# BOOM reference v1.3 6/19/98

    ======================================================================
                            Part I Linedef Types
    ======================================================================

    #######################
    Section 0. Terminology
    #######################

    In BOOM actions are caused to happen thru linedef types.
    BOOM has three kinds of linedef types:

    Regular     - the linedef types that were already in DOOM II v1.9

    Extended    - linedef types not in DOOM II v1.9 but less than 8192
                  in value

    Generalized - linedef types over 8192 in value that contain bit
                  fields that independently control the actions of the sector
                  affected.

    A linedef with non-zero linedef type is called a linedef trigger. A
    linedef trigger is always activated in one of three ways - pushing on
    the first sidedef of the linedef, walking over the linedef, or
    shooting the linedef with an impact weapon (fists, chainsaw, pistol,
    shotgun, double barreled, or chaingun).

    Linedefs activated by pushing on them come in two varieties. A manual
    linedef affects the sector on the second sidedef of the line pushed.
    A switched linedef affects all sectors that have the same tag field
    as the linedef that was pushed.

    Nearly all switched, walkover, and gun linedefs operate on the sectors
    with the same tag as that in the tag field of the linedef.

    Some linedefs are never activated per se, but simply create or control
    an effect thru their existence and properties, usually affecting the
    sectors sharing the linedef's tags. There are also a few special case
    like line-line teleporters and exit linedefs that do not affect
    sectors.

    Some linedefs are only triggerable once, others are triggerable as
    many times as you like.

    Triggering types are denoted by the letters P, S, W, and G for
    manual(push), switched, walkover, and gun. Their retriggerability is
    denoted by a 1 or R following the letter. So the triggering types for
    linedefs are:

    P1 PR S1 SR W1 WR G1 GR

    Often linedef actions depend on values in neighboring sectors. A
    neighboring sector is one that shares a linedef in common, just
    sharing a vertex is not sufficient.

    In DOOM only one action on a sector could occur at a time. BOOM
    supports one floor action, one ceiling action, and one lighting
    action simultaneously.

    ################
    Section 1. Doors
    ################

    A door is a sector, usually placed between two rooms, whose ceiling
    raises to open, and lowers to close.

    A door is fully closed when its ceiling height is equal to its floor
    height.

    A door is fully open when its ceiling height is 4 less than the lowest
    neighbor ceiling adjacent to it.

    A door may be set to an intermediate state initially, or thru the action
    of a linedef trigger that affects ceilings or floors. The door is passable
    to a player when its ceiling is at least 56 units higher than its floor.
    In general the door is passable to a monster or a thing when its ceiling
    is at least the monster or thing's height above the floor.

    If a door has a ceiling height ABOVE the fully open height, then an
    open door action moves the ceiling to the fully open height
    instantly.

    If a door has a ceiling height BELOW the fully closed height (that is
    the ceiling of the door sector is lower than the floor of the door
    sector) a close door action moves the ceiling to the fully closed
    height instantly.

    --------------------------
    Section 1.1 Door functions
    --------------------------

    Open, Wait, Then Close

    On activation, door opens fully, waits a specified period, then
    closes fully.

    Open and Stay Open

    On activation, door opens fully and remains there.

    Close and Stay Closed

    On activation, door closes fully, and remains there.

    Close, Wait, Then Open

    On activation, door closes fully, waits a specified period, then
    opens fully.

    ------------------------------
    Section 1.2 Varieties of doors
    ------------------------------

    A door can be triggered by pushing on it, walking over or pressing a
    linedef trigger tagged to it, or shooting a linedef tagged to it.
    These are called manual, walkover, switched, or gun doors resp.

    Since a push door (P1/PR) has no use for its tag, BOOM has extended
    the functionality to include changing any tagged sectors to maximum
    neighbor lighting on fully opening, then to minimum neighbor lighting
    on fully closing. This is true for regular, extended, and generalized
    doors with push triggers.

    A door trigger can be locked. This means that the door function will only
    operate if the player is in possession of the right key(s). Regular
    and extended door triggers only care if the player has a key of the
    right color, they do not care which. Generalized door triggers
    can distinguish between skull and card keys, and can also require
    any key, or all keys in order to activate.

    A door can have different speeds, slow, normal, fast or turbo.

    A door can wait for different amounts of time.

    A door may or may not be activatable by monsters.

    Any door function except Close and Stay Closed, when closing and
    encountering a monster or player's head will bounce harmlessly off
    that head and return to fully open. A Close and Stay Closed will rest
    on the head until it leaves the door sector.

    ------------------------------
    Section 1.3 Door linedef types
    ------------------------------

    Regular and Extended Door Types
    ---------------------------------------------------------------
    #        Class   Trig   Lock   Speed    Wait  Monst    Function

    1        Reg     PR     No     Slow     4s    Yes      Open, Wait, Then Close
    117      Reg     PR     No     Fast     4s    No       Open, Wait, Then Close
    63       Reg     SR     No     Slow     4s    No       Open, Wait, Then Close
    114      Reg     SR     No     Fast     4s    No       Open, Wait, Then Close
    29       Reg     S1     No     Slow     4s    No       Open, Wait, Then Close
    111      Reg     S1     No     Fast     4s    No       Open, Wait, Then Close
    90       Reg     WR     No     Slow     4s    No       Open, Wait, Then Close
    105      Reg     WR     No     Fast     4s    No       Open, Wait, Then Close
    4        Reg     W1     No     Slow     4s    No       Open, Wait, Then Close
    108      Reg     W1     No     Fast     4s    No       Open, Wait, Then Close

    31       Reg     P1     No     Slow     --    No       Open and Stay Open
    118      Reg     P1     No     Fast     --    No       Open and Stay Open
    61       Reg     SR     No     Slow     --    No       Open and Stay Open
    115      Reg     SR     No     Fast     --    No       Open and Stay Open
    103      Reg     S1     No     Slow     --    No       Open and Stay Open
    112      Reg     S1     No     Fast     --    No       Open and Stay Open
    86       Reg     WR     No     Slow     --    No       Open and Stay Open
    106      Reg     WR     No     Fast     --    No       Open and Stay Open
    2        Reg     W1     No     Slow     --    No       Open and Stay Open
    109      Reg     W1     No     Fast     --    No       Open and Stay Open
    46       Reg     GR     No     Slow     --    No       Open and Stay Open

    42       Reg     SR     No     Slow     --    No       Close and Stay Closed
    116      Reg     SR     No     Fast     --    No       Close and Stay Closed
    50       Reg     S1     No     Slow     --    No       Close and Stay Closed
    113      Reg     S1     No     Fast     --    No       Close and Stay Closed
    75       Reg     WR     No     Slow     --    No       Close and Stay Closed
    107      Reg     WR     No     Fast     --    No       Close and Stay Closed
    3        Reg     W1     No     Slow     --    No       Close and Stay Closed
    110      Reg     W1     No     Fast     --    No       Close and Stay Closed

    196      Ext     SR     No     Slow     30s   No       Close, Wait, Then Open
    175      Ext     S1     No     Slow     30s   No       Close, Wait, Then Open
    76       Reg     WR     No     Slow     30s   No       Close, Wait, Then Open
    16       Reg     W1     No     Slow     30s   No       Close, Wait, Then Open

    Regular and Extended Locked Door Types
    ---------------------------------------------------------------
    #        Class   Trig   Lock   Speed    Wait  Monst    Function

    26       Reg     PR     Blue   Slow     4s    No       Open, Wait, Then Close
    28       Reg     PR     Red    Slow     4s    No       Open, Wait, Then Close
    27       Reg     PR     Yell   Slow     4s    No       Open, Wait, Then Close

    32       Reg     P1     Blue   Slow     --    No       Open and Stay Open
    33       Reg     P1     Red    Slow     --    No       Open and Stay Open
    34       Reg     P1     Yell   Slow     --    No       Open and Stay Open
    99       Reg     SR     Blue   Fast     --    No       Open and Stay Open
    134      Reg     SR     Red    Fast     --    No       Open and Stay Open
    136      Reg     SR     Yell   Fast     --    No       Open and Stay Open
    133      Reg     S1     Blue   Fast     --    No       Open and Stay Open
    135      Reg     S1     Red    Fast     --    No       Open and Stay Open
    137      Reg     S1     Yell   Fast     --    No       Open and Stay Open

    There are two generalized door linedef types, Generalized Door, and
    Generalized Locked Door. The following tables show the possibilities
    for each parameter, any combination of parameters is allowed:

    Slow and Fast represent the same speeds as slow and fast regular doors. Normal
    is twice as fast as slow, Fast is twice normal, Turbo is twice Fast.

    Generalized Door Types
    ---------------------------------------------------------------
    #        Class   Trig   Lock   Speed    Wait  Monst    Function

    3C00H-   Gen     P1/PR  No     Slow     1s    Yes      Open, Wait, Then Close
    4000H            S1/SR         Normal   4s    No       Open and Stay Open
                     W1/WR         Fast     9s             Close and Stay Closed
                     G1/GR         Turbo    30s            Close, Wait, Then Open

    Generalized Locked Door Types
    ---------------------------------------------------------------
    #        Class   Trig   Lock   Speed    Wait  Monst    Function

    3800H-   Gen     P1/PR  Any    Slow     1s    No       Open, Wait, Then Close
    3C00H            S1/SR  Blue   Normal   4s             Open and Stay Open
                     W1/WR  Red    Fast     9s             Close and Stay Closed
                     G1/GR  Yell   Turbo    30s            Close, Wait, Then Open
                            BlueC
                            RedC
                            YellC
                            BlueS
                            RedS
                            YellS
                            All3
                            All6

    #################
    Section 2. Floors
    #################

    ----------------------------
    Section 2.1 Floor targets
    ----------------------------

    Lowest Neighbor Floor (LnF)

    This means that the floor moves to the height of the lowest
    neighboring floor including the floor itself. If the floor
    direction is up (only possible with generalized floors) motion is
    instant, else at the floor's speed.

    Next Neighbor Floor (NnF)

    This means that the floor moves up to the height of the lowest
    adjacent floor greater in height than the current, or down to the
    height of the highest adjacent floor less in height than the current,
    as determined by the floor's direction. Instant motion is not
    possible in this case. If no such floor exists, the floor does not move.

    Lowest Neighbor Ceiling (LnC)

    This means that the floor height changes to the height of the lowest
    ceiling possessed by any neighboring sector, including that floor's
    ceiling. If the target height is in the opposite direction to floor
    motion, motion is instant, otherwise at the floor action's speed.

    8 Under Lowest Neighbor Ceiling (8uLnC)

    This means that the floor height changes to 8 less than the height
    of the lowest ceiling possessed by any neighboring sector, including
    that floor's ceiling. If the target height is in the opposite
    direction to floor motion, motion is instant, otherwise at the floor
    action's speed.

    Highest Neighbor Floor (HnF)

    This means that the floor height changes to the height of the highest
    neighboring floor, excluding the floor itself. If no neighbor floor
    exists, the floor moves down to -32000. If the target height is in
    the opposite direction to floor motion, the motion is instant,
    otherwise it occurs at the floor action's speed.

    8 Above Highest Neighbor Floor (8aHnF)

    This means that the floor height changes to 8 above the height of
    the highest neighboring floor, excluding the floor itself. If no
    neighbor floor exists, the floor moves down to -31992. If the target
    height is in the opposite direction to floor motion, the motion is
    instant, otherwise it occurs at the floor action's speed.

    Ceiling

    The floor moves up until its at ceiling height, instantly if floor
    direction is down (only available with generalized types), at the
    floor speed if the direction is up.

