camera tween movement

setView.ts

import { Vector3 } from 'three'
import * as TWEEN from 'tween'

export type Callback = () => void

export function setView(position: Vector3, target: Vector3, duration = 0, callback: Callback = null) {
	let endPosition = position.clone()
	let endTarget = target.clone()

	const startPosition = this.position.clone()
	const startTarget = this.getPivot()

	const easing = TWEEN.Easing.Quartic.Out

	if (duration === 0) {
		this.position.copy(endPosition)
		this.lookAt(endTarget)
	}
	else {
		let value = { x: 0 }
		let tween = new TWEEN.Tween(value).to({ x: 1 }, duration)
		tween.easing(easing)

		tween.onUpdate(() => {
			let t = value.x

			this.position.set(
	    			(1 - t) * startPosition.x + t * endPosition.x,
				(1 - t) * startPosition.y + t * endPosition.y,
				(1 - t) * startPosition.z + t * endPosition.z
			)
			this.lookAt(new THREE.Vector3(
				(1 - t) * startTarget.x + t * endTarget.x,
				(1 - t) * startTarget.y + t * endTarget.y,
				(1 - t) * startTarget.z + t * endTarget.z,
			))
		})

		tween.start()

		if (callback !== null) {
			tween.onComplete(() => callback())
		}
	}
}