====
qbsp
====

qbsp - Compile a Quake BSP file from a MAP source file

Synopsis
--------

**qbsp** [OPTION]... SOURCFILE [DESTFILE]

Description
-----------

:program:`qbsp` is a tool used in the creation of maps for the **id Software**
game **Quake**. qbsp takes a .map file as input and produces a .bsp file
playable in the Quake engine. If the ``DESTFILE`` argument is not
supplied, the output filename will be chosen by stripping the file
extension (if any) from ``SOURCEFILE`` and appending the .bsp extension.

Options
-------

.. program:: qbsp

.. option:: -nofill

   Doesn't perform outside filling

.. option:: -filltype auto | inside | outside

   Whether to fill the map from the outside in (lenient), from the inside out
   (aggressive), or to automatically decide based on the hull being used.

.. option:: -filldetail [n]

   Whether to fill enclosed pockets of empty space surrounded by solid detail. Default is 1 (enabled).

.. option:: -nomerge

   Don't perform face merging.

.. option:: -noedgereuse

   Don't reuse edges (may be useful for debugging software rendering).

.. option:: -noclip

   Doesn't build clip hulls (only applicable for Q1-like BSP formats).

.. option:: -noskip

   Doesn't remove faces using the :texture:`skip` texture

.. option:: -nodetail

   Treat all detail brushes as structural.

.. option:: -onlyents

   Only updates .map entities

.. option:: -verbose
            -v

   Print out more .map information.

   Note, this switch no longer implies :option:`-loghulls`; use that if you want to see
   statistics for collision hulls.

.. option:: -loghulls

   Print log output for collision hulls.

.. option:: -logbmodels

   Print log output for bmodels.

.. option:: -quiet
            -noverbose

   Suppress non-important messages (equivalent to :option:`-nopercent` :option:`-nostat` :option:`-noprogress`).

.. option:: -log

   Write log files. Enabled by default.

.. option:: -nolog

   Don't write log files.

.. option:: -chop

   Adjust brushes to remove intersections if possible. Enabled by default.

.. option:: -nochop

   Do not chop intersecting brushes.

.. option:: -chopfragment

   Always do full fragmentation for chop.

.. option:: -splitsky

   Doesn't combine sky faces into one large face.

.. option:: -splitspecial
   
   Doesn't combine sky and water faces into one large face. This allows
   for statically lit water.

.. option:: -litwater
            -splitturb

   Enable lit liquids. This allows for statically lit water in compatible source ports,
   which still works but renders as fullbright on non-supporting source ports.
   The only downside is that water faces will be split up more, as per :option:`-subdivide`.
   Enabled by default.

.. option:: -transwater

   In Q1 mode, compiles maps for transparent water (lets vis see through liquids). Enabled by default.
   Has no effect in Q2 mode, because this is controlled by the mapper in Q2.

.. option:: -notranswater

   Computes portal information for opaque water

.. option:: -oldaxis

   Use the original QBSP texture alignment algorithm. Enabled by default.

.. option:: -nooldaxis

   Use alternate texture alignment algorithm. The default is to use the
   original QBSP texture alignment algorithm, which required the
   :option:`-oldaxis` switch in tyrutils-ericw v0.15.1 and earlier.

.. option:: -forcegoodtree

   Force use of expensive processing for SolidBSP stage. Often results
   in a more optimal BSP file in terms of file size, at the expense of
   extra processing time.

.. option:: -leaktest

   Makes it a compile error if a leak is detected.

.. option:: -nopercent

   Prevents output of percent completion information

.. option:: -nostat

   Don't output statistic messages.

.. option:: -noprogress

   Don't output progress messages.

.. option:: -nocolor

   Don't output ANSI color codes (in case the terminal doesn't recognize colors, e.g. TB).

.. option:: -q2bsp

   Target Quake II and the vanilla Q2BSP format, automatically switching to Qbism format
   if necessary (unless :option:`-noallowupgrade` is specified.)

.. option:: -qbism

   Target Quake II and use Qbism's extended Quake II BSP format.

.. option:: -q2rtx

   Adjust settings to best support Q2RTX.

.. option:: -hexen2

   Generate a hexen2 bsp. This can be used in addition to :option:`-bsp2` to avoid
   clipnode issues.

.. option:: -bsp2

   Create the output BSP file in BSP2 format. Allows the creation of
   much larger and more complex maps than the original BSP 29 format).

