attribute  vec4 vPosition;
attribute  vec4 vNormal;
varying vec4 color;

uniform vec4 AmbientProduct, DiffuseProduct, SpecularProduct;
uniform mat4 ModelView;
uniform mat4 Projection;
uniform vec4 LightPosition;
uniform float Shininess;
void main()
{


    vec3 pos = -(ModelView * vPosition).xyz;
    vec3 light = LightPosition.xyz;
    vec3 L = normalize( light - pos );

	
    vec3 E = normalize( -pos );
    vec3 H = normalize( L + E );

    // Transform vertex normal into eye coordinates
       
    vec3 N = normalize( (ModelView*vNormal).xyz);

    // Compute terms in the illumination equation
    vec4 ambient = AmbientProduct;

    float Kd = max( dot(L, N), 0.0 );
    vec4  diffuse = Kd*DiffuseProduct;

    float Ks = pow( max(dot(N, H), 0.0), Shininess );
    vec4  specular = Ks * SpecularProduct;
    
    if( dot(L, N) < 0.0 ) {
	specular = vec4(0.0, 0.0, 0.0, 1.0);
    } 

    gl_Position = Projection * ModelView * vPosition;
    
    color = ambient + diffuse +specular;
    
    color.a = 1.0;
}