mirror of https://github.com/ZDoom/zdbsp.git
577 lines
27 KiB
HTML
577 lines
27 KiB
HTML
<HTML>
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<HEAD>
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<TITLE>ZDBSP Documentation</TITLE>
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<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
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<META NAME="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
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</HEAD>
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<BODY>
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<H1>About ZDBSP</H1>
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<P>ZDBSP is a stand-alone version of ZDoom's internal node builder. This node
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builder was written with two design goals in mind:</P>
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<OL>
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<LI>
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It must be fast. The original node builder was just going to be used to fix map
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errors in ZDoom. After adding GL nodes support, ZDoomGL also started using it
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as a preprocessing step for any maps without existing GL nodes. In both
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cases, the node builder needed to be quick in order to minimize the
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time the user was forced to wait before playing a map.
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<LI>
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Polyobject bleeding must be minimized. The node builder was tested with the
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standard Hexen maps and several user maps, and it has been able to prevent
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bleeding on all properly-formed maps. (Note that it is impossible to prevent
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polyobject bleeding in all circumstances. See the polyobjects section below for
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rules you should follow for best results.)</LI></OL>
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<h1>License</h1>
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<p>This program is free software; you can redistribute it and/or modify it under
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the terms of the <a href="http://www.gnu.org/licenses/gpl.html">GNU General Public
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License</a> as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.</p>
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<p>This program is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
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PARTICULAR PURPOSE. See the GNU General Public License for more details.</p>
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<p>You can also find a copy of the license as the file COPYING in the source
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distribution.</p>
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<H1>Using ZDBSP with WadAuthor</H1>
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<P>First, copy zdbsp.exe to your WadAuthor directory. Then start WadAuthor and
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choose "Options..." from its Tools menu. Select the "Files" tab and choose
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"External" for Node Building. This activates the Command text box so that you
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can type text into it. Copy and paste any of the following into it based on
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what you want to do.</P>
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<P>Create a map that can be played with Doom or any source port:</P>
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<BLOCKQUOTE dir="ltr" style="MARGIN-RIGHT: 0px">
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<P>zdbsp -R -m$_Mapname $_Wadfile -o$_Wadfile</P>
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</BLOCKQUOTE>
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<P dir="ltr">Create a map that will only be played with ZDoom. This will be
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ZDoom-only because it creates a zero-length REJECT lump. ZDoom is smart enough
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to know that a zero-length REJECT lump is the same thing as a REJECT lump
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filled with zeros, so you can save space:</P>
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<BLOCKQUOTE dir="ltr" style="MARGIN-RIGHT: 0px">
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<P dir="ltr">zdbsp -r -m$_Mapname $_Wadfile -o$_Wadfile</P>
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</BLOCKQUOTE>
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<P dir="ltr">Create a map with both regular and GL nodes so that ZDoomGL does not
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need to build GL nodes:</P>
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<BLOCKQUOTE dir="ltr" style="MARGIN-RIGHT: 0px">
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<P dir="ltr">zdbsp -rg -m$_Mapname $_Wadfile -o$_Wadfile</P>
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</BLOCKQUOTE>
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<H1 dir="ltr">ZDBSP command line options</H1>
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<P dir="ltr">ZDBSP supports several command line options to affect its behavior. If
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you forget what they are, you can view a quick summary of them by running ZDBSP
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without any options. They are also listed below in more detail than the listing
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ZDBSP provides. Note that these options are case-sensitive, so -r is not the
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same thing as -R. You can use either the long form of an option or the short
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form depending on your preference.</P>
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<dl>
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<dt>--help</dt>
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<dd>
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Displays a summary of all ZDBSP's command line options, as if you had run ZDBSP
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without any options.</dd>
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<dt>--version or -V</dt>
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<dd>
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Displays ZDBSP's version number.</dd>
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<dt>--map=<i>MAP</i> or -m<i>MAP</i></dt>
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<dd>
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When you use this option, ZDBSP will only build the nodes for one map in a wad
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instead of rebuilding the nodes for every map contained in the wad. <i>MAP</i> should
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be the map's full name (e.g. MAP01 or E1M1)</dd>
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<dt>--output=<i>FILE</i> or -o<i>FILE</i></dt>
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<dd>
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Normally, ZDBSP creates a new wad named tmp.wad. You can use this option to
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make it write to a different file instead. In the case of WadAuthor, this is
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used to make ZDBSP overwrite the original file with the new one, because that
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is what WadAuthor expects the nodebuilder to do.</dd>
