GL图形库

GL.PushMatrix();//将模型、视图和投影矩阵保存到矩阵堆栈顶部。
GL.PopMatrix();//出栈
mat:Material.SetPass(0);//设置材质通道
GL.LoadOrtho();//将正交投影加载到投影矩阵中，将标识加载到 模型和视图矩阵中。

GL.Begin(GL.QUADS);//绘制类型为四边形
GL.Begin(GL.TRIANGLES);//绘制类型为三角形
GL.Begin(GL.LINES);//绘制类型为直线

GL.Vertex(new Vector3(x1 / Screen.width, y1 / Screen.height, 0));//屏幕坐标为真实坐标除屏幕长宽,提供一个顶点
GL.Vertex3(x1 / Screen.width, y1 / Screen.height, 0);//提供一个顶点，上面的和下面的作用一致们就是参数不一样

绘制直线

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

public class Scripts_07_15 : MonoBehaviour
{
    public Material material;
    // Start is called before the first frame update
    void Start()
    {
        
    }

    // Update is called once per frame
    void Update()
    {
        
    }
    private void OnPostRender()
    {
        if(!material)
        {
            Debug.LogError("请给资源赋值");
            return ;
        }
        material.SetPass(0);
        GL.LoadOrtho();
        GL.Begin(GL.LINES);
        DrawLine(0, 0, 200, 100);
        DrawLine(0, 50, 200, 150);
        DrawLine(0, 100, 200, 200);
        GL.End();
    }
    void DrawLine(float x1, float y1, float x2,float y2)
    {
        GL.Vertex(new Vector3(x1 / Screen.width, y1 / Screen.height, 0));//屏幕坐标为真实坐标除屏幕长宽
        GL.Vertex(new Vector3(x2 / Screen.width, y2 / Screen.height, 0));
    }
}

用鼠标在屏幕绘制线条

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

public class Scripts_07_16 : MonoBehaviour
{
    public Material material;
    public List<Vector3> lineInfo;
    private bool draw;
    // Start is called before the first frame update
    void Start()
    {
        lineInfo = new List<Vector3>();
    }

    // Update is called once per frame
    void Update()
    {
        if(Input.GetMouseButton(0))
        {
            lineInfo.Add(Input.mousePosition);
            draw = true;
        }
        if(Input.GetMouseButtonUp(0))
        {
            lineInfo.Clear();
            draw = false;
        }
    }
    private void OnGUI()
    {
        GUILayout.Label("当前鼠标x轴的位置：" + Input.mousePosition.x);
        GUILayout.Label("当前鼠标z轴的位置：" + Input.mousePosition.y);
    }
    private void OnPostRender()
    {
        if (!draw) return;
        if(!material)
        {
            Debug.LogError("请给材质资源包赋值");
            return;
        }
        material.SetPass(0);
        GL.LoadOrtho();
        GL.Begin(GL.LINES);
        int length = lineInfo.Count;
        for (int i = 0; i < length - 1; i++)
            DrawLine(lineInfo[i].x, lineInfo[i].y, lineInfo[i + 1].x, lineInfo[i + 1].y);
        GL.End();
    }
    void DrawLine(float x0, float y0, float x1, float y1)
    {
        GL.Vertex(new Vector3(x0 / Screen.width, y0 / Screen.height, 0));//提供一个顶点
        GL.Vertex(new Vector3(x1 / Screen.width, y1 / Screen.height, 0));
    }
}

绘制四边形

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

public class Scripts_07_17 : MonoBehaviour
{
    public Material mat0, mat1, mat2;
    // Start is called before the first frame update
    void Start()
    {
        
    }

    // Update is called once per frame
    void Update()
    {
        
    }
    private void OnPostRender()
    {
        DrawRect(100, 100, 100, 100, mat0);//绘制矩形
        DrawRect(250, 100, 100, 100, mat1);
        DrawQuads(15, 5, 10,115, 95, 110, 90, 10, mat2);//绘制四边形
    }
    void DrawRect(float x, float y, float width, float height, Material mat)
    {
        GL.PushMatrix();//将模型、视图和投影矩阵保存到矩阵堆栈顶部。
        mat.SetPass(0);//设置材质通道
        GL.LoadOrtho();//将正交投影加载到投影矩阵中，将标识加载到 模型和视图矩阵中。
        GL.Begin(GL.QUADS);

