Severi Salminen <sev### [at] NOTTHISsaunalahtifiinvalid> wrote:
> Nicolas Alvarez wrote:
>
> > AFAIK, this algorithm doesn't shoot rays per pixel, really. Just lots of
> > rays, and starting from the light.
> >
> > Note it's not the common "backwards raytracing" like POV-Ray has. This
> > is forwards.
>
> I think it actually does shoot rays from camera. The ray shooting
> recursive function returns when an emitting surface (or certain depth)
> is found. It actually doesn't matter (from physics point of view) where
> you start: from camera of from the light as the ray paths are identical.
I confirm, the start is from the camera, not from light.

> In brute force
> you keep on going (shooting random rays from diffuse surfaces) and you
> hope you hit a light at some point. And that is why all light sources
> must basically have surface to be able to hit.
I can't explain better. A small adding : with the use of portals, the light
source can have null surface (like light point).

Regards,
Fidos.

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