How to make a 2D Shader works with OnGUI() through Graphics.DrawTexture()

Hello,

I just got that problem, so here a mini tutorial to help anyone running into it.

So if you want to use a custom 2D Shader within your OnGUI(), you'll have to use :

Code (csharp):

1. Graphics.DrawTexture(screenRect : Rect, texture : Texture, mat : Material = null)

with 'mat' referencing your custom Shader.

To make your Shader work correctly, you'll have to add these lines to it, at start of SubShader :

Code (csharp):

1. SubShader
2.     {
3.         Tags { "Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent" }
4.         Lighting Off
5.         Cull Off
6.         ZTest Always
7.         ZWrite Off
8.         Fog { Mode Off }

Me, I didn't at 1st, and it was working fine in the Editor, but didn't work in the Webplayer nor in the Windows Build : nothing was appearing.
After a few tests, I discovered it didn't work in the same way with original Unity shaders, except "GUI/Text Shader" that produced a white output.
So I downloaded the legacy shaders (from here : http://unity3d.com/download_unity/builtin_shaders.zip ), and checked the "Font.Shader" where I found the mentioned lines.
Maybe not all of them are necessary, but I didn't take the time to test all 1 by 1...

 

Change this Queue to Overlay, so you make sure its rendered last.

 

Thanks for the info, Aubergine !