1 /*
  2 /// 功能： 绘制箭头
  3 /// 时间：
  4 /// 版本：
  5 */
  6 
  7 using System.Collections;
  8 using System.Collections.Generic;
  9 using UnityEngine;
 10 using UnityEngine.UI;
 11 
 12 [AddComponentMenu("UI/Effects/Arrow")]
 13 [RequireComponent(typeof(Image))]
 14 [ExecuteInEditMode]
 15 public class Arrow : BaseMeshEffect
 16 {
 17     public enum DirectionType
 18     {
 19         Left,
 20         Right,
 21         Up,
 22         Down,
 23     }
 24 
 25     public DirectionType directionType;
 26 
 27     public float width = 1;
 28     public float height = 1;
 29     public float angle;
 30     public Color color;
 31 
 32     private Image image;
 33 
 34     protected override void Start()
 35     {
 36         image = this.GetComponent<Image>();
 37     }
 38 
 39     public override void ModifyMesh(VertexHelper vh)
 40     {
 41         vh.Clear();
 42 
 43         List<Vector3> vertexList = new List<Vector3>();
 44         Vector3 v0=Vector3.zero;
 45         Vector3 v1=Vector3.zero;
 46         Vector3 v2=Vector3.zero;
 47         Vector3 v3=Vector3.zero;
 48         Vector3 v4 = Vector3.zero;
 49 
 50         //有5个点"
 51         switch (directionType)
 52         {
 53             case DirectionType.Left:
 54                 v1 = new Vector3(-width, 0);
 55                 v2 = new Vector3(-width - height / Mathf.Tan(angle * Mathf.PI / 180), height / 2);
 56                 v3 = new Vector3(-width, height);
 57                 v4 = new Vector3(0, height);
 58                 break;
 59             case DirectionType.Right:
 60                 v1 = new Vector3(width, 0);
 61                 v2 = new Vector3(width + height / Mathf.Tan(angle * Mathf.PI / 180), height / 2);
 62                 v3 = new Vector3(width, height);
 63                 v4 = new Vector3(0, height);
 64                 break;
 65             case DirectionType.Up:
 66                 v1 = new Vector3(width, 0);
 67                 v2 = new Vector3(width,height);
 68                 v3 = new Vector3(width/2, height+height/Mathf.Tan(angle*Mathf.PI/180));
 69                 v4 = new Vector3(0, height);
 70                 break;
 71             case DirectionType.Down:
 72                 v1 = new Vector3(width, 0);
 73                 v2 = new Vector3(width, -height);
 74                 v3 = new Vector3(width / 2, -height - height / Mathf.Tan(angle * Mathf.PI / 180));
 75                 v4 = new Vector3(0, -height);
 76                 break;
 77             default:
 78                 break;
 79         }
 80 
 81         vertexList.Add(v0, v1, v2, v3, v4);
 82 
 83         for (int i = 0; i < vertexList.Count; i++)
 84         {
 85             vh.AddVert(vertexList[i], color, Vector3.zero);
 86         }
 87 
 88         vh.AddTriangle(0, 1, 2);
 89         vh.AddTriangle(0, 1, 3);
 90         vh.AddTriangle(1, 2, 3);
 91         vh.AddTriangle(2, 3, 4);
 92         vh.AddTriangle(3, 4, 0);
 93         vh.AddTriangle(0, 1, 4);
 94     }
 95 
 96     private void Update()
 97     {
 98         image.SetVerticesDirty();
 99     }
100 }

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