uniform sampler2D	VisibleUnit;
uniform sampler2D	InfraRedUnit;
uniform sampler2D	WaterVaporUnit;
uniform float		Visible;
uniform float		InfraRed;
uniform float		WaterVapor;
uniform float		VisibleThreshold;
uniform float		InfraRedThreshold;
uniform float		WaterVaporThreshold;
uniform float		Brightness;




void
main()
{
	vec3 visibleColor    = texture2D( VisibleUnit, gl_TexCoord[0].st ).rgb;
	vec3 infraredColor   = texture2D( InfraRedUnit, gl_TexCoord[0].st ).rgb;
	infraredColor = vec3(1.,1.,1.) - infraredColor;
	vec3 watervaporColor = texture2D( WaterVaporUnit, gl_TexCoord[0].st ).rgb;

	// float visibleLum    = dot( visibleColor, Coefs );
	// float infraredLum   = dot( infraredColor, Coefs );
	// float watervaporLum = dot( watervaporColor, Coefs );

	// vec3 weights = vec3( Visible, InfraRed, WaterVapor );
	// vec3 lums = vec3( visibleLum, infraredLum, watervaporLum );

	// float t = clamp(  dot( weights, lums ),  0., 1.  );
	// vec3 rgb = Rainbow( t );

	vec3 rgb;

	if( visibleColor.r - visibleColor.g  > .25   &&   visibleColor.r - visibleColor.b > .25 )
	{
		rgb = vec3( 1., 1., 0. );	// state outlines become yellow
	}
	else
	{
		rgb = Visible*visibleColor  +  InfraRed*infraredColor  +  WaterVapor*watervaporColor;
		rgb /= 3.;
		vec3 coefs = vec3( 0.296, 0.240, 0.464 );
		float visibleInten = dot(coefs,visibleColor);
		float infraredInten = dot(coefs,infraredColor);
		float watervaporInten = dot(coefs,watervaporColor);
		if( visibleInten > VisibleThreshold  &&  infraredInten < InfraRedThreshold  &&  watervaporInten > WaterVaporThreshold )
		{
			rgb = vec3( 0., 1., 0. );
		}
		else
		{
			rgb *= Brightness;
			rgb = clamp( rgb, 0., 1. );
		}
	}

	gl_FragColor = vec4( rgb, 1. );
}