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<dt>--no-prune or -q</dt>
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<dd>
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When you use this option, ZDBSP will not remove unused sidedefs or sectors from
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a map. ZDBSP will always remove 0-length linedefs from a map even when you use
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this option because it is possible for them to make the game crash under
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certain circumstances. Moreover, ZDoom will itself remove 0-length linedefs and
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rebuild the nodes if it finds any.</dd>
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<dt>--no-nodes or -N</dt>
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<dd>
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This option causes ZDBSP to take the node information from the old wad file and
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write it to the new wad file. I can't think of any reason why you would want to
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do this, but it is provided as an option nonetheless.</dd>
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<dt>--gl or -g</dt>
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<dd>
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This option causes ZDBSP to build two sets of nodes for a map: One set of
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regular nodes and one set of GL nodes. Because ZDBSP is doing twice the work,
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it will take twice as long to finish.</dd>
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<dt>--gl-matching or -G</dt>
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<dd>
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Like the previous option, this one will also make ZDBSP generate GL nodes.
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However, it will only build one set of nodes and then strip the extra GL
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information from them to create the normal nodes. Because of this, it is faster
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than the previous option when you want to create GL nodes, but the normal nodes
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will generally be less efficient because they were created from the GL nodes.</dd>
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<dt>--gl-v5 org -5</dt>
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<dd>
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Always write GL nodes using the v5 GL node specification. Normally, v5 GL nodes
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are only written if they exceed the limits of v2 GL nodes. Since v2 GL nodes are
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more widely supported than v5 GL nodes and v5 GL nodes are only useful for very
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large maps, you should generally not use this option. If you do not specify this
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option, v5 GL nodes will still be automatically written if they are required, and
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if they are not, the more space-efficient v2 GL nodes will be created instead.
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</dd>
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<dt>--compress or -z</dt>
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<dd>Compresses the node information. Compressed nodes take up less space than
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uncompressed nodes, they are the only way to save nodes with more than 65535 segs, and
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they also have higher vertex precision than normal nodes, reducing the possibility
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of slime trails. If GL nodes are built, they will be compressed as well.</dd>
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<dt>--compress-normal or -Z</dt>
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<dd>This is exactly like the previous option, except GL nodes will not be compressed.</dd>
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<dt>--extended or -X</dt>
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<dd>Creates extended nodes. This is exactly like --compress, except the resultant nodes
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are uncompressed.</dd>
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<dt>--empty-blockmap or -b</dt>
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<dd>
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This option writes a zero-length BLOCKMAP to the wad. As of this writing, ZDoom
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is the only port that will detect this and build the BLOCKMAP itself.</dd>
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<dt>--empty-reject or -r</dt>
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<dd>
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When this option is used, ZDBSP will write a zero-length REJECT to the wad. As
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of this writing, ZDoom is the only port that supports this. A zero-length
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REJECT is the same thing as a reject filled with zeros. Since ZDBSP does not
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generate a REJECT table, and the usefulness of having a REJECT is questionable,
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you should always use this option if you intend for the map to be played solely
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with ZDoom.</dd>
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<dt>--zero-reject or -R</dt>
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<dd>
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This option is similar to the previous one, except ZDBSP will actually write
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out a full-sized REJECT lump filled with zeros. If you play with ZDoom, this is
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just wasted space, but other ports and Doom itself require a full-sized REJECT
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lump to work.</dd>
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<dt>--no-reject or -E</dt>
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<dd>
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This option makes ZDBSP copy the REJECT lump from the old wad to the new wad
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unchanged. However, if it detects that the old REJECT is the wrong size for the
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number of sectors in the map, it will be removed as if you had used the
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--empty-reject option.</dd>
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<dt>--no-polyobjs or -P</dt>
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<dd>
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This option disables ZDBSP's polyobject detection code. If you are building
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nodes for a map without polyobjects, you might be able to save a fraction of a
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second from the build time by using this option, but there is generally no
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reason to use it.</dd>
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<dt>--no-timing or -t</dt>
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<dd>
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If you don't care how long it takes to build nodes, use this option and ZDBSP
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won't tell you.</dd>
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<dt>--no-sse</dt>
