A.D.A. Amiga Demoscene Archive

I've got my FD tunnel up and running, and I would like to do deformations on it like done in tractor beam / tbl and showbase shape. I'm at a loss, it must be done in the quadratic equations, but I'm not sure where and what factors should be placed within them. Any clues?

What you want to alter is the norm you are using that defines the isosurface. L2 will be a normal circular tunnel, L1 will be a square tunnel. I guess what one would do to morph between two is to interpolate between two different norms.

Thanks for the reply. I've tried this a bit on my freedir planes, interpolating to the freedir tunnel. Not really a beauty, to be honest. More ore less, what I'm looking for is the same effect as TBL / Captured Dreams, second freedir tunnel.

http://ada.untergrund.net/?p=demo&i=254

The second to last screenie on that one. I have no idea how to deform the tunnel like that. Any clues ?

@uzo: is this tunnel going to end up in a demo or intro? Are you planning one doing a demo? Would be cool :)

And while i can't help you on the question, it's cool to see that your tunnel is up and running. Always wanted to do a tunnel... but never did. Hope somebody can help with your question.

Thanks z5_!

This is just me researching all this stuff. Not sure if it will ever become an amiga demo.

uzo:

First, simplify the problem a bit by always assuming that the camera is in the center of the tunnel. (that is, the camera can rotate freely but only move along the Z axis.)

Then, in your ray<->cylinder intersection, modulate the cylinder's radius by a sinewave-lookalike function depending on which direction (in the XY plane) that the intersection ray is going. That is: let the radius of the tunnel change between different rays cast during the same frame.

Thanks Kalms! I was trying to just that, but without the simplification to t = rad / sqrt(directionx*directionx + directiony*directiony); I couldn't get it to work. Got it up and running now and think I understand how to go back to free x and y origin too. Thanks so much!