Image Effect help

Unity Engine
1

I’m trying to make a script which can be placed onto a camera to make the camera render only the reds of a scene. Here’s what I have so far:

Script placed onto camera

var redMat : Material;

function OnRenderImage (source : RenderTexture, destination : RenderTexture)
{
	RenderTexture.active = destination;
	redMat.SetTexture ("_MainTex", source);
}

And this is the shader applied to the redMat:

Shader "Red Filter" {
	Properties {
		_MainTex ("Texture", RECT) = ""
	}
	SubShader {
		Pass {
			ColorMask R
			Blend One One
			SetTexture [_MainTex]
		}
	}
}

All this seems to do is create thick soft lines around the edge of the screen. Anyone know what I’m doing wrong?

Thanks

2

You’re not rendering anything into destination render texture. Take a look at Material.SetPass documentation for quite small image effect to get your started.

Next step should be: change the shader to select only the red channel of the input texture. This would probably be easiest with a small Cg fragment program (instead of trying to do that via SetTexture).