我想使用四元数设置向量的绝对全局旋转。
假设我有一个函数f(v, q)
,它将向量v
旋转为四元数q
.
THREE.Vector3
有一个 .applyQuaternion
函数,它将旋转应用于向量,但这是相对旋转。例如,函数调用 f(f(v, q), q)
将应用 q
两次。相反,我期望 f(f(v, q), q) = f(v, q)
因为 q
是向量的绝对旋转。
我知道我可以计算一些deltaQ = currentQ.premultiply(q.inverse())
,然后调用.applyQuaternion
,但我不知道如何查询 currentQ 或向量的当前旋转,以便我可以“撤消”它并应用新的四元数。
感谢您的帮助!
编辑:
理想情况下,我希望绕世界坐标空间中定义的点旋转,这就是为什么我有 object.worldToLocal
和 object.localToWorld
调用。然而,当我进行这些转换时,轨道物体会飞离 map 。
const scene = new THREE.Scene();
const camera = new THREE.PerspectiveCamera( 75, window.innerWidth/window.innerHeight, 0.1, 1000 );
const renderer = new THREE.WebGLRenderer();
renderer.setSize( window.innerWidth, window.innerHeight );
document.body.appendChild( renderer.domElement );
/* const orbitControls = new THREE.OrbitControls(camera, renderer.domElement); */
// CONSTRUCT ORBITER
const orbitGeometry = new THREE.SphereGeometry(0.1, 32, 32);
const orbitMaterial = new THREE.MeshBasicMaterial({colors: 0xff0000});
const orbiter = new THREE.Mesh(orbitGeometry, orbitMaterial);
// CONSTRUCT GLOBAL AXES
const xDir = new THREE.Vector3(1, 0, 0);
const yDir = new THREE.Vector3(0, 1, 0);
const zDir = new THREE.Vector3(0, 0, 1);
const origin = new THREE.Vector3(0, 0, 0);
const xArrowWorld = new THREE.ArrowHelper(xDir, origin, 3, 0xFF00FF);
const yArrowWorld = new THREE.ArrowHelper(yDir, origin, 3, 0xffff00);
const zArrowWorld = new THREE.ArrowHelper(zDir, origin, 3, 0x00b7eb);
const worldAxes = new THREE.Group();
worldAxes.add(xArrowWorld);
worldAxes.add(yArrowWorld);
worldAxes.add(zArrowWorld);
// CONSTRUCT MARKER
const sphereGeometry = new THREE.SphereGeometry(0.1, 32, 32);
const sphereMaterial = new THREE.MeshBasicMaterial({color: 0xffffff});
const marker = new THREE.Mesh(sphereGeometry, sphereMaterial);
// scene.add(axes);
scene.add(marker);
scene.add(orbiter);
scene.add(worldAxes);
camera.position.z = 5;
camera.position.y = 3;
camera.position.x = 3;
camera.lookAt(worldAxes.position);
marker.position.set(1, 0, 0);
function rotateEuler(object, point, eulerX, eulerY, eulerZ, isExtrinsic = false) {
if (isExtrinsic) {
object.rotation.order = 'ZYX';
} else {
object.rotation.order = 'XYZ';
}
const q = new THREE.Quaternion();
const eul = new THREE.Euler(eulerX, eulerY, eulerZ, object.rotation.order);
q.setFromEuler(eul);
rotateQuaternionAroundPoint(object, point, q);
}
function rotateQuaternionAroundPoint(object, point, q) {
object.rotation.set(0, 0, 0)
object.position.set(0, 0, 0);
object.localToWorld(object.position);
object.position.sub(point);
object.position.applyQuaternion(q);
object.position.add(point);
object.worldToLocal(object.position);
}
let rotY = 0;
let rotationPoint = marker.localToWorld(marker.position.clone());
function animate() {
requestAnimationFrame( animate );
rotY += 0.01;
rotateEuler(orbiter, rotationPoint, 0, rotY, 0, true);
renderer.render( scene, camera );
}
animate();
<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/110/three.min.js"></script>
最佳答案
最简单的方法是将 Vector3
重置为其初始状态,然后将四元数应用于此重置向量。这会从方程中删除任何先前的旋转。例如,假设向量的默认状态指向'UP'
:
function f(v, q) {
v.set(0, 1, 0);
v.applyQuaternion(q);
return v;
}
关于javascript - 在 THREE.js 中使用四元数设置向量的全局旋转,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/61147807/