Wait! I finally got the right equation! I was trying to change only the red green or blue value based on how much of each was present, but I needed to multiply them all by one universal fraction! Here's my results (by the way I wasn't really looking for an outline):


And the code:

Code:

---

 material mat_rgb 
{	
	effect = "		
	sampler2D g_samSrcColor;

	float4 MyShader( float2 Tex : TEXCOORD0 ) : COLOR0
	{
		float4 Color;
		int Color_all;
		float multiplyer;
		Color = tex2D( g_samSrcColor, Tex.xy);
		Color_all = ((Color.r + Color.g + Color.b)/3)/.167;
		multiplyer = (Color_all * .167)/((Color.r + Color.g + Color.b)/3);
		Color.r = (Color.r * multiplyer);
		Color.g = (Color.g * multiplyer);
		Color.b = (Color.b * multiplyer);
		return Color;
	}


	technique PostProcess
	{
		pass p1
		{
			VertexShader = null;
			PixelShader = compile ps_2_0 MyShader();
		}

	}
	";
} 

---