// TODO: implement this function to fill in values for ray.col

// using phong shading. Make sure your vectors are normalized, and

// clamp colour values to 1.0.

//

// It is assumed at this point that the intersection information in ray

// is available. So be sure that traverseScene() is called on the ray

// before this function.

Colour KA = (*ray.intersection.mat).ambient;

Colour KD = (*ray.intersection.mat).diffuse;

Colour KS = (*ray.intersection.mat).specular;

double alpha = (*ray.intersection.mat).specular_exp;

Colour IA = _col_ambient;

Colour ID = _col_diffuse;

Colour IS = _col_specular;

// std::cout << ray.intersection.untransformedPoint

double x = 0;

double y = 0;

x = ray.intersection.untransformedPoint[0]+1;

y = ray.intersection.untransformedPoint[1]+1;

x*=1000;

y*=1000;

// std::cout << x << "," << y << std::endl;

if ((int)x/20 % 2 == (int)y/20 % 2) {

KA = (*ray.intersection.mat).ambient2;

KD = (*ray.intersection.mat).diffuse2;

KS = (*ray.intersection.mat).specular2;

}

if (ray.inShadow) {

Colour shade = KA*IA;

shade.clamp();

ray.col = shade;

return;

}

Vector3D N = (ray.intersection.normal);

N.normalize();

Vector3D L = (_pos - ray.intersection.point);

L.normalize();

Vector3D V = (-ray.dir);

V.normalize();

Vector3D R = ((2 * (L.dot(N)) * N) - L);

R.normalize();

double max1 = fmax(0.0, N.dot(L));

double vr_alpha = pow(V.dot(R), alpha);

double max2 = fmax(0.0, vr_alpha);

Colour shade = KA * IA + KD * (max1 * ID) + KS * (max2 * IS);

shade.clamp();

ray.col = shade;