Consider ray tracing a scene containing only a sphere defined by its centre [cx, cy, cy] and its radius r. i) A particular ray intersects the sphere at position [x, y, z]. In terms of x, y, z. cx, cy and cz, what is the surface normal vector at the point of intersection? ii) If the scene contains only a single distant point light source, describe whether each of the two types of shadowing will be present in the scene