Render to texture with own shader

Unity Engine
1

Hi,
i have wrote small skript from material example with my shader material,but i have white screen.
Here ist skript for camera

using UnityEngine;
using System.Collections;

public class CameraPostProcessing : MonoBehaviour {

	public Shader shader;


	Material m;

	void Start () {
	

		m = new Material(shader);

		
/*		m = new Material (
"Shader \"Hidden/Invert\" {" +
"SubShader {" +
" Pass {" +
" ZTest Always Cull Off ZWrite Off" +
" SetTexture [_MainTex] { combine one-texture }" +
" }" +
"}" +
"}"
);*/
	}



	void OnRenderImage(RenderTexture source, RenderTexture dest){

RenderTexture.active = dest;
source.SetGlobalShaderProperty ("_MainTex");

GL.PushMatrix ();
GL.LoadOrtho ();

// activate the first pass (in this case we know it is the only pass)
m.SetPass (0);
// draw a quad
		
GL.Begin (GL.QUADS);
GL.TexCoord2 (0.0f, 0.0f); GL.Vertex3 (0.0f, 0.0f, 0.1f);
GL.TexCoord2 (1.0f, 0.0f); GL.Vertex3 (1.0f, 0.0f, 0.1f);
GL.TexCoord2 (1.0f, 1.0f); GL.Vertex3 (1.0f, 1.0f, 0.1f);
GL.TexCoord2 (0.0f, 1.0f); GL.Vertex3 (0.0f, 1.0f, 0.1f);
GL.End ();

GL.PopMatrix (); 

		}
}

and here shader

Shader "ColorShader" {

Properties {
    _Color ("Main Color", Color) = (1,1,1,0.5)
    _MainTex ("Texture", RECT) = "white" { }
}
SubShader {
    Pass {
ZTest Always Cull Off ZWrite Off
//Fog { Mode Off }
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma fragmentoption ARB_fog_exp2

#include "UnityCG.cginc"

float4 _Color;
sampler2D _MainTex;

struct v2f {
    V2F_POS_FOG;
    float2  uv : TEXCOORD0;
};

v2f vert (appdata_base v)
{
    v2f o;
    PositionFog( v.vertex, o.pos, o.fog );
    o.uv = TRANSFORM_UV(0);
    return o;
}

half4 frag (v2f i) : COLOR
{
    half4 texcol = tex2D( _MainTex, i.uv );
    return texcol *  _Color;
	//return half4(1,0,0,1);
}
ENDCG

    }
}
Fallback "VertexLit"




}

I want just source Texture on Quad drawing.
Thanks

2

If i make in shader :

return half4(1,0,0,1);

then quad red,but wenn i use RenderTexture in return color then all white.Is it right:

	void OnRenderImage(RenderTexture source, RenderTexture dest){
	
RenderTexture.active = dest;
source.SetGlobalShaderProperty ("_MainTex");

GL.PushMatrix ();
GL.LoadOrtho ();

m.SetPass (0);

		
GL.Begin (GL.QUADS);
GL.TexCoord2 (0.0f, 0.0f); GL.Vertex3 (0.0f, 0.0f, 0.1f);
GL.TexCoord2 (1.0f, 0.0f); GL.Vertex3 (1.0f, 0.0f, 0.1f);
GL.TexCoord2 (1.0f, 1.0f); GL.Vertex3 (1.0f, 1.0f, 0.1f);
GL.TexCoord2 (0.0f, 1.0f); GL.Vertex3 (0.0f, 1.0f, 0.1f);
GL.End ();

GL.PopMatrix (); 

		}