Hi

I´m trying to implement a Stochastic Path tracer using the pseudo code described in the book Advanced Global Illumination by Dutré, Bala and Bekaert. I´m doing it in c++. I think I understand the algorithm but the whole thing about radiance makes me a bit confused.

Right now I have implemented basicly everything to get started with the actual tracing. I have a scene with objects like spheres and planes. These I can calculate intersection and give material proerpties. I also have a vector class wich handles the linear algebra.

My scene description looks like the one in this tutorial: link, where I can set diffuse, and reflection constants and the color of objects.

Now to my question: the pseudo code in the book uses radiance. How do I calculate the radiance in for example: radiance leaving the light source, Le? Is my scene description wrong if I want to use radiance? In the tutorial they dont seem to use radiance at all. Is radiance same as (r,g,b)?

So when when the pseudo code says this for direct illumination with a single light source: estimatedRadiance += Le * BRDF * G(x,y) * V(x,y) / pdf(k), I just replace the Le with the color of the light source? Where does the color of the object that is intersected go? Or should I put the color of the lightsource * the color of the object hit = Le?

If I want to do the computation with radiance instead of the actual color values how would my scene description look like then? And how do I convert the radiance values to (r,g,b) so I can display the image on my computer?