    24 Units (24)

    The floor moves 24 units in the floor action's direction. Instant
    motion is not possible with this linedef type.

    32 Units (32)

    The floor moves 32 units in the floor action's direction. Instant
    motion is not possible with this linedef type.

    512 Units (512)

    The floor moves 512 units in the floor action's direction. Instant
    motion is not possible with this linedef type.

    Shortest Lower Texture (SLT)

    The floor moves the height of the shortest lower texture on the
    boundary of the sector, in the floor direction. Instant motion is not
    possible with this type. In the case that there is no surrounding
    texture the motion is to -32000 or +32000 depending on direction.

    None

    Some pure texture type changes are provided for changing the floor
    texture and/or sector type without moving the floor.

    --------------------------------
    Section 2.2 Varieties of floors
    --------------------------------

    A floor can be activated by pushing on a linedef bounding it
    (generalized types only), or by pushing on a switch with the same tag
    as the floor sector, or by walking over a linedef with the same tag
    as the floor, or by shooting a linedef with the same tag as the
    floor with an impact weapon.

    A floor can move either Up or Down.

    A floor can move with speeds of Slow, Normal, Fast, or Turbo. If the
    target height specified by the floor function (see Floor Targets
    above) is in the opposite direction to the floor's motion, then
    travel is instantaneous, otherwise its at the speed specified.

    A floor action can be a texture change type, in which case after the
    action the floor texture of the affected floor, and possibly the
    sector type of the affected floor are changed to those of a model
    sector. The sector type may be zeroed instead of copied from the
    model, or not changed at all. These change types are referred to
    below as Tx (texture only), Tx0 (type zeroed), and TxTy (texture and
    type changed). The model sector for the change may be the sector on
    the first sidedef of the trigger (trigger model) or the sector with
    floor at destination height across the lowest numbered two-sided
    linedef surrounding the affected sector (numeric model). If no model
    sector exists, no change occurs. If a change occurs, floor texture is
    always affected, lighting is never affected, even that corresponding
    to the sector's type, nor is any other sector property other than the
    sector's type.

    Numeric model algorithm:

    1) Find all floors adjacent to the tagged floor at destination height
    2) Find the lowest numbered linedef separating those floors from that tagged
    3) The sector on the other side of that linedef is the model

    A floor action can have the crush property, in which case players and
    monsters are crushed when the floor tries to move above the point
    where they fit exactly underneath the ceiling. This means they take
    damage until they die, leave the sector, or the floor action is stopped.
    A floor action never reverses on encountering an obstacle, even if
    the crush property is not true, the floor merely remains in the same
    position until the obstacle is removed or dies, then continues.

    -------------------------------
    Section 2.3 Floor linedef types
    -------------------------------

    Regular and Extended Floor Types
    -------------------------------------------------------------------
    #     Class   Trig   Dir Spd   Chg  Mdl Mon Crsh  Target

    60    Reg     SR     Dn  Slow  None --  No  No    Lowest Neighbor Floor
    23    Reg     S1     Dn  Slow  None --  No  No    Lowest Neighbor Floor
    82    Reg     WR     Dn  Slow  None --  No  No    Lowest Neighbor Floor
    38    Reg     W1     Dn  Slow  None --  No  No    Lowest Neighbor Floor

    177   Ext     SR     Dn  Slow  TxTy Num No  No    Lowest Neighbor Floor
    159   Ext     S1     Dn  Slow  TxTy Num No  No    Lowest Neighbor Floor
    84    Reg     WR     Dn  Slow  TxTy Num No  No    Lowest Neighbor Floor
    37    Reg     W1     Dn  Slow  TxTy Num No  No    Lowest Neighbor Floor

    69    Reg     SR     Up  Slow  None --  No  No    Next Neighbor Floor
    18    Reg     S1     Up  Slow  None --  No  No    Next Neighbor Floor
    128   Reg     WR     Up  Slow  None --  No  No    Next Neighbor Floor
    119   Reg     W1     Up  Slow  None --  No  No    Next Neighbor Floor

    132   Reg     SR     Up  Fast  None --  No  No    Next Neighbor Floor
    131   Reg     S1     Up  Fast  None --  No  No    Next Neighbor Floor
    129   Reg     WR     Up  Fast  None --  No  No    Next Neighbor Floor
    130   Reg     W1     Up  Fast  None --  No  No    Next Neighbor Floor

    222   Ext     SR     Dn  Slow  None --  No  No    Next Neighbor Floor
    221   Ext     S1     Dn  Slow  None --  No  No    Next Neighbor Floor
    220   Ext     WR     Dn  Slow  None --  No  No    Next Neighbor Floor
    219   Ext     W1     Dn  Slow  None --  No  No    Next Neighbor Floor

    64    Reg     SR     Up  Slow  None --  No  No    Lowest Neighbor Ceiling
    101   Reg     S1     Up  Slow  None --  No  No    Lowest Neighbor Ceiling
    91    Reg     WR     Up  Slow  None --  No  No    Lowest Neighbor Ceiling
    5     Reg     W1     Up  Slow  None --  No  No    Lowest Neighbor Ceiling
    24    Reg     G1     Up  Slow  None --  No  No    Lowest Neighbor Ceiling

    65    Reg     SR     Up  Slow  None --  No  Yes   Lowest Neighbor Ceiling - 8
    55    Reg     S1     Up  Slow  None --  No  Yes   Lowest Neighbor Ceiling - 8
    94    Reg     WR     Up  Slow  None --  No  Yes   Lowest Neighbor Ceiling - 8
    56    Reg     W1     Up  Slow  None --  No  Yes   Lowest Neighbor Ceiling - 8

    45    Reg     SR     Dn  Slow  None --  No  No    Highest Neighbor Floor
    102   Reg     S1     Dn  Slow  None --  No  No    Highest Neighbor Floor
    83    Reg     WR     Dn  Slow  None --  No  No    Highest Neighbor Floor
    19    Reg     W1     Dn  Slow  None --  No  No    Highest Neighbor Floor

    70    Reg     SR     Dn  Fast  None --  No  No    Highest Neighbor Floor + 8
    71    Reg     S1     Dn  Fast  None --  No  No    Highest Neighbor Floor + 8
    98    Reg     WR     Dn  Fast  None --  No  No    Highest Neighbor Floor + 8
    36    Reg     W1     Dn  Fast  None --  No  No    Highest Neighbor Floor + 8

    180   Ext     SR     Up  Slow  None --  No  No    Absolute 24
    161   Ext     S1     Up  Slow  None --  No  No    Absolute 24
    92    Reg     WR     Up  Slow  None --  No  No    Absolute 24
    58    Reg     W1     Up  Slow  None --  No  No    Absolute 24

    179   Ext     SR     Up  Slow  TxTy Trg No  No    Absolute 24
    160   Ext     S1     Up  Slow  TxTy Trg No  No    Absolute 24
    93    Reg     WR     Up  Slow  TxTy Trg No  No    Absolute 24
    59    Reg     W1     Up  Slow  TxTy Trg No  No    Absolute 24

    176   Ext     SR     Up  Slow  None --  No  No    Abs Shortest Lower Texture
    158   Ext     S1     Up  Slow  None --  No  No    Abs Shortest Lower Texture
    96    Reg     WR     Up  Slow  None --  No  No    Abs Shortest Lower Texture
    30    Reg     W1     Up  Slow  None --  No  No    Abs Shortest Lower Texture

    178   Ext     SR     Up  Slow  None --  No  No    Absolute 512
    140   Reg     S1     Up  Slow  None --  No  No    Absolute 512
    147   Ext     WR     Up  Slow  None --  No  No    Absolute 512
    142   Ext     W1     Up  Slow  None --  No  No    Absolute 512

    190   Ext     SR     --  ----  TxTy Trg No  No    None
    189   Ext     S1     --  ----  TxTy Trg No  No    None
    154   Ext     WR     --  ----  TxTy Trg No  No    None
    153   Ext     W1     --  ----  TxTy Trg No  No    None

    78    Ext     SR     --  ----  TxTy Num No  No    None
    241   Ext     S1     --  ----  TxTy Num No  No    None
    240   Ext     WR     --  ----  TxTy Num No  No    None
    239   Ext     W1     --  ----  TxTy Num No  No    None

    The following tables show the possibilities for generalized floor
    linedef type parameters. Any combination of parameters is allowed:

    Slow and Fast represent the same speeds as slow and fast regular
    floors. Normal is twice as fast as slow, Fast is twice normal, Turbo
    is twice Fast.

    Generalized Floor Types
    ---------------------------------------------------------------------------
    #      Class   Trig   Dir Spd   *Chg *Mdl Mon Crsh  Target

    6000H- Gen     P1/PR  Up  Slow   None Trg Yes Yes   Lowest Neighbor Floor
    7FFFH          S1/SR  Dn  Normal Tx   Num No  No    Next Neighbor Floor
                   W1/WR      Fast   Tx0                Lowest Neighbor Ceiling
                   G1/GR      Turbo  TxTy               Highest Neighbor Floor
                                                        Ceiling
                                                        24
                                                        32
    *Mon(ster) enabled must be No if                    Shortest Lower Texture
    Chg field is not None

    Tx = Texture copied only           Trg = Trigger Model
    Tx0 = Texture copied and Type->0   Num = Numeric Model
    TxTy = Texture and Type copied

    ####################
    Section 3. Ceilings
    ####################

    ----------------------------
    Section 3.1 Ceiling Targets
    ----------------------------

    Highest Neighbor Ceiling (HnC)

    This means that the ceiling moves to the height of the highest
    neighboring ceiling NOT including the ceiling itself. If the ceiling
    direction is down (only possible with generalized ceilings) motion is
    instant, else at the ceiling's speed. If no adjacent ceiling exists
    the ceiling moves to -32000 units.

    Next Neighbor Ceiling (NnC)

    This means that the ceiling moves up to the height of the lowest
    adjacent ceiling greater in height than the current, or to the
    height of the highest adjacent ceiling less in height than the current,
    as determined by the ceiling's direction. Instant motion is not
    possible in this case. If no such ceiling exists, the ceiling does
    not move.

    Lowest Neighbor Ceiling (LnC)

    This means that the ceiling height changes to the height of the lowest
    ceiling possessed by any neighboring sector, NOT including itself.
    If the target height is in the opposite direction to ceiling
    motion, motion is instant, otherwise at the ceiling action's speed.
    If no adjacent ceiling exists the ceiling moves to 32000 units.

    Highest Neighbor Floor (HnF)

    This means that the ceiling height changes to the height of the
    highest neighboring floor, excluding the ceiling's floor itself. If
    no neighbor floor exists, the ceiling moves down to -32000 or the
    ceiling's floor, whichever is higher. If the target height is in the
    opposite direction to ceiling motion, the motion is instant,
    otherwise it occurs at the ceiling action's speed.

    Floor

    The ceiling moves down until its at floor height, instantly if
    ceiling direction is up (only available with generalized types), at
    the ceiling speed if the direction is down.

    8 Above Floor (8aF)

    This means that the ceiling height changes to 8 above the height of
    the ceiling's floor. If the target height is in the opposite direction
    to ceiling motion, the motion is instant, otherwise it occurs at the
    ceiling action's speed.

    24 Units (24)

    The ceiling moves 24 units in the ceiling action's direction. Instant
    motion is not possible with this linedef type.

    32 Units (32)

    The ceiling moves 32 units in the ceiling action's direction. Instant
    motion is not possible with this linedef type.

