在 Raycast2D 上实例化对象并旋转实例

Question

我想沿着另一个游戏对象的轮廓移动一个游戏对象的实例。它是 Unity 中的 2D 项目。

我当前的代码：

Vector3 mousePosition = m_camera.ScreenToWorldPoint(Input.mousePosition);
    RaycastHit2D hit = Physics2D.Raycast(new Vector2(mousePosition.x, mousePosition.y), new Vector2(player.transform.position.x, player.transform.position.y));
    if (hit.collider != null &&  hit.collider.gameObject.tag == "Player") {
        if (!pointerInstance) {
            pointerInstance = Instantiate(ghostPointer, new Vector3(hit.point.x, hit.point.y, -1.1f), Quaternion.identity);
        } else if(pointerInstance) {
            pointerInstance.gameObject.transform.position = new Vector3(hit.point.x, hit.point.y, -1.1f);
            pointerInstance.gameObject.transform.eulerAngles = new Vector3(0f, 0f, hit.normal.x);
        }

    }

不幸的是，gameObject 没有朝向鼠标旋转，而且 playerObject 左侧的位置有时也会关闭。我尝试将 Instantiate() 与 Quaternion.LookRotation(hit.normal) 一起使用，但也不走运。

这是我想要实现的粗略草图：

感谢任何帮助。谢谢！

Answer 1

最好使用数学方法而不是物理方法（光线投射），因为在光线投射中你必须多次投射光线来检查命中点并旋转你的物体，这会使你的游戏滞后。

将此脚本附加到您的实例化对象：

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour
{
    public Transform Player;

    void Update()
    {
        //Rotating Around Circle(circular movement depend on mouse position)
        Vector3 targetScreenPos = Camera.main.WorldToScreenPoint(Player.position);
        targetScreenPos.z = 0;//filtering target axis
        Vector3 targetToMouseDir = Input.mousePosition - targetScreenPos;

        Vector3 targetToMe = transform.position - Player.position;

        targetToMe.z = 0;//filtering targetToMe axis

        Vector3 newTargetToMe = Vector3.RotateTowards(targetToMe, targetToMouseDir,  /* max radians to turn this frame */ 2, 0);

        transform.position = Player.position +  /*distance from target center to stay at*/newTargetToMe.normalized;


        //Look At Mouse position
        var objectPos = Camera.main.WorldToScreenPoint(transform.position);
        var dir = Input.mousePosition - objectPos;
        transform.rotation = Quaternion.Euler(0, 0, Mathf.Atan2(dir.y, dir.x) * Mathf.Rad2Deg);

    }
}

有用的解释

阿坦2:

atan2(y,x) gives you the angle between the x-axis and the vector (x,y), usually in radians and signed such that for positive y you get an angle between 0 and π, and for negative y the result is between −π and 0. https://math.stackexchange.com/questions/67026/how-to-use-atan2

Returns the angle in radians whose Tan is y/x. Return value is the angle between the x-axis and a 2D vector starting at zero and terminating at (x,y). https://docs.unity3d.com/ScriptReference/Mathf.Atan2.html

Mathf.Rad2Deg:

Radians-to-degrees conversion constant (Read Only).

This is equal to 360 / (PI * 2).

在 Raycast2D 上实例化对象并旋转实例

Instantiate Object on Raycast2D hit and rotate Instance

c#

quaternions

unity3d

unity5

unity2d