For real-world application, the light from an source would have infinite directions, how do we deal with that?
rohta
^I had a similar question -- we talk a lot about ray intersection from here; is it because this mostly applies to looking at light sources and shadows?
Max
I'm not quite sure what you mean about infinite direction. If you mean infinite extent, this is modeled by the above expression: t can grow arbitrarily large. If you mean starting at infinity, that could also be modeled by a 'directional' light source that generates parallel rays from outside the scene.
Further, ray intersection is useful for many things, not just computing paths to light emitters. In the path tracer you will be tracing light rays in all directions against all objects in a scene, and more generally you might use ray intersection for physics simulation, geometric queries, selecting things on screen, etc.
For real-world application, the light from an source would have infinite directions, how do we deal with that?
^I had a similar question -- we talk a lot about ray intersection from here; is it because this mostly applies to looking at light sources and shadows?
I'm not quite sure what you mean about infinite direction. If you mean infinite extent, this is modeled by the above expression: t can grow arbitrarily large. If you mean starting at infinity, that could also be modeled by a 'directional' light source that generates parallel rays from outside the scene.
Further, ray intersection is useful for many things, not just computing paths to light emitters. In the path tracer you will be tracing light rays in all directions against all objects in a scene, and more generally you might use ray intersection for physics simulation, geometric queries, selecting things on screen, etc.