    Shortest Upper Texture (SUT)

    The ceiling moves the height of the shortest upper texture on the
    boundary of the sector, in the ceiling direction. Instant motion is not
    possible with this type. In the case that there is no surrounding
    texture the motion is to -32000 or +32000 depending on direction.

    ----------------------------------
    Section 3.2 Varieties of ceilings
    ----------------------------------

    A ceiling can be activated by pushing on a linedef bounding it
    (generalized types only), or by pushing on a switch with the same tag
    as the ceiling sector, or by walking over a linedef with the same tag
    as the ceiling, or by shooting a linedef with the same tag as the
    ceiling with an impact weapon (generalized types only).

    A ceiling can move either Up or Down.

    A ceiling can move with speeds of Slow, Normal, Fast, or Turbo. If the
    target height specified by the ceiling function (see Ceiling Targets
    above) is in the opposite direction to the ceiling's motion, then
    travel is instantaneous, otherwise its at the speed specified.

    A ceiling action can be a texture change type, in which case after
    the action the ceiling texture of the affected ceiling, and possibly
    the sector type of the affected ceiling are changed to those of a
    model sector. The sector type may be zeroed instead of copied from
    the model, or not changed at all. These change types are referred to
    below as Tx (texture only), Tx0 (type set to 0), and TxTy (texture
    and type copied from model). The model sector for the change may be
    the sector on the first sidedef of the trigger (trigger model) or the
    sector with ceiling at destination height across the lowest numbered
    two-sided linedef surrounding the affected sector (numeric model). If
    no model sector exists, no change occurs. If a change occurs, ceiling
    texture is always affected, lighting is never affected, even that
    corresponding to the sector's type, nor is any other sector property
    other than the sector's type.

    Numeric model algorithm:

    1) Find all ceilings adjacent to the tagged ceiling at destination height
    2) Find the lowest numbered linedef separating those ceilings from that tagged
    3) The sector on the other side of that linedef is the model

    A ceiling action can have the crush property (generalized types only),
    in which case players and monsters are crushed when the ceiling tries
    to move below the point where they fit exactly underneath the
    ceiling. This means they take damage until they die, leave the
    sector, or the ceiling action is stopped.  A ceiling action never
    reverses on encountering an obstacle, even if the crush property is
    not true, the ceiling merely remains in the same position until the
    obstacle is removed or dies, then continues.

    ---------------------------------
    Section 3.3 Ceiling linedef types
    ---------------------------------

    Regular and Extended Ceiling Types
    -------------------------------------------------------------------
    #     Class   Trig   Dir Spd   *Chg *Mdl Mon Crsh Target

    43    Reg     SR     Dn  Fast  None  --  No  No   Floor
    41    Reg     S1     Dn  Fast  None  --  No  No   Floor
    152   Ext     WR     Dn  Fast  None  --  No  No   Floor
    145   Ext     W1     Dn  Fast  None  --  No  No   Floor

    186   Ext     SR     Up  Slow  None  --  No  No   Highest Neighbor Ceiling
    166   Ext     S1     Up  Slow  None  --  No  No   Highest Neighbor Ceiling
    151   Ext     WR     Up  Slow  None  --  No  No   Highest Neighbor Ceiling
    40    Reg     W1     Up  Slow  None  --  No  No   Highest Neighbor Ceiling

    187   Ext     SR     Dn  Slow  None  --  No  No   8 Above Floor
    167   Ext     S1     Dn  Slow  None  --  No  No   8 Above Floor
    72    Reg     WR     Dn  Slow  None  --  No  No   8 Above Floor
    44    Reg     W1     Dn  Slow  None  --  No  No   8 Above Floor

    205   Ext     SR     Dn  Slow  None  --  No  No   Lowest Neighbor Ceiling
    203   Ext     S1     Dn  Slow  None  --  No  No   Lowest Neighbor Ceiling
    201   Ext     WR     Dn  Slow  None  --  No  No   Lowest Neighbor Ceiling
    199   Ext     W1     Dn  Slow  None  --  No  No   Lowest Neighbor Ceiling

    206   Ext     SR     Dn  Slow  None  --  No  No   Highest Neighbor Floor
    204   Ext     S1     Dn  Slow  None  --  No  No   Highest Neighbor Floor
    202   Ext     WR     Dn  Slow  None  --  No  No   Highest Neighbor Floor
    200   Ext     W1     Dn  Slow  None  --  No  No   Highest Neighbor Floor

    Generalized Ceiling Types
    ---------------------------------------------------------------------------
    #      Class   Trig   Dir Spd   *Chg *Mdl Mon Crsh  Target

    4000H- Gen     P1/PR  Up  Slow   None Trg Yes Yes   Highest Neighbor Ceiling
    5FFFH          S1/SR  Dn  Normal Tx   Num No  No    Next Neighbor Ceiling
                   W1/WR      Fast   Tx0                Lowest Neighbor Ceiling
                   G1/GR      Turbo  TxTy               Highest Neighbor Floor
                                                        Floor
                                                        24
                                                        32
    *Mon(ster) enabled must be No if                    Shortest Upper Texture
    Chg field is not None

    Tx = Texture copied only           Trg = Trigger Model
    Tx0 = Texture copied and Type->0   Num = Numeric Model
    TxTy = Texture and Type copied

    ############################
    Section 4. Platforms (Lifts)
    ############################

    A platform is basically a floor action involving two heights. The
    simple raise platform actions, for example, differ from the
    corresponding floor actions in that if they encounter an obstacle,
    they reverse direction and return to their former height.

    The most often used kind of platform is a lift which travels from its
    current height to the target height, then waits a specified time and
    returns to it former height.

    -----------------------------
    Section 4.1 Platform Targets
    -----------------------------

    Lowest Neighbor Floor

    This means that the platforms "low" height is the height of the
    lowest surrounding floor, including the platform itself. The "high"
    height is the original height of the floor.

    Next Lowest Neighbor Floor

    This means that the platforms "low" height is the height of the
    highest surrounding floor lower than the floor itself. If no lower
    floor exists, no motion occurs as the "low" and "high" heights are
    then both equal to the floors current height.

    Lowest Neighbor Ceiling

    This means that the platforms "low" height is the height of the
    lowest surrounding ceiling unless this is higher than the floor
    itself. If no adjacent ceiling exists, or is higher than the floor no
    motion occurs as the "low" and "high" heights are then both equal to
    the floors current height.

    Lowest and Highest Floor

    This target sets the "low" height to the lowest neighboring floor,
    including the floor itself, and the "high" height to the highest
    neighboring floor, including the floor itself. When this target is
    used the floor moves perpetually between the two heights. Once
    triggered this type of linedef runs permanently, even if the motion
    is temporarily suspended with a Stop type. No other floor action can
    be commanded on the sector after this type is begun.

    Ceiling

    This target sets the "high" height to the ceiling of the sector and
    the "low" height to the floor height of the sector and is only used in
    the instant toggle type that switches the floor between the ceiling
    and its original height on each activation. This is also the ONLY
    instant platform type.

    Raise Next Floor

    This means that the "high" height is the lowest surrounding floor
    higher than the platform. If no higher adjacent floor exists no
    motion will occur.

    Raise 24 Units

    The "low" height is the original floor height, the "high" height is 24
    more.

    Raise 32 Units

    The "low" height is the original floor height, the "high" height is 32
    more.

    -----------------------------------
    Section 4.2 Varieties of Platforms
    -----------------------------------

    A platform can be activated by pushing on a linedef bounding it
    (generalized types only), or by pushing on a switch with the same tag
    as the platform sector, or by walking over a linedef with the same tag
    as the platform, or by shooting a linedef with the same tag as the
    platform with an impact weapon.

    A platform can move with speeds of Slow, Normal, Fast, or Turbo.
    Only the instant toggle platform moves instantly, all others move at
    the platform's speed.

    A platform can have a delay, in between when it reaches "high" height
    and returns to "low" height, or at both ends of the motion in the
    case of perpetual lifts.

    A platform action can be a texture change type, in which case after
    the action the floor texture of the affected floor, and possibly the
    sector type of the affected floor are changed to those of a model
    sector. The sector type may be zeroed instead of copied from the
    model, or not changed at all. These change types are referred to
    below as Tx (texture only), Tx0 (type zeroed), and TxTy (texture and
    type changed). The model sector for the change is always the sector
    on the first sidedef of the trigger (trigger model).  If a change
    occurs, floor texture is always affected, lighting is never affected,
    even that corresponding to the sector's type, nor is any other sector
    property other than the sector's type.

    -----------------------------------
    Section 4.3 Platform Linedef types
    -----------------------------------

    Regular and Extended Platform Types
    -------------------------------------------------------------------
    #     Class  Trig   Dly Spd  Chg  Mdl Mon Target

    66    Reg    SR     --  Slow Tx   Trg No  Raise 24 Units
    15    Reg    S1     --  Slow Tx   Trg No  Raise 24 Units
    148   Ext    WR     --  Slow Tx   Trg No  Raise 24 Units
    143   Ext    W1     --  Slow Tx   Trg No  Raise 24 Units

    67    Reg    SR     --  Slow Tx0  Trg No  Raise 32 Units
    14    Reg    S1     --  Slow Tx0  Trg No  Raise 32 Units
    149   Ext    WR     --  Slow Tx0  Trg No  Raise 32 Units
    144   Ext    W1     --  Slow Tx0  Trg No  Raise 32 Units

    68    Reg    SR     --  Slow Tx0  Trg No  Raise Next Floor
    20    Reg    S1     --  Slow Tx0  Trg No  Raise Next Floor
    95    Reg    WR     --  Slow Tx0  Trg No  Raise Next Floor
    22    Reg    W1     --  Slow Tx0  Trg No  Raise Next Floor
    47    Reg    G1     --  Slow Tx0  Trg No  Raise Next Floor

    181   Ext    SR     3s  Slow None --  No  Lowest and Highest Floor (perpetual)
    162   Ext    S1     3s  Slow None --  No  Lowest and Highest Floor (perpetual)
    87    Reg    WR     3s  Slow None --  No  Lowest and Highest Floor (perpetual)
    53    Reg    W1     3s  Slow None --  No  Lowest and Highest Floor (perpetual)

    182   Ext    SR     --  ---- ---- --  --  Stop
    163   Ext    S1     --  ---- ---- --  --  Stop
    89    Reg    WR     --  ---- ---- --  --  Stop
    54    Reg    W1     --  ---- ---- --  --  Stop

    62    Reg    SR     3s  Slow None --  No  Lowest Neighbor Floor (lift)
    21    Reg    S1     3s  Slow None --  No  Lowest Neighbor Floor (lift)
    88    Reg    WR     3s  Slow None --  No  Lowest Neighbor Floor (lift)
    10    Reg    W1     3s  Slow None --  No  Lowest Neighbor Floor (lift)

    123   Reg    SR     3s  Fast None --  No  Lowest Neighbor Floor (lift)
    122   Reg    S1     3s  Fast None --  No  Lowest Neighbor Floor (lift)
    120   Reg    WR     3s  Fast None --  No  Lowest Neighbor Floor (lift)
    121   Reg    W1     3s  Fast None --  No  Lowest Neighbor Floor (lift)

    211   Ext    SR     --  Inst None --  No  Ceiling (toggle)
    212   Ext    WR     --  Inst None --  No  Ceiling (toggle)

    Generalized Lift Types
    ---------------------------------------------------------------------------
    #      Class   Trig   Dly Spd    Mon  Target

    3400H- Gen     P1/PR  1s  Slow   Yes  Lowest Neighbor Floor
    37FFH          S1/SR  3s  Normal No   Next Lowest Neighbor Floor
                   W1/WR  5s  Fast        Lowest Neighbor Ceiling
                   G1/GR  10s Turbo       Lowest and Highest Floor (perpetual)

    ############################
    Section 5. Crusher Ceilings
    ############################

    A crusher ceiling is a linedef type that causes the ceiling to cycle
    between its starting height and 8 above the floor, damaging
    monsters and players that happen to be in between. Barrels explode
    when crushed.

