Q2PRO Client Manual
===================
Andrey Nazarov <skuller@skuller.net>

About
-----
Q2PRO is an enhanced, multiplayer oriented Quake 2 client, compatible
with existing Quake 2 ports and licensed under GPLv2. This document provides
descriptions of console variables and commands added to or modified by Q2PRO
since the original Quake 2 release. Cvars and commands inherited from original
Quake 2 are not described here (yet).

Variables
---------

Netcode
~~~~~~~

Q2PRO client supports separation of outgoing packet rate, physics frame rate
and rendering frame rate. Separation of physics and rendering frame rates is
accomplished in R1Q2 ‘cl_async’ style and is enabled by default.

In addition to this, Q2PRO network protocol is able to pack several input
commands into the single network packet for outgoing packet rate reduction.
This is very useful for some types of network links like Wi-Fi that can't deal
with large number of small packets and cause packet delay or loss. Q2PRO
protocol is only in use when connected to a Q2PRO server.

For the default Quake 2 protocol and R1Q2 protocol a hacky solution exists,
which exploits dropped packet recovery mechanism for the purpose of packet
rate reduction. This hack is disabled by default.

cl_protocol::
    Specifies preferred network protocol version to use when connecting to
    servers.  If the server doesn't support the specified protocol, client will
    fall back to the previous supported version. Default value is 0.
        - 0 — automatically select the highest protocol version supported
        - 34 — use default Quake 2 protocol
        - 35 — use enhanced R1Q2 protocol
        - 36 — use enhanced Q2PRO protocol

cl_maxpackets::
    Number of packets client sends per second. 0 means no particular limit.
    Unless connected using Q2PRO protocol, this variable is ignored and packets
    are sent in sync with client physics frame rate, controlled with
    ‘cl_maxfps’ variable. Default value is 30.

cl_fuzzhack::
    Enables ‘cl_maxpackets’ limit even if Q2PRO protocol is not in use by
    dropping packets. This is not a generally recommended thing to do, but can
    be enabled if nothing else helps to reduce ping. Default value is 0
    (disabled).

cl_packetdup::
    Number of backup movement commands client includes in each new packet,
    directly impacts upload rate. Unless connected using Q2PRO protocol,
    hardcoded value of 2 backups per packet is used. Default value is 1.

cl_instantpacket::
    Specifies if important events such as pressing ‘+attack’ or ‘+use’ are sent
    to the server immediately, ignoring any rate limits. Default value is 1
    (enabled).

cl_async::
    Controls rendering frame rate and physics frame rate separation. Default
    value is 1. Influence of ‘cl_async’ on client framerates is summarized in
    the table below.
        - 0 — run synchronous, like original Quake 2 does
        - 1 — run asynchronous
        - 2 — run asynchronous, limit rendering frame rate to monitor's vertical
        retrace frequency (supported only by X11/GLX drivers)

.Rate limits depending on ‘cl_async’ value
[options="header"]
|===================================================================
| Value of ‘cl_async’ | Rendering          | Physics   | Main loop
| 0                   | cl_maxfps          | cl_maxfps | cl_maxfps
| 1                   | r_maxfps           | cl_maxfps | _unlimited_
| 2                   | _vertical refresh_ | cl_maxfps | _unlimited_
|===================================================================

r_maxfps::
    Specifies maximum rendering frame rate if ‘cl_async’ is set to 1, otherwise
    ignored.  Default value is 0, which means no particular limit.

cl_maxfps::
    Specifies client physics frame rate if ‘cl_async’ 1 or 2 is used.
    Otherwise, limits both rendering and physics frame rates. Default value is
    60.

cl_gibs::
    Controls rendering of entities with ‘EF_GIB’ flag set. When using Q2PRO
    protocol, disabling this saves some bandwidth since the server stops
    sending these entities at all. Default value is 1 (enabled).

cl_gun::
    Controls rendering of the player's own gun model. When using R1Q2 or Q2PRO
    protocol, disabling this saves some bandwidth since the server stops
    sending gun updates at all. Default value is 1 (enabled).

cl_footsteps::
    Controls footstep sounds. When using Q2PRO protocol, disabling this saves
    some bandwidth since the server stops sending footstep events at all.
    Default value is 1 (enabled).

cl_updaterate::
    Specifies the perferred update rate requested from Q2PRO servers. Only used
    when server is running in variable FPS mode, otherwise default rate of 10
    packets per second is used. Specified rate should evenly divide native
    server frame rate.  Default value is 0, which means to use the highest
    update rate available (that is, native server frame rate).


Network
~~~~~~~

