Unity3D笔记十八 GL图像库

　　1、绘制2D图像的时需要使用GL.LoadOrtho()方法来将图形映射到平面中。

　　2、所有绘制相关的内容都要写在OnPostRender()方法中。

　　3、有关GL图像库的脚本需要绑定到Hierarchy视图中Camera上，否则无法显示绘制的图像。

　　4、在GL图像库的平面坐标系中，每个点的横坐标和纵坐标都应当是0与1之间的浮点数，而真实的像素坐标需要根据这个浮点数来计算

一、绘制线

　　别忘了添加物理材质public Material material;

using UnityEngine;
using System.Collections;

/// <summary>
/// GL 图像库
/// 1、GL图像库是底层的图像库，主要功能是使用程序来绘制常见的2D与3D几何图形。这些图形
/// 具有一定的特殊性，它们不属于3D网格图形，只会以面的形式渲染
///
/// 2、绘制2D图像时，需要使用GL.LoadOrtho()方法来将图形映射在平面中，绘制的是3D图形，就无须使用此方法
///
/// 3、使用GL图像库时，需要将所有绘制相关的内容写在OnPostRender()方法中
/// </summary>
public class _7_5 : MonoBehaviour
{
    /// <summary>
    /// 绘制线段的材质
    /// </summary>
    public Material material;

    private void OnPostRender()
    {
        if (!material)
        {
            Debug.Log("请给材质资源赋值");
            return;
        }
        material.SetPass();//设置该材质通道，0为默认值
        GL.LoadOrtho();//设置绘制2D图像
        GL.Begin(GL.LINES);//表示开始绘制，绘制类型为线段
        DrawLine(, , , );//绘制线段0
        DrawLine(, , , );//绘制线段1
        DrawLine(, , , );//绘制线段2
        GL.End();//结束绘制
    }

    private void DrawLine(float x1, float y1, float x2, float y2)
    {
        //绘制线段，需要将屏幕中某个点的像素坐标除以屏幕宽或高
        GL.Vertex(new Vector3(x1 / Screen.width, y1 / Screen.height, ));// ['vɜ:teks] n. 最高点；顶点；<数>（三角形、圆锥体等与底相对的）顶；
        GL.Vertex(new Vector3(x2 / Screen.width, y2 / Screen.height, ));
    }

    // Use this for initialization
    void Start()
    {

    }

    // Update is called once per frame
    void Update()
    {

    }
}

二、绘制曲线

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
/// <summary>
/// 绘制曲线
/// </summary>
public class _7_5_1 : MonoBehaviour
{
    /// <summary>
    /// 绘制线段材质
    /// </summary>
    public Material material;

    private List<Vector3> lineInfo;
    // Use this for initialization
    void Start()
    {
        //初始化鼠标线段链表
        lineInfo = new List<Vector3>();
    }

    // Update is called once per frame
    void Update()
    {
        //将每次鼠标改变的位置存储进链表
        lineInfo.Add(Input.mousePosition);
    }

    private void OnGUI()
    {
        GUILayout.Label("当前鼠标x轴位置" + Input.mousePosition.x);
        GUILayout.Label("当前鼠标y轴位置" + Input.mousePosition.y);
    }

    private void OnPostRender()
    {
        if (!material)
        {
            Debug.LogError("请给材质资源赋值");
            return;
        }
        material.SetPass();//设置该材质通道，0为默认值
        GL.LoadOrtho();//设置绘制2D图像
        GL.Begin(GL.LINES);//表示开始绘制，绘制类型为线段
        for (int i = ; i < lineInfo.Count - ; i++)
        {
            Vector3 start = lineInfo[i];
            Vector3 end = lineInfo[i + ];
            //绘制线段
            DrawLine(start.x, start.y, end.x, end.y);
        }
        GL.End();
    }
    /// <summary>
    /// 绘制线段
    /// </summary>
    /// <param name="x1"></param>
    /// <param name="y1"></param>
    /// <param name="x2"></param>
    /// <param name="y2"></param>
    private void DrawLine(float x1, float y1, float x2, float y2)
    {
        //绘制线段，需要将屏幕中某个点的像素坐标点除以屏幕宽或高
        GL.Vertex(new Vector3(x1 / Screen.width, y1 / Screen.height, ));// [ˈvɜ:ˌteks] 最高点；顶点
        GL.Vertex(new Vector3(x2 / Screen.width, y2 / Screen.height, ));
    }
}

