Unity3D 实操OpenGL函数

今天让大家学习一下Unity3d里面的OpenGL 自带的API ，我们可以通过简单的使用OpenGL来在场景中利用相机渲染绘制图形。官方学习文档：https://docs.unity3d.com/ScriptReference/GL.html
1.第一步：通过相关官方的文档，我们可以了解GL接口以及一些标准OpenGL函数；
2.第二步：我们直接进入实操模式；
2.0 新建项目，在场景中创建Camera，并且附加OpenGLTest.cs 组件；
2.1 OpenGLTest.cs 代码如下（具体可以直接参考官方文档）；

using System.Collections;using System.Collections.Generic;using UnityEngine;public class OpenGLTest : MonoBehaviour {        public int lineCount = 80;        public float radius = 4f;        static Material lineMaterial;        public void OnRenderObject()        {                CreateLineMaterial();                // Apply the line material                lineMaterial.SetPass(0);                GL.PushMatrix();                // Set transformation matrix for drawing to                // match our transform                GL.MultMatrix(transform.localToWorldMatrix);                // Draw lines                GL.Begin(GL.LINES);                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.End();                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", 0);                }        }}

2.2 运行项目看绘制的线条；