Using tweens.js

Video Lecture

Description

Tweenjs is a JavaScript tweening engine.

A tween (from in-between) is a concept that allows you to change the values of the properties of an object smoothly. We can decide how long it should take, and if there should be a delay, and what to do each time the tween is updated, whether it should repeat and other things.

Install Tween

Since Three r151, tween.module.min.js is no longer supplied by the Threejs library as shown in the video. Instead, we can install it from its official repository.

npm install @tweenjs/tween.js

It comes with its own type definitions, so it is also no longer necessary to manually set up a type definition for the library as shown in the video.

The import syntax has also changed. Use,

import TWEEN from '@tweenjs/tween.js'

Tween Easing Options

TWEEN.Easing._equation_._direction_

TWEEN.Easing.*equation*.*direction*

Start Scripts

./src/client/client.ts

Warning

Tween is now installed from the official repository rather than using it directly from the local Threejs libs folder as demonstrated in the video. Don't forget to Install Tween

import * as THREE from 'three'
import { OrbitControls } from 'three/examples/jsm/controls/OrbitControls'
import { GLTFLoader } from 'three/examples/jsm/loaders/GLTFLoader'
import Stats from 'three/examples/jsm/libs/stats.module'
import TWEEN from '@tweenjs/tween.js'

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.z = 2

const renderer = new THREE.WebGLRenderer()
//renderer.physicallyCorrectLights = true //deprecated
renderer.useLegacyLights = false //use this instead of setting physicallyCorrectLights=true property
renderer.shadowMap.enabled = true
renderer.setSize(window.innerWidth, window.innerHeight)
document.body.appendChild(renderer.domElement)

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

const sceneMeshes: THREE.Mesh[] = []
let monkey: THREE.Mesh

const loader = new GLTFLoader()
loader.load(
    'models/monkey_textured.glb',
    function (gltf) {
        gltf.scene.traverse(function (child) {
            if ((child as THREE.Mesh).isMesh) {
                const m = child as THREE.Mesh
                m.receiveShadow = true
                m.castShadow = true
                if (child.name === 'Plane') {
                    sceneMeshes.push(m)
                } else if (child.name === 'Suzanne') {
                    monkey = m
                }
            }
            if ((child as THREE.Light).isLight) {
                const l = child as THREE.SpotLight
                l.castShadow = true
                l.shadow.bias = -0.003
                l.shadow.mapSize.width = 2048
                l.shadow.mapSize.height = 2048
            }
        })
        scene.add(gltf.scene)
    },
    (xhr) => {
        console.log((xhr.loaded / xhr.total) * 100 + '% loaded')
    },
    (error) => {
        console.log(error)
    }
)

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

const raycaster = new THREE.Raycaster()
const mouse = new THREE.Vector2()

function onDoubleClick(event: MouseEvent) {
    mouse.set(
        (event.clientX / renderer.domElement.clientWidth) * 2 - 1,
        -(event.clientY / renderer.domElement.clientHeight) * 2 + 1
    )
    raycaster.setFromCamera(mouse, camera)

    const intersects = raycaster.intersectObjects(sceneMeshes, false)

    if (intersects.length > 0) {
        // const p = intersects[0].point
        // controls.target.set(p.x, p.y, p.z)
        // new TWEEN.Tween(controls.target)
        //     .to({
        //         x: p.x,
        //         y: p.y,
        //         z: p.z
        //     }, 500)
        //     //.delay (1000)
        //     .easing(TWEEN.Easing.Cubic.Out)
        //     //.onUpdate(() => render())
        //     .start()
    }
}
renderer.domElement.addEventListener('dblclick', onDoubleClick, false)

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

function animate() {
    requestAnimationFrame(animate)

    controls.update()

    TWEEN.update()

    render()

    stats.update()
}

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

animate()

./src/typings/tween.js/index.d.ts

Warning

It is no longer necessary to manually set up a type definition for Tween as shown in the video. A type definition is now included with the official Tween install. Don't forget to Install Tween

Create a new folder called ./src/typings/tween.js/ and add the TypeScript definition file for tween.js and name it index.d.ts

// It is no longer necessary to add this type definition. See warning above.
export class tween {
    Tween: typeof Tween
    update(time?: number): boolean
    getAll(): Tween[]
    removeAll(): void
    add(tween: Tween): void
    remove(tween: Tween): void
    Easing: {
        Linear: {
            None: (amount: number) => number
        }
        Quadratic: {
            In: (amount: number) => number
            Out: (amount: number) => number
            InOut: (amount: number) => number
        }
        Cubic: {
            In: (amount: number) => number
            Out: (amount: number) => number
            InOut: (amount: number) => number
        }
        Quartic: {
            In: (amount: number) => number
            Out: (amount: number) => number
            InOut: (amount: number) => number
        }
        Quintic: {
            In: (amount: number) => number
            Out: (amount: number) => number
            InOut: (amount: number) => number
        }
        Sinusoidal: {
            In: (amount: number) => number
            Out: (amount: number) => number
            InOut: (amount: number) => number
        }
        Exponential: {
            In: (amount: number) => number
            Out: (amount: number) => number
            InOut: (amount: number) => number
        }
        Circular: {
            In: (amount: number) => number
            Out: (amount: number) => number
            InOut: (amount: number) => number
        }
        Elastic: {
            In: (amount: number) => number
            Out: (amount: number) => number
            InOut: (amount: number) => number
        }
        Back: {
            In: (amount: number) => number
            Out: (amount: number) => number
            InOut: (amount: number) => number
        }
        Bounce: {
            In: (amount: number) => number
            Out: (amount: number) => number
            InOut: (amount: number) => number
        }
    }
}
declare type EasingFunction = (amount: number) => number
declare class Tween {
    constructor(object: any)
    isPlaying(): boolean
    isPaused(): boolean
    to(properties: {}, duration?: number): this
    duration(value: number): this
    start(time?: number | string): this
    stop(): this
    end(): this
    pause(time: number): this
    resume(time: number): this
    delay(amount: number): this
    repeat(times: number): this
    repeatDelay(amount: number): this
    onStart(callback: (object: any) => void): this
    onUpdate(callback: (object: any, elapsed: number) => void): this
    onRepeat(callback: (object: any) => void): this
    onComplete(callback: (object: any) => void): this
    onStop(callback: (object: any) => void): this
    easing(easing: EasingFunction): this
    chain(tween: Tween): this
}

