Re: WAD Conversion sketch

Uffe Friis Lichtenberg (
Mon, 25 Mar 1996 11:38:57 +0100 (MET)

Date: Mon, 25 Mar 1996 11:38:57 +0100 (MET)
From: Uffe Friis Lichtenberg <>
Subject: Re: WAD Conversion sketch
In-Reply-To: <>

On Mon, 18 Mar 1996, Bernd Kreimeier wrote:

> >From: Uffe Friis Lichtenberg <>
> >we do need a 3D BSP tree
> If I am not mistaken, you could simply copy the 2D BSP into
> a matching 3D BSP, and convert the information from the old
> NODES and SSECTORS. Think about it.

I just tried creating a small example to prove my point, and somehow
proved yours, hehe :)

Anyway, it seems you are right: we could convert the SSEGS of Doom
(convex structures) to Quake leaves because there would only be 1 ceiling
for each SSEG and only 1 floor. As long as the split-planes are chosen to
be vertical (ie. normal=(x,0,z)) -- as they would be if converted from
Doom -- the floors and ceilings would be the last planes to be insert
into the BSP tree and thus not intersect anything.

> >the floors and ceilings are planes and have to be partitioned
> You are perfectly right. In fact, this might be the most
> difficult task to solve. It breaks down to creating closed
> polygons from SECTORS and LINEDEFS for each floor (ceilings
> will have the same partitions), and using the 2D BSP NODES
> info (namely the partition lines) to split the SECTORS'
> polygon into the Leaf2D surfaces. I already added this
> to the proposal.

But couldn't the floor and ceiling surfaces be created using the convex
information from the SSEG structure?

(It's been awhile since I hacked Doom, so my terminology might be off...)

> >misc. remarks on conversion, DXF, intermediate file formats
> All very true. However, I am skeptical that any file format
> not done by id will ever be agreed upon. Anybody remember the
> porposal by Tom Neff (WAD Interchange Format)?

Yeah, I remember that one. But it didn't have quite the same idea as one
for Quake -- ie. letting us distribute levels... But I think you are
right, any file format not from id won't survive long :)

Anyway, id would probably analyse our fileformat and make some small
changes just to tease us... >;) (Things are bound to change with every
version up until registered, so why bother anyway?)

> >>The WAD will have to have only one floor/ceiling per xy plane,
> >>i.e. the DOOM world geometry restrictions
> >But where do you find wads that fulfil this requirement?
> Hmmm? Any WAD that can be used with DOOM does :-).

Only one floor/ceiling per xy plane: disallow multiple sectors to have
floors/ceilings with the same z-coordinates...

I think I misunderstood you. You mean that each sector only has one
floor/ceiling xy plane, right? (Which then also applies to SSEGs, which
hopefully could be our path through conversion hell.)

Uffe. [uphfe]