Lerping between multiple materials

Hi

I have a few scripts with various different material lerps and they all work fine.
I now have an plane object (crosshair) that I want to have 4 different materials depending on a timer.
But the script doesnt work at all. Is it possible to change between multiple materials?
If not, any suggestions? I can get it to work using GUI but the position changes to where I have the object.

Cheers

Code (csharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class Crosshair : MonoBehaviour {
5.    
6.     public Material materialDefault;
7.     public Material materialRed;
8.     public Material materialBlue;
9.     public Material materialGreen;
10.     public Material materialYellow;
11.    
12.     // Use this for initialization
13.     void Start () {
14.    
15.          renderer.material = materialDefault;
16.     }
17.    
18.     // Update is called once per frame
19.     void Update () {
20.        
21.         if(Timing.red)
22.             renderer.material.Lerp(materialDefault, materialRed, 1.0f);
23.         else if(Timing.blue)
24.             renderer.material.Lerp(materialDefault, materialBlue, 1.0f);
25.         else if(Timing.green)
26.             renderer.material.Lerp(materialDefault, materialGreen, 1.0f);
27.         else if(Timing.yellow)
28.             renderer.material.Lerp(materialDefault, materialYellow, 1.0f);
29.        
30.     }
31. }
32.  

 

Why not just have one material with 4 textures that you can lerp between inside of the shader?

 

Thanks for the suggestion but I have no experience with shaders.
Just looking through them now, they cant access script variables can they?
Because most of my stuff is based around a timing class and all other classes get their data passed from it and the material changes would also require this to work the way I hope