c# - 在 Unity 2D 中拖动对象

Question

我一直在寻找适用于 Unity 2D 的对象拖动脚本。我在网上找到了一个很好的方法，但它似乎只适用于Unity 3D。这对我不利，因为我正在制作 2D 游戏并且它不会以这种方式与“墙壁”发生碰撞。

我曾尝试将其重写为 2D，但使用 Vectors 时遇到了错误。

如果你能帮我把它改写成二维的，我会很高兴。

这是在 3D 中运行的代码:

using UnityEngine;
using System.Collections;

[RequireComponent(typeof(BoxCollider))]

public class Drag : MonoBehaviour {
    private Vector3 screenPoint;
    private Vector3 offset;

void OnMouseDown() {

    offset = gameObject.transform.position - Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z));
}

void OnMouseDrag()
{
    Vector3 curScreenPoint = new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z);
    Vector3 curPosition = Camera.main.ScreenToWorldPoint(curScreenPoint) + offset;
    transform.position = curPosition;
}
}

Answer 1

对于那些使用此代码有问题的人，我使用 ScreenPointToRay 来使用代数光线转换(快速)来确定物体应该放置在距相机多远的位置。这适用于正交和透视相机

此外，对象可以使用Collider 来被拖动。所以没有必要使用 [RequireComponent(typeof(BoxCollider2D))]。

对我来说效果很好的最终代码是:

using UnityEngine;
using System.Collections;

public class DragDrop : MonoBehaviour {
    // The plane the object is currently being dragged on
    private Plane dragPlane;

    // The difference between where the mouse is on the drag plane and 
    // where the origin of the object is on the drag plane
    private Vector3 offset;

    private Camera myMainCamera; 

    void Start()
    {
        myMainCamera = Camera.main; // Camera.main is expensive ; cache it here
    }

    void OnMouseDown()
    {
        dragPlane = new Plane(myMainCamera.transform.forward, transform.position); 
        Ray camRay = myMainCamera.ScreenPointToRay(Input.mousePosition); 

        float planeDist;
        dragPlane.Raycast(camRay, out planeDist); 
        offset = transform.position - camRay.GetPoint(planeDist);
    }

    void OnMouseDrag()
    {   
        Ray camRay = myMainCamera.ScreenPointToRay(Input.mousePosition); 

        float planeDist;
        dragPlane.Raycast(camRay, out planeDist);
        transform.position = camRay.GetPoint(planeDist) + offset;
    }
}