三、绘制四边形

　　绘制四边形，需要使用GL.Begin(GL.QUADS)方法

using UnityEngine;
using System.Collections;

public class _7_5_3 : MonoBehaviour
{
    /// <summary>
    /// 可用材质0
    /// </summary>
    public Material material0;
    /// <summary>
    /// 可用材质1
    /// </summary>
    public Material material1;
    /// <summary>
    /// 可用材质2
    /// </summary>
    public Material material2;

    private void OnPostRender()
    {
        //绘制正四边形
        DrawRect(, , , , material0);
        DrawRect(, , , , material1);
        //绘制无规则四边形
        DrawQuads(, , , , , , , , material2);
    }

    /// <summary>
    /// 绘制正四边形
    /// </summary>
    /// <param name="x">x轴起始坐标</param>
    /// <param name="y">y轴起始坐标</param>
    /// <param name="width">正四边形的宽</param>
    /// <param name="height">正四边形的高</param>
    /// <param name="material"></param>
    private void DrawRect(float x, float y, float width, float height, Material material)
    {
        GL.PushMatrix();   // [ˈmeɪtrɪks]n. <数>矩阵；模型；基质；母体，子宫
        material.SetPass();
        GL.LoadOrtho();
        GL.Begin(GL.QUADS);//绘制类型为四边形
        GL.Vertex3(x / Screen.width, y / Screen.height, );//['vɜ:teks] n. 最高点；顶点
        GL.Vertex3(x / Screen.width, (y + height) / Screen.height, );
        GL.Vertex3((x + width) / Screen.width, (y + height) / Screen.height, );
        GL.Vertex3((x + width) / Screen.width, y / Screen.height, );
        GL.End();
        GL.PopMatrix();
    }

    /// <summary>
    /// 绘制无规则的四边形
    /// </summary>
    /// <param name="x1">起始点1的横坐标</param>
    /// <param name="y1">起始点1的纵坐标</param>
    /// <param name="x2">起始点2的横坐标</param>
    /// <param name="y2">起始点2的纵坐标</param>
    /// <param name="x3">起始点3的横坐标</param>
    /// <param name="y3">起始点3的纵坐标</param>
    /// <param name="x3">起始点4的横坐标</param>
    /// <param name="y3">起始点4的纵坐标</param>
    /// <param name="material">material</param>
    private void DrawQuads(float x1, float y1, float x2, float y2, float x3, float y3, float x4, float y4, Material material)
    {
        GL.PushMatrix();
        material.SetPass();
        GL.LoadOrtho();
        GL.Begin(GL.QUADS);//绘制类型为四边形
        GL.Vertex3(x1 / Screen.width, y1 / Screen.height, );
        GL.Vertex3(x2 / Screen.width, y2 / Screen.height, );
        GL.Vertex3(x3 / Screen.width, y3 / Screen.height, );
        GL.Vertex3(x4 / Screen.width, y4 / Screen.height, );
        GL.End();
        GL.PopMatrix();
    }

    // Use this for initialization
    void Start()
    {

    }

    // Update is called once per frame
    void Update()
    {

    }
}

四、绘制三角形

　　使用GL.Begin(GL.TRIANGLE)方法,参数为三角形的类型。['traɪæŋɡl]n. 三角形；三人一组；三角铁；三角板

using UnityEngine;
using System.Collections;
/// <summary>
/// 绘制三角形
/// 使用GL.Vertex3()方法确定三角形三个顶点的位置，并将绘制三角形
///的所有方法封装在DrawTriangle()方法中，最后使用GL.End()方法将三角形显示在屏幕中。
///需要说明的是，在调用DrawTriangle()方法时，需要将三个点的坐标与材质传入该方法。
/// </summary>
public class _7_5_4 : MonoBehaviour
{
    /// <summary>
    /// 材质
    /// </summary>
    public Material material;

    private void OnPostRender()
    {
        //绘制三角形
        DrawTriangle(, , , , , , material);
    }
    /// <summary>
    ///绘制三角形
    ///Triangle n. 三角形；三人一组['traɪæŋɡl]
    /// </summary>
    private void DrawTriangle(float x1, float y1, float x2, float y2, float x3, float y3, Material material)
    {
        material.SetPass();
        GL.LoadOrtho();
        GL.Begin(GL.TRIANGLES);//绘制三角形
        GL.Vertex3(x1 / Screen.width, y1 / Screen.height, );
        GL.Vertex3(x2 / Screen.width, y2 / Screen.height, );
        GL.Vertex3(x3 / Screen.width, y3 / Screen.height, );
        GL.End();
    }

    // Use this for initialization
    void Start()
    {

    }

    // Update is called once per frame
    void Update()
    {

    }
}

五、绘制3D几何图形

using UnityEngine;
using System.Collections;