    Once a crusher ceiling is started it remains running for the
    remainder of the level even if temporarily suspended with a stop type.
    No other ceiling action can be used in that sector thereafter.

    ----------------------------------
    Section 5.1 Varieties of Crushers
    ----------------------------------

    A crusher can be activated by pushing on a linedef bounding it
    (generalized types only), or by pushing on a switch with the same tag
    as the crusher sector, or by walking over a linedef with the same tag
    as the crusher, or by shooting a linedef with the same tag as the
    crusher with an impact weapon (generalized types only).

    A crusher has a speed: slow, normal, fast, or turbo. The slower the
    speed, the more damage the crusher does when crushing, simply thru
    being applied longer. When a slow or normal crusher is moving down
    and encounters something to crush, it slows down even more, by a
    factor of 8. This persists until it reaches bottom of stroke and
    starts up again. Fast and turbo crushers do not slow down.

    A crusher can be silent. The regular silent crusher makes platform
    stop and start noises at top and bottom of stroke. The generalized
    silent crusher is completely quiet.

    A crusher linedef is provided to stop a crusher in its current
    position. Care should be used that this doesn't lock the player out
    of an area of the wad if the crusher is too low to pass. A crusher
    can be restarted, but not changed, with any crusher linedef.

    ----------------------------------
    Section 5.2 Crusher Linedef Types
    ----------------------------------

    Regular and Extended Crusher Types
    -------------------------------------------------------------------
    #     Class  Trig   Spd  Mon Silent Action

    184   Ext    SR     Slow No  No     Start
    49    Reg    S1     Slow No  No     Start
    73    Reg    WR     Slow No  No     Start
    25    Reg    W1     Slow No  No     Start

    183   Ext    SR     Fast No  No     Start
    164   Ext    S1     Fast No  No     Start
    77    Reg    WR     Fast No  No     Start
    6     Reg    W1     Fast No  No     Start

    185   Ext    SR     Slow No  Yes    Start
    165   Ext    S1     Slow No  Yes    Start
    150   Ext    WR     Slow No  Yes    Start
    141   Reg    W1     Slow No  Yes    Start

    188   Ext    SR     ---- --  --     Stop
    168   Ext    S1     ---- --  --     Stop
    74,   Reg    WR     ---- --  --     Stop
    57,   Reg    W1     ---- --  --     Stop

    Generalized Crusher Types
    ---------------------------------------------------------------------------
    #      Class   Trig   Spd    Mon  Silent

    2F80H- Gen     P1/PR  Slow   Yes  Yes
    2FFFH          S1/SR  Normal No   No
                   W1/WR  Fast
                   G1/GR  Turbo

    ##########################
    Section 6. Stair Builders
    ##########################

    A stair builder is a linedef type that sets a sequence of sectors
    defined by a complex rule to an ascending or descending sequence of
    heights.

    The rule for stair building is as follows:

    1) The first step to rise or fall is the tagged sector. It rises or
    falls by the stair stepsize, at the stair speed, in the stair
    direction..

    2) To find the next step (sector) affected examine each two-sided
    linedef with first sidedef facing into the previous step in numerical
    order. For each such linedef if the sector on the other side is
    already active, or has already risen from this stair, the linedef is
    skipped. If textures are not ignored then any linedef with a
    different floor texture on its second side is also skipped. The next step
    to rise is the sector on the other side of the first linedef not
    skipped. If none exists, stair building ceases.

    The next step moves to the height of the previous step plus or minus
    the stepsize depending on the direction the stairs build, up or down.
    If the motion is in the same direction as the stairs build, it occurs
    at stair build speed, otherwise it is instant.

    3) Repeat step 2 until stair building ceases.

    ----------------------------------------
    Section 6.1 Varieties of Stair Builders
    ----------------------------------------

    A stair can be activated by pushing on a linedef bounding it
    (generalized types only), or by pushing on a switch with the same tag
    as the stair sector, or by walking over a linedef with the same tag
    as the stair, or by shooting a linedef with the same tag as the
    stair with an impact weapon (generalized types only).

    Only extended and generalized stair types are retriggerable. The
    extended retriggerable stairs are mostly useless, though triggering a
    stair with stepsize 8 twice might be used. The generalized
    retriggerable stairs alternate building up and down on each
    activation which is much more useful.

    A stair can build up or down (generalized types only).

    A stair can have a step size of 4, 8, 16, or 24. Only generalized
    types support stepsize of 4 or 24.

    A stair can have build speeds of slow, normal, fast or turbo. Only
    generalized types support speeds of normal or turbo.

    A stair can stop on encountering a different texture or ignore
    (generalized types only) different textures and continue.

    Only the regular build fast, stepsize 16 stair has the property that
    monsters and players can be crushed by the motion, all others do not
    crush.

    ----------------------------------------------------
    Section 6.2 Regular and Extended Stair Builder Types
    ----------------------------------------------------

    Regular and Extended Stairs Types
    -------------------------------------------------------------------
    #     Class  Trig  Dir Spd   Step Ignore Mon

    258   Ext    SR    Up  Slow  8    No     No
    7     Reg    S1    Up  Slow  8    No     No
    256   Ext    WR    Up  Slow  8    No     No
    8     Reg    W1    Up  Slow  8    No     No

    259   Ext    SR    Up  Fast  16   No     No
    127   Reg    S1    Up  Fast  16   No     No
    257   Ext    WR    Up  Fast  16   No     No
    100   Reg    W1    Up  Fast  16   No     No

    Generalized Stairs Types
    ---------------------------------------------------------------------------
    #      Class   Trig   Dir Spd     Step  Ignore Mon

    3000H- Gen     P1/PR  Up  Slow    4     Yes    Yes
    33FFH          S1/SR  Dn  Normal  8     No     No
                   W1/WR      Fast    16
                   G1/GR      Turbo   24

    ####################
    Section 7 Elevators
    ####################

    An elevator is a linedef type that moves both floor and ceiling
    together. All elevator linedefs are extended, there are no regular or
    generalized elevator types. Instant elevator motion is not possible,
    and monsters cannot activate elevators. All elevator triggers are
    either switched or walkover.

    -----------------------------
    Section 7.1 Elevator Targets
    -----------------------------

    Next Highest Floor

    The elevator floor moves to the lowest adjacent floor higher than the
    elevator's floor, the ceiling staying the same height above the floor.
    If there is no higher floor the elevator doesn't move.

    Next Lowest Floor

    The elevator floor moves to the highest adjacent floor lower than the
    current floor, the ceiling staying the same height above the floor. If
    there is no lower floor the elevator doesn't move.

    Current Floor

    The elevator floor moves to the height of the floor on the first
    sidedef of the triggering line, the ceiling remaining the same height
    above the elevator floor.

    -----------------------------------
    Section 7.2 Elevator Linedef Types
    -----------------------------------

    Extended Elevator types
    -------------------------------------------------------------------
    #     Class  Trig  Spd    Target

    230   Ext    SR    Fast   Next Highest Floor
    229   Ext    S1    Fast   Next Highest Floor
    228   Ext    WR    Fast   Next Highest Floor
    227   Ext    W1    Fast   Next Highest Floor

    234   Ext    SR    Fast   Next Lowest Floor
    233   Ext    S1    Fast   Next Lowest Floor
    232   Ext    WR    Fast   Next Lowest Floor
    231   Ext    W1    Fast   Next Lowest Floor

    238   Ext    SR    Fast   Current Floor
    237   Ext    S1    Fast   Current Floor
    236   Ext    WR    Fast   Current Floor
    235   Ext    W1    Fast   Current Floor

    ###################
    Section 7 Lighting
    ###################

    The lighting linedef types change the lighting in the tagged sector.
    All are regular or extended types, there are no generalized lighting
    types. All are switched or walkovers.

    -----------------------------
    Section 7.1 Lighting Targets
    -----------------------------

    Lights to Minimum Neighbor

    Each tagged sector is set to the minimum light level found in any
    adjacent sector. The tagged sectors are changed in numerical order,
    and this may influence the result.

    Lights to Maximum Neighbor

    Each tagged sector is set to the maximum light level found in any
    adjacent sector. The tagged sectors are changed in numerical order,
    and this may influence the result.

    Blinking

    Each tagged sector begins blinking between two light levels. The
    brighter level is the light level in the tagged sector. The darker
    level is the minimum neighbor light level, or 0 if all neighbor
    sectors have lighting greater than or equal to the sector's at the
    time of activation. The blinking is non-synchronous, beginning 1-9
    gametics after activation, with a dark period of 1 sec (35 gametics)
    and a bright period of 1/7 sec (5 gametics).

    35 Units

    Each tagged sector is set to a light level of 35 units.

    255 Units

    Each tagged sector is set to a light level of 255 units.

    -----------------------------------
    Section 7.2 Lighting Linedef Types
    -----------------------------------

    Regular and Extended Lighting types
    -------------------------------------------------------------------
    #     Class  Trig  Target

    139   Reg    SR    35 Units
    170   Ext    S1    35 Units
    79    Reg    WR    35 Units
    35    Reg    W1    35 Units

    138   Reg    SR    255 Units
    171   Ext    S1    255 Units
    81    Reg    WR    255 Units
    13    Reg    W1    255 Units

    192   Ext    SR    Maximum Neighbor
    169   Ext    S1    Maximum Neighbor
    80    Reg    WR    Maximum Neighbor
    12    Reg    W1    Maximum Neighbor

    194   Ext    SR    Minimum Neighbor
    173   Ext    S1    Minimum Neighbor
    157   Ext    WR    Minimum Neighbor
    104   Reg    W1    Minimum Neighbor

    193   Ext    SR    Blinking
    172   Ext    S1    Blinking
    156   Ext    WR    Blinking
    17    Reg    W1    Blinking

    ################
    Section 8 Exits
    ################

    An exit linedef type ends the current level bringing up the
    intermission screen with its report of kills/items/secrets or frags
    in the case of deathmatch. Obviously, none are retriggerable, and
    none require tags, since no sector is affected.

    ---------------------------
    Section 8.1 Exit Varieties
    ---------------------------

    An exit can be activated by pushing on a switch with the exit type
    or  by walking over a linedef with the exit type, or by shooting a
    linedef with the exit type with an impact weapon.

    An exit can be normal or secret. The normal exit simply ends the
    level and takes you to the next level via the intermission screen. A
    secret exit only works in a special level depending on the IWAD being
    played. In DOOM the secret exits can be on E1M3, E2M5, or E3M6. In
    DOOM II they can be in levels 15 and 31. If a secret exit is used in
    any other level, it brings you back to the start of the current
    level. In DOOM the secret exits go from E1M3 to E1M9, E2M5 to E2M9,
    and E3M6 to E3M9. In DOOM II they go from 15 to 31 and from 31 to 32.
    In DOOM II a normal exit from 31 or 32 goes to level 16.

