## Search found 7 matches

Wed Aug 26, 2015 4:17 am
Forum: General Development
Topic: A better way to sample a sphere (w.r.t. solid angle)
Replies: 16
Views: 20806

### Re: A better way to sample a sphere (w.r.t. solid angle)

Hi Yurika, Ah, you're right, I misunderstood your post! I understand your method now. However, I think there's still a subtle problem with it. (I ran into this, too!) The problem is that sampling the visible area from the inside of the sphere samples it uniformly, but sampling it from outside of th...
Tue Aug 25, 2015 10:56 pm
Forum: General Development
Topic: A better way to sample a sphere (w.r.t. solid angle)
Replies: 16
Views: 20806

### Re: A better way to sample a sphere (w.r.t. solid angle)

Hi yuriks, Sorry for the late reply, but I think your method doesn't quite work...I ran into the same problem also! The problem is that the point of intersection is in general not tangent to the sphere, so the triangle formed by it, the center of the sphere, and the origin of the ray isn't a right ...
Sun Aug 10, 2014 11:50 pm
Forum: General Development
Topic: how to modify light "power and color" after rendering
Replies: 14
Views: 9933

### Re: how to modify light "power and color" after rendering

If you re-render the whole image then you have the overhead of creating paths, tracing rays, sampling, calculating cosines, etc. which doesn't really vary by light but that's still being repeated anyway. If you use the light-vector approach then that's only computed once and you save on that computa...
Sun Aug 10, 2014 9:24 pm
Forum: General Development
Topic: how to modify light "power and color" after rendering
Replies: 14
Views: 9933

### Re: how to modify light "power and color" after rendering

Your understanding still seems somewhat confused (sorry if that's not indeed the case), so here's an alternative way to explain it: Light intensity is additive. That means that rendering a scene with N light sources is the same as rendering the scene with only one light source active at a time. Here...
Fri Aug 01, 2014 2:24 am
Forum: General Development
Topic: A better way to sample a sphere (w.r.t. solid angle)
Replies: 16
Views: 20806

### Re: A better way to sample a sphere (w.r.t. solid angle)

EDIT: This algorithm is incorrect! See akalin's post below. I've had a similar confusion while reading PBRT. I like to derive all algorithms myself from first principles, so while deriving the sphere sampling one I arrived at an (in my opinion) simpler solution, and couldn't find any drawbacks with...
Thu Jul 31, 2014 7:20 pm
Forum: My First...
Topic: MIS with more than one light
Replies: 1
Views: 4179

### MIS with more than one light

Hello, first time poster here. It seems like this is the only ray-tracer development community around! :cry: In my spare time, I'm reading PBRT and developing a ray/path/hacktracer of my own. Using the book for a mathematical and technical foundation but then trying to apply my own ideas. Recently I...
Thu Jul 31, 2014 6:00 pm
Forum: Visuals
Topic: Glitch Pictures anyone?
Replies: 81
Views: 110599