clipka <ano### [at] anonymousorg> wrote:

> Congratulations, it seems like you've just found out what a BRDF is...
> now to my problem of generating random numbers with a distribution that
> is reasonably close to a given BRDF (in order to get an efficient
> sampling), while keeping track of the probability of the numbers we're
> generating (in order to compensate for the virtually inevitable mismatch) ;)

Thanks!   Do I win a prize?   :D

So, after skimming some of the literature, I have a much better idea of what
you're specifically looking for - some form of Importance Sampling.

If you can post a graph of the BRDF that you're trying to simulate for the
purposes of your sampling algorithm, or a means of plotting it themselves, then
that might give anyone following along a nudge forward.

It seems that for any given function plotted between A and B, the probability of
having X land in that interval is the integral (S) of that function.

So, for my square root spline sampling function, f(x) = pow(x, 0.5)
so S(pow(x, 0.5) = 1/1.5 * pow(x, 1.5).

Also,

My apologies, but I'm trying to figure out what you actually mean when you say
"keep track of the probability..."

Do you tallying up the actual results of the random sampling so that you can do
a summation and then divide by the number of random samples?

Post a reply to this message