Reproducing the "before Fresnel" and "after Fresnel" picture

Hi Jamis,

here's the hollow sphere only:




and here's the glass sphere only:




As you can see, both of them are fully black...
Here's the code:        (ReflactiveIndex::glass = 1.5)



World w{};



Plane wall{};

wall.setTransform(translation(0, 0, 10) * rotate_x(1.5708));



SolidPattern clrA{Color{0.15, 0.15, 0.15}};

SolidPattern clrB{Color{0.85, 0.85, 0.85}};

CheckersPattern checkers{makePattern_ptr<SolidPattern>(clrA), makePattern_ptr<SolidPattern>(clrB)};

wall.material.pattern = makePattern_ptr<CheckersPattern>(checkers);



wall.material.ambient = 0.8;

wall.material.diffuse = 0.2;

wall.material.specular = 0;

w.addShape<Plane>(wall);



Sphere glassSphere{};



Material glass{};

glass.color = Color{1, 1, 1};

glass.ambient = 0;

glass.diffuse = 0;

glass.specular = 0.9;

glass.shininess = 300;

glass.reflective = 0.9;

glass.transparency = 0.9;

glass.refractive_index = RefractiveIndex::glass;



glassSphere.material = glass;

w.addShape<Sphere>(glassSphere);



Material hollow{};

hollow.color = Color{1, 1, 1};

hollow.ambient = 0;

hollow.diffuse = 0;

hollow.specular = 0.9;

hollow.shininess = 300;

hollow.reflective = 0.9;

hollow.transparency = 0.9;

hollow.refractive_index = 1.0000034;



Sphere hollowSphere{};

hollowSphere.setTransform(scaling(0.5, 0.5, 0.5));

hollowSphere.material = hollow;

w.addShape<Sphere>(hollowSphere);



w.light = PointLight{point(2, 10, -5), Color{0.9, 0.9, 0.9}};



Camera cam{600, 600, .45};

cam.setTransformation(view_transform(point(0, 0, -5), point(0, 0, 0), vector(0, 1, 0)));



w.render(cam).toPPM("C:\\Users\\tompe\\desktop\\scene.ppm");