uniform vec4  Color;
varying float LightIntensity;
varying vec3  MCposition;


uniform sampler3D Noise3;
uniform float Min, Max;
uniform float Scale;

#undef WANT_RED_AT_EDGES

void main()
{
	vec4  nv  = texture3D( Noise3, Scale*MCposition );
	float sum = nv[0] + nv[1] + nv[2] + nv[3];	// .5 -> 1.5???
	sum = ( sum -.5 ); 				// 0. -> 1.

	if( sum < Min )
		discard;

	if( sum > Max )
		discard;

	gl_FragColor = vec4( LightIntensity*Color.rgb, 1. );

#ifdef WANT_RED_AT_EDGES
	if( sum < Min + .05 )
		gl_FragColor = vec4( LightIntensity*vec3(1.,0.,0.), 1. );
#endif

}