    -----------------------------------
    Section 8.2 Exit Linedef Types
    -----------------------------------

    Regular and Extended Exit types
    -------------------------------------------------------------------
    #     Class  Trig  Type

    11    Reg    S1    Normal
    52    Reg    W1    Normal
    197   Ext    G1    Normal

    51    Reg    S1    Secret
    124   Reg    W1    Secret
    198   Ext    G1    Secret

    ######################
    Section 9 Teleporters
    ######################

    A teleporter is a linedef that when crossed or switched makes the
    player or monster appear elsewhere in the level. There are only
    regular and extended teleporters, no generalized teleporters exist
    (yet).  Teleporters are the only direction sensitive walkover
    triggers in DOOM (to allow them to be exited without teleporting
    again). They must be crossed from the first sidedef side in order to
    work.

    The place that the player or monster appears is set in one of two
    ways. The more common is by a teleport thing in the sector tagged to
    the teleport line. The newer completely player preserving line-line
    silent teleport makes the player appear relative to the exit line
    (identified by having the same tag as the entry line) with the same
    orientation, position, momentum and height that they had relative to
    the entry line just before teleportation. A special kind of line-line
    teleporter is also provided that reverses the player's orientation by
    180 degrees.

    In the case of several lines tagged the same as the teleport line, or
    several sectors tagged the same, or several teleport things in the
    tagged sector, in all cases the lowest numbered one is used.

    In DOOM crossing a W1 teleport line in the wrong direction used it
    up, and it was never activatable. In BOOM this is not the case, it
    does not teleport but remains active until next crossed in the right
    direction.

    If the exit of a teleporter is blocked a monster (or anything besides
    a player) will not teleport thru it. However if the exit of teleporter
    is blocked a player will, including into a down crusher, a monster,
    or another player. In the latter two cases the monster/player
    occupying the spot dies messily, and this is called a telefrag.

    -------------------------------
    Section 9.1 Teleport Varieties
    -------------------------------

    A teleporter can be walkover or switched, and retriggerable or not.

    A teleporter can have destination set by a teleport thing in the
    tagged sector, or by a line tagged the same as the teleport line.
    These are called thing teleporters and line teleporters resp.

    A teleporter can preserve orientation or set orientation from the
    position, height, and angle of the teleport thing. Note a thing
    destination teleporter always sets position, though it may preserve
    orientation otherwise.

    A teleporter can produce green fog and a whoosh noise, or it can be
    silent, in which case it does neither.

    A teleporter can transport monsters only, or both players and
    monsters.

    -----------------------------------
    Section 9.2 Teleport Linedef types
    -----------------------------------

    Regular and Extended Teleport types
    -------------------------------------------------------------------
    #     Class  Trig  Silent Mon Plyr Orient    Dest

    195   Ext    SR    No     Yes Yes  Set       TP thing in tagged sector
    174   Ext    S1    No     Yes Yes  Set       TP thing in tagged sector
    97    Reg    WR    No     Yes Yes  Set       TP thing in tagged sector
    39    Reg    W1    No     Yes Yes  Set       TP thing in tagged sector

    126   Reg    WR    No     Yes No   Set       TP thing in tagged sector
    125   Reg    W1    No     Yes No   Set       TP thing in tagged sector
    269   Ext    WR    Yes    Yes No   Set       TP thing in tagged sector
    268   Ext    W1    Yes    Yes No   Set       TP thing in tagged sector

    210   Ext    SR    Yes    Yes Yes  Preserve  TP thing in tagged sector
    209   Ext    S1    Yes    Yes Yes  Preserve  TP thing in tagged sector
    208   Ext    WR    Yes    Yes Yes  Preserve  TP thing in tagged sector
    207   Ext    W1    Yes    Yes Yes  Preserve  TP thing in tagged sector

    244   Ext    WR    Yes    Yes Yes  Preserve  Line with same tag
    243   Ext    W1    Yes    Yes Yes  Preserve  Line with same tag
    263   Ext    WR    Yes    Yes Yes  Preserve  Line with same tag (reversed)
    262   Ext    W1    Yes    Yes Yes  Preserve  Line with same tag (reversed)

    267   Ext    WR    Yes    Yes No   Preserve  Line with same tag
    266   Ext    W1    Yes    Yes No   Preserve  Line with same tag
    265   Ext    WR    Yes    Yes No   Preserve  Line with same tag (reversed)
    264   Ext    W1    Yes    Yes No   Preserve  Line with same tag (reversed)

    ##################
    Section 10 Donuts
    ##################

    A donut is a very specialized linedef type that lowers a pillar in a
    surrounding pool, while raising the pool and changing its texture and
    type.

    The tagged sector is the pillar, and its lowest numbered line must be
    two-sided. The sector on the other side of that is the pool. The pool
    must have a two-sided line whose second sidedef does not adjoin the
    pillar, and the sector on the second side of the lowest numbered such
    linedef is the model for the pool's texture change. The model sector
    floor also provides the destination height both for lowering the
    pillar and raising the pool.

    No generalized donut linedefs exist, and all are switched or
    walkover.

    ---------------------------------
    Section 10.1 Donut Linedef types
    ---------------------------------

    Regular and Extended Donut types
    -------------------------------------------------------------------
    #     Class  Trig

    191   Ext    SR
    9     Reg    S1
    155   Ext    WR
    146   Ext    W1

    #############################
    Section 11 Property Transfer
    #############################

    These linedefs are special purpose and are used to transfer
    properties from the linedef itself or the sector on its first sidedef
    to the tagged sector(s). None are triggered, they simply exist.

    Extended Property Transfer Linedefs
    -------------------------------------------------------------------
    #     Class  Trig Description

    213   Ext --   Set Tagged Floor Lighting to Lighting on 1st Sidedef's Sector

    Used to give the floor of a sector a different light level from the
    remainder of the sector. For example bright lava in a dark room.

    261   Ext --   Set Tagged Ceiling Lighting to Lighting on 1st Sidedef's Sector

    Used to give the ceiling of a sector a different light level from the
    remainder of the sector.

    260   Ext --   Make Tagged Lines (or this line if tag==0) Translucent

    Used to make 2s normal textures translucent. If tag==0, then this linedef's
    normal texture is made translucent if it's 2s, and the default translucency
    map TRANMAP is used as the filter. If tag!=0, then all similarly-tagged 2s
    linedefs' normal textures are made translucent, and if this linedef's first
    sidedef contains a valid lump name for its middle texture (as opposed to a
    texture name), and the lump is 64K long, then that lump will be used as the
    translucency filter instead of the default TRANMAP, allowing different
    filters to be used in different parts of the same maps. If the first side's
    normal texture is not a valid translucency filter lump name, it must be a
    valid texture name, and will be displayed as such on this linedef.

    242   Ext --   Set Tagged Lighting, Flats Heights to 1st Sidedef's Sector,
                   and set colormap based on sidedef textures.

    This allows the tagged sector to have two levels -- an actual floor and
    ceiling, and another floor or ceiling where more flats are rendered. Things
    will stand on the actual floor or hang from the actual ceiling, while this
    function provides another rendered floor and ceiling at the heights of the
    sector on the first sidedef of the linedef. Typical use is "deep water" that
    can be over the player's head.

         ----------------------------------  < real sector's ceiling height
        |         real ceiling             | < control sector's ceiling texture
        |                                  |
        |                                  | < control sector's lightlevel
        |              A                   |
        |                                  | < upper texture as colormap
        |                                  |
        |                                  | < control sector's floor texture
         ----------------------------------  < control sector's ceiling height
        |         fake ceiling             | < real sector's ceiling texture
        |                                  |
        |                                  | < real sector's lightlevel
        |              B                   |
        |                                  | < normal texture as colormap
        |                                  |
        |          fake floor              | < real sector's floor texture
         ----------------------------------  < control sector's floor height
        |                                  | < control sector's ceiling texture
        |                                  |
        |                                  | < control sector's lightlevel
        |              C                   |
        |                                  | < lower texture as colormap
        |                                  |
        |          real floor              | < control sector's floor texture
         ----------------------------------  < real sector's floor height

    Boom sectors controlled by a 242 linedef are partitioned into 3 spaces.
    The viewer's xyz coordinates uniquely determine which space they are in.

    If they are in space B (normal space), then the floor and ceiling textures
    and lightlevel from the real sector are used, and the colormap from the 242
    linedef's first sidedef's normal texture is used (COLORMAP is used if it's
    invalid or missing). The floor and ceiling are rendered at the control
    sector's heights.

    If they are in space C ("underwater"), then the floor and ceiling textures
    and lightlevel from the control sector are used, and the lower texture in
    the 242 linedef's first sidedef is used as the colormap.

    If they are in space A ("head over ceiling"), then the floor and ceiling
    textures and lightlevel from the control sector are used, and the upper
    texture in the 242 linedef's first sidedef is used as the colormap.

    If only two of these adjacent partitions in z-space are used, such as
    underwater and normal space, one has complete control over floor textures,
    ceiling textures, light level, and colormaps, in each of the two partitions.
    The control sector determines the textures and lighting in the more "unusual"
    case (e.g. underwater).

    It's also possible for the fake floor to extend below the real floor, in
    which case an invisible platform / stair effect is created. In that case,
    the picture looks like this (barring any ceiling effects too):

         ----------------------------------  < real sector's ceiling texture
        |   real ceiling = fake ceiling    |
        |                                  |
        |                                  |
        |              B                   | < real sector's lightlevel
        |                                  | < normal texture's colormap
        |                                  |
        |          real floor              |
         ----------------------------------  < invisible, no texture drawn
        |                                  |
        |                                  |
        |                                  | < real sector's lightlevel
        |              C                   | < normal texture's colormap
        |                                  |
        |                                  |
        |          fake floor              | < real sector's floor texture
         ----------------------------------  < fake sector's floor height

    In this case, since the viewer is always at or above the fake floor, no
    colormap/lighting/texture changes occur -- the fake floor just gets drawn
    at the control sector's height, but at the real sector's lighting and
    texture, while objects stand on the higher height of the real floor.

    It's the viewer's position relative to the fake floor and/or fake ceiling,
    which determines whether the control sector's lighting and textures should
    be used, and which colormap should be used. If the viewer is always between
    the fake floor and fake ceiling, then no colormap, lighting, or texture
    changes occur, and the view just sees the real sector's textures and light
    level drawn at possibly different heights.

    If the viewer is below the fake floor height set by the control sector, or is
    above the fake ceiling height set by the control sector, then the corresponding
    colormap is used (lower or upper texture name), and the textures and lighting
    are taken from the control sector rather than the real sector. They are still
    stacked vertically in standard order -- the control sector's ceiling is always
    drawn above the viewer, and the control sector's floor is always drawn below
    the viewer.

    The kaleidescope effect only occurs when F_SKY1 is used as the control sector's
    floor or ceiling. If F_SKY1 is used as the control sector's ceiling texture,
    then under water, only the control sector's floor appears, but it "envelops"
    the viewer. Similarly, if F_SKY1 is used as the control sector's floor texture,
    then when the player's head is over a fake ceiling, the control sector's
    ceiling is used throughout.

    F_SKY1 causes HOM when used as a fake ceiling between the viewer and normal
    space. Since there is no other good use for it, this kaleidescope is an
    option turned on by F_SKY1. Note that this does not preclude the use of sky
    REAL ceilings over deep water -- this is the control sector's ceiling, the
    one displayed when the viewer is underwater, not the real one.

    A colormap has the same size and format as Doom's COLORMAP. Extra colormaps
    may defined in Boom by adding them between C_START and C_END markers in wads.
    Colormaps between C_START and C_END are automatically merged by Boom with any
    previously defined colormaps.

