stupid hemicubes!

Started by
5 comments, last by Mulligan 21 years, 4 months ago
I''ve finally gotten about 90% of the hemicube code working in my great radiosity endeavor, but am having trouble with one part. I place the camera on a patch, then render the front view, top, left bottom and right each to its own texture. This works, kind of. In my attempt to verify that the views were captured correctly, I construct a cube and apply the textures to it. I then move my camera to the center of the cube and view the cube from the inside. What I SHOULD be seeing is the view of the scene from that patche''s point of view, but what I actually see are all unaligned and googly. now my questions: Do you think I''m going about my testing in the wrong way? or do you know of a better way to test it?
Advertisement
You''ll have to post some screenshots of what you mean, it sounds like it should be working but there are any number of things you could have done wrong.
Well, after more testing, I think the problem is due to an incorrect perspective. I use:

gluPerspective( 45.0f, (float)TEXTURE_SIZE / (float)TEXTURE_SIZE, 0.01f , 250.0f );

which I believe is causing the view to be too zoomed in. Do you see anything bladently wrong with that?
quote:
Do you see anything bladently wrong with that?

Yes The FOV angle must be 90° for a hemicube view.
Thanks! That makes sense.

Ok, i did that, and it works much better, but now everything is just slightly unaligned. For now its close enough.

If I just forget about perfecting it right now (which I will do later) do you think that it would have a huge impact on how realistic my lighting looks?

Once again, thanks for the quick responses!

[edited by - Mulligan on December 5, 2002 3:32:16 PM]
quote:Original post by Mulligan
If I just forget about perfecting it right now (which I will do later) do you think that it would have a huge impact on how realistic my lighting looks?


No, since you''re just adding the values anyway, so it doesn''t matter if they''re slightly out of line except MAYBE just a tiny bit at the edges of the cube. Anyway, I doubt it''ll be enough to matter. It''s the kind of thing that you''d probably like to fix, but, until you get it fixed, it''s barely matters anyway.
Hmm, depends, actually. If you use a gathering algorithm, then it won't matter very much. The patch will receive a tiny little amount less light, that won't be visible. But if you use a shooting algorithm, it will probably create very visible artifacts: Imagine a bright area light shooting energy to the (dark) patches around it. It will shoot everywhere, but at the edges of the hemicube. Ie. there will be reciever patches missing, which will result in ugly black lines.


[edited by - Yann L on December 5, 2002 1:57:29 PM]

This topic is closed to new replies.

Advertisement