//--------------------------------------------------------
//    [Author]:           玩个游戏
//    [  Date ]:           Wednesday, August 23, 2017
//--------------------------------------------------------
using UnityEngine;
using UnityEngine.Sprites;
using UnityEngine.UI;


[RequireComponent(typeof(RectTransform))]
public class Hexagon:BaseMeshEffect {

    const float SQUARE_ROOT_THREE = 1.732f;
    Vector3[] positions = new Vector3[3];

    RectTransform m_RectTransform;
    public RectTransform rectTransform {
        get {
            return m_RectTransform ?? (m_RectTransform = this.transform as RectTransform);
        }
    }

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

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

        var uv = this.image != 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) / this.rectTransform.rect.width;
        var uvScaleY = (uv.w - uv.y) / this.rectTransform.rect.height;

        var xoffset = this.rectTransform.rect.width * 0.5f;
        var yoffset = this.rectTransform.rect.height * 0.5f;

        this.positions[0] = new Vector3(0,yoffset);
        this.positions[1] = new Vector3(-xoffset,yoffset * (1f - SQUARE_ROOT_THREE));
        this.positions[2] = new Vector3(xoffset,yoffset * (1f - SQUARE_ROOT_THREE));

        for(var i = 0;i < 3;i++) {
            var position = this.positions[i];
            var uv0 = new Vector2(position.x * uvScaleX + uvCenterX,position.y * uvScaleY + uvCenterY);
            var vertex = UIUtility.PackageUIVertex(position,uv0,this.image.color);
            vh.AddVert(vertex);

            position = this.positions[i] * -1f;
            uv0 = new Vector2(position.x * uvScaleX + uvCenterX,position.y * uvScaleY + uvCenterY);
            vertex = UIUtility.PackageUIVertex(position,uv0,this.image.color);
            vh.AddVert(vertex);
        }

        vh.AddTriangle(0,2,4);
        vh.AddTriangle(1,3,5);
    }

}