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<dd>Disables all SSE optimizations in the nodebuilder, which can be useful if you just
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want to measure the kind of speed up SSE or SSE2 provides.</dd>
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<dt>--no-sse2</dt>
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<dd>Disables all SSE2 optimizations in the nodebuilder. SSE1 will still be used if
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your processor supports it. Unless you want to compare the speed difference
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between SSE and SSE2, there is again little reason to use this option.</dd>
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<dt>--warn or -w</dt>
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<dd>
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Displays extra warning messages that ZDBSP might generate while building GL
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nodes. The nodes will still be usable if warnings occur, and warnings are not
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unlikely. If you have strange display problems with GL nodes, turning on the
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warning messages may help you locate the problem.</dd>
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<dt>--partition=<i>NNN</i> or -p<i>NNN</i></dt>
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<dd>
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This option controls the maximum number of segs that will be considered for
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splitters at each node. The default is 64. By increasing it, you might be able
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to generate "better" nodes, but you get diminishing returns the higher you make
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it. High values are also slower than low ones.</dd>
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<dt>--split-cost=<i>NNN</i> or -s<i>NNN</i></dt>
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<dd>
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This option adjusts how hard ZDBSP tries to avoid splitting segs. The default
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value is 8. By increasing this, ZDBSP will try harder to avoid splitting segs.
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If you decrease it, ZDBSP will split segs more frequently. More splits mean the
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BSP tree will usually be more balanced, but it will also take up more room.</dd>
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<dt>--diagonal-cost=<i>NNN</i> or -d<i>NNN</i></dt>
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<dd>
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This option controls how hard ZDBSP tries to avoid using diagonal splitters.
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The default value is 16. A higher value means that diagonal splitters will be
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more likely to be used. This can sometimes help to reduce the number of segs in
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a map. The reason avoiding diagonal splitters is important is because normal
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nodes do not store any fractional information for the vertices that segs use,
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so you are more likely to see slime trails with diagonal splitters than with
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horizontal or vertical splitters.</dd>
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<dt>--view or -v</dt>
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<dd>
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Under Windows, this displays a viewer that will let you inspect a map's
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subsectors, nodes, and REJECT. To scroll the map around, drag it with your
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right mouse button. The viewer was created to assist with debugging with the GL
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nodes. It is not very user-friendly nor is it bug-free. In fact, if you try to
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build nodes for more than one map with this option, there is a good chance
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ZDBSP will crash.</dd>
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</dl>
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<h1>Polyobjects</h1>
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<p>One of ZDBSP's most important features is that it tries very hard to avoid
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polyobject bleeding. To make this feature work, however, you must design your
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maps properly. You do this be ensuring that your polyobjects are always shown
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inside a <i>convex</i> sector. This is referring to the area where the
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polyobjects appear in the game, not where they appear in an editor. If you do
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not know what convex means, think of triangles, squares and circles. They are
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all convex. If you have a sector shaped like the letter C, that is not convex.</p>
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<p>Ironically, an example of what <i>not</i> to do is in Hexen's MAP01. The
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polyobject doors at the very start of that map do not appear in a convex area.
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ZDBSP has been tuned so that they will display properly with the default
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options, but you should not count on this for your own maps.</p>
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<p>If ZDBSP has to split a linedef around a polyobject's display area, it will
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print a message indicating where this happened so that you can inspect the area
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and fix it. For example, when you use ZDBSP on hexen.wad, it outputs these
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warnings for MAP01:</p>
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<pre class="code"> Split seg 929 (-1176,1312)-(-1088,1312) of sector 265 on line 572
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Split seg 931 (-1088,1312)-(-1000,1312) of sector 265 on line 573</pre>
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<p>The important pieces of information here are the coordinates of the segs that
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were split and the lines those segs were made from. In this case, both lines
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572 and 573 were split. Because they surround a polyobject's display area,
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ideally they should not be split, so you need to look at the map in an editor
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to determine what made them split. This happens because the area is not convex,
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so you need to look for a line in the same "loop" that, if you made it longer,
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could cross the line that was split. In this example, lines 575 and 579 are
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responsible for splitting line 572, and lines 576 and 578 are responsible for
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splitting line 573. You can fix the error by reworking the area so that it is
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convex, either by moving lines 575, 579, 576, and 578, or by adding additional
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lines to separate each half into four convex pieces.