.. option:: -2psb

   Create the output BSP file in 2PSB format. This an earlier version of
   the BSP2 format, supported by the RMQ engine (and thus is also known
   as the BSP2rmq or RMQe bsp format).

   .. deprecated:: 1.0
      Use :option:`-bsp2` instead.

.. option:: -allowupgrade

   Allow formats to "upgrade" to compatible extended formats when a limit is
   exceeded (e.g. Quake BSP to BSP2, or Quake 2 BSP to Qbism BSP). Enabled by default.

.. option:: -noallowupgrade

   Opt out of :option:`-allowupgrade`.

.. option:: -hlbsp

   Create the output BSP file in Half-Life's format. Note that the hull
   size differences prevent this from being generally usable for the
   vanilla quake gamecode. This cannot be used in combination with the
   :option:`-bsp2` argument.

.. option:: -add [mapfile]

   The given map file will be appended to the base map.

.. option:: -leakdist [n]

   Space between leakfile points (default 0, which does not write any inbetween points)

.. option:: -subdivide [n]

   Use different texture subdivision (default 240). Lower values will
   harm framerates. Higher values may not be supported. DP+FTEQW+QSS
   support up to 4080 (unless lightmap scaling is in use), but such
   values will cause other engines to crash-to-console. Use zero to
   specify no subdivision.

.. option:: -nosubdivide

   Disable subdivision. Requires a compatible source port. See also :option:`-subdivide`.

.. option:: -lmscale n

   Change global lmscale (force :bmodel-key:`_lmscale` key on all entities).
   Outputs the LMSCALE BSPX lump.

.. option:: -software

   Change settings to allow for (or make adjustments to optimize for the lack of) software support.

.. option:: -nosoftware

   Explicitly drop support for software renderers.

.. option:: -wadpath <dir>

   Search this directory for wad files (default is cwd). Multiple
   :option:`-wadpath` args may be used. This argument is ignored for wads
   specified using an absolute path.

.. option:: -xwadpath <dir>

   Like :option:`-wadpath`, except textures found using the specified path will
   NOT be embedded into the bsp (equivelent to :option:`-notex`, but for only
   textures from specific wads). You should use this for wads like
   halflife's standard wad files, but q1bsps require an engine extension
   and players are not nearly as likely to have the same wad version.

.. option:: -path "/path/to/folder" <multiple allowed>

   Additional paths or archives to add to the search path, mostly for loose files.

.. option:: -defaultpaths

   Whether the compiler should attempt to automatically derive game/base paths for
   games that support it. Enabled by default.

.. option:: -nodefaultpaths

   Opt out of :option:`-defaultpaths`.

.. option:: -oldrottex

   Use old method of texturing rotate\_ brushes where the mapper aligns
   textures for the object at (0 0 0).

.. option:: -midsplitsurffraction n

   If 0 (default), use :option:`-maxnodesize` for deciding when to switch to midsplit bsp heuristic.

   If 0 < midsplitSurfFraction <= 1, switch to midsplit if the node contains more than this
   fraction of the model's total surfaces. Try 0.15 to 0.5. Works better than maxNodeSize for
   maps with a 3D skybox (e.g. +-128K unit maps)

.. option:: -midsplitbrushfraction n

   Switch to cheaper BSP partitioning test if a node contains this % of brushes in the map.

.. option:: -maxnodesize [n]

   Switch to the cheap spatial subdivion bsp heuristic when splitting
   nodes of this size (in any dimension). This gives much faster qbsp
   processing times on large maps and should generate better bsp trees
   as well. From txqbsp-xt, thanks rebb. (default 1024, 0 to disable)

.. option:: -wrbrushes
            -bspx

   Includes a list of brushes for brush-based collision. This
   allows for arbitrary collision sizes in engines that support it,
   currently only FTEQW.

.. option:: -wrbrushesonly
            -bspxonly

   :option:`-wrbrushes` combined with :option:`-noclip` argument. This is NOT backwards
   compatible.

.. option:: -bmodelcontents

   Allow bmodels to have contents other than "solid" in Q1 based games,
   e.g. water in a func_door. This is supported in FTEQW; in winquake,
   the bmodel will have no collision.

   Q2 supports this feature natively and this option has no effect.

.. option:: -notriggermodels

   For supported game code only: triggers will not write a model out,
   and will instead just write out their mins/maxs.

