using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using Unity.VisualScripting;
using System.Collections.Generic;

[ExecuteInEditMode]
public class PolygonUIMesh : Image
{
    public List<Transform> points = new List<Transform>();

    private void OnGUI()
    {
        // 实时检测更新绘制 OnPopulateMesh 中 transform.child 位置
        SetAllDirty();
    }

    /// <summary>
    /// 根据 transform.child 位置 绘制 Mesh
    /// </summary>
    /// <param name="vh"></param>
    protected override void OnPopulateMesh(VertexHelper vh)
    {
        if (points.Count <= 2)
        {
            return;
        }

        Color32 color32 = color;
        vh.Clear();

        GenerateSimpleSprite(vh, false);
    }

    void GenerateSimpleSprite(VertexHelper vh, bool lPreserveAspect)
    {
        //Vector4 v = GetDrawingDimensions(lPreserveAspect);
        var uv = (sprite != null) ? UnityEngine.Sprites.DataUtility.GetOuterUV(sprite) : Vector4.zero;

        var color32 = color;
        vh.Clear();
        //vh.AddVert(new Vector3(v.x, v.y), color32, new Vector2(uv.x, uv.y));
        //vh.AddVert(new Vector3(v.x, v.w), color32, new Vector2(uv.x, uv.w));
        //vh.AddVert(new Vector3(v.z, v.w), color32, new Vector2(uv.z, uv.w));
        //vh.AddVert(new Vector3(v.z, v.y), color32, new Vector2(uv.z, uv.y));

        //vh.AddTriangle(0, 1, 2);
        //vh.AddTriangle(2, 3, 0);

        // 几何图形的顶点，本例中根据子节点坐标确定顶点
        vh.AddVert(points[0].localPosition, color32, new Vector2(uv.x, uv.y));
        vh.AddVert(points[1].localPosition, color32, new Vector2(uv.x, uv.w));
        vh.AddVert(points[2].localPosition, color32, new Vector2(uv.z, uv.w));
        vh.AddVert(points[3].localPosition, color32, new Vector2(uv.z, uv.y));

        vh.AddTriangle(0, 1, 2);
        vh.AddTriangle(2, 3, 0);

        //for (int i = 0; i < (transform.childCount - 2); i++)
        //{
        //    // 几何图形中的三角形
        //    vh.AddTriangle(i + 1, i + 2, 0);

        //}
    }

    /// <summary>
    /// 点的辅助绘制
    /// </summary>
    private void OnDrawGizmos()
    {
        if (transform.childCount == 0)
        {
            return;
        }

        for (int i = 0; i < transform.childCount; i++)
        {
            Gizmos.DrawSphere(transform.GetChild(i).position, 2.55f);
            Gizmos.DrawIcon(transform.GetChild(i).position, "numbers/numbers_" + i + ".PNG", false);
        }

    }
}