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</p>
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<p>Below are some illustrations. The areas where the two polyobjects appear have
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been highlighted.</p>
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<blockquote>
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<p align="center">This first image shows the area as it appears in hexen.wad,
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unmodified. Note that neither side is convex, so ZDBSP will need to split each
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side into two subsectors. The extra subsectors have been highlighted in a
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brighter color to illustrate how ZDBSP splits them.<br />
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<img src="poly_bad.png" alt="The Original Area"></p>
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<p align="center">In the next image, the lines have been moved to make each side
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convex.<br />
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<img src="poly_mov.png" alt="Convex Areas made by Moving Lines">
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</p>
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<p align="center">In the final image, new two-sided lines have been added to make
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each polyobject's display area rectangular. Unlike the line-moving method
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above, this does not alter the area's appearance. Notice that this looks a lot
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like the way ZDBSP split them in the first image. The difference is that by
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adding the extra lines yourself, you have control over how the split is done
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and ZDBSP does not need to guess about the best way to make the area convex.<br />
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<img src="poly_new.png" alt="Convex Areas made by Adding Lines"></p>
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</blockquote>
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<p>Unfortunately, if you use WadAuthor, ZDBSP's output window will not normally
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appear long enough for you to actually read it. You can get around this by
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adding the -v option to the zdbsp command line that WadAuthor uses (see the
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Using ZDBSP with WadAuthor section). Then its output will stay around until you
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close the ZDBSP viewer.</p>
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<h1>Compressed Nodes</h1>
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<p>The following information describes the format used to store compressed nodes.
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If you are just a regular user, you can skip this section.</p>
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<p>Compressed nodes contain all the same information as regular nodes but are
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stored in a single lump and compressed as a zlib data stream. They also support
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more than 65535 segs and vertices by storing them using four bytes instead of
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two.</p>
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<p>The first four bytes of the compressed nodes are a four-character (uncompressed)
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signature. This can be either 'ZNOD' for regular nodes or 'ZGLN' for GL nodes.
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If there are more than 65534 lines in the map, the signature 'ZGL2' is used
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for GL nodes instead. (Note that this can only happen with UDMF maps, because
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the binary map format does not allow more lines than that.) There is also a third
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variant of 'ZGLN': 'ZGL3' is identical to 'ZGL2' but expands the node's splitter
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field to fixed point coordinates.
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Following the signature is the zlib data stream. For a description of its
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format, see the zlib documentation. When you decompress it, the following
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information is obtained in this order:</p>
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<ol>
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<li>
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Vertex information</li>
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<li>
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Subsector information</li>
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<li>
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Segs information</li>
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<li>
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Nodes information</li></ol>
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<h2>Types</h2>
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<p>The following sections use these types:</p>
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<dl>
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<dt><b>BYTE</b></dt><dd>A single unsigned byte. The number can be in the range [0,
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255].</dd>
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<dt><b>WORD</b></dt><dd>An unsigned integer stored in two bytes. The number can be
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in the range [0, 65535].</dd>
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<dt><b>SWORD</b></dt><dd>A signed integer stored in two bytes. The number can be
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in the range [-32768, 32767].</dd>
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<dt><b>DWORD</b></dt><dd>An unsigned integer stored in four bytes. The number can
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be in the range [0, 4294967295].</dd>
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<dt><b>FIXED</b></dt><dd>A signed 16.16 fixed-point number stored in four bytes. The
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most-significant two bytes store the integer part of the number, and the
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least-significant two bytes store the fractional part of the number. The number can
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be in the approximate range [-32768.99998, 32767.99998].</dd>
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</dl>
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<p>All multi-byte numbers are stored with their least significant byte first (i.e.