.. option:: -notex

   Write only placeholder textures, to depend upon replacements. This
   avoids inclusion of third-party copyrighted images inside your maps,
   but is not backwards compatible but will work in FTEQW and QSS.

   Note that the textures still need to be available to qbsp.

   Technical details: ``LUMP_TEXTURES`` is still written, but each texture
   within is the ``dmiptex_t`` header only (with no texture data following),
   with ``offsets`` all set to 0.

   This only has effect in Q1 family games.

.. option:: -missing_textures_as_zero_size

   Writes missing textures (i.e. ones that qbsp can't find) as 0x0 placeholders.

   This is not backwards compatible and will produce .bsp's that crash
   unsupporting engines. However, it can be useful when you want to run
   qbsp + light on a map that you are missing the corresponding .wad for.

   This only has effect in Q1 family games.

.. option:: -notjunc

   Alias for :option:`-tjunc none`

.. option:: -tjunc mwt | none | retopologize | rotate

   T-junction fix level:

   none
      Don't attempt to fix T-junctions. This is only for engines or formats
      that prefer micro-cracks over degenerate triangles. If you don't know
      what that means, don't set this.

   rotate
      Allow faces' vertices to be rotated to prevent zero-area triangles.

   retopologize
      If a face still has zero-area triangles, allow it to be re-topologized
      by splitting it into multiple fans.

   mwt
      Attempt to triangulate faces (along with their T-junction fixes)
      using a `MWT <https://en.wikipedia.org/wiki/Minimum-weight_triangulation>`_
      first, only falling back to the prior two steps if it fails.


.. option:: -noextendedsurfflags

   Don't write .texinfo file, even if it would normally be needed (debug)

.. option:: -omitdetail

   Detail brushes are omitted from the compile.

.. option:: -omitdetailwall

   :classname:`func_detail_wall` brushes are omitted from the compile.

.. option:: -omitdetailillusionary

   :classname:`func_detail_illusionary` brushes are omitted from the compile.

.. option:: -omitdetailfence

   :classname:`func_detail_fence` brushes are omitted from the compile.

.. option:: -convert <fmt>

   Convert a .MAP to a different .MAP format. fmt can be:

   quake
      Q1 vanilla map format.

   quake2
      Q2 vanilla map format.

   valve
      Valve 220 map format.

   bp
      Brush Primitives format.

   Conversions to "quake" or "quake2"
   format may not be able to match the texture alignment in the source
   map, other conversions are lossless. The converted map is saved to
   <source map name>-<fmt>.map.

.. option:: -includeskip

   Emit skip/nodraw faces (default is to discard them). Mainly for Q2RTX.

.. option:: -threads n

   Set number of threads to use. By default, qbsp will attempt to
   use all available hardware threads.

.. option:: -lowpriority

   Run in a lower priority, to free up headroom for other processes. Enabled by default.

.. option:: -aliasdef <aliases.def> [...]

   Adds alias definition files, which can transform entities in the .map into other entities.

   For example, given this alias definition file:

   .. code-block:: none
      :caption: aliases.def

      misc_torch1 // source classname
      {
      "classname" "misc_model" // classname to transform into
      "model" "torch1.mdl"
      }

      misc_torch2
      {
      "classname" "misc_model"
      "model" "torch2.mdl"
      }

   and an input map file:

   .. code-block:: none

      {
      "classname" "misc_torch1"
      "model" "override.mdl"
      }

      {
      "classname" "misc_torch2"
      }

   the following will be output in the .bsp's entity lump:

   .. code-block:: none

      {
      "classname" "misc_model"
      "model" "override.mdl" // key/value from map takes precedence
      }

      {
      "classname" "misc_model"
      "model" "torch2.mdl" // key/value from alias file
      }

.. option:: -texturedefs "path/to/file.def" <multiple allowed>

   Path to a texture definition file, which can transform textures in the .map into other textures.

.. option:: -epsilon n

   Customize epsilon value for point-on-plane checks.

.. option:: -microvolume n

   Microbrush volume.

.. option:: -outsidedebug

   Write a .map after outside filling showing non-visible brush sides.

.. option:: -debugchop

   Write a .map after ChopBrushes.

.. option:: -debugleak

   Write more diagnostic files for debugging leaks.

.. option:: -debugbspbrushes

   Save bsp brushes after BrushBSP to a .map, for visualizing BSP splits.

.. option:: -debugleafvolumes

   Save bsp leaf volumes after BrushBSP to a .map, for visualizing BSP splits.

