GL.LINES

Description

Mode for Begin: draw lines.

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 or GL.LoadPixelMatrix. To set up the screen for drawing in 3D, use GL.LoadIdentity followed by GL.MultMatrix with the desired transformation matrix.

See Also: GL.Begin, GL.End.

    // Draws a line from "startVertex" var to the curent mouse position.
    var mat : Material;
    private var startVertex : Vector3;
    private var mousePos : Vector3;
    startVertex = Vector3(0,0,0);

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

    function 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(Vector3(mousePos.x/Screen.width, mousePos.y/Screen.height, 0));
        GL.End();
        GL.PopMatrix();
    }

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    public Material mat;
    private Vector3 startVertex;
    private Vector3 mousePos;
    void Update() {
        mousePos = Input.mousePosition;
        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();
    }
    void Example() {
        startVertex = new Vector3(0, 0, 0);
    }
}