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little-endian).</p>
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<h2>Vertex information</h2>
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<table>
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<tr>
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<td>DWORD</td>
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<td><i>OrgVerts</i></td>
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<td>Number of vertices used from the VERTEXES lump</td>
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</tr>
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<tr>
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<td>DWORD</td>
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<td><i>NewVerts</i></td>
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<td>Number of additional vertices that follow</td>
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</tr>
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<tr>
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<td colspan="3" bgcolor="#dddddd">Repeat <i>NewVerts</i> times:</td>
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</tr>
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<tr>
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<td>FIXED</td>
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<td><i>X</i></td>
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<td>X-Coordinate</td>
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</tr>
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<tr>
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<td>FIXED</td>
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<td><i>Y</i></td>
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<td>Y-Coordinate</td>
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</tr>
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</table>
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<p>These are all the <i>additional</i> vertices that the segs use. Unlike normal
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nodes, extra vertices are not added to the VERTEXES lump. When determining
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which vertex <i>v</i> a seg uses, if <i>v</i> < <i>OrgVerts</i>, then <i>v</i> is
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a vertex in the VERTEXES lump. Otherwise, when <i>v</i> >= <i>OrgVerts</i>, <i>v</i>
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- <i>OrgVerts</i> is the index of a vertex stored here.</p>
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<p>Like version 2 GL nodes, the vertices stored here are represented as 16.16 fixed
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point numbers in order to maintain the full precision of the Doom engine.</p>
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<h2>Subsector information</h2>
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<table>
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<tr>
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<td>DWORD</td>
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<td><i>NumSubsectors</i></td>
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<td>Number of subsectors</td>
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</tr>
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<tr>
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<td colspan="3" bgcolor="#dddddd">Repeat <i>NumSubsectors</i> times:</td>
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</tr>
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<tr>
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<td>DWORD</td>
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<td>NumSegs</td>
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<td>Number of segs for this subsector</td>
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</tr>
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</table>
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<p>Unlike normal nodes, the first seg in each subsector is not stored. This can be
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inferred by the ordering of the subsectors. The first subsector always starts