    WATERMAP is a colormap predefined by Boom which can be used to provide a
    blue-green tint while the player is under water. WATERMAP can be modified by
    pwads.

    Ceiling bleeding may occur if required upper textures are not used.

    223   Ext --   Length Sets Friction in tagged Sector,Sludge<100, Ice>100

    The length of the linedef with type 223 controls the amount of friction
    experienced by the player in the tagged sector, when in contact with the
    floor. Lengths less than 100 are sticker than normal, lengths greater than
    100 are slipperier than normal. The effect is only present in the tagged
    sector when its friction enable bit (bit 8) in the sector type is set.
    This allows the flat to be changed in conjunction with turning the effect
    on or off thru texture/type changes.

    Constant pushers
    ----------------
    Two types of constant pushers are available, wind and current. Depending
    on whether you are above, on, or below (special water sectors) the ground
    level, the amount of force varies.

    The length of the linedef defines the 'full' magnitude of the force, and
    the linedef's angle defines the direction.

         line type         above  on   under
         ---------         -----  --   -----
         wind       224    full  half  none
         current    225    none  full  full

    The linedef should be tagged to the sector where you want the effect. The
    special type of the sector should have bit 9 set (0x200). If this bit
    is turned off, the effect goes away. For example, a fan creating a wind
    could be turned off, and the wind dies, by changing the sector type and
    clearing that bit.

    Constant pushers can be combined with scrolling effects and point
    pushers.

    224  Ext  --   Length/Direction Sets Wind Force in tagged Sectors

    225  Ext  --   Length/Direction Sets Current Force in tagged Sectors

    Point pushers
    -------------
    Two types of point pushers are available, push and pull.

    The previous implementation of these was SECTOR-SPECIFIC. The new
    implementation ignores sector boundaries and provides the effect in a
    circular area whose center is defined by a Thing of type 5001 (push)
    or 5002 (pull). You now also don't have to set any option flags on these
    Things. A new linedef type of 226 is used to control the effect, and this
    line should be tagged to the sector with the 5001/5002 Thing.

    The length of the linedef defines the 'full' magnitude of the force, and
    the force is inversely proportional to distance from the point source. If
    the length of the controlling linedef is L, then the force is reduced to
    zero at a distance of 2L.

    The angle of the controlling linedef is not used.

    The sector where the 5001/5002 Things reside must have bit 9 set (0x200)
    in its type. If this is turned off, the effect goes away.

    Point pushers can be combined with scrolling effects and constant
    pushers.

    226  Ext  --   Length Sets Point Source Wind/Current Force in Tagged Sectors

    ###########################################
    Section 12 Scrolling Walls, Flats, Objects
    ###########################################

    Static Scrollers

    The most basic kind of scrolling linedef causes some part of the tagged
    sector or tagged wall to scroll, in proportion to the length of the
    linedef the trigger is on, and according to the direction that trigger
    linedef lies. For each 32 units of length of the trigger, the tagged
    object scrolls 1 unit per frame. Since the length of a linedef doesn't
    change during gameplay, these types are static, the scrolling effect
    remains constant during gameplay. However, these effects can be combined
    with, and/or canceled by, other scrollers.

    250    -- Scroll Tagged Ceiling

    The ceiling of the tagged sector scrolls in the direction of the linedef
    trigger, 1 unit per frame for each 32 units of linedef trigger length.
    Objects attached to the ceiling do not move.

    251    -- Scroll Tagged Floor

    The floor of the tagged sector scrolls in the direction of the linedef
    trigger, 1 unit per frame for each 32 units of linedef trigger length.
    Objects resting on the floor do not move.

    252    -- Carry Objects on Tagged Floor

    Objects on the floor of the tagged sector move in the direction of the
    linedef trigger, 1 unit per frame for each 32 units of linedef trigger
    length. The floor itself does not scroll.

    253    -- Scroll Tagged Floor, Carry Objects

    Both the floor of the tagged sector and objects resting on that floor
    move in the direction of the linedef trigger, 1 unit per frame for each
    32 units of linedef trigger length.

    254    -- Scroll Tagged Wall, Same as Floor/Ceiling

    Walls with the same tag as the linedef trigger scroll at the same
    rate as a floor or ceiling controlled by one of 250-253, allowing
    their motion to be synchronized. When the linedef trigger is not
    parallel to the wall, the component of the linedef in the direction
    perpendicular to the wall causes the wall to scroll vertically. The
    length of the component parallel to the wall sets the horizontal
    scroll rate, the length of the component perpendicular to the wall
    sets the vertical scroll rate.

    Simple Static Scrollers

    For convenience three simpler static scroll functions are provided
    for when you just need a wall to scroll and don't need to control its
    rate and don't want to bother with proportionality.

    255    -- Scroll Wall Using Sidedef Offsets

    For simplicity, a static scroller is provided that scrolls the first
    sidedef of a linedef, based on its x- and y- offsets. No tag is used.
    The x offset controls the rate of horizontal scrolling, 1 unit per
    frame per x offset, and the y offset controls the rate of vertical
    scrolling, 1 unit per frame per y offset.

    48     -- Animated wall, Scrolls Left

    A linedef with this type scrolls its first sidedef left at a
    constant rate of 1 unit per frame.

    85     -- Animated wall, Scrolls Right

    A linedef with this type scrolls its first sidedef right at a
    constant rate of 1 unit per frame.

    Dynamic Scrolling

    To achieve dynamic scrolling effects, the position or rate of scrolling
    is controlled by the relative position of the floor and ceiling of the
    sector on the scrolling trigger's first sidedef. The direction of
    scrolling remains controlled by the direction of the linedef trigger.
    Either the floor or ceiling may move in the controlling sector, or
    both. The control variable is the amount of change in the sum of the
    floor and ceiling heights.

    All scroll effects are additive, and thus two or more effects may
    reinforce and/or cancel each other.

    Displacement Scrollers

    In the first kind, displacement scrolling, the position of the scrolled
    objects or walls changes proportionally to the motion of the floor or
    ceiling in the sector on the first sidedef of the scrolling trigger.
    The proportionality is set by the length of the linedef trigger. If it
    is 32 units long, the wall, floor, ceiling, or object moves 1 unit for
    each unit the floor or ceiling of the controlling sector moves. If it
    is 64 long, they move 2 units per unit of relative floor/ceiling motion
    in the controlling sector and so on.

    245    -- Scroll Tagged Ceiling w.r.t. 1st Side's Sector

    The tagged sector's ceiling texture scrolls in the direction of the
    scrolling trigger line, when the sector on the trigger's first sidedef
    changes height. The amount moved is the height change times the trigger
    length, divided by 32. Objects attached to the ceiling do not move.

    246    -- Scroll Tagged Floor w.r.t. 1st Side's Sector

    The tagged sector's floor texture scrolls in the direction of the
    scrolling trigger line when the sector on the trigger's first sidedef
    changes height. The amount moved is the height change times the trigger
    length, divided by 32. Objects on the floor do not move.

    247    -- Push Objects on Tagged Floor wrt 1st Side's Sector

    Objects on the tagged sector's floor move in the direction of the
    scrolling trigger line when the sector on the trigger's first sidedef
    changes height. The amount moved is the height change times the trigger
    length, divided by 32.

    248    -- Push Objects & Tagged Floor wrt 1st Side's Sector

    The tagged sector's floor texture, and objects on the floor, move in
    the direction of the scrolling trigger line when the sector on the
    trigger's first sidedef changes height.  The amount moved is the height
    change times the trigger length, divided by 32.

    249    -- Scroll Tagged Wall w.r.t 1st Side's Sector

    Walls with the same tag as the linedef trigger scroll at the same
    rate as a floor or ceiling controlled by one of 245-249, allowing
    their motion to be synchronized. When the linedef trigger is not
    parallel to the wall, the component of the linedef in the direction
    perpendicular to the wall causes the wall to scroll vertically. The
    length of the component parallel to the wall sets the horizontal
    scroll displacement, the length of the component perpendicular to
    the wall sets the vertical scroll displacement. The distance scrolled
    is the controlling sector's height change times the trigger length,
    divided by 32.

    Accelerative Scrollers

    The second kind of dynamic scrollers, accelerative scrollers, also
    react to height changes in the sector on the first sidedef of the
    linedef trigger, but the RATE of scrolling changes, not the
    displacement. That is, changing the controlling sector's height
    speeds up or slows down the scrolling by the change in height
    times the trigger's length, divided by 32.

    An on/off scroller can be made by using an accelerative scroller
    and any linedef that changes the controlling sector's heights.
    If a scroll effect which is initially on is desired, then the
    accelerative scroller should be combined with a static one which
    turns the scroll effect on initially. The accelerative scroller
    would then need to be set up to cancel the static scroller's
    effect when the controlling sector's height changes.

    214    -- Accel Tagged Ceiling w.r.t. 1st Side's Sector

    The tagged sector's ceiling's rate of scroll changes in the direction
    of the trigger linedef (use vector addition if already scrolling) by
    the change in height of the sector on the trigger's first sidedef
    times the length of the linedef trigger, divided by 32. For example,
    if the ceiling is motionless originally, the linedef trigger is 32
    long, and the ceiling of the controlling sector moves 1 unit, the
    tagged ceiling will start scrolling at 1 unit per frame.

    215    -- Accel Tagged Floor w.r.t. 1st Side's Sector

    The tagged sector's floor's rate of scroll changes in the direction of
    the trigger linedef (use vector addition if already scrolling) by the
    change in height of the sector on the trigger's first sidedef times
    the length of the linedef trigger, divided by 32. For example, if
    the floor is motionless originally, the linedef trigger is 32 long,
    and the ceiling of the controlling sector moves 1 unit, the tagged
    floor will start scrolling at 1 unit per frame.

    216    -- Accel Objects on Tagged Floor wrt 1st Side's Sector

    Objects on the tagged sector's floor's rate of motion changes in the
    direction of the trigger linedef (use vector addition if already
    moving) by the change in height of the sector on the trigger's first
    sidedef times the length of the linedef trigger divided by 32. For
    example, if the objects are motionless originally, the linedef trigger
    is 32 long, and the ceiling of the controlling sector moves 1 unit,
    the objects on the tagged floor will start moving at 1 unit per frame.

    217    -- Accel Objects&Tagged Floor wrt 1st Side's Sector

    The tagged sector's floor, and objects on it, change its rate of
    motion in the direction of the trigger linedef (use vector addition
    if already moving) by the change in height of the sector on the
    trigger's first sidedef times the length of the linedef trigger, divided
    by 32. For example, if the floor and objects are motionless originally,
    the linedef trigger is 32 long, and the ceiling of the controlling
    sector moves 1 unit, the objects and the tagged floor will start moving
    at 1 unit per frame.

    218    -- Accel Tagged Wall w.r.t 1st Side's Sector

    Walls with the same tag as the linedef trigger increase their
    scroll rate in sync with a floor or ceiling controlled by one of
    214-217. When the linedef trigger is not parallel to the wall, the
    component of the linedef in the direction perpendicular to the wall
    causes the wall to increase its vertical scroll rate. The length of
    the component parallel to the wall sets the change in horizontal
    scroll rate, the length of the component perpendicular to the wall
    sets the change in vertical scroll rate. The rate change is the height
    change times the trigger length, divided by 32.

    ======================================================================

    #######################################################
    Section 13 Detailed Generalized Linedef Specification
    #######################################################

    BOOM has added generalized linedef types that permit the parameters
    of linedef actions to be nearly independently chosen.

