./dist/client/index.html

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="utf-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1" />
        <title>
            Three.js TypeScript Tutorials by Sean Bradley :
            https://sbcode.net/threejs
        </title>
        <style>
            body {
                overflow: hidden;
                margin: 0px;
            }

            #animationsPanel {
                position: absolute;
                top: 40px;
                right: 10px;
                width: 300px;
                height: auto;
                border: 1px solid white;
                color: white;
                font-family: monospace;
                font-size: 17px;
            }

            #animationsPanel ul {
                padding: 4px;
                list-style-type: none;
            }

            #btnPlayAll {
                position: absolute;
                top: 10px;
                right: 10px;
                width: 300px;
                display: none;
            }

            #dropzone {
                position: absolute;
                width: 140px;
                height: 90px;
                left: 10px;
                top: 50px;
                border: 10px dotted gray;
                background-color: lightgray;
                padding: 20px;
                font-family: monospace;
                font-size: 17px;
            }

            #dropzone p {
                pointer-events: none;
            }
        </style>
    </head>

    <body>
        <div id="dropzone">
            <p>Drag (uncompressed) animated gLTF/gLB here</p>
        </div>
        <button id="btnPlayAll">Play All</button>
        <div id="animationsPanel"></div>
        <script type="module" src="bundle.js"></script>
    </body>
</html>

./src/client/client.ts

import * as THREE from 'three'
import { OrbitControls } from 'three/examples/jsm/controls/OrbitControls'
import { GLTF, GLTFLoader } from 'three/examples/jsm/loaders/GLTFLoader'
import Stats from 'three/examples/jsm/libs/stats.module'

const scene = new THREE.Scene()
scene.add(new THREE.AxesHelper(5))

const camera = new THREE.PerspectiveCamera(
    75,
    window.innerWidth / window.innerHeight,
    0.1,
    1000
)
camera.position.set(4, 4, 4)

const renderer = new THREE.WebGLRenderer()
renderer.setSize(window.innerWidth, window.innerHeight)
document.body.appendChild(renderer.domElement)

const controls = new OrbitControls(camera, renderer.domElement)
controls.enableDamping = true

let mixer: THREE.AnimationMixer
let modelReady = false

const gltfLoader = new GLTFLoader()

const dropzone = document.getElementById('dropzone') as HTMLDivElement

dropzone.ondragover = dropzone.ondragenter = function (evt) {
    evt.preventDefault()
}
dropzone.ondrop = function (evt: DragEvent) {
    evt.stopPropagation()
    evt.preventDefault()

    //clear the scene
    for (let i = scene.children.length - 1; i >= 0; i--) {
        scene.remove(scene.children[i])
    }
    //clear the checkboxes
    const myNode = document.getElementById('animationsPanel') as HTMLDivElement
    while (myNode.firstChild) {
        myNode.removeChild(myNode.lastChild as any)
    }

    const axesHelper = new THREE.AxesHelper(5)
    scene.add(axesHelper)

    const light1 = new THREE.DirectionalLight(new THREE.Color(0xffcccc))
    light1.position.set(-1, 1, 1)
    scene.add(light1)

    const light2 = new THREE.DirectionalLight(new THREE.Color(0xccffcc))
    light2.position.set(1, 1, 1)
    scene.add(light2)

    const light3 = new THREE.DirectionalLight(new THREE.Color(0xccccff))
    light3.position.set(0, -1, 0)
    scene.add(light3)

    const files = (evt.dataTransfer as DataTransfer).files
    const reader = new FileReader()
    reader.onload = function () {
        gltfLoader.parse(
            reader.result as string,
            '/',
            (gltf: GLTF) => {
                console.log(gltf.scene)

                mixer = new THREE.AnimationMixer(gltf.scene)

                console.log(gltf.animations)

                if (gltf.animations.length > 0) {
                    const animationsPanel = document.getElementById(
                        'animationsPanel'
                    ) as HTMLDivElement
                    const ul = document.createElement('UL') as HTMLUListElement
                    const ulElem = animationsPanel.appendChild(ul)

                    gltf.animations.forEach((a: THREE.AnimationClip, i) => {
                        const li = document.createElement('UL') as HTMLLIElement
                        const liElem = ulElem.appendChild(li)

                        const checkBox = document.createElement(
                            'INPUT'
                        ) as HTMLInputElement
                        checkBox.id = 'checkbox_' + i
                        checkBox.type = 'checkbox'
                        checkBox.addEventListener('change', (e: Event) => {
                            if ((e.target as HTMLInputElement).checked) {
                                mixer
                                    .clipAction((gltf as any).animations[i])
                                    .play()
                            } else {
                                mixer
                                    .clipAction((gltf as any).animations[i])
                                    .stop()
                            }
                        })
                        liElem.appendChild(checkBox)

                        const label = document.createElement(
                            'LABEL'
                        ) as HTMLLabelElement
                        label.htmlFor = 'checkbox_' + i
                        label.innerHTML = a.name
                        liElem.appendChild(label)
                    })

                    if (gltf.animations.length > 1) {
                        const btnPlayAll = document.getElementById(
                            'btnPlayAll'
                        ) as HTMLButtonElement
                        btnPlayAll.addEventListener('click', (e: Event) => {
                            mixer.stopAllAction()
                            gltf.animations.forEach(
                                (a: THREE.AnimationClip) => {
                                    mixer.clipAction(a).play()
                                }
                            )
                        })

                        btnPlayAll.style.display = 'block'
                    }
                } else {
                    const animationsPanel = document.getElementById(
                        'animationsPanel'
                    ) as HTMLDivElement
                    animationsPanel.innerHTML = 'No animations found in model'
                }

                scene.add(gltf.scene)

                const bbox = new THREE.Box3().setFromObject(gltf.scene)
                controls.target.x = (bbox.min.x + bbox.max.x) / 2
                controls.target.y = (bbox.min.y + bbox.max.y) / 2
                controls.target.z = (bbox.min.z + bbox.max.z) / 2

                modelReady = true
            },
            (error) => {
                console.log(error)
            }
        )
    }
    reader.readAsArrayBuffer(files[0])
}

window.addEventListener('resize', onWindowResize, false)
function onWindowResize() {
    camera.aspect = window.innerWidth / window.innerHeight
    camera.updateProjectionMatrix()
    renderer.setSize(window.innerWidth, window.innerHeight)
    render()
}

const stats = Stats()
document.body.appendChild(stats.dom)

const clock = new THREE.Clock()

function animate() {
    requestAnimationFrame(animate)

    controls.update()

    if (modelReady) mixer.update(clock.getDelta())

    render()

    stats.update()
}

function render() {
    renderer.render(scene, camera)
}

animate()

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