Lecture 13: Global Illumination & Path Tracing (29)
abhi-n-anand
What is the purpose of the two rays -W_i and W_i? Am I correct to assume that the former is reflected light from the object whereas the latter is the source of light?
DaddyGang
The transport function tr(p,w) returns a surface point. So Lo(tr(p, wi), -wi) = Lo(p', -wi), which is equal to Li(p, wi), meaning that the "amount of light" concentrating at a particular point p' toward direction -wi is equal to that at point p going at direction wi. I don't think there are explicit "source" and "reflection" here, but just a way of calculating light transfer.
borongzhang
I don't really understand this part... why the reflected light from the object equals to the source of light. Where are those cos theta terms
What is the purpose of the two rays -W_i and W_i? Am I correct to assume that the former is reflected light from the object whereas the latter is the source of light?
The transport function tr(p,w) returns a surface point. So Lo(tr(p, wi), -wi) = Lo(p', -wi), which is equal to Li(p, wi), meaning that the "amount of light" concentrating at a particular point p' toward direction -wi is equal to that at point p going at direction wi. I don't think there are explicit "source" and "reflection" here, but just a way of calculating light transfer.
I don't really understand this part... why the reflected light from the object equals to the source of light. Where are those cos theta terms