unity---GL实现案例

GL

C#实现

不管是画任何东西都需要Begin()和End()函数；

画线

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class GL_Line : MonoBehaviour
{
    // Start is called before the first frame update
    // public Material material;
    void OnPostRender()
    {
        // if(!material){
        //     Debug.LogError("请给材质赋值？？");
        //     return;
        // }
        // material.SetPass(0);
        GL.LoadOrtho();
        GL.Begin(GL.LINES);
           GL.Color(new Color(255,0,0));//线段颜色
           GL.Vertex(new Vector3(0,0,0));
           GL.Vertex(new Vector3(100f/Screen.width,100f/Screen.height,0));
        GL.End();
    }
}

画曲线

根据鼠标位置实时画线

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class GL_Curve : MonoBehaviour
{
    // Start is called before the first frame update
    List<Vector3> lineInfo;
    void Start(){
        lineInfo=new List<Vector3>();
    }
    void Update() {
    //    if(Input.GetMouseButton(0))   // 添加这句话可以控制开始  结束
         lineInfo.Add(new Vector3(Input.mousePosition.x/Screen.width,Input.mousePosition.y/Screen.height,0));
    }
    void OnPostRender()
    {
       GL.LoadOrtho();
        GL.Begin(GL.LINES);
        GL.Color(new Color(255,0,0));
        for(int i = 0;i<lineInfo.Count-1;i++){
            GL.Vertex(lineInfo[i]);
            GL.Vertex(lineInfo[i+1]);
        }
           //GL.Vertex(new Vector3(100,100,0));
        GL.End();
    }
}

画正方体

需要准备四个点，位置都是浮点数

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class GL_Quads : MonoBehaviour
{
    // Start is called before the first frame update
    private void OnPostRender() {
        GL.LoadOrtho();
        GL.Begin(GL.QUADS);
        GL.Color(new Color(255,0,0));
           GL.Vertex(new Vector3(0,0,0));
           GL.Vertex(new Vector3(300f/Screen.width,0,0));
            GL.Vertex(new Vector3(300f/Screen.width,300f/Screen.height,0));
            GL.Vertex(new Vector3(0,300f/Screen.height,0)); 
        GL.End();
    }
}

LineRenderer画线

推荐这篇博客 LineRenderer画线

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class GL_Line1 : MonoBehaviour
{
    // Start is called before the first frame update
    public LineRenderer lineRenderer;
    // Update is called once per frame
    void Start()
    {
       lineRenderer.positionCount=4;
       lineRenderer.startWidth=0.1f;
       lineRenderer.endWidth=0.1f;
    }
    Vector3 v0=new Vector3(1f,0,0);
    Vector3 v1=new Vector3(2f,0,0);
    Vector3 v2=new Vector3(3f,0,0);
    Vector3 v3=new Vector3(4f,0,0);
    private void Update() {
        lineRenderer.SetPosition(0,v0);
         lineRenderer.SetPosition(1,v1);
          lineRenderer.SetPosition(2,v2);
           lineRenderer.SetPosition(3,v3);
    }
}