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at seg 0, and each following subsector begins with the seg immediately after
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the previous subsector's last seg.</p>
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<h2>Segs information</h2>
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<p>The specific layout for this section depends on whether the data stream
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represents normal nodes or GL nodes. In each case, the segs are stored in an 11
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byte structure, but their contents differ slightly. <i>There is no padding to make
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these align to DWORD boundaries.</i>
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</p>
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<h3>Normal nodes ('ZNOD' signature)</h3>
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<table>
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<tr>
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<td>DWORD</td>
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<td><i>NumSegs</i></td>
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<td>Number of segs</td>
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</tr>
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<tr>
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<td colspan="3" bgcolor="#dddddd">Repeat <i>NumSegs</i> times:</td>
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</tr>
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<tr>
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<td>DWORD</td>
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<td><i>v1</i></td>
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|
<td>Seg's first vertex</td>
|
|
</tr>
|
|
<tr>
|
|
<td>DWORD</td>
|
|
<td><i>v2</i></td>
|
|
<td>Seg's second vertex</td>
|
|
</tr>
|
|
<tr>
|
|
<td>WORD</td>
|
|
<td><i>line</i></td>
|
|
<td>The linedef this seg came from</td>
|
|
</tr>
|
|
<tr>
|
|
<td>BYTE</td>
|
|
<td><i>side</i></td>
|
|
<td>The linedef's side this seg came from (0=front, 1=back)</td>
|
|
</tr>
|
|
</table>
|
|
<p>Note that unlike uncompressed nodes, the seg's angle and offset are not
|
|
included. ZDoom does not need this information, and other ports that wish to
|
|
support compressed nodes can recompute them trivially.</p>
|
|
<h3>GL nodes ('ZGLN' signature)</h3>
|
|
<table>
|
|
<tr>
|
|
<td>DWORD</td>
|
|
<td><i>NumSegs</i></td>
|
|
<td>Number of segs</td>
|
|
</tr>
|
|
<tr>
|
|
<td colspan="3" bgcolor="#dddddd">Repeat <i>NumSegs</i> times:</td>
|
|
</tr>
|
|
<tr>
|
|
<td>DWORD</td>
|
|
<td><i>v1</i></td>
|
|
<td>Seg's first vertex</td>
|
|
</tr>
|
|
<tr>
|
|
<td>DWORD</td>
|
|
<td><i>partner</i></td>
|
|
<td>Seg's partner seg (0xFFFFFFFF if none)</td>
|
|
</tr>
|
|
<tr>
|
|
<td>WORD</td>
|
|
<td><i>line</i></td>
|
|
<td>The linedef this seg came from (0xFFFF if none)</td>
|
|
</tr>
|
|
<tr>
|
|
<td>BYTE</td>
|
|
<td><i>side</i></td>
|
|
<td>The linedef's side this seg came from (0=front, 1=back) (ignored if no line)</td>
|
|
</tr>
|
|
</table>
|
|
<h3>GL nodes ('ZGL2' and 'ZGL3' signature)</h3>
|
|
<table>
|
|
<tr>
|
|
<td>DWORD</td>
|
|
<td><i>NumSegs</i></td>
|
|
<td>Number of segs</td>
|
|
</tr>
|
|
<tr>
|
|
<td bgcolor="#dddddd" colspan="3">Repeat <i>NumSegs</i> times:</td>
|
|
</tr>
|
|
<tr>
|
|
<td>DWORD</td>
|
|
<td><i>v1</i></td>
|
|
<td>Seg's first vertex</td>
|
|
</tr>
|
|
<tr>
|
|
<td>DWORD</td>
|
|
<td><i>partner</i></td>
|
|
<td>Seg's partner seg (0xFFFFFFFF if none)</td>
|
|
</tr>
|
|
<tr>
|
|
<td>DWORD</td>
|
|
<td><i>line</i></td>
|
|
<td>The linedef this seg came from (0xFFFFFFFF if none)</td>
|
|
</tr>
|
|
<tr>
|
|
<td>BYTE</td>
|
|
<td><i>side</i></td>
|
|
<td>The linedef's side this seg came from (0=front, 1=back) (ignored if no line)</td>
|
|
</tr>
|
|
</table>
|
|
<p>Unlike standard GL nodes, each seg's second vertex is not stored. This is
|
|
because GL subsectors must form a closed area. In other words, one seg's second
|
|
vertex is the same as the next seg's first vertex. The subsector information
|
|
contains everything you need to know to close each area and start a new one.</p>
|
|
<p>Example: Suppose you have not read any segs yet, and the first subsector has
