//--------------------------------------------------------
//    [Author]:           第二世界
//    [  Date ]:           Thursday, August 10, 2017
//--------------------------------------------------------
using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using UnityEngine.Sprites;
using System;


[DisallowMultipleComponent]
[RequireComponent(typeof(Image))]
public class CustomImage:BaseMeshEffect {

    [SerializeField]
    Vector2[] m_Points;
    public Vector2[] points {
        get {
            return this.m_Points;
        }
        set {
            this.m_Points = value;
            SetVerticesDirty();
        }
    }

    private Image m_Image;
    public Image image {
        get {
            return this.m_Image ?? (this.m_Image = this.AddMissingComponent<Image>());
        }
    }

    public void SetVerticesDirty() {
        this.graphic.SetVerticesDirty();
    }

    public override void ModifyMesh(VertexHelper vh) {
        vh.Clear();

        if(this.image == null) {
            throw new NullReferenceException();
        }

        if(this.points == null || this.points.Length < 3) {
            return;
        }

        var width = this.image.rectTransform.rect.width;
        var height = this.image.rectTransform.rect.height;

        var uv = this.image.overrideSprite != null ? DataUtility.GetOuterUV(this.image.overrideSprite) : Vector4.zero;
        var uvcenterX = (uv.x + uv.z) * 0.5f;
        var uvcenterY = (uv.y + uv.w) * 0.5f;
        var uvscaleX = (uv.z - uv.x) / width;
        var uvscaleY = (uv.w - uv.y) / height;

        for(var i = 0;i < this.points.Length;i++) {
            var point = this.points[i];

            var position = new Vector2(point.x,point.y);
            var uv0 = new Vector2(position.x * uvscaleX + uvcenterX,position.y * uvscaleY + uvcenterY);
            var vertex = UIUtility.PackageUIVertex(position,uv0,this.image.color);
            vh.AddVert(vertex);
        }

        var vertexCount = this.points.Length;
        var index = 0;
        for(;index < vertexCount - 2;index++) {
            vh.AddTriangle(index,index + 1,index + 2);
        }
    }

}