.. option:: -debugexpand [single hull index] or [mins_x mins_y mins_z maxs_x maxs_y maxs_z]

   Write expanded hull .map for debugging/inspecting hulls/brush bevelling.

.. option:: -keepprt

   Avoid deleting the .prt file on leaking maps.

.. option:: -maxedges n

   The max number of edges/vertices on a single face before it is split into another face. 0 means unlimited.

   Default is 0 for Q2, and 64 for Q1.

.. option:: -worldextent n

   Explicitly provide world extents; 0 will auto-detect. Default 0.

.. option:: -forceprt1

   Force a PRT1 output file even if PRT2 is required for vis.

.. option:: -objexport

   Export the map file as .OBJ models during various compilation phases.


Game Path Specification
-----------------------

To compile a Q2 map, the compilers usually need to be able to locate an installation of the game. e.g. the .map might reference a texture name like ``e1u1/clip``, but qbsp needs to open the corresponding .wal file to look up the content/surface flags (playerclip, etc.) which are then written to the .bsp.

We use the terminology:

basedir
  The directory containing the base game (e.g. ``id1`` or ``baseq2``). Can be an absolute path, e.g. ``c:/quake2/baseq2`` or ``c:/quake/id1``.

gamedir
  Optional mod directory, e.g. ``ad`` or ``c:/quake/ad``. If a gamedir is specified it will be added to the search path at a higher priority than the basedir.

The common cases are:

- place your .map in ``<quake2>/baseq2/maps`` and compile it there, qbsp will auto detect the basedir/gamedir.
- for compiling a .map located elsewhere, use e.g.:

  .. code::

     qbsp -basedir "c:/quake2/baseq2" input.map

  or

  .. code::

     qbsp -basedir "c:/quake2/baseq2" -gamedir mymod input.map

.. option:: -gamedir "relative/path" or "C:/absolute/path"

   Override the default mod base directory. if this is not set, or if it is relative, it will be derived from
   the input file or the basedir if specified.

.. option:: -basedir "relative/path" or "C:/absolute/path"

   Override the default game base directory. if this is not set, or if it is relative, it will be derived
   from the input file or the gamedir if specified.

.. option:: -filepriority archive | loose

   Which types of archives (folders/loose files or packed archives) are higher priority and chosen first
   for path searching.

Special Texture Names
---------------------

The contents inside a brush depend on the texture name(s) assigned to
it.

By default brush contents are solid unless they have a special name.
All faces of a brush must have textures which indicate the same
contents. Mixed content types will cause qbsp to print an error and
exit.

.. texture:: *slime
             *lava
             *

   In all Q1-like games, names beginning with an asterisk are liquids. A prefix of ``*slime``
   indicates slime, ``*lava`` is for lava, and anything else beginning with
   ``*`` will have contents as water.

.. texture:: skip

   Any surfaces assigned a texture name of *skip* will be compiled into the
   bsp as invisible surfaces. Solid surfaces will still be solid (e.g. the
   play can't walk or shoot through them) but they will not be drawn.
   Water, slime and lava surfaces can be made invisible using the texture
   names *\*waterskip*, *\*slimeskip* and *\*lavaskip* respectively.

.. texture:: hint

   Hint surfaces cause a bsp split and portal to be generated the on the
   surface plane, after which they are removed from the final bsp - they
   are neither visible, nor structural. Strategic placement of hint
   surfaces can be used by a map author to optimise the PVS calculations so
   as to limit overdraw by the engine (see also: **vis**\ (1)).

   Use a texture with the name *hintskip* on any surfaces of a hint brush
   which you don't want to generate bsp splits or portals. All surfaces of
   a hint brush must use either the *hint* or *hintskip* texture name.

.. texture:: origin

   An origin brush (all faces textured with "origin") can be added to a
   brush entity (but not detail or compiler-internal entities like
   func_group). Doing so causes all of the brushes in the brush entitiy to
   be translated so the center of the origin brush lines up with 0 0 0. The
   entity key "origin" is then automatically set on the brush entity to the
   original cooridnates of the center of the "origin" brush before it was
   translated to 0 0 0.

   In Hexen 2, origin brushes are the native way of marking the center
   point of the rotation axis for rotating entities.

   In Quake, origin brushes can be used to make some map hacks easier to
   set up that would otherwise require placing brushes at the world origin
   and entering an "origin" value by hand.

