glbsp - GL Nodes builder for DOOM ports
glbsp [options] input.wad ... [-o output.wad]
glBSP is a nodes builder specially designed to be used with OpenGL-
based DOOM game engines. It adheres to the "GL-Friendly Nodes"
specification, which means it adds some new special nodes to a WAD file
that makes it very easy for an OpenGL DOOM engine to compute the
polygons needed for drawing the levels.
Options begin with a single dash (you can also use two dashes like in
many GNU programs). Running glBSP without any options will show an
Show a summary of all the options.
Quieter output. Information about each level (like the number
of linedefs, blockmap size, etc) is not displayed when this
option is given, and a few other messages are skipped.
Important messages, like failure to build a certain level, are
Allows glBSP to cheat a bit and re-use the original node
information to create the GL nodes, doing it much faster. Use
this option to enable this feature. The message "Using original
nodes to speed things up" will be shown.
The downside to reusing the original nodes is that they may not
be as good as the ones glBSP normally creates, e.g. the special
checks to minimise slime-trails don’t kick in, and the -factor
value doesn’t have much effect.
Shows extra warning messages, which detail various non-serious
problems that glBSP has while analysing the level structure.
Often these warnings show a real problem in the level (e.g. a
non-closed sector or invalid sidedef), so they are worth
checking now and then.
glBSP usually detects if the normal node info (i.e. the non-GL
variety) is present: when yes, it is left untouched, otherwise
glBSP creates it. This option forces glBSP to replace the
normal node data with newly constructed nodes.
-c -factor <num>
Sets the cost assigned to seg splits. Factor can be any number
from 1 to 32, and larger values make seg splits more costly (and
thus glBSP tries harder to avoid them), but smaller values
produce better BSP trees. The default value is known to be a
Pack sidedefs, by detecting which sidedefs are identical and
removing the duplicates, producing a smaller PWAD.
NOTE: this may make your level a lot harder to edit! Therefore
this is most useful when producing the final WAD for public
Normally glBSP will create an simple REJECT map for each level.
This options prevents any existing REJECT map, such as one time-
consumingly built by a dedicated reject builder, from being
The following options are rarely needed:
-v1 .. -v5
Specify the version of the "GL Nodes" spec to use (either 1, 2,
3 or 5). V1 is considered obsolete now. The default is V2.
Giving -v3 or -v5 will force certain lumps to use the new
formats, but is only useful for testing since glBSP will
automatically switch to V5 format whenever the ordinary limits
Merge duplicate vertices at the same location into a single
vertex. This is usually safe, but is not done by default
because some engines (e.g. Risen3D) need the duplicate vertices
to stay separate for a special effect.
Lets glBSP detect and handle the "One-Sided Window" mapping
trick. This can cause problems in some engines so it is
disabled by default.
-b -maxblock <num>
Sets the limit of the number of blocks the BLOCKMAP may contain
before we truncate it. Default is 16000. When the level is too
large to fit, glBSP will truncate the blockmap, so it covers
less area on the level. This means that in the parts it doesn’t
cover (at the outer edges) there is no collision detection: you
can walk through walls and other objects and bullets/missiles
don’t hit anything. On very large but sparse levels, using a
larger value (e.g. 30000) may help.
A more serious problem is when the blockmap overflows. The
blockmap created would be invalid, and could crash the DOOM
engine when used. glBSP will create an empty blockmap instead,
causing modern ports to build their own blockmap.
Turn off the progress indicator.
Forces glBSP to not create the normal node information when it
detects that it is absent.
Removes any unused sectors that are found in the level. This
has the potential to cause problems, since in certain scripting
languages (e.g. EDGE’s RTS, or Doom Legacy’s Fragglescript) some
commands use sector numbers directly, and pruning unused sectors
can cause those references to become invalid.
New in version 2.20 is support for response files. These are files
containing a list of options. You specify the response file by
prefixing it with ’@’. For example:
The "@argfile.rsp" on the command line will be replaced with the
contents of that file. New-line characters are treated like spaces.
Recursion (using ’@’ inside a response file) is not supported.
When the normal nodes overflow, older versions of glBSP would simply
write out the invalid node data. glBSP 2.20 and higher now write the
node data in the ZDBSP format (originally created for the ZDoom
Andrew Apted created glBSP and glBSPX and continues to maintain them.
Andrew Baker, Janis Legzdinsh, André Majoral and Darren Salt have
contributed code, and Marc Pullen helped with the documentation.
glBSP was originally based on BSP 2.3 (C) Colin Reed and Lee Killough,
which was created from the basic theory stated in DEU5 (OBJECTS.C) by
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2 of the License, or (at your
option) any later version.
This program is is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
The glBSP Homepage: http://glbsp.sourceforge.net/
July 2007 glbsp(1)