net_enable_ipv6::
    Enables IPv6 support. Default value is 1 on systems that support IPv6 and 0
    otherwise.
      - 0 — disable IPv6, use IPv4 only
      - 1 — enable IPv6, but prefer IPv4 over IPv6 when resolving host names
      with multiple addresses
      - 2 — enable IPv6, use normal address resolver priority configured by OS

net_ip::
    Specifies network interface address client should use for outgoing UDP
    connections using IPv4.  Default value is empty, which means that default
    network interface is used.

net_ip6::
    Specifies network interface address client should use for outgoing UDP
    connections using IPv6.  Default value is empty, which means that default
    network interface is used. Has no effect unless ‘net_enable_ipv6’ is set to
    non-zero value.

net_clientport::
    Specifies UDP port number client should use for outgoing connections (using
    IPv4 or IPv6).  Default value is -1, which means that random port number is
    chosen at socket creation time.

net_maxmsglen::
    Specifies maximum server to client packet size client will request from
    servers. 0 means no hard limit. Default value is conservative 1390 bytes.
    It is nice to have this variable as close to your network link MTU as
    possible (accounting for headers). Thus for normal Ethernet MTU of 1500
    bytes 1462 can be specified (10 bytes quake header, 8 bytes UDP header, 20
    bytes IPv4 header). Higher values may cause IP fragmentation which is
    better to avoid. Servers will cap this variable to their own maximum
    values.  Please don't change this variable unless you know exactly what you
    are doing.

net_chantype::
    Specifies if enhanced Q2PRO network channel implementation is enabled when
    connecting to Q2PRO servers. Q2PRO netchan supports application-level
    fragmentation of datagrams that results is better gamestate compression
    ratio and faster map load times.  Default value is 1 (enabled).

Triggers
~~~~~~~~

cl_beginmapcmd::
    Specifies command to be executed each time client enters a new map. Default
    value is empty.

cl_changemapcmd::
    Specifies command to be executed each time client begins loading a new map.
    Default value is empty.

cl_disconnectcmd::
    Specifies command to be executed each time client disconnects from the
    server. Default value is empty.

See also ‘trigger’ client command description.


Effects
~~~~~~~

.Color specification
********************
Colors can be specified in one of the following formats:

- #RRGGBBAA, where R, G, B and A are hex digits
- #RRGGBB, which implies alpha value of FF
- #RGB, which is expanded to #RRGGBB by duplicating digits
- one of the predefined color names (black, red, etc)
********************

cl_railtrail_type::
    Defines which type of rail trail effect to use. Default value is 0.
      - 0 — use original effect
      - 1 — use alternative effect, draw rail core only
      - 2 — use alternative effect, draw rail core and spiral

NOTE: Rail trail variables listed below apply to the alternative effect only.

cl_railtrail_time::
    Time, in seconds, for the rail trail to be visible. Default value is 1.0.

cl_railcore_color::
    Color of the rail core beam. Default value is "red".

cl_railcore_width::
    Width of the rail core beam. Default value is 3.

cl_railspiral_color::
    Color of the rail spiral. Default value is "blue".

cl_railspiral_radius::
    Radius of the rail spiral. Default value is 3.

cl_disable_particles::
    Disables rendering of particles for the following effects. This variable is
    a bitmask. Default value is 0.
      - 1 — grenade explosions
      - 2 — grenade trails
      - 4 — rocket explosions
      - 8 — rocket trails

.Bitmasks
TIP: Bitmask cvars allow multiple features to be enabled. To enable the needed
set of features, their values need to be summed.

cl_disable_explosions::
    Disables rendering of animated models for the following effects. This
    variable is a bitmask. Default value is 0.
      - 1 — grenade explosions
      - 2 — rocket explosions

cl_noglow::
    Disables the glowing effect on bonus entities like ammo, health, etc.
    Default value is 0 (glowing enabled).

cl_gunalpha::
    Specifies opacity level of the player's own gun model. Default value is 1
    (fully opaque).