   Note that, unlike the Hipnotic rotation support in QBSP, using origin
   brushes does not cause the model bounds to be expanded. (With Hipnotic
   rotation this was to ensure that the model is not vis culled, regardless
   of its rotated angle.) Origin brushes are useful for more than just
   rotation, and doing this bounds expansion would break some use cases, so
   if you're going to rotate a model with an origin brush you might need to
   expand the bounds of it a bit using clip brushes so it doesn't get vis
   culled.

Half-Life BSP Specific
^^^^^^^^^^^^^^^^^^^^^^

If :option:`-hlbsp` is in use, the following exta texture prefixes are recognized:

.. texture:: !slime
             !lava
             !

   These act the same as names beginning with ``*`` and create liquids.

.. texture:: !cur_0
             !cur_90
             !cur_180
             !cur_270
             !cur_up
             !cur_dwn

   These prefixes generate water with the given current direction:

   ===================== =====
   Content type          Value
   ===================== =====
   CONTENTS_CURRENT_0    -9
   CONTENTS_CURRENT_90   -10
   CONTENTS_CURRENT_180  -11
   CONTENTS_CURRENT_270  -12
   CONTENTS_CURRENT_UP   -13
   CONTENTS_CURRENT_DOWN -14
   ===================== =====

   During the BSP process, they act like water with extra modifier flags.

   .. note::

      Different from the vanilla HL compiler, we don't generate faces between different ``CONTENTS_CURRENT_*`` textured
      volumes.

External Map Prefab Support
---------------------------

This qbsp has a prefab system using a point entity named
"misc_external_map". The idea is, each "misc_external_map" imports
brushes from an external .map file, applies rotations specified by the
"_external_map_angles" key, then translates them to the "origin" key of
the "misc_external_map" entity. Finally, the classname of the
"misc_external_map" is switched to the one provided by the mapper in the
"_external_map_classname" key. (The "origin" key is also cleared to "0 0
0" before saving the .bsp).

The external .map file should consist of worldspawn brushes only,
although you can use func_group for editing convenience. Brush entities
are merged with the worldspawn brushes during import. All worldspawn
keys, and any point entities are ignored. Currently, this means that the
"wad" key is not handled, so you need to add any texture wads required
by the external .map file to your main map.

Note that you can set other entity keys on the "misc_external_map" to
configure the final entity type. e.g. if you set
"_external_map_classname" to "func_door", you can also set a
"targetname" key on the "misc_external_map", or any other keys for
"func_door".

.. other-key:: _external_map
   
   Specifies the filename of the .map to import.

.. other-key:: _external_map_classname
   
   What entity you want the external map to turn in to. You can use
   internal qbsp entity types such as :classname:`func_detail`, or a regular bmodel
   classname like "func_wall" or "func_door".

.. other-key:: _external_map_angles

   Rotation for the prefab, "pitch yaw roll" format. Assuming the
   exernal map is facing the +X axis, positive pitch is down. Yaw of
   180, for example, would rotate it to face -X.

.. other-key:: _external_map_angle

   Short version of :other-key:`_external_map_angles` for when you want to specify
   just a yaw rotation.

.. other-key:: _external_map_scale

   Scale factor for the prefab, defaults to 1. Either specify a single
   value or three scales, "x y z".

Detail Brush Support
--------------------

This version of qbsp supports detail brushes which are similar in
concept to Quake 2's detail brushes. They don't seal the map (previous
versions did).

To be compatible with existing Quake 1 mapping tools, detail brushes can
be added by creating an entity with classname "func_detail". When qbsp
reads the map file, it will add any brushes included in a func_detail
entity into the worldspawn as details and remove the func_detail entity.
Any number of func_detail entities can be used (useful for grouping) and
all included brushes will be added to the worldspawn.

Here is an example entity definition suitable to add the the .QC files
used by BSP Editor:

::

       /*QUAKED func_detail (0.5 0.5 0.9) ?
       Detail brushes add visual details to
       the world, but do not block visibility.
       func_detail entities are merged into
       the worldspawn entity by the qbsp compiler
       and do not appear as separate entities in
       the compiled bsp.
       */

For WorldCraft in .FGD format (untested):

::

       @SolidClass color(128 128 230) = func_detail: "Detail" []

For Radiant in .ENT format:

::

       <group name="func_detail" color="0 .5 .8">
       Detail brushes add visual details to the world, but do not
       block visibility. func_detail entities are merged into the
       worldspawn entity by the qbsp compiler and do not appear as
       separate entities in the compiled bsp.
       </group>

