simple arbitrary-3D-line-drawing-class for Unity3D

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

public class LineDraw : MonoBehaviour
{
    static LineDraw instance = null;
    float widthStart = 0.1f;
    float widthFinish = 0.1f;
    ShaderOptionEnum shader = ShaderOptionEnum.SelfIlluminDiffuse;
    Color color = Color.red;

    string[] shaders = {"Self-Illumin/Diffuse", "Particles/Additive"};//, "VertexLit", "Diffuse"};
    public enum ShaderOptionEnum {SelfIlluminDiffuse = 0, ParticlesAdditive};
    //public class LineData{Vector3 a, b; float s, f; ShaderOptionEnum shader; Color c1, c2;}

    public void SetWidth_(float widthStart, float widthFinish)
    {
        this.widthStart = widthStart;
        this.widthFinish = widthFinish;
    }

    public void SetShaderOption_(ShaderOptionEnum shader)
    {
        this.shader = shader;
    }

    public void SetColor_(Color color)
    {
        this.color = color;
    }

    public static void SetShaderOption(ShaderOptionEnum shader){instance.SetShaderOption_(shader);}
    public static void SetColor(Color color){instance.SetColor_(color);}
    public static void SetWidth(float widthStart, float widthFinish){instance.SetWidth_(widthStart, widthFinish);}

    List<GameObject> temp = new List<GameObject>();
    List<GameObject> unusedTemp = new List<GameObject>();

    void LateUpdate()
    {
        for(int i = 0; i < temp.Count; ++i)
        {
            temp[i].active = false;
            unusedTemp.Add(temp[i]);
        }
        temp.Clear();

//      t += Time.deltaTime;
//      if(t >= 360) t-=360;
//      Quaternion q = Quaternion.AngleAxis(t * 360, Vector3.forward);
//      Vector3 v = q * new Vector3(-1,-1,-1);
//      LineDraw.AddTemporary(Vector3.zero, v);
    }
//  float t = 0;

    void Start()
    {
        if(instance == null)
            instance = this;
//      GameObject g = LineDraw.AddPersistent(new Vector3(-1,-1,-2), new Vector3(5,1,-2));
//      Destroy(g, 3);
    }

    GameObject GetLineGameObject()
    {
        GameObject go;
        if(unusedTemp.Count > 0)
        {
            int lastIndex = unusedTemp.Count-1;
            go = unusedTemp[lastIndex];
            unusedTemp.RemoveAt(lastIndex);
            go.active = true;
        }else{
            go = new GameObject("line");
            go.AddComponent<LineRenderer>();
        }
        go.transform.parent = transform;
        return go;
    }

    public GameObject AddLine_(Vector3 a, Vector3 b, bool persistent)
    {
        int numPoints = 2;
        GameObject lineg = GetLineGameObject();
        LineRenderer lineRenderer = lineg.GetComponent<LineRenderer>();
        string shaderName = shaders[(int)shader];
        if(lineRenderer.material.shader.name != shaderName)
        {
            UnityEngine.Shader shaderObject = Shader.Find(shaderName);
            lineRenderer.material = new Material(shaderObject);
        }
        lineRenderer.material.color = color;
        lineRenderer.castShadows = false;
        lineRenderer.receiveShadows = false;
        lineRenderer.SetColors(color, color);
        lineRenderer.SetWidth(widthStart, widthFinish);
        lineRenderer.SetVertexCount(numPoints);
        lineRenderer.SetPosition(0, a);
        lineRenderer.SetPosition(1, b);
        //lineg.transform.position = (a+b)/2;
        if(!persistent)
        {
            temp.Add(lineg);
        }
        return lineg;
    }
    public static GameObject AddPersistent(Vector3 a, Vector3 b){return instance.AddLine_(a, b, true);}
    public static void AddTemporary(Vector3 a, Vector3 b){instance.AddLine_(a, b, false);}
}