[Assignment 1] if condition regarding the example program

[LihengGong]

In part 2 in the example program, there is one if condition

 if (ray_on_xy.norm()<sphere_radius)
            {
                // The ray hit the sphere, compute the exact intersection point
                Vector3d ray_intersection(ray_on_xy(0),ray_on_xy(1),
                        sqrt(sphere_radius*sphere_radius - ray_on_xy.squaredNorm()));
                .....
           }

Question is: Is this if condition just an optimization or is it part of the ray tracing algorithm?
My understanding from the lecture notes is that for orthographic, all the ray’s starting points formed a square instead of a circle.

Thank you

[hankstag]

yes, it's just a simple way to test whether the ray intersects with the sphere in the example case; you need to modify it

[LihengGong]

Thank you.