What should be written to the .map file is a simple entity with one or
more brushes. E.g.:

::

       {
       "classname" "func_detail"
       {
       ( -176  80  0 ) ( -208  80  0 ) ( -208  48  0 ) COP1_1 0 0 0 1.0 1.0
       ( -192 -80 64 ) ( -208 -80  0 ) ( -192 -64 64 ) COP1_1 0 0 0 1.0 1.0
       ( -176 -80  0 ) ( -192 -80 64 ) ( -176 -64  0 ) COP1_1 0 0 0 1.0 1.0
       ( -16   48  0 ) (  -16  64 64 ) (    0  48  0 ) COP1_1 0 0 0 1.0 1.0
       ( -16   64 64 ) (  -16  80  0 ) (    0  64 64 ) COP1_1 0 0 0 1.0 1.0
       }
       }

When qbsp detects detail brushes, it outputs a modified portal file
format with the header PRT2 (default is PRT1). This portal file contains
extra information needed by vis to compute the potentially visible set
(PVS) for the map/bsp. So you will also need a vis util capable of
processing the PRT2 file format.

Compiler-internal bmodels
-------------------------

.. classname:: func_group

   Bmodel that has no effect; qbsp moves the brushes back into the worldspawn entity.

   The usefulness comes from the ability to set :ref:`model-entity-keys` on the brushes inside the func_group.

.. classname:: func_detail

   Solid detail. Can't be seen inside, splits world faces. Doesn't seal map.

.. classname:: func_detail_illusionary

   func_detail variant with no collision (players / monsters / gunfire) and
   doesn't split world faces. Doesn't cast shadows unless enabled with
   :bmodel-key:`_shadow` "1". Useful for hanging vines. Still creates BSP leafs, which
   is unavoidable without a new .bsp file format.

   Intersecting func_detail_illusionary brushes don't clip each other; this
   is intended to make trees/shrubs/foliage easier with :bmodel-key:`_mirrorinside` "1".

.. classname:: func_detail_wall

   func_detail variant that doesn't split world faces. Useful for when you
   want a decoration touching a floor or wall to not split the floor/wall
   faces (you'll get some overdraw instead.) If it completely covers up a
   world face, that face will get clipped away, so it's not suitable for
   fence textures; see func_detail_fence instead.

   Intersecting func_detail_wall brushes don't clip each other.

.. classname:: func_detail_fence

   Similar to :classname:`func_detail_wall` except it's suitable for fence textures,
   never clips away world faces. Useful for fences, grates, etc., that are
   solid and block gunfire.

   Intersecting func_detail_fence brushes don't clip each other.


.. _model-entity-keys:

Model Entity Keys
-----------------

.. bmodel-key:: "_lmscale" "n"

   Generates an LMSHIFT bspx lump for use by a light util. Note that
   both scaled and unscaled lighting will normally be used.

   .. todo:: This is broken since 2.0.0-alpha1

.. bmodel-key:: "_mirrorinside" "n"

   Set to 1 to save mirrored inside faces for bmodels, so when the
   player view is inside the bmodel, they will still see the faces.
   (e.g. for func_water, func_illusionary, :classname:`func_detail_illusionary`, :classname:`func_detail_fence`, etc.)

.. bmodel-key:: "_chop_order" "n"

   Override the order of brushes in the map file, which affects which face "wins" in the CSG phase when there are
   multiple overlapping coplanar brushes. Provided since most .map editors don't directly expose the brush order.

   All brushes are initially 0; setting this to 1 would make a brush appear after anything in the map file, and so
   clip away coplanar faces from other brushes.

   For example, you could make a :classname:`func_group` with "_chop_order" "1", and apply it to a light fixture
   which is coplanar with a floor or ceiling, to ensure the light fixture is visible in-game, without going to the
   trouble of cutting a hole in the floor/ceiling for it.

.. bmodel-key:: "_hulls" "n"

   Bitmap ("Flags" type in FGD) that selects for which hulls collision data
   will be generated. eg. a decimal value of 11 (0b1011) would generate hull 0, hull 1,
   and hull 3.
   Faces are computed using data from hull 0, not generating this hull will
   prevent a bmodel from being rendered, acting as a CLIP brush only active for
   the specified hulls.

   Defaults to 0 which will generate clipnodes for all hulls.

