[Assignment 1] Question about Orthographic View

[LihengGong]

For Orthographic View, suppose line equation is p(t) = e + td

Sphere is: (p - c)·(p - c) = R^2

Then d is parallel to axis z, and e is in x-y plane, so that e·d = 0 ?

[danielepanozzo]

Hi, I don't understand the question, could you please elaborate? The only difference between Orthographic and Perspective is how you generate the rays: the intersection code should be the same. For the assignment, you should not make any assumption on d and e.

[LihengGong]

Thank you. I'll talk to you then.

[LihengGong]

Just add one comment: I was trying to understand the provided example program so that I can understand how ray tracing algorithm works in source code's perspective.

My understanding of the provided example is that

• the sphere is centered in the original(0, 0, 0)
• using orthographic view, the direction of the ray(call it d) is parallel to axis z
• camera location(call it e) is in (x, y) plane(or plane z=0) so that z · e = 0.

From the above, the determinate of the example is written as:

sqrt(sphere_radius*sphere_radius - ray_on_xy.squaredNorm())

[LihengGong]

My guess is that the answer is yes. Will close this for now.

[danielepanozzo]

Yes, that's correct.