[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(0, 0), Color.red, Vector2.zero);
        vh.AddVert(new Vector3(0, 100), Color.green, Vector2.zero);
        vh.AddVert(new Vector3(100, 100), Color.black, Vector2.zero);
        vh.AddTriangle(0, 1, 2);
    }
}

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(0, 0), Color.red, Vector2.zero);
        vh.AddVert(new Vector3(0, 100), Color.green, Vector2.zero);
        vh.AddVert(new Vector3(100, 100), Color.black, Vector2.zero);
        vh.AddVert(new Vector3(100, 0), Color.blue, Vector2.zero);
        vh.AddTriangle(0, 1, 2);
        vh.AddTriangle(2, 3, 0);
    }
}

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[4];

        verts[0].position = new Vector3(0, 0);
        verts[0].color = Color.red;
        verts[0].uv0 = Vector2.zero;

        verts[1].position = new Vector3(0, 100);
        verts[1].color = Color.green;
        verts[1].uv0 = Vector2.zero;

        verts[2].position = new Vector3(100, 100);
        verts[2].color = Color.black;
        verts[2].uv0 = Vector2.zero;

        verts[3].position = new Vector3(100, 0);
        verts[3].color = Color.blue;
        verts[3].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(0, 0), Color.red, Vector2.zero);
        vh.AddVert(new Vector3(0, 100), Color.green, Vector2.zero);
        vh.AddVert(new Vector3(100, 100), Color.black, Vector2.zero);
        vh.AddVert(new Vector3(100, 0), Color.blue, Vector2.zero);
        vh.AddTriangle(0, 1, 2);
        vh.AddTriangle(2, 3, 0);

        //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, 0);
        Debug.Log(vertex.color);
        vh.PopulateUIVertex(ref vertex, 3);
        Debug.Log(vertex.color);

        //SetUIVertex，设置顶点数据
        vertex.color = Color.yellow;
        vh.SetUIVertex(vertex, 3);
    }
}

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(0, 0);
        vert0.color = Color.red;
        vert0.uv0 = Vector2.zero;
        verts.Add(vert0);

        UIVertex vert1 = new UIVertex();
        vert1.position = new Vector3(0, 100);
        vert1.color = Color.green;
        vert1.uv0 = Vector2.zero;
        verts.Add(vert1);

        UIVertex vert2 = new UIVertex();
        vert2.position = new Vector3(100, 100);
        vert2.color = Color.black;
        vert2.uv0 = Vector2.zero;
        verts.Add(vert2);

        UIVertex vert3 = new UIVertex();
        vert3.position = new Vector3(100, 0);
        vert3.color = Color.blue;
        vert3.uv0 = Vector2.zero;
        verts.Add(vert3);

        List<int> indices = new List<int>() { 0, 1, 2, 2, 3, 0 };
        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(0, 0);
        vert0.color = Color.red;
        vert0.uv0 = Vector2.zero;
        verts.Add(vert0);

        UIVertex vert1 = new UIVertex();
        vert1.position = new Vector3(0, 100);
        vert1.color = Color.green;
        vert1.uv0 = Vector2.zero;
        verts.Add(vert1);

        UIVertex vert2 = new UIVertex();
        vert2.position = new Vector3(100, 100);
        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(0, 0), Color.red, Vector2.zero);
        vh.AddVert(new Vector3(0, 100), Color.green, Vector2.zero);
        vh.AddVert(new Vector3(100, 100), Color.black, Vector2.zero);
        vh.AddTriangle(0, 1, 2);

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