1.2 Different spheres' shading model and where to put second light

[mafshar]

Hi,

For 1.2, should we have one scene where there is diffuse shading, one with spectral, one with ambient, and one with all three? Also where does the second light source come in? Can someone please clarify.

Thank you in advance!

[jiangzhongshi]

Hi,

You can have one with diffuse and one with all three. Specular or ambient alone won't produce meaningful results.

For the second light source, you can decide its position on your own, but please make sure it has some effect in your scene.

Best,
Zhongshi

[mafshar]

Okay thank you!

And for Specular Shading, it is my understanding that vector v is the normalized vector that represents the direction of the camera. That is, it is the origin vector normalized. Is this correct, or am I missing something?

[jiangzhongshi]

v represents the direction from intersection point to the viewer, not the ray you are casting. ray_intersection in the sample code represents the coordinate of the intersection point for the given ray.

[mafshar]

Yes, I meant to say origin.

[jiangzhongshi]

The correct way is the following. You cast a ray to the objects. If an intersection occurs, denote p as the intersection point. Normalize the direction from p to the viewer eye position will give you v.