    To support these, DETH has been modified to support them via dialogs
    for each generalized type; each dialog allows the parameters for
    that type to be independently specified by choice from a array of
    radio buttons. A parser has also been added to support reading back
    the function of a generalized linedef from its type number.

    NOTE to wad authors:

    This requires a lot of type numbers, 20608 in all so far. Some
    editors may object to the presence of these new types thru assuming
    that a lookup table of size 256 suffices (or some other reason). For
    those that must continue to use such an editor, it may be necessary
    to stick to the old linedef types, which are still present.

    We are also providing command line tools to set these linedef types,
    independent of which editor you happen to use, but they are a lot
    less slick, and more difficult to use than DETH. See TRIGCALC.EXE and
    CLED.EXE in the EDITUTIL.ZIP package of the BOOM distribution.

    == Generalized Linedef Ranges =======================================

    There are types for Floors, Ceilings, Doors, Locked Doors, Lifts,
    Stairs, and Crushers. The allocation of linedef type field numbers is
    according to the following table:

    Type            Start      Length   (Dec)
    -----------------------------------------------------------------
    Floors          0x6000     0x2000  (8192)
    Ceilings        0x4000     0x2000  (8192)
    Doors           0x3c00     0x0400  (1024)
    Locked Doors    0x3800     0x0400  (1024)
    Lifts           0x3400     0x0400  (1024)
    Stairs          0x3000     0x0400  (1024)
    Crushers        0x2F80     0x0080   (128)
    -----------------------------------------------------------------
    Totals:  0x2f80-0x7fff     0x5080  (20608)

    ======================================================================

    The following sections define the placement and meaning of the bit
    fields within each linedef category. Fields in the description are
    listed in increasing numeric order.

    Some nomenclature:

    Target height designations:

    H means highest, L means lowest, N means next, F means floor, C means
    ceiling, n means neighbor, Cr means crush, sT means shortest
    lower texture.

    Texture change designations:

    c0n  change texture, change sector type to 0, numeric model change
    c0t  change texture, change sector type to 0, trigger model change
    cTn  change texture only, numeric model change
    cTt  change texture only, trigger model change
    cSn  change texture and sector type to model's, numeric model change
    cSt  change texture and sector type to model's, trigger model change

    A trigger model change uses the sector on the first side of the
    trigger for its model. A numeric model change looks at the sectors
    adjoining the tagged sector at the target height, and chooses the one
    across the lowest numbered two sided line for its model. If no model
    exists, no change occurs. Note that in DOOM II v1.9, no model meant
    an illegal sector type was generated.

    ------------------------------------------------------------------
    generalized floors (8192 types)

    field   description                       NBits   Mask     Shift
    ------------------------------------------------------------------

    trigger W1/WR/S1/SR/G1/GR/D1/DR            3     0x0007      0
    speed   slow/normal/fast/turbo             2     0x0018      3
    model   trig/numeric -or- nomonst/monst    1     0x0020      5
    direct  down/up                            1     0x0040      6
    target  HnF/LnF/NnF/LnC/C/sT/24/32         3     0x0380      7
    change  nochg/zero/txtonly/type            2     0x0c00      10
    crush   no/yes                             1     0x1000      12

    DETH Nomenclature:

    W1[m] F->HnF DnS [c0t] [Cr]
    WR[m] F->LnF DnN [c0n]
    S1[m] F->NnF DnF [cTt]
    SR[m] F->LnC DnT [cTn]
    G1[m] F->C   UpS [cSt]
    GR[m] FbysT  UpN [cSn]
    D1[m] Fby24  UpF
    DR[m] Fby32  UpT

    Notes:

    1) When change is nochg, model is 1 when monsters can activate trigger
       otherwise monsters cannot activate it.
    2) The change fields mean the following:
       nochg   - means no texture change or type change
       zero    - means sector type is zeroed, texture copied from model
       txtonly - means sector type unchanged, texture copied from model
       type    - means sector type and floor texture are copied from model
    3) down/up specifies the "normal" direction for moving. If the
       target specifies motion in the opposite direction, motion is instant.
       Otherwise it occurs at speed specified by speed field.
    4) Speed is 1/2/4/8 units per tic
    5) If change is nonzero then model determines which sector is copied.
       If model is 0 its the sector on the first side of the trigger.
       if model is 1 (numeric) then the model sector is the sector at
       destination height on the opposite side of the lowest numbered
       two sided linedef around the tagged sector. If it doesn't exist
       no change occurs.

    ------------------------------------------------------------------
    generalized ceilings (8192 types)

    field   description                        NBits   Mask     Shift
    ------------------------------------------------------------------

    trigger W1/WR/S1/SR/G1/GR/D1/DR             3     0x0007      0
    speed   slow/normal/fast/turbo              2     0x0018      3
    model   trig/numeric -or- nomonst/monst     1     0x0020      5
    direct  down/up                             1     0x0040      6
    target  HnC/LnC/NnC/HnF/F/sT/24/32          3     0x0380      7
    change  nochg/zero/txtonly/type             2     0x0c00      10
    crush   no/yes                              1     0x1000      12

    DETH Nomenclature:

    W1[m] C->HnC DnS [Cr] [c0t]
    WR[m] C->LnC DnN      [c0n]
    S1[m] C->NnC DnF      [cTt]
    SR[m] C->HnF DnT      [cTn]
    G1[m] C->F   UpS      [cSt]
    GR[m] CbysT  UpN      [cSn]
    D1[m] Cby24  UpF
    DR[m] Cby32  UpT

    Notes:

    1) When change is nochg, model is 1 when monsters can activate trigger
       otherwise monsters cannot activate it.
    2) The change fields mean the following:
       nochg   - means no texture change or type change
       zero    - means sector type is zeroed, texture copied from model
       txtonly - means sector type unchanged, texture copied from model
       type    - means sector type and ceiling texture are copied from model
    3) down/up specifies the "normal" direction for moving. If the
       target specifies motion in the opposite direction, motion is instant.
       Otherwise it occurs at speed specified by speed field.
    4) Speed is 1/2/4/8 units per tic
    5) If change is nonzero then model determines which sector is copied.
       If model is 0 its the sector on the first side of the trigger.
       if model is 1 (numeric) then the model sector is the sector at
       destination height on the opposite side of the lowest numbered
       two sided linedef around the tagged sector. If it doesn't exist
       no change occurs.

    ------------------------------------------------------------------
    generalized doors (1024 types)

    field   description                       NBits    Mask     Shift
    ------------------------------------------------------------------

    trigger W1/WR/S1/SR/G1/GR/D1/DR            3      0x0007      0
    speed   slow/normal/fast/turbo             2      0x0018      3
    kind    odc/o/cdo/c                        2      0x0060      5
    monster n/y                                1      0x0080      7
    delay   1/4/9/30 (secs)                    2      0x0300      8

    DETH Nomenclature:

    W1[m] OpnD{1|4|9|30}Cls S
    WR[m] Opn               N
    S1[m] ClsD{1|4|9|30}Opn F
    SR[m] Cls               T
    G1[m]
    GR[m]
    D1[m]
    DR[m]

    Notes:

    1) The odc (Open, Delay, Close) and cdo (Close, Delay, Open) kinds use
       the delay field. The o (Open and Stay) and c (Close and Stay) kinds
       do not.
    2) The precise delay timings in gametics are: 35/150/300/1050
    3) Speed is 2/4/8/16 units per tic

    ------------------------------------------------------------------
    generalized locked doors (1024 types)

    field   description                       NBits    Mask     Shift
    ------------------------------------------------------------------

    trigger W1/WR/S1/SR/G1/GR/D1/DR            3      0x0007      0
    speed   slow/normal/fast/turbo             2      0x0018      3
    kind    odc/o                              1      0x0020      5
    lock    any/rc/bc/yc/rs/bs/ys/all          3      0x01c0      6
    sk=ck   n/y                                1      0x0200      9

    DETH Nomenclature:

    W1[m] OpnDCls           S Any
    WR[m] Opn               N R{C|S|K}
    S1[m]                   F B{C|S|K}
    SR[m]                   T Y{C|S|K}
    G1[m]                     All{3|6}
    GR[m]
    D1[m]
    DR[m]

    Notes:

    1) Delay for odc kind is constant at 150 gametics or about 4.333 secs
    2) The lock field allows any key to open a door, or a specific key to
       open a door, or all keys to open a door.
    3) If the sk=ck field is 0 (n) skull and cards are different keys,
       otherwise they are treated identically. Hence an "all" type door
       requires 3 keys if sk=ck is 1, and 6 keys if sk=ck is 0.
    4) Speed is 2/4/8/16 units per tic

    -------------------------------------------------------------------
    generalized lifts (1024 types)

    field   description                       NBits    Mask     Shift
    -------------------------------------------------------------------

    trigger W1/WR/S1/SR/G1/GR/D1/DR            3      0x0007      0
    speed   slow/normal/fast/turbo             2      0x0018      3
    monster n/y                                1      0x0020      5
    delay   1/3/5/10 (secs)                    2      0x00c0      6
    target  LnF/NnF/LnC/LnF<->HnF(perp.)       2      0x0300      8

    DETH Nomenclature:

    W1[m] Lft  F->LnFD{1|3|5|10}    S
    WR[m]      F->NnFD{1|3|5|10}    N
    S1[m]      F->LnCD{1|3|5|10}    F
    SR[m]      HnF<->LnFD{1|3|5|10} T
    G1[m]
    GR[m]
    D1[m]
    DR[m]

    Notes:

    1) The precise delay timings in gametics are: 35/105/165/350
    2) Speed is 1/2/4/8 units per tic
    3) If the target specified is above starting floor height, or does not
       exist the lift does not move when triggered. NnF is Next Lowest
       Neighbor Floor.
    4) Starting a perpetual lift between lowest and highest neighboring floors
       locks out all other floor actions on the sector, even if it is stopped
       with the non-extended stop perpetual floor function.

    -------------------------------------------------------------------
    generalized stairs (1024 types)

    field   description                       NBits    Mask     Shift
    -------------------------------------------------------------------

    trigger W1/WR/S1/SR/G1/GR/D1/DR            3      0x0007      0
    speed   slow/normal/fast/turbo             2      0x0018      3
    monster n/y                                1      0x0020      5
    step    4/8/16/24                          2      0x00c0      6
    dir     dn/up                              1      0x0100      8
    igntxt  n/y                                1      0x0200      9

    DETH Nomenclature:

    W1[m] Stair Dn s4  S [Ign]
    WR[m]       Up s8  N
    S1[m]          s16 F
    SR[m]          s24 T
    G1[m]
    GR[m]
    D1[m]
    DR[m]

    Notes:

    1) Speed is .25/.5/2/4 units per tic
    2) If igntxt is 1, then the staircase will not stop building when
       a step does not have the same texture as the previous.
    3) A retriggerable stairs builds up and down alternately on each
       trigger.

    -------------------------------------------------------------------
    generalized crushers (128 types)

    field   description                       NBits    Mask     Shift
    -------------------------------------------------------------------

    trigger W1/WR/S1/SR/G1/GR/D1/DR            3      0x0007      0
    speed   slow/normal/fast/turbo             2      0x0018      3
    monster n/y                                1      0x0020      5
    silent  n/y                                1      0x0040      6

    DETH Nomenclature:

    W1[m] Crusher S [Silent]
    WR[m]         N
    S1[m]         F
    SR[m]         T
    G1[m]
    GR[m]
    D1[m]
    DR[m]

    Notes:

    1) Speed is 1/2/4/8 units per second, faster means slower damage as usual.
    2) If silent is 1, the crusher is totally quiet, no start/stop sounds

    ======================================================================
                            Part II Sector Types
    ======================================================================

    BOOM is backward compatible with DOOM's sector types. All types 0-17
    have the same meaning they did under DOOM. Types 18-31 are reserved
    for extended sector types, that work like DOOM's and share the
    limitation that only one type can be active in a sector at once. No
    extended sector types are implemented at this time.

