问题描述
我正在尝试使用 Tweenjs 为 ThreeJS 相机旋转设置动画,我在调整 camera.position 时没有问题,但由于某种原因,camera.rotation 拒绝更改?
我使用 ThreeJS 官方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
基本上归结为它的工作原理:
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()
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,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,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>
解决方法
所以出于某种原因,我必须做的不是直接补间camera.rotation
,而是创建了一个临时对象oldRot
,补间那个,以及补间集的onUpdate
camera.rotation
到 oldRot
。
所以,而不是这样:
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,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。如果有人知道,我很想知道为什么。