declare const TWEEN: tween

./src/client/tsconfig.json

Warning

It is no longer necessary to modify the tsconfig.json since Tween is now installed from the official repository rather than using it directly from the local Threejs lib folder as demonstrated in the video. A type definition is now included in the official Tween install and is already correctly linked. Don't forget to Install Tween

~~Update the compiler options paths to point to the new tween.js typescript definition file.~~

// It is no longer necessary to modify the tsconfig.json. See warning above.
{
    "compilerOptions": {
        "target": "ES6",
        "moduleResolution": "node",
        "strict": true,
        "paths": {
            "three/examples/jsm/libs/tween.module.min": ["../typings/tween.js"]
        }
    },
    "include": ["**/*.ts"]
}

Final Script

./src/client/client.ts

import * as THREE from 'three'
import { OrbitControls } from 'three/examples/jsm/controls/OrbitControls'
import { GLTFLoader } from 'three/examples/jsm/loaders/GLTFLoader'
import Stats from 'three/examples/jsm/libs/stats.module'
import TWEEN from '@tweenjs/tween.js'

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.z = 2

const renderer = new THREE.WebGLRenderer()
//renderer.physicallyCorrectLights = true //deprecated
renderer.useLegacyLights = false //use this instead of setting physicallyCorrectLights=true property
renderer.shadowMap.enabled = true
renderer.setSize(window.innerWidth, window.innerHeight)
document.body.appendChild(renderer.domElement)

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

const sceneMeshes: THREE.Mesh[] = []
let monkey: THREE.Mesh

const loader = new GLTFLoader()
loader.load(
    'models/monkey_textured.glb',
    function (gltf) {
        gltf.scene.traverse(function (child) {
            if ((child as THREE.Mesh).isMesh) {
                let m = child as THREE.Mesh
                m.receiveShadow = true
                m.castShadow = true
                if (child.name === 'Plane') {
                    sceneMeshes.push(m)
                } else if (child.name === 'Suzanne') {
                    monkey = m
                }
            }
            if ((child as THREE.Light).isLight) {
                const l = child as THREE.SpotLight
                l.castShadow = true
                l.shadow.bias = -0.003
                l.shadow.mapSize.width = 2048
                l.shadow.mapSize.height = 2048
            }
        })
        scene.add(gltf.scene)
    },
    (xhr) => {
        console.log((xhr.loaded / xhr.total) * 100 + '% loaded')
    },
    (error) => {
        console.log(error)
    }
)

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

const raycaster = new THREE.Raycaster()
const mouse = new THREE.Vector2()

function onDoubleClick(event: MouseEvent) {
    mouse.set(
        (event.clientX / renderer.domElement.clientWidth) * 2 - 1,
        -(event.clientY / renderer.domElement.clientHeight) * 2 + 1
    )
    raycaster.setFromCamera(mouse, camera)

    const intersects = raycaster.intersectObjects(sceneMeshes, false)

    if (intersects.length > 0) {
        const p = intersects[0].point

        //controls.target.set(p.x, p.y, p.z)

        // new TWEEN.Tween(controls.target)
        //     .to({
        //         x: p.x,
        //         y: p.y,
        //         z: p.z
        //     }, 500)
        //     //.delay (1000)
        //     .easing(TWEEN.Easing.Cubic.Out)
        //     //.onUpdate(() => render())
        //     .start()

        new TWEEN.Tween(monkey.position)
            .to(
                {
                    x: p.x,
                    // y: p.y + 1,
                    z: p.z,
                },
                500
            )
            .start()

        new TWEEN.Tween(monkey.position)
            .to(
                {
                    // x: p.x,
                    y: p.y + 3,
                    // z: p.z,
                },
                250
            )
            //.delay (1000)
            .easing(TWEEN.Easing.Cubic.Out)
            //.onUpdate(() => render())
            .start()
            .onComplete(() => {
                new TWEEN.Tween(monkey.position)
                    .to(
                        {
                            // x: p.x,
                            y: p.y + 1,
                            // z: p.z,
                        },
                        250
                    )
                    //.delay (250)
                    .easing(TWEEN.Easing.Bounce.Out)
                    //.onUpdate(() => render())
                    .start()
            })
    }
}
renderer.domElement.addEventListener('dblclick', onDoubleClick, false)

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

function animate() {
    requestAnimationFrame(animate)

    controls.update()

    TWEEN.update()

    render()

    stats.update()
}

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

animate()

Useful Links

tween.js GitHub

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	Threejs and TypeScript
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	Design Patterns Python
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