#version 330 compatibility

uniform float   uKa, uKd, uKs;		// coefficients of each type of lighting
uniform float   uShininess;		// specular exponent
uniform float uS0, uT0, uD;		// square pattern

in  vec2  vST;			// texture coords
in  vec3  vN;			// normal vector
in  vec3  vL;			// vector from point to light
in  vec3  vE;			// vector from point to eye


void
main( )
{
	vec3 Normal    = normalize(vN);
	vec3 Light     = normalize(vL);
	vec3 Eye       = normalize(vE);

	vec3 SpecularColor = vec3( 1., 1., 1. );
	vec3 myColor = vec3(1.0, 0.5, 0.0 );
	float ds = uD;
	float dt = uD;
	if(	uS0-ds/2. <= vST.s  &&  vST.s <= uS0+ds/2.  && 
		uT0-dt/2. <= vST.t  &&  vST.t <= uT0+dt/2.  )
	{
			myColor = vec3( 1., 0., 0. );
	}

	vec3 ambient = uKa * myColor;

	float d = max( dot(Normal,Light), 0. );       // only do diffuse if the light can see the point
	vec3 diffuse = uKd * d * myColor;

	float s = 0.;
	if( dot(Normal,Light) > 0. )	          // only do specular if the light can see the point
	{
		vec3 ref = normalize(  reflect( -Light, Normal )  );
		s = pow( max( dot(Eye,ref),0. ), uShininess );
	}
	vec3 specular = uKs * s * SpecularColor.rgb;
	gl_FragColor = vec4( ambient + diffuse + specular,  1. );
}