Three.js：围绕对象的旋转？

Question

我尝试制作太阳系。我的行星在圆周运动：

this.obj.position.x = (this.positionX*20) * Math.cos( this.ange );
this.obj.position.z = (this.positionX*20) * Math.sin( this.ange );
this.ange = this.ange + this.rotationAhisSpeed;

月球如何绕地球旋转？我知道地球的位置，但是余弦和正弦如何计算？

Answer 1

让一个对象环绕另一个对象非常简单。

let earth = {
    x,
    y,
    z,
    orbitDistance,
    angle,
    angleSpeed
}

let moon = {
    x,
    y,
    z,
    orbitDistance,
    angle,
    angleSpeed
}

// Assume the object properties are filled out

earth.x = earth.orbitDistance * Math.sin( earth.angle );
earth.z = earth.orbitDistance * Math.cos( earth.angle );

// Starting from the Eath's position will make it the origin of the Moon's orbit
moon.x = earth.x + moon.orbitDistance * Math.sin( moon.angle );
moon.z = earth.z + moon.orbitDistance * Math.cos( moon.angle );

earth.angle += earth.angleSpeed;
moon.angle += moon.angleSpeed;