/// <summary>
/// 绘制 3D几何图形
/// </summary>
public class _7_5_5 : MonoBehaviour
{

    #region 材质
    public Material material0;
    public Material material1;
    public Material material2;
    #endregion

    private void OnPostRender()
    {
        //绘制正四边形
        DrawRect(, , , , material0);
        DrawRect(, , , , material1);
        //绘制无规则四边形
        DrawQuads(, , , , , , , , material2);
    }
    /// <summary>
    /// 绘制正四边形
    /// </summary>
    /// <param name="x">x轴起始坐标</param>
    /// <param name="y">y轴起始坐标</param>
    /// <param name="width">正四边形的宽</param>
    /// <param name="height">正四边形的高</param>
    /// <param name="material">material</param>
    private void DrawRect(float x, float y, float width, float height, Material material)
    {
        GL.PushMatrix();
        material.SetPass();
        GL.Begin(GL.QUADS);//四边形
        GL.Vertex3(x / Screen.width, y / Screen.height, );
        GL.Vertex3(x / Screen.width, (y + height) / Screen.height, );
        GL.Vertex3((x + width) / Screen.width, (y + height) / Screen.height, );
        GL.Vertex3(x / Screen.width, (y + height) / Screen.height, );
        GL.End();
        GL.PopMatrix();
    }

    /// <summary>
    /// 绘制无规则四边形
    /// </summary>
    /// <param name="x1">起始点1的横坐标</param>
    /// <param name="y1">起始点1的纵坐标</param>
    /// <param name="x2">起始点2的横坐标</param>
    /// <param name="y2">起始点2的纵坐标</param>
    /// <param name="x3">起始点3的横坐标</param>
    /// <param name="y3">起始点3的纵坐标</param>
    /// <param name="x4">起始点4的横坐标</param>
    /// <param name="y4">起始点4的纵坐标</param>
    /// <param name="material">material</param>
    private void DrawQuads(float x1, float y1, float x2, float y2, float x3, float y3, float x4, float y4,
                           Material material)
    {
        GL.PushMatrix();//[ˈmeɪtrɪks] n. <数>矩阵；模型；基质；母体，子宫
        material.SetPass();
        GL.Begin(GL.QUADS);
        GL.Vertex3(x1 / Screen.width, y1 / Screen.height, );
        GL.Vertex3(x2 / Screen.width, y2 / Screen.height, );
        GL.Vertex3(x3 / Screen.width, y3 / Screen.height, );
        GL.Vertex3(x4 / Screen.width, y4 / Screen.height, );
        GL.End();
        GL.PopMatrix();
    }

    // Use this for initialization
    void Start()
    {

    }

    // Update is called once per frame
    void Update()
    {

    }
}

六、绘制线

　　任何一个模型都由若干网格面组成，而每一个面又由若干个三角形组成，也就是说，模型是由若干个三角形面组成的

using UnityEngine;
using System.Collections;

public class _7_5_7 : MonoBehaviour
{

    #region 构成三角形1的三个顶点位置
    Vector3 v0 = new Vector3(, , );

    Vector3 v1 = new Vector3(, , );

    Vector3 v2 = new Vector3(, , );
    #endregion
    //构成三角形2的三个顶点位置
    Vector3 v3 = new Vector3(-, , );
    Vector3 v4 = new Vector3(, -, );
    Vector3 v5 = new Vector3(, , -);
    //构成三角形1的贴图比例
    Vector2 u0 = new Vector2(, );
    Vector2 u1 = new Vector2(, );
    Vector2 u2 = new Vector2(, );
    //构成三角形2的贴图比例
    Vector2 u3 = new Vector2(, );
    Vector2 u4 = new Vector2(, );
    Vector2 u5 = new Vector2(, );

    // Use this for initialization
    void Start()
    {
        //得到网格渲染器对象
        MeshFilter meshFilter = (MeshFilter)GameObject.Find("face").GetComponent(typeof(MeshFilter));
        Mesh mesh = meshFilter.mesh; //通过渲染器对象得到网格对象
        mesh.vertices = new Vector3[] { v0, v1, v2, v3, v4, v5 };// n. 至高点，头顶；最高点( vertex的名词复数 )；[ˈvə:tisi:z]
        mesh.uv = new Vector2[] { v0, v1, v2, v3, v4, v5 };//设置三角形面上的贴图比例
        mesh.triangles = new int[] { , , , , ,  };//[t'raɪæŋɡlz] n. 三角形( triangle的名词复数 )；
    }

    // Update is called once per frame
    void Update()
    {

    }
}