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Quake Editing Digest Volume 1 : Number 14

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Published in 
quake editing digest
 · 20 Apr 2024

quake-editing-digest      Thursday, 21 March 1996      Volume 01 : Number 014 

Re: Legal issues (was: WAD conversion sketch)
Visibility Lists Revisited
just another brick in the wall.. [RANDOM TITLE]


From: Herschel Giansiracusa <>
Date: Wed, 20 Mar 1996 09:25:48 -0600
Subject: Re: Legal issues (was: WAD conversion sketch)

On Tue, 19 Mar 1996, Jim Elson wrote:

> However, there is another factor in this equation: Exactly WHY did id release
> the test in the form they did? (monsters, etc.) It's not as if they are
> stupid enough to believe that no one would try to implement them or that
> they could care less what we could do with it. Of course, I don't explain
> a candid answer to this from them, but it is an interesting question and
> the possibilities might shed some light on id's plans concerning editors,
> utilities, etc.

It seems like id wanted to get some "Quake hacking" going to increase to
popularity of the Qtest1, so they made it easy for us hackers to get started
by doing that thing with the monsters... Just think, without that now
famous "fun with hex" post on doom-editing a couple days after the
release of Qtest1, decoding the PAK and all of it's sub-formats would've
progressed much slower.



From: (David Etherton)
Date: Wed, 20 Mar 1996 12:10:25 +0800
Subject: Visibility Lists Revisited

[Olivier has probably already figured this out and written it up in
the specs, but just in case...]

It looks like the visibility lists are RLE compressed. The encoding
is very simple: if a byte is nonzero, it contains the visibility data
for the next eight leaves. If it is zero, the next byte contains
a skip count. This skip count (probably) means that the next (count<<3)
leaves are not visible. I guess that it means they're *not* visible
because I see lots of (consecutive) 0xFF's in the visibility lists of

It seems like RLE compressing 0xFF's as well as 0x00's would work
well, but who am I to question to id gods? :)

I'm reasonably sure that I'm on the right track, because every visibility
list in test1.bsp "unpacks" to 57 bytes, or 456 leaves. While there
are 494 leaves on test1.bsp, leaves 452 and onward all have a visibility
offset of -1. Not sure whether that means "all visible" or "none
visible" yet. [Note floor((452+7)>>3)==57]

[I also just ran test2.bsp through, and it sees them all as 118 bytes
long, and the first leaf with a visoffs of -1 is 941]

I'm still not sure whether the bit test for testing individual unpacked
visibility bytes is (1<<(offset&7)) or (128>>(offset&7)); my usual
sanity check of "any leaf should be able to see itself" still
doesn't work consistently for either method.

I hope this furthers the Great Hacking Effort...

- -dce


From: "Muad'Dib" <>
Date: Wed, 20 Mar 1996 14:01:00 -0700
Subject: just another brick in the wall.. [RANDOM TITLE]

Responding :* One EXE for all? (was Re: Legal stuff)

> It could be made sufficently hard to remove if it was a key that was
> spread throughout the WAD and was used to construct some weird
> checkdigit at the end. It could remain undocumented, so nobody could
> remove it and the EXE would be the only thing that had to know how to
> look for it.
> That way everyone could make whatever editor they wanted, and if you
> didn't have the registered WAD, then you would not be able to play
> the add-on levels. In fact, the editor-designers wouldn't have to worry
> about checking for registered versions of the game at all, because the
> EXE would handle it.

This is a thingy for ID to do. They will figure out how they wanna do that.
I don't think we need to worry. As EvilGenius or someone said, we're not
making something Shareware compatable, we're making something test compatable.
It will almost definitely not work with shareware, so when there is a
registered out, it'll be updated for that.

Muad'Dib <>
The Mouse a.k.a. Greg Alexander


End of quake-editing-digest V1 #14

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