|
|
four segs. Therefore, the second vertex for the first four segs can be
|
|
determined to be:</p>
|
|
<blockquote><table>
|
|
<tr>
|
|
<td>Seg 0</td>
|
|
<td>Second vertex is Seg 1's first vertex</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Seg 1</td>
|
|
<td>Second vertex is Seg 2's first vertex</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Seg 2</td>
|
|
<td>Second vertex is Seg 3's first vertex</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Seg 3</td>
|
|
<td>Second vertex is Seg 0's first vertex (because this is the last seg in the
|
|
subsector)</td>
|
|
</tr>
|
|
</table>
|
|
</blockquote>
|
|
<p>So for each subsector, all but the last seg's second vertex will be the same as
|
|
the next seg's first vertex. The last seg's second vertex will be the same as
|
|
the first seg's first vertex.</p>
|
|
<h2>Node information</h2>
|
|
<p>Only 'ZGL3' nodes structure this differently from standard nodes.</p>
|
|
<h3>All nodes formats except 'ZGL3'</h3>
|
|
<table>
|
|
<tr>
|
|
<td>DWORD</td>
|
|
<td><i>NumNodes</i></td>
|
|
<td>Number of nodes</td>
|
|
</tr>
|
|
<tr>
|
|
<td colspan="3" bgcolor="#dddddd">Repeat <i>NumNodes</i> times:</td>
|
|
</tr>
|
|
<tr>
|
|
<td>4 SWORDs</td>
|
|
<td><i>X</i>, <i>Y</i>, <i>dX</i>, <i>dY</i></td>
|
|
<td>Splitter for this node</td>
|
|
</tr>
|
|
<tr>
|
|
<td>4 SWORDs</td>
|
|
<td><i>Top</i>, <i>Bottom</i>, <i>Left</i>, <i>Right</i></td>
|
|
<td>Bounding box for <i>Child0</i></td>
|
|
</tr>
|
|
<tr>
|
|
<td>4 SWORDs</td>
|
|
<td><i>Top</i>, <i>Bottom</i>, <i>Left</i>, <i>Right</i></td>
|
|
<td>Bounding box for <i>Child1</i></td>
|
|
</tr>
|
|
<tr>
|
|
<td>2 DWORDs</td>
|
|
<td><i>Child0</i>, <i>Child1</i></td>
|
|
<td>References to child nodes or subsectors</td>
|
|
</tr>
|
|
</table>
|
|
<h3>Nodes with 'ZGL3' signature</h3>
|
|
<table>
|
|
<tr>
|
|
<td>DWORD</td>
|
|
<td><i>NumNodes</i></td>
|
|
<td>Number of nodes</td>
|
|
</tr>
|
|
<tr>
|
|
<td colspan="3" bgcolor="#dddddd">Repeat <i>NumNodes</i> times:</td>
|
|
</tr>
|
|
<tr>
|
|
<td>4 FIXEDs</td>
|
|
<td><i>X</i>, <i>Y</i>, <i>dX</i>, <i>dY</i></td>
|
|
<td>Splitter for this node</td>
|
|
</tr>
|
|
<tr>
|
|
<td>4 SWORDs</td>
|
|
<td><i>Top</i>, <i>Bottom</i>, <i>Left</i>, <i>Right</i></td>
|
|
<td>Bounding box for <i>Child0</i></td>
|
|
</tr>
|
|
<tr>
|
|
<td>4 SWORDs</td>
|
|
<td><i>Top</i>, <i>Bottom</i>, <i>Left</i>, <i>Right</i></td>
|
|
<td>Bounding box for <i>Child1</i></td>
|
|
</tr>
|
|
<tr>
|
|
<td>2 DWORDs</td>
|
|
<td><i>Child0</i>, <i>Child1</i></td>
|
|
<td>References to child nodes or subsectors</td>
|
|
</tr>
|
|
</table>
|
|
<p>As with standard nodes, a child's high bit is set to indicate that it is a
|
|
subsector and cleared to indicate that it is another node. Just remember that
|
|
the child references are stored using four bytes each instead of two.</p>
|
|
<h2>Compressed node storage</h2>
|
|
<p>Normal nodes (signature 'ZNOD') are stored in a map's NODES lump. Bear in mind
|
|
that compressed nodes are contained entirely within a single lump rather than
|
|
in three separate lumps.</p>
|
|
<p>GL nodes (signature 'ZGLN') are stored in a map's SSECTORS lump. Unlike regular
|
|
GL nodes, no new lumps are created for compressed GL nodes.</p>
|
|
<p>The SEGS lump is left unused and should be written with a length of 0. I may
|
|
find some way to "hijack" this lump in the future, so programs that read
|
|
compressed nodes must not assume that if the SEGS lump is non-empty, then
|
|
compressed nodes are not used.</p>
|
|
<p>For UDMF maps, nodes a stored in the map's ZNODES lump. These will only be
|
|
'ZGLN' or 'ZGL2' format nodes. Non-GL nodes are not supported for UDMF.</p>
|
|
<h2>Extended nodes</h2>
|
|
<p>For the benefit of ports not wishing to support zlib decompression of nodes,
|
|
there are variants of the compressed node formats without compression. These
|
|
are referred to extended nodes, and differ only from their compressed counterparts
|
|
in that their contents are not compressed. They use a different signature to
|
|
distinguish them from compressed nodes:</p>
|
|
<ul><li>ZNOD -> XNOD</li>
|
|
<li>ZGLN -> XGLN</li>
|
|
<li>ZGL2 -> XGL2</li>
|
|
<li>ZGL3 -> XGL3</li></ul>
|
|
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|
|
</HTML>
|