GL的功能比較強，但unity中開放的接口比較少。（個人版不能用）

我在項目中是用兩個相機，一個設置為不清處模式，渲染到RenderTexture上，另一個渲染主場景。

  1 public class GLLine : MonoBehaviour
  2 {
  3     /*GL比較底層，難控制，Unity開放的接口不多，能用到的不多，
  4      *有時間繼續學習深入研究
  5      *
  6      */
  7     private List<Vector3> linePos;
  8     private bool startDraw = false
 
;
  9     private Vector3 oldMousePosition;
 10     public float StepSize = 80f;//每次差值的步長
 11     public float size = 60f;//每個單獨模塊的寬度
 12     public Material LineMaterial;
 13     public Color color = Color.red;
 14     public float roud = 30;
 15 
 16     void Start()
 17     {
 18 
 19         linePos = new
 
 List<Vector3>();
 20 
 21 
 22     }
 23 
 24     void Update()
 25     {
 26         if (Input.GetMouseButtonDown(0))
 27         {
 28             oldMousePosition = Input.mousePosition;
 29             color = Color.red;
 30             startDraw = true;
 31         }
 32         if
 
 (Input.GetMouseButtonUp(0))
 33         {
 34             startDraw = false;
 35             linePos.Clear();//清理繪制點，不然每幀都會重新繪制
 36         }
 37         if (Input.GetMouseButtonDown(1))
 38         {
 39             oldMousePosition = Input.mousePosition;
 40             startDraw = true;
 41             color = Color.white;
 42         }
 43         if (Input.GetMouseButtonUp(1))
 44         {
 45             startDraw = false;
 46             linePos.Clear();//清理繪制點，不然每幀都會重新繪制
 47         }
 48         if (startDraw)
 49         {
 50             if (StepSize == 0) return;
 51             var newMousePosition = (Vector2)Input.mousePosition;
 52             if (Vector2.Distance(newMousePosition, oldMousePosition) < size) return;
 53             float stepCount = Vector2.Distance(oldMousePosition, newMousePosition) / StepSize + 1;
 54             for (int i = 0; i < stepCount; i++)
 55             {
 56                 var subMousePosition = Vector3.Lerp(oldMousePosition, newMousePosition, i / stepCount);
 57                 linePos.Add(subMousePosition);
 58             }
 59             oldMousePosition = newMousePosition;
 60 
 61         }
 62 
 63 
 64 
 65 
 66 
 67     }
 68     /// <summary>
 69     /// 引擎自動調用
 70     /// </summary>
 71     public void OnRenderObject()
 72     {
 73         GL.PushMatrix();
 74         LineMaterial.SetPass(0);
 75         for (int i = 0; i < linePos.Count - 1; i++)
 76         {
 77             Vector3 startPos = linePos[i];
 78             Vector3 endPos = linePos[i + 1];
 79             DrawLineFun(startPos.x, startPos.y, endPos.x, endPos.y);
 80         }
 81         GL.PopMatrix();
 82 
 83     }
 84     void DrawLineFun(float x1, float y1, float x2, float y2)
 85     {
 86 
 87         DrawRect(x1 - roud, y1 - roud, 2 * roud, color);
 88     }
 89 
 90     void DrawRect(float x, float y, float width, Color myColor)
 91     {
 92 
 93         float height = width;
 94         //繪制2D圖像  
 95         GL.LoadOrtho();
 96         GL.Begin(GL.QUADS);
 97         GL.Color(myColor);
 98         GL.TexCoord3(0, 0, 0);//設置貼圖 畫純色時去掉
 99         GL.Vertex3(x / Screen.width, y / Screen.height, 0);
100         GL.TexCoord3(0, 1, 0);//設置貼圖 畫純色時去掉
101         GL.Vertex3(x / Screen.width, (y + height) / Screen.height, 0);
102         GL.TexCoord3(1, 1, 0);//設置貼圖 畫純色時去掉
103         GL.Vertex3((x + width) / Screen.width, (y + height) / Screen.height, 0);
104         GL.TexCoord3(1, 0, 0);//設置貼圖 畫純色時去掉
105         GL.Vertex3((x + width) / Screen.width, y / Screen.height, 0);
106         GL.End();
107 
108     }
109 }

Unity3D 畫筆實現系列02-UnityGL