Now that I think about it, if there are rendering techniques based on randomness, then I guess rendering the same thing twice won't give you the same image (correct me if I'm wrong about this though). Is there ever a situation in graphics where we desire being deterministic and will avoid using random techniques?
keenan
@dchen1 So-called "random" numbers are actually produced by a psuedorandom number generator. These are deterministic algorithms that produce numbers that "look random," with varying degrees of success depending on the algorithm. The good news, then, is that you can generate the same image twice by just starting your pseudorandom generator with the same initial "seed" each time. But no guarantee that you will get a similar image as, e.g., you move to the next frame of animation---or if you make a small change to your code!
By the way, the question of whether "truly random" numbers can be generated---or even if they're well-defined!---is a really interesting one, and a lot less clear-cut than you might expect. Avi Wigderson has given a nice public lecture on this topic.
Now that I think about it, if there are rendering techniques based on randomness, then I guess rendering the same thing twice won't give you the same image (correct me if I'm wrong about this though). Is there ever a situation in graphics where we desire being deterministic and will avoid using random techniques?
@dchen1 So-called "random" numbers are actually produced by a psuedorandom number generator. These are deterministic algorithms that produce numbers that "look random," with varying degrees of success depending on the algorithm. The good news, then, is that you can generate the same image twice by just starting your pseudorandom generator with the same initial "seed" each time. But no guarantee that you will get a similar image as, e.g., you move to the next frame of animation---or if you make a small change to your code!
By the way, the question of whether "truly random" numbers can be generated---or even if they're well-defined!---is a really interesting one, and a lot less clear-cut than you might expect. Avi Wigderson has given a nice public lecture on this topic.