        GL.Vertex3(x/Screen.width, y/Screen.height, 0);
        GL.Vertex3(x / Screen.width, (y+height) / Screen.height, 0);
        GL.Vertex3((x+width) / Screen.width, (y +height) / Screen.height, 0);
        GL.Vertex3((x+width) / Screen.width, y / Screen.height, 0);
        GL.End();
        GL.PopMatrix();//出栈
    }
    void DrawQuads(float x1,float y1, float x2, float y2, float x3, float y3, float x4, float y4, Material mat)
    {
        GL.PushMatrix();
        mat.SetPass(0);
        GL.LoadOrtho();
        GL.Begin(GL.QUADS);
        GL.Vertex3(x1/Screen.width, y1/Screen.height, 0);
        GL.Vertex3(x2/Screen.width, y2/Screen.height, 0);
        GL.Vertex3(x3/Screen.width, y3/Screen.height, 0);
        GL.Vertex3(x4/Screen.width, y4/Screen.height, 0);
        GL.End();
        GL.PopMatrix();
    }
}

绘制三角形

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

public class Scripts_07_18 : MonoBehaviour
{
    public Material mat;
    // Start is called before the first frame update
    void Start()
    {
        
    }

    // Update is called once per frame
    void Update()
    {
        
    }
    private void OnPostRender()
    {
        DrawTringle(100, 0, 100, 200, 200, 100, mat);
    }
    void DrawTringle(float x1, float y1 ,float x2, float y2, float x3, float y3, Material mat)
    {
        mat.SetPass(0);
        GL.LoadOrtho();
        GL.Begin(GL.TRIANGLES);
        GL.Vertex3(x1 / Screen.width, y1 / Screen.height, 0);//提供一个顶点 
        GL.Vertex3(x2 / Screen.width, y2 / Screen.height, 0);
        GL.Vertex3(x3 / Screen.width, y3 / Screen.height, 0);
        GL.End();
    }
}

绘制3D图形（尚存在问题）

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

public class Scripts_07_19 : MonoBehaviour
{
	public Material mat0;
	public Material mat1;
	public Material mat3;
    private void Start()
    {
        
    }
    void OnPostRender()
	{
		//绘制正四边形
		DrawRect(100, 100, 100, 100, mat0);
		DrawRect(250, 100, 100, 100, mat1);
		//绘制无规则四边形
		DrawQuads(15, 5, 10, 115, 95, 110, 90, 10, mat3);
	}
	void DrawRect(float x, float y, float width, float height, Material mat)
	{
		GL.PushMatrix();
		mat.SetPass(0);
		//绘制类型为四边形
		GL.Begin(GL.QUADS);
		GL.Vertex3(x / Screen.width, y / Screen.height, 0);
		GL.Vertex3(x / Screen.width, (y + height) / Screen.height, 0);
		GL.Vertex3((x + width) / Screen.width, (y + height) / Screen.height, 0);
		GL.Vertex3((x + width) / Screen.width, y / Screen.height, 0);

		GL.End();
		GL.PopMatrix();
	}
	void DrawQuads(float x1, float y1, float x2, float y2, float x3, float y3, float x4, float y4, Material mat)
	{
		GL.PushMatrix();
		mat.SetPass(0);
		//绘制类型为四边形
		GL.Begin(GL.QUADS);
		GL.Vertex3(x1 / Screen.width, y1 / Screen.height, 0);
		GL.Vertex3(x2 / Screen.width, y2 / Screen.height, 0);
		GL.Vertex3(x3 / Screen.width, y3 / Screen.height, 0);
		GL.Vertex3(x4 / Screen.width, y4 / Screen.height, 0);
		GL.End();
		GL.PopMatrix();
	}
}