KeatonMill

16th July 2002 21:08 UTC

1-plane DM
Hey guys, I've been working on 3D DMs. I can produce a two plane floor/ceiling type DM, however there is a lot of distortion between the planes.
Two questions:
1. How can I make there be only one plane to look at?
2. How can I get rid of the distortion?
I tried looking at UnConeD's Winamp Disco, but he used a different way of creating the original two planes effect than I did.
My current preset is attached.

UnConeD

16th July 2002 22:07 UTC

Raytracing
I use raytracing... it's a totally different approach, but it allows you to do complex effects like tunnels and such.

Or those really cool new effects I have ready for Whacko AVS V :D :weird: :p

KeatonMill

16th July 2002 23:32 UTC

How does that work?

UnConeD

17th July 2002 14:40 UTC

For every point on the DM grid, you trace a ray from the camera origin through the space and intersect it with your primitives (it's hard to do anything above quadrics though) to find the point of intersection closest to the camera. Then, you need to find the texture coordinates to wrap the current image/buffer around the 3D shape, and use those as x,y.

uNDefineD

18th July 2002 01:50 UTC

UC: Couldn't you use alphablending? Or is that the pussy's way out. :p

UnConeD

18th July 2002 09:30 UTC

uNDefineD: What exactly do you mean? I was talking about making more complicated shapes and arrangements like only one plane or combinations of them. If you use the 'superscope-approach', you're mostly limited to two parallel planes.
For the distortion the best solution is indeed alpha-blending. In the original Winamp Disco preset I used an image though, because I didn't know about alpha-blending back then.

dirkdeftly

18th July 2002 09:47 UTC

Well...back on topic - that's a question I've had for a while, too. UnConeD did it in WAVS4, but I'm unable to see how. Theoretically, all you do is move the camera very close to one of the planes when it rotates, and when it rotates away from the camera, move towards the other plane. On either side you alpha out the other plane. The trouble is doing this. I haven't tried yet.

UnConeD

18th July 2002 10:33 UTC

Hmmm? Actually the reason you probably get a second plane is because you need to make sure you only find intersection points in front of the camera. If you have a point above a plane and trace a ray that doesn't intersect the plane, then the ray that runs in the opposite direction *will* intersect.

If you use the superscope-like approach (x=x3/(z3+1)) then you're tied to the planar arrangement of the DM grid. But actually I'm not sure, I've never used that technique.

The alpha-fadeout I used in WAVS4 (I assume you mean in Hypernet and Energy Ball?) was to prevent too much distortion when the camera was close and looking almost parallel to the plane.

uNDefineD

18th July 2002 14:59 UTC

Sorry, I might be a little out of the loop here. I meant the plane-division effect you had going in Alien Chessboard from WAVS2. Or is that a whole new ball game to this?

Just to check if I'm on the right path, could you tell me if you used the raytracing approach in creating Nuclear Warfare? Cause if it is, I might be able to understand it further.

---

On a side note, NDD2 is nearly half-finished and the last few presets are kicking the crap out of the previous pack, if I may say so myself. ETA so far is mid-late August.

UnConeD

18th July 2002 15:37 UTC

Every 3D DM I make uses the ray-tracing. In Nuclear warfare, I raytrace a sphere and calculate x,y as latitude and longtitude (phi and theta in spherical coordinates).

dirkdeftly

19th July 2002 18:31 UTC

I still don't understand ray-tracing that well, I prefer to go with the straight math that will get me a desired effect. Such as, with the 2-plane DM, rotating the image, then making z=1/y and y=sign(y), then performing the translation (x=x/z; y=y/z);

Nic01

20th July 2002 01:17 UTC

For more raytracing, just search through Google...

Go to fuzzyphoton.*********** - A good site with many links, and one of the links is to a site have the maths behind Raytracing...

Ah, good ol' Google, bringing us UnConeD and giving us salvage in case of hair-tearing questions...