.. bmodel-key:: "_chop" "n"

   Set to 0 to prevent these brushes from being chopped; this is an alias for setting :bmodel-key:`_chop_order` to 1.

   .. deprecated:: 2.0.0
      Prefer the more flexible :bmodel-key:`_chop_order` instead.

.. bmodel-key:: "_noclipfaces" "n"

   Set to 1 to suppress the usual qbsp behaviour where two touching brushes of the same content type will have the
   touching portion clipped away.

   This is useful for things that can be seen inside, such as :classname:`func_detail_illusionary`,
   :classname:`func_detail_fence`, liquids, bmodels, etc.

   Behaviour is unspecified for coplanar faces; in 0.18 it caused z-fighting, and in 2.0.0-alpha it doesn't currently.


Other Special-Purpose Entities
------------------------------

.. classname:: func_illusionary_visblocker

   For creating vis-blocking illusionary brushes (similar to
   :classname:`func_detail_illusionary` or "func_illusionary". The player can walk
   through them.) This gives the same effect as water brushes when the
   :option:`-notranswater` flag is used, except the interior of these brushes are
   saved as CONTENTS_EMPTY. One thing to be aware of is, if the player's
   view is very close to the faces of these brushes, they might be able to
   see into the void (depending on the engine). Fitzquake family engines
   have a workaround for this that is enabled if the brushes are textured
   with a water texture ("*" prefix).

Map Compatibility
-----------------

In addition to standard Quake 1 .map files, ericw-tools QBSP is
compatible with:

-  Floating point brush coordinates and texture alignments

-  Valve's 220 map format as produced by the *Hammer* editor

-  Extended texture positioning as supported by the *QuArK* editor

-  Standard Quake 2 map format (leading paths in texture names are
   stripped and any extra surface properties are ignored)

-  Brush Primitives produce by Radiant editors (normally a Quake 3
   format)

Metadata formats
----------------

.wal_json
^^^^^^^^^

For Q2 mapping, .wal textures contain metadata specifying the texture's content flags, surface flags, and "value",
which are used if the mapper doesn't override them in the .map file. For example, a lava texture can default to
emitting light, having a lava content type, and having a surface warp effect.

The final values get baked into the .bsp and so game engine doesn't need the metadata for anything.

For increased flexibility, we support a JSON metadata format, which can override the .wal's metadata or provide
it when using image format like .tga instead of .wal.

To use a .wal_json file, place it in the same directory where the .wal would be, e.g.
``baseq2/textures/e1u1/water.wal_json`` would correspond to: ``baseq2/textures/e1u1/water.png``.

All of the values are optional.

.. code:: json

   {
       // valid instances of "contents"; either:
       // - a case-insensitive string containing the textual representation
       //   of the content type
       // - a number
       // - an array of the two above, which will be OR'd together
       "contents": [ "SOLID", 8 ],
       "contents": 24,
       "contents": "SOLID",

       // valid instances of "flags"; either:
       // - a case-insensitive string containing the textual representation
       //   of the surface flags
       // - a number
       // - an array of the two above, which will be OR'd together
       "flags": [ "SKY", 16 ],
       "flags": 24,
       "flags": "SKY",

       // "value" must be an integer
       "value": 1234,

       // "animation" must be the name of the next texture in
       // the chain.
       "animation": "e1u1/comp2",

       // width/height are allowed to be supplied in order to
       // have the editor treat the surface as if its dimensions
       // are these rather than the ones pulled in from the image
       // itself. they must be integers.
       "width": 64,
       "height": 64,

       // color to use for lighting bounces. if specified, this
       // is used instead of averaging the pixels of the image.
       "color": [255, 128, 64]
   }

Author
------

| Eric Wasylishen
| Kevin Shanahan (aka Tyrann) - http://disenchant.net
| Based on source provided by id Software and Greg Lewis

Reporting Bugs
--------------

| Please post bug reports at
  https://github.com/ericwa/ericw-tools/issues.
| Improvements to the documentation are welcome and encouraged.

Copyright
---------

| Copyright (C) 2017 Eric Wasylishen
| Copyright (C) 2013 Kevin Shanahan
| Copyright (C) 1997 Greg Lewis
| Copyright (C) 1997 id Software
| License GPLv2+: GNU GPL version 2 or later
| <http://gnu.org/licenses/gpl2.html>.

This is free software: you are free to change and redistribute it. There
is NO WARRANTY, to the extent permitted by law.
