From: etherton@megatek.com (David Etherton)
Message-Id: <9603181746.AA25580@fuzz.megatek>
Subject: Re: Visibility Lists
To: quake-editing@nvg.unit.no
Date: Mon, 18 Mar 1996 09:46:28 -0800 (PST)
In-Reply-To: <9603181711.AA25455@fuzz.megatek> from "David Etherton" at Mar 18, 96 09:11:28 am
Here's a data dump from test1.bsp:
VISILIST SIZE 14039
494 total leaves, 1068 total nodes
leaf 0: visoffs=0 {0 bits since last}
leaf 1: visoffs=0 {0 bits since last}
leaf 2: visoffs=29 {232 bits since last}
leaf 3: visoffs=54 {200 bits since last}
leaf 4: visoffs=76 {176 bits since last}
leaf 5: visoffs=102 {208 bits since last}
leaf 6: visoffs=125 {184 bits since last}
leaf 7: visoffs=148 {184 bits since last}
leaf 8: visoffs=171 {184 bits since last}
leaf 9: visoffs=197 {208 bits since last}
leaf 10: visoffs=223 {208 bits since last}
leaf 11: visoffs=246 {184 bits since last}
leaf 12: visoffs=272 {208 bits since last}
leaf 13: visoffs=298 {208 bits since last}
leaf 14: visoffs=321 {184 bits since last}
leaf 15: visoffs=344 {184 bits since last}
leaf 16: visoffs=370 {208 bits since last}
leaf 17: visoffs=393 {184 bits since last}
leaf 18: visoffs=416 {184 bits since last}
leaf 19: visoffs=442 {208 bits since last}
leaf 20: visoffs=468 {208 bits since last}
leaf 21: visoffs=494 {208 bits since last}
leaf 22: visoffs=520 {208 bits since last}
....
I suspect there's something weird about the visibility lists.
While all of the offsets are within the boundaries of the
visibility list, and some of the lists do run off the end
of the end of the lump, I find the fact that all of the
visibility lists overlap is rather disturbing. I can't
see how sharing the same bit pattern between multiple visibility
lists could ever be useful.
I suspect that there's an offset and length field that we don't
know about yet which would allow us to say that all leaves not
in a specified range are either visible or invisible; leaves
within the specified range check the visibility bitmask.
Also, several of the later leaves have a visibility offset
of -1; does that mean no other leaves are visible from here
or all other leaves are visible from here?
-David
-- David Etherton | Megatek Corporation | "Shop as usual, and avoid panic buying."