无法补间 ThreeJS 相机旋转

Question

我正在尝试使用 TweenJS 为 ThreeJS 相机旋转设置动画，补间 camera.position 没问题，但出于某种原因 camera.rotation 拒绝更改？

我使用官方 ThreeJS 文档中的代码设置了一个最小示例：https://threejs.org/docs/index.html#manual/en/introduction/Creating-a-scene

基本上归结为它如何正常工作：

new TWEEN.Tween(camera.position).to({x: newPos.x, y: newPos.y, z: newPos.z}).start()

虽然这根本不起作用：

new TWEEN.Tween(camera.rotation).to({x: newRot.x, y: newRot.y, z: newRot.z}).start()

我认为代码应该很清楚：

var scene = new THREE.Scene();
var camera = new THREE.PerspectiveCamera( 75, window.innerWidth/window.innerHeight, 0.1, 1000 );

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

var geometry = new THREE.BoxGeometry( 1, 1, 1 );
var material = new THREE.MeshBasicMaterial( { color: 0x00ff00 } );
var cube = new THREE.Mesh( geometry, material );
scene.add( cube );

camera.position.z = 5;

var animate = function () {
  requestAnimationFrame( animate );

  cube.rotation.x += 0.01;
  cube.rotation.y += 0.01;

  renderer.render( scene, camera );
  
  TWEEN.update(); // NOTE: I added this too
};

animate();

// NOTE: I added this:
// In a few seconds, tween the camera rotation
setTimeout(() => {
  const newRot = {x: 1, y: 1, z: 1};

  console.log('Changing camera rotation from:');
  console.log(camera.rotation);
  console.log('to:');
  console.log(newRot);

  new TWEEN.Tween(camera.rotation).to({x: newRot.x, y: newRot.y, z: newRot.z}).start().onComplete(() => {
    // Note that it doesn't change at all?
    console.log('Camera rotation changed:');
    console.log(camera.rotation);
    
    // Manually setting the rotation works fine??
    console.log('Manually changing camera rotation:');
    camera.rotation.x = newRot.x;
    camera.rotation.y = newRot.y;
    camera.rotation.z = newRot.z;
  });
  
  // Tweening the position is no problem??
  const newPos = {x: 0, y: 0, z: 2};
  
  new TWEEN.Tween(camera.position).to({x: newPos.x, y: newPos.y, z: newPos.z}).start()
}, 5000);

body { margin: 0; }
canvas { width: 100%; height: 100% }

<script src="https://cdnjs.cloudflare.com/ajax/libs/tween.js/16.3.5/Tween.min.js"></script>
<script src="https://threejs.org/build/three.js"></script>

Answer 1

所以出于某种原因，我必须做的是解决这个问题，而不是直接补间 camera.rotation，我创建了一个临时对象 oldRot，补间了它，然后 onUpdate将 camera.rotation 设置为 oldRot。

所以，而不是这个：

const newRot = {x: 1, y: 1, z: 1};

new TWEEN.Tween(camera.rotation).to({x: newRot.x, y: newRot.y, z: newRot.z}).start();

我现在有这个：

const newRot = {x: 1, y: 1, z: 1};
const oldRot = {x: camera.rotation.x, y: camera.rotation.y, z: camera.rotation.z};

new TWEEN.Tween(oldRot).to(newRot).start().onUpdate(() => {
    camera.rotation.x = oldRot.x;
    camera.rotation.y = oldRot.y;
    camera.rotation.z = oldRot.z;
});

无论出于何种原因，这都有效。很想知道 为什么 如果有人知道的话。

无法补间 ThreeJS 相机旋转

Unable to Tween ThreeJS Camera Rotation

javascript

tween

three.js