Plane boundaries are different

[razasy299]

My output

Expected output

The plane boundaries are solid lines in my output. I have checked all my formulas and they match the book. Any advice on how to debug this?

[darren-moore]

My guess is that it's the diffuse shading. I'd turn off everything except for the diffuse to debug. Make sure you're normalizing correctly (#29), but the sphere looks okay.
Check that you're factoring in the light color/intensity for the diffuse and specular components too.