    ####################################
    Section 14. Regular Sector types
    ####################################

    From Matt Fell's Unofficial DOOM Spec the DOOM sector types are:

    Dec Hex Class   Description
    -------------------------------------------------------------------
     0  00  -       Normal, no special characteristic.
     1  01  Light   random off
     2  02  Light   blink 0.5 second
     3  03  Light   blink 1.0 second
     4  04  Both    -10/20% health AND light blink 0.5 second
     5  05  Damage  -5/10% health
     7  07  Damage  -2/5% health
     8  08  Light   oscillates
     9  09  Secret  a player must stand in this sector to get credit for
                      finding this secret. This is for the SECRETS ratio
                      on inter-level screens.
    10  0a  Door    30 seconds after level start, ceiling closes like a door.
    11  0b  End     -10/20% health. If a player's health is lowered to less
                      than 11% while standing here, then the level ends! Play
                      proceeds to the next level. If it is a final level
                      (levels 8 in DOOM 1, level 30 in DOOM 2), the game ends!
    12  0c  Light   blink 0.5 second, synchronized
    13  0d  Light   blink 1.0 second, synchronized
    14  0e  Door    300 seconds after level start, ceiling opens like a door.
    16  10  Damage  -10/20% health

    17  11  Light   flickers on and off randomly

    Note that BOOM will NEVER exit the game on an illegal sector type, as
    was the case with DOOM. The sector type will merely be ignored.

    ####################################
    Section 15. Generalized sector types
    ####################################

    BOOM also provides generalized sector types, based on bit fields,
    that allow several sector type properties to be independently
    specified for a sector. Texture change linedefs can be used to switch
    some or all of these properties dynamically, outside lighting.

    Bits 0 thru 4 specify the lighting type in the sector, the same codes
    that DOOM used are employed:

    Dec Bits 4-0   Description
    -------------------------------------------------------------------
    0   00000      Normal lighting
    1   00001      random off
    2   00010      blink 0.5 second
    3   00011      blink 1.0 second
    4   00100      -10/20% health AND light blink 0.5 second
    8   01000      oscillates
    12  01100      blink 0.5 second, synchronized
    13  01101      blink 1.0 second, synchronized
    17  10001      flickers on and off randomly

    Bits 5 and 6 set the damage type of the sector, with the usual
    5/10/20 damage units per second.

    Dec Bits 6-5   Description
    -------------------------------------------------------------------
    0   00         No damage
    32  01         5  units damage per sec (halve damage in TYTD skill)
    64  10         10 units damage per sec
    96  11         20 units damage per sec

    Bit 7 makes the sector count towards the secrets total at game end

    Dec Bit 7      Description
    -------------------------------------------------------------------
    0    0         Sector is not secret
    128  1         Sector is secret

    Bit 8 enables the ice/mud effect controlled by linedef 223

    Dec Bit 8      Description
    -------------------------------------------------------------------
    0    0         Sector friction disabled
    256  1         Sector friction enabled

    Bit 9 enables the wind effects controlled by linedefs 224-226

    Dec Bit 9      Description
    -------------------------------------------------------------------
    0    0         Sector wind disabled
    512  1         Sector wind enabled

    Bits 10 and 11 are not implemented yet, but are reserved for use in
    sound control. Bit 10 will suppress all sounds within the sector,
    while bit 11 will disable any sounds due to floor or ceiling motion
    by the sector.

    ======================================================================
                            Part III Linedef Flags
    ======================================================================

    Only one new linedef flag is implemented, called PassThru, which
    allows a push or switch linedef trigger to pass the push action thru
    it to ones within range behind it. In this way BOOM is capable of
    setting off many actions with a single push. Note that the limitation
    of one floor action, one ceiling action, and one lighting action per
    sector affected still applies however.

    The new linedef flag is bit 9, value 512, in the linedef flags word.

    ======================================================================
                            Part IV Thing Flags
    ======================================================================

    BOOM has implemented two new thing flags, "not in DM" and "not in
    COOP", which in combination with the existing "not in Single" flag,
    usually called "Multiplayer", allow complete control over a level's
    inventory and monsters, in any game mode.

    If you want a thing to be only available in Single play, you set both
    the "not in DM" and "not in COOP" flags. Other combinations are
    similar.

    "not in DM"   is bit 5, value 32, in the thing flags word.
    "not in COOP" is bit 6, value 64, in the thing flags word.

    ======================================================================
                            Part V Thing Types
    ======================================================================

    BOOM has implemented two new thing types as well, MT_PUSH (5001), and
    MT_PULL(5002). These control the origin of the point source wind
    effect controlled by linedef types 225 and 226, and set whether the
    wind blows towards or away from the origin depending on which is
    used.

    ======================================================================
                            Part VI BOOM Predefined Lumps
    ======================================================================

    BOOM supports resources embedded in the .EXE that are loaded before
    all other resources. They can be replaced by resources of the same
    name in the IWAD or add-on PWADs. These resources can be extracted
    into a wad thru use of the command:

    BOOM -dumplumps predef.wad

    You can then extract the resources from predef.wad to alter them for
    replacement purposes.

    Menu text
    ---------
    M_HORSEN       Mouse horizontal sensitivity menu
    M_VERSEN       Mouse vertical sensitivity menu
    M_SETUP        Setup menu entry in main menu
    M_KEYBND       Key Bindings entry in setup menu
    M_AUTO         Automap entry in setup menu
    M_CHAT         Chat string entry in setup menu
    M_ENEM         Enemies options entry in setup menu
    M_STAT         Status bar and Hud entry in setup menu
    M_WEAP         Weapons entry in setup menu
    M_MESS         Message option entry in setup menu
    M_COLORS       Palette color picker diagram
    M_PALNO        Xed-out symbol for unused automap features
    M_BUTT1        Setup reset button off state
    M_BUTT2        Setup reset button on state

    Font chars
    ----------
    STCFN096       ` character for standard DOOM font

    STBR123        HUD font bargraph char, full, 4 vertical bars
    STBR124        HUD font bargraph char, partial, 3 vertical bars
    STBR125        HUD font bargraph char, partial, 2 vertical bars
    STBR126        HUD font bargraph char, partial, 1 vertical bars
    STBR127        HUD font bargraph char, empty, 0 vertical bars

    DIG0         HUD font 0 char
    DIG1         HUD font 1 char
    DIG2         HUD font 2 char
    DIG3         HUD font 3 char
    DIG4         HUD font 4 char
    DIG5         HUD font 5 char
    DIG6         HUD font 6 char
    DIG7         HUD font 7 char
    DIG8         HUD font 8 char
    DIG9         HUD font 9 char
    DIGA         HUD font A char
    DIGB         HUD font B char
    DIGC         HUD font C char
    DIGD         HUD font D char
    DIGE         HUD font E char
    DIGF         HUD font F char
    DIGG         HUD font G char
    DIGH         HUD font H char
    DIGI         HUD font I char
    DIGJ         HUD font J char
    DIGK         HUD font K char
    DIGL         HUD font L char
    DIGM         HUD font M char
    DIGN         HUD font N char
    DIGO         HUD font O char
    DIGP         HUD font P char
    DIGQ         HUD font Q char
    DIGR         HUD font R char
    DIGS         HUD font S char
    DIGT         HUD font T char
    DIGU         HUD font U char
    DIGV         HUD font V char
    DIGW         HUD font W char
    DIGX         HUD font X char
    DIGY         HUD font Y char
    DIGZ         HUD font Z char
    DIG45        HUD font - char
    DIG47        HUD font / char
    DIG58        HUD font : char
    DIG91        HUD font [ char
    DIG93        HUD font ] char

    Status bar
    ----------
    STKEYS6        Both blue keys graphic
    STKEYS7        Both yellow keys graphic
    STKEYS8        Both red keys graphic

    Box chars
    ---------
    BOXUL        Upper left corner of box
    BOXUC        Center of upper border of box
    BOXUR        Upper right corner of box
    BOXCL        Center of left border of box
    BOXCC        Center of box
    BOXCR        Center of right border of box
    BOXLL        Lower left corner of box
    BOXLC        Center of lower border of box
    BOXLR        Lower right corner of box

    Lumps missing in v1.1
    ---------------------
    STTMINUS       minus sign for neg frags in status bar
    WIMINUS        minus sign for neg frags on end screen
    M_NMARE        nightmare skill menu string
    STBAR          status bar background
    DSGETPOW       sound for obtaining power-up

    Text end screen
    ---------------
    ENDBOOM        Text displayed at end of game, 80X25 with attributes

    Sprites
    -------
    TNT1A0         Invisible sprite for push/pull controller things

    Switches and Animations
    -----------------------
    SWITCHES       Definition of switch textures recognized
    ANIMATED       Definition of animated textures and flats recognized

    SWITCHES format:

    The SWITCHES lump makes the names of the switch textures used in the
    game known to the engine. It consists of a list of records each 20
    bytes long, terminated by an entry (not used) whose last 2 bytes are 0.

    9 bytes        Null terminated string naming "off" state texture for switch
    9 bytes        Null terminated string naming "on" state texture for switch
    2 bytes        Short integer for the IWADs switch will work in
                    1=shareware
                    2=registered/retail DOOM or shareware
                    3=DOOM II, registered/retail DOOM, or shareware
                    0=terminates list of known switches

    ANIMATED format:

    The ANIMATED lump makes the names of the animated flats and textures
    known to the engine. It consists of a list of records, each 23 bytes
    long, terminated by a record (not used) whose first byte is -1 (255).

    1 byte         -1 to terminate list, 0 if a flat, 1 if a texture
    9 bytes        Null terminated string naming last texture/flat in animation
    9 bytes        Null terminated string naming first texture/flat in animation
    4 bytes        Animation speed, number of frames between animation changes

    The utility package contains a program, SWANTBLS.EXE that will
    generate both the SWITCHES and ANIMATED lumps from a text file. An
    example is provided, DEFSWANI.DAT that generates the standard set of
    switches and animations for DOOM.

    Colormaps
    ---------
    WATERMAP       Custom greenish colormap for underwater use

    The WATERMAP lump has the same format as COLORMAP, 34 tables of 256
    bytes each, see the UDS for details. Note that colormaps you add to
    a PWAD must be between C_START and C_END markers.

    The utility package contains a program, CMAPTOOL.EXE, that will
    generate custom colormaps for use with BOOM. It also includes 7
    premade colormaps, and an add-on wad containing them.

    Color translation tables
    ------------------------
    CRBRICK        Translates red range to brick red
    CRTAN          Translates red range to tan
    CRGRAY         Translates red range to gray
    CRGREEN        Translates red range to green
    CRBROWN        Translates red range to brown
    CRGOLD         Translates red range to dark yellow
    CRRED          Translates red range to red range (no change)
    CRBLUE         Translates red range to light blue
    CRBLUE2        Translates red range to dark blue (status bar numerals)
    CRORANGE       Translates red range to orange
    CRYELLOW       Translates red range to light yellow

    These tables are used to translate the red font characters to other
    colors. They are made replaceable in order to support custom palettes
    in TC's better. Note however that the font character graphics must
    be defined using the palette indices for the standard red range of the
    palette 176-191.

    -END OF DOCUMENT----------------------------------------------------------