[Unity实战]自定义mesh

参考链接：http://blog.csdn.net/zuoyamin/article/details/9287507

对于自定义mesh，有三点很重要：

1.顶点个数=三角形数+2；三角形顶点数=3*三角形数

2.顶点创建的顺序最好是顺时针或者逆时针创建的，这样可以大大地减少算法的复杂度

3.顶点绘制的顺序必须是顺时针或者逆时针绘制的，这样才能正确地绘制以顶点为边界点的图形，顶点绘制的顺序参考mesh.triangles

using UnityEngine;
using System.Collections;

[RequireComponent(typeof(MeshFilter))]
[RequireComponent(typeof(MeshRenderer))]
public class CustomMesh : MonoBehaviour {

}

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using UnityEditor;

//使用前最好先锁定Inspector面板！
[CustomEditor(typeof(CustomMesh))]
public class CustomMeshEditor : Editor {

    private List<Vector3> vertices = new List<Vector3>();
    private int[] triangles;

    void OnSceneGUI()
    {
        CustomMesh customMesh = (CustomMesh)target;

        for (int i = 0; i < vertices.Count; i++)
        {
            Handles.PositionHandle(vertices[i], Quaternion.identity);
            Handles.Label(vertices[i], i.ToString());
        }
        if (vertices.Count > 1)
        {
            Handles.DrawPolyLine(vertices.ToArray());
            Handles.DrawLine(vertices[vertices.Count - 1], vertices[0]);
        }     

        //在OnSceneGUI()中只能通过Handles来绘制新视图
        //如果你想引入GUI的元素哪么就需要使用BeginGUI()和EndGUI()组合的使用。
        Handles.BeginGUI();
        GUILayout.BeginArea(new Rect(0, 0, 100, 100));

        if (GUILayout.Button("创建点"))
        {
            vertices.Add(customMesh.transform.position);
        }
        if (GUILayout.Button("撤销点"))
        {
            vertices.RemoveAt(vertices.Count - 1);
        }
        if (GUILayout.Button("导出mesh"))
        {
            Mesh mesh = new Mesh();

            int triangleAmount = vertices.Count - 2;
            triangles = new int[3 * triangleAmount];

            //根据三角形的个数，来计算绘制三角形的顶点顺序（索引）
            //顺序必须为顺时针或者逆时针
            for (int i = 0; i < triangleAmount; i++)
            {
                triangles[3 * i] = 0;//固定第一个点
                triangles[3 * i + 1] = i + 1;
                triangles[3 * i + 2] = i + 2;
            }

            mesh.vertices = vertices.ToArray();
            mesh.triangles = triangles;

            AssetDatabase.CreateAsset(mesh, "Assets/CustomMesh.asset");
        }
        GUILayout.EndArea();
        Handles.EndGUI();
    }
}