[UGUI]修改顶点

参考链接：

https://blog.csdn.net/jk823394954/article/details/53870779

说明：unity版本5.3，新建一个Image，挂上以下的脚本

一.图形绘制

1.绘制三角形

 using UnityEngine;
 using UnityEngine.UI;

 public class TestMesh : BaseMeshEffect {

     public override void ModifyMesh(VertexHelper vh)
     {
         vh.Clear();
         vh.AddVert(new Vector3(, ), Color.red, Vector2.zero);
         vh.AddVert(new Vector3(, ), Color.green, Vector2.zero);
         vh.AddVert(new Vector3(, ), Color.black, Vector2.zero);
         vh.AddTriangle(, , );
     }
 }

2.绘制正方形(绘制两个三角形)

 using UnityEngine;
 using UnityEngine.UI;

 public class TestMesh : BaseMeshEffect {

     public override void ModifyMesh(VertexHelper vh)
     {
         vh.Clear();
         vh.AddVert(new Vector3(, ), Color.red, Vector2.zero);
         vh.AddVert(new Vector3(, ), Color.green, Vector2.zero);
         vh.AddVert(new Vector3(, ), Color.black, Vector2.zero);
         vh.AddVert(new Vector3(, ), Color.blue, Vector2.zero);
         vh.AddTriangle(, , );
         vh.AddTriangle(, , );
     }
 }

3.绘制正方形(绘制一个正方形)

 using UnityEngine;
 using UnityEngine.UI;

 public class TestMesh : BaseMeshEffect {

     public override void ModifyMesh(VertexHelper vh)
     {
         vh.Clear();
         UIVertex[] verts = new UIVertex[];

         verts[].position = new Vector3(, );
         verts[].color = Color.red;
         verts[].uv0 = Vector2.zero;

         verts[].position = new Vector3(, );
         verts[].color = Color.green;
         verts[].uv0 = Vector2.zero;

         verts[].position = new Vector3(, );
         verts[].color = Color.black;
         verts[].uv0 = Vector2.zero;

         verts[].position = new Vector3(, );
         verts[].color = Color.blue;
         verts[].uv0 = Vector2.zero;

         vh.AddUIVertexQuad(verts);
     }
 }

二.相关api

 using UnityEngine;
 using UnityEngine.UI;

 public class TestMesh : BaseMeshEffect {

     public override void ModifyMesh(VertexHelper vh)
     {
         vh.Clear();
         vh.AddVert(new Vector3(, ), Color.red, Vector2.zero);
         vh.AddVert(new Vector3(, ), Color.green, Vector2.zero);
         vh.AddVert(new Vector3(, ), Color.black, Vector2.zero);
         vh.AddVert(new Vector3(, ), Color.blue, Vector2.zero);
         vh.AddTriangle(, , );
         vh.AddTriangle(, , );

         //顶点有4个，索引有6个
         Debug.Log(vh.currentIndexCount);
         Debug.Log(vh.currentVertCount);

         //PopulateUIVertex，返回顶点数据。当前取值范围：0-3
         UIVertex vertex = new UIVertex();
         vh.PopulateUIVertex(ref vertex, );
         Debug.Log(vertex.color);
         vh.PopulateUIVertex(ref vertex, );
         Debug.Log(vertex.color);

         //SetUIVertex，设置顶点数据
         vertex.color = Color.yellow;
         vh.SetUIVertex(vertex, );
     }
 }

输出：

Stream流批量操作：

1.AddUIVertexStream，批量添加顶点

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

 public class TestMesh : BaseMeshEffect {

     public override void ModifyMesh(VertexHelper vh)
     {
         vh.Clear();
         List<UIVertex> verts = new List<UIVertex>();

         UIVertex vert0 = new UIVertex();
         vert0.position = new Vector3(, );
         vert0.color = Color.red;
         vert0.uv0 = Vector2.zero;
         verts.Add(vert0);

         UIVertex vert1 = new UIVertex();
         vert1.position = new Vector3(, );
         vert1.color = Color.green;
         vert1.uv0 = Vector2.zero;
         verts.Add(vert1);

         UIVertex vert2 = new UIVertex();
         vert2.position = new Vector3(, );
         vert2.color = Color.black;
         vert2.uv0 = Vector2.zero;
         verts.Add(vert2);

         UIVertex vert3 = new UIVertex();
         vert3.position = new Vector3(, );
         vert3.color = Color.blue;
         vert3.uv0 = Vector2.zero;
         verts.Add(vert3);

         List<int> indices = new List<int>() { , , , , ,  };
         vh.AddUIVertexStream(verts, indices);
     }
 }

2.AddUIVertexTriangleStream，批量添加三角形顶点，长度必须是3的倍数

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

 public class TestMesh : BaseMeshEffect {

     public override void ModifyMesh(VertexHelper vh)
     {
         vh.Clear();
         List<UIVertex> verts = new List<UIVertex>();

         UIVertex vert0 = new UIVertex();
         vert0.position = new Vector3(, );
         vert0.color = Color.red;
         vert0.uv0 = Vector2.zero;
         verts.Add(vert0);

         UIVertex vert1 = new UIVertex();
         vert1.position = new Vector3(, );
         vert1.color = Color.green;
         vert1.uv0 = Vector2.zero;
         verts.Add(vert1);

         UIVertex vert2 = new UIVertex();
         vert2.position = new Vector3(, );
         vert2.color = Color.black;
         vert2.uv0 = Vector2.zero;
         verts.Add(vert2);

         vh.AddUIVertexTriangleStream(verts);
     }
 }

3.GetUIVertexStream，获取所有顶点数据

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

 public class TestMesh : BaseMeshEffect {

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

         vh.AddVert(new Vector3(, ), Color.red, Vector2.zero);
         vh.AddVert(new Vector3(, ), Color.green, Vector2.zero);
         vh.AddVert(new Vector3(, ), Color.black, Vector2.zero);
         vh.AddTriangle(, , );

         List<UIVertex> stream = new List<UIVertex>();
         vh.GetUIVertexStream(stream);
         foreach (UIVertex v in stream)
         {
             Debug.Log(v.color);
         }
     }
 }