Unity2D-如何在2D游戏中围绕圆形移动和旋转游戏对象? [英] Unity2D - How to move AND rotate a gameobject around a circle in a 2D game?

问题描述

我正在尝试围绕目标行星(目前只是一个圆圈)移动和旋转一些云.我的机芯下降了，但是我真的在旋转部分上挣扎.我希望它与圆上的位置成比例旋转，但是我一直试图猜测正确的数字.这是代码:

I'm trying to move and rotate some clouds around a target planet (which is just a circle at the moment). I got the movement down, but I am really struggling with the rotation part. I want it to rotate in proportion to where it is on the circle but I'm stuck trying to guesstimate the right numbers. Here is the code:

public class CloudMovement : MonoBehaviour
{
    public GameObject target;
    private float RotateSpeed = .05f;
    private float Radius = 1.0f;

    private Vector2 center;
    private float angle;

    private void Start()
    {
        center = target.transform.localPosition;
        Radius = target.transform.localScale.x / 1.5f;
    }

    private void Update()
    {

        angle = angle + RotateSpeed * Time.deltaTime;
        this.transform.Rotate (Vector3.forward * -angle * Time.deltaTime);

        Vector2 offset = new Vector2(Mathf.Sin(angle), Mathf.Cos(angle)) * Radius;
        this.transform.position = center + offset;
    }
}

推荐答案

using UnityEngine;

public class CloudMovement : MonoBehaviour
{
    // X Y radius
    public Vector2 Velocity = new Vector2(1, 0); 

    // rotational direction
    public bool Clockwise = true;

    [Range(0, 5)] 
    public float RotateSpeed = 1f;
    [Range(0, 5)]
    public float RotateRadiusX = 1f;
    [Range(0, 5)]
    public float RotateRadiusY = 1f;        

    private Vector2 _centre;
    private float _angle;

    private void Start()
    {
        _centre = transform.position;
    }

    private void Update()
    {
        _centre += Velocity * Time.deltaTime;    
        _angle += (Clockwise ? RotateSpeed : -RotateSpeed) * Time.deltaTime;    
        var x = Mathf.Sin(_angle) * RotateRadiusX;
        var y = Mathf.Cos(_angle) * RotateRadiusY;    
        transform.position = _centre + new Vector2(x, y);
    }

    void OnDrawGizmos()
    {
        Gizmos.DrawSphere(_centre, 0.1f);
        Gizmos.DrawLine(_centre, transform.position);
    }
}

---

编辑选项2 :RotateAround

一个最新的选项，嵌入到Unity 中-您还可以尝试RotateAround函数

A more recent option, baked into Unity -- you can also try RotateAround function

Vector3 point = new Vector3(10,0,0);
Vector3 axis =  new Vector3(0,0,1);
transform.RotateAround(point, axis, Time.deltaTime * 10);

transform.RotateAround()取Vector3 Point Axis &浮点角(以度为单位).

transform.RotateAround() takes a Vector3 PointAxis&float Angle` in degrees.

轴为旋转方向.

同一件事，带有一个工作示例，从这里开始

Same thing, with a working sample from here

public class CloudMovement : MonoBehaviour {

 public float speed;
 public Transform target;

 private Vector3 zAxis = new Vector3(0, 0, 1);

 void FixedUpdate () {
     transform.RotateAround(target.position, zAxis, speed); 
 }
}

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