Unity使用OpenGL绘制经纬线圈

using System.Collections;

using System.Collections.Generic;

using UnityEngine;

public class LatLonGridGL : MonoBehaviour {

    /// <summary>

    /// 地球半径

    /// </summary>

    public float R = ;

    /// <summary>

    /// 纬线圈数(不包括南极点和北极点)

    /// </summary>

    public int latNum = ;

    /// <summary>

    /// 经线数

    /// </summary>

    public int lonNum = ;

    /// <summary>

    /// 一条纬线圈分段

    /// </summary>

    public int latSegment = ;

    /// <summary>

    /// 一条经线（半圆）分段

    /// </summary>

    public int lonSegment = ;

    /// <summary>

    /// 网格颜色

    /// </summary>

    public Color color = Color.white;

    /// <summary>

    /// 显示度数

    /// </summary>

    private Object latlonText3D;

    private List<List<Vector3>> latLines = new List<List<Vector3>>();

    private List<List<Vector3>> lonLines = new List<List<Vector3>>();

    /// <summary>

    /// 里面包含了shader

    /// </summary>

    static Material lineMaterial;

    void Start()

    {

        float latSpan = Mathf.PI / (latNum + );//纬线间隔度数

        float lonSpan = Mathf.PI *  / lonNum;//经线间隔度数

        float anglePerLatSeg = Mathf.PI *  / latSegment;//一条纬线每一段对应的度数

        float anglePerLonSeg = Mathf.PI / lonSegment;//一条经线每一段对应的度数

        latlonText3D = Resources.Load("LatLonText3D", typeof(GameObject));

        // 纬度度数

        for (int r = ; r < latNum + ; r++)

        {

            GameObject obj = Instantiate(latlonText3D, this.transform) as GameObject;

            obj.transform.position = new Vector3(R * Mathf.Sin(latSpan * r), R * Mathf.Cos(latSpan * r), );

            obj.GetComponent<TextMesh>().text = (int)(Mathf.Rad2Deg * (latSpan * r)) -  + "°";

            obj.GetComponent<TextMesh>().fontSize = ;

            obj.transform.localScale = new Vector3(0.01f, 0.01f, 0.01f);

            obj.GetComponent<TextMesh>().color = Color.red;

        }

        //经度度数

        for (int c = ; c < lonNum; c++)

        {

            GameObject obj = Instantiate(latlonText3D, this.transform) as GameObject;

            obj.transform.position = new Vector3(R * Mathf.Cos(lonSpan * c), , R * Mathf.Sin(lonSpan * c));

            obj.GetComponent<TextMesh>().text = (int)(Mathf.Rad2Deg * (lonSpan * c)) + "°";

            obj.GetComponent<TextMesh>().fontSize = ;

            obj.transform.localScale = new Vector3(0.01f, 0.01f, 0.01f);

            obj.GetComponent<TextMesh>().color = Color.yellow;

        }

        // 绘制纬线圈

        for (int r = ; r < latNum; r++)

        {

            //顶点

            List<Vector3> vertices = new List<Vector3>();

            for (int n = ; n < latSegment+; n++)

            {

                Vector3 v;

                v.x = R * Mathf.Sin(latSpan * (r + )) * Mathf.Cos(anglePerLatSeg * n);

                v.y = R * Mathf.Cos(latSpan * (r + ));

                v.z = R * Mathf.Sin(latSpan * (r + )) * Mathf.Sin(anglePerLatSeg * n);

                vertices.Add(v);

            }

            latLines.Add(vertices);

        }

        // 绘制经线圈

        for (int c = ; c < lonNum; c++)

        {

            //顶点

            List<Vector3> vertices = new List<Vector3>();

            for (int n = ; n < lonSegment+; n++)

            {

                Vector3 v;

                v.x = R * Mathf.Sin(anglePerLonSeg * n) * Mathf.Cos(lonSpan * c);

                v.y = R * Mathf.Cos(anglePerLonSeg * n);

                v.z = R * Mathf.Sin(anglePerLonSeg * n) * Mathf.Sin(lonSpan * c);

                vertices.Add(v);

            }

            lonLines.Add(vertices);

        }

    }

    public void OnRenderObject()

    {

        CreateLineMaterial();

        // Apply the line material

        lineMaterial.SetPass();

        GL.PushMatrix();

        // Set transformation matrix for drawing to

        // match our transform

        GL.MultMatrix(transform.localToWorldMatrix);

        // Draw lines

        foreach (List<Vector3> vertices in latLines)

        {

            GL.Begin(GL.LINE_STRIP);

            GL.Color(color);

            //GL.Color(new Color(0, 0.5f, 1, 0.5F));

            foreach (Vector3 ver in vertices)

            {

                GL.Vertex3(ver.x, ver.y, ver.z);

            }

            GL.End();

        }

        foreach (List<Vector3> vertices in lonLines)

        {

            GL.Begin(GL.LINE_STRIP);

            GL.Color(color);

            //GL.Color(new Color(0, 0.5f, 1, 1.0F));

            foreach (Vector3 ver in vertices)

            {

                GL.Vertex3(ver.x, ver.y, ver.z);

            }

            GL.End();

        }

        /*for (int i = 0; i < lineCount; ++i)

        {

            float a = i / (float)lineCount;

            float angle = a * Mathf.PI * 2;

            // Vertex colors change from red to green

            GL.Color(new Color(a, 1 - a, 0, 0.8F));

            // One vertex at transform position

            //GL.Vertex3(0, 0, 0);

            // Another vertex at edge of circle

            GL.Vertex3(Mathf.Cos(angle) * radius, Mathf.Sin(angle) * radius, 0);

        }*/

        GL.PopMatrix();

    }

    void OnPostRender()

    {

        // Set your materials

        GL.PushMatrix();

        // yourMaterial.SetPass( );

        // Draw your stuff

        GL.PopMatrix();

    }

    static void CreateLineMaterial()

    {

        if (!lineMaterial)

        {

            // Unity has a built-in shader that is useful for drawing

            // simple colored things.

            Shader shader = Shader.Find("Hidden/Internal-Colored");

            lineMaterial = new Material(shader);

            lineMaterial.hideFlags = HideFlags.HideAndDontSave;

            // Turn on alpha blending

            lineMaterial.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);

            lineMaterial.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);

            // Turn backface culling off

            lineMaterial.SetInt("_Cull", (int)UnityEngine.Rendering.CullMode.Off);

            // Turn off depth writes

            lineMaterial.SetInt("_ZWrite", );

        }

    }

}