# LINES

> Mode for GL.Begin: draw lines.

## Definition

* **Type:** Field
* **Namespace:** [UnityEngine](/engine/6000.5/script-reference/unityengine.md)
* **Assembly:** UnityEngine.CoreModule

```csharp
public const int LINES = 1
```

### Remarks

Draws lines between each pair of vertices passed. If you pass four vertices, A, B, C and D, two lines are drawn: one between A and B, and one between C and D.

To set up the screen for drawing in 2D, use [GL.LoadOrtho](/engine/6000.5/script-reference/unityengine/gl/loadortho.md) or [GL.LoadPixelMatrix](/engine/6000.5/script-reference/unityengine/gl/loadpixelmatrix.md). To set up the screen for drawing in 3D, use [GL.LoadIdentity](/engine/6000.5/script-reference/unityengine/gl/loadidentity.md) followed by [GL.MultMatrix](/engine/6000.5/script-reference/unityengine/gl/multmatrix.md) with the desired transformation matrix.

Additional Resources: [GL.Begin](/engine/6000.5/script-reference/unityengine/gl/begin.md), [GL.End](/engine/6000.5/script-reference/unityengine/gl/end.md).

### Examples

```csharp
//Attach this script to a GameObject with a Camera component

using UnityEngine;

public class Example : MonoBehaviour
{
    // Draws a line from "startVertex" var to the curent mouse position.
    public Material mat;
    Vector3 startVertex;
    Vector3 mousePos;

    void Start()
    {
        startVertex = Vector3.zero;
    }

    void Update()
    {
        mousePos = Input.mousePosition;
        // Press space to update startVertex
        if (Input.GetKeyDown(KeyCode.Space))
        {
            startVertex = new Vector3(mousePos.x / Screen.width, mousePos.y / Screen.height, 0);
        }
    }

    void OnPostRender()
    {
        if (!mat)
        {
            Debug.LogError("Please Assign a material on the inspector");
            return;
        }
        GL.PushMatrix();
        mat.SetPass(0);
        GL.LoadOrtho();

        GL.Begin(GL.LINES);
        GL.Color(Color.red);
        GL.Vertex(startVertex);
        GL.Vertex(new Vector3(mousePos.x / Screen.width, mousePos.y / Screen.height, 0));
        GL.End();

        GL.PopMatrix();
    }
}
```