varying vec3 Normal;

void main()
{    
    vec4 p;
    
    // the light position is already stored in eye space coordinates
    //lightDir = normalize(vec3(gl_LightSource[0].position));

    // convert normal to eye space coordinates using gl_NormalMatrix
    // gl_NormalMatrix is built in uniform matrix provided by GLSL
    // representing the inverse transpose model-view matrix
    Normal = normalize(gl_NormalMatrix * gl_Normal); 
        
   // this time I am not doing: gl_Position = gl_ProjectionMatrix * gl_ModelViewMatrix * gl_Vertex; 
   // I will let the geometry shader handle that part    
   //  gl_Position = ftransform();
   gl_Position =  gl_Vertex;
}