Unity 不規則按鈕Custom2DCollider

有時候產品需求按鈕不能是長方形，要三角形，五邊形，甚至五角星行，這時你是不是方了，怎麼做？？？

別雞凍，其實unity有現成的哦！！！PolygonCollider2D！！！

給你的UI加上這個組件PolygonCollider2D，你就可以自定義形狀了！

當然形狀也可以代碼控制，就是設置不規則圖形的頂點位置，代碼如下：

using UnityEngine;
using System.Collections;
using UnityEngine.EventSystems;

public class CustonCollider2D : MonoBehaviour, IPointerClickHandler
{

    /// <summary>
    /// 多邊形碰撞器
    /// </summary>
    private PolygonCollider2D polygonCollider;
    private RectTransform rectTransform;

    void Start()
    {
        //獲取多邊形碰撞器
        polygonCollider = transform.GetComponent<PolygonCollider2D>();
        //獲取RectTransform
        rectTransform = transform.GetComponent<RectTransform>();


        Vector2[] v = new Vector2[6];
        v[0] = new Vector2(-40, -15);
        v[1] = new Vector2(-20, 40);
        v[2] = new Vector2(25, 30);
        v[3] = new Vector2(40, 0);
        v[4] = new Vector2(40, -40);
        v[5] = new Vector2(-40, -40);
        SetPolygonColliderPoints(v);
    }

    public void OnPointerClick(PointerEventData eventData)
    {
        //這裏做一些鼠標點擊位置相對於Collider的位置處理
        Vector2 local;
        local.x = eventData.position.x - (float)Screen.width / 2.0f - rectTransform.localPosition.x;
        local.y = eventData.position.y - (float)Screen.height / 2.0f - rectTransform.localPosition.y;


        bool isIn = IsPointInPolygon(local, polygonCollider.points);
        Debug.Log("看我有沒有點擊到你的Collider之內: " + isIn);
    }

    /// <summary>
    /// 設置PolyCollider2D的頂點的位置
    /// </summary>
    /// <param name="vecs">Collider的頂點位置信息，最好按順序編排，3個頂點以上才能構成一個平面哦</param>
    public void SetPolygonColliderPoints(Vector2[] vecs)
    {
        polygonCollider.points = vecs;
    }


    /// <summary>
    /// 判斷鼠標點擊點是否在PolygonCollider2D之內
    /// </summary>
    /// <param name="point">鼠標點擊位置</param>
    /// <param name="polygon">Collider的頂點位置信息</param>
    /// <returns></returns>
    public bool IsPointInPolygon(Vector2 point, Vector2[] polygon)
    {
        int polygonLength = polygon.Length;
        int i = 0;
        bool inside = false;


        float pointX = point.x;
        float pointY = point.y;


        float startX, startY, endX, endY;
        Vector2 endPoint = polygon[polygonLength - 1];
        endX = endPoint.x;
        endY = endPoint.y;
        while (i < polygonLength)
        {
            startX = endX;
            startY = endY;
            endPoint = polygon[i++];
            endX = endPoint.x;
            endY = endPoint.y;
            inside ^= (endY > pointY ^ startY > pointY) && ((pointX - endX) < (pointY - endY) * (startX - endX) / (startY - endY));
        }
        return inside;
    }
}