Sound Subsystem
~~~~~~~~~~~~~~~

s_enable::
    Specifies which sound engine to use. Default value is 1.
      - 0 — sound is disabled
      - 1 — use DMA sound engine
      - 2 — use OpenAL sound engine

s_ambient::
    Specifies if ambient sounds are played. Default value is 1.
      - 0 — all ambient sounds are disabled
      - 1 — all ambient sounds are enabled
      - 2 — only ambient sounds from visible entities are enabled (rocket
        flybys, etc)
      - 3 — only ambient sounds from player entity are enabled (railgun hum,
        hand grenade ticks, etc)

s_auto_focus::
    Specifies the minimum focus level main Q2PRO window should have for sound
    to be activated.  Default value is 0.
      - 0 — sound is always activated
      - 1 — sound is activated when main window is visible, and deactivated
      when it is iconified, or moved to another desktop
      - 2 — sound is activated when main window has input focus, and deactivated
      when it loses it

s_swapstereo:
    Swap left and right audio channels. Only effective when using DMA sound
    engine. Default value is 0 (don't swap).

al_driver::
    Specifies the name of OpenAL driver to use. Default value is ‘openal32’
    on Windows, and ‘libopenal.so.1’ on Linux.

al_device::
    Specifies the name of OpenAL device to use. Format of this value depends on
    your OpenAL implementation. Default value is empty, which means default
    sound output device is used.

TIP: On Windows, there are two well-known OpenAL implementations available:
http://connect.creativelabs.com/openal/[OpenAL32] from Creative, with
support for harware acceleration on certain audio cards, and an open source
software implementation named http://kcat.strangesoft.net/openal.html[OpenAL Soft].
Both should work with Q2PRO, but to get the results most perceptually close to
original Quake 2 sound, I recommend using OpenAL Soft. Creative's
implementation seems to perform some default effects processing even when not
requested, and that makes it sound somewhat differently. With OpenAL Soft in
stereo configuration I can't really tell if I'm using OpenAL or default Quake 2
sound engine. Of course you can install both implementations and switch between
them by changing ‘al_driver’ variable between ‘openal32’ and ‘soft_oal’.


Graphical Console
~~~~~~~~~~~~~~~~~

con_clock::
    Toggles drawing of the digital clock at the lower right corner of console.
    Default value is 0 (disabled).

con_height::
    Fraction of the screen in-game console occupies. Default value is 0.5.

con_alpha::
    Opacity of in-game console background. 0 is fully transparent, 1 is opaque.
    Default value is 1.

con_scale::
    Scaling factor of the console text. Takes effect in OpenGL mode only.
    Default value is 1. Automatically scales depending on current display
    resolution when set to 0.

con_font::
    Font used for drawing console text. Default value is "conchars".

con_background::
    Image used as console background. Default value is "conback".

con_notifylines::
    Number of the last console lines displayed in the notification area in
    game.  Default value is 4.

con_history::
    Specifies how many lines to save into console history file before exiting
    Q2PRO, to be reloaded on next startup. Maximum number of history lines is
    128. Default value is 0.

con_scroll::
    Controls automatic scrolling of console text when some event occurs. This
    variable is a bitmask. Default value is 0.
      - 1 — when new command is entered
      - 2 — when new lines are printed


Game Screen
~~~~~~~~~~~

scr_draw2d::
    Toggles drawing of 2D elements on the screen. Default value is 2.
      - 0 — do not draw anything
      - 1 — do not draw stats program
      - 2 — draw everything

scr_showturtle::
    Toggles drawing of various network error conditions at the lower left
    corner of the screen. Default value is 1 (draw all errors except of
    SUPPRESSED, CLIENTDROP and SERVERDROP). Values higher than 1 draw all
    errors.

.Types of network errors
************************
[horizontal]
SERVERDROP:: Packets from server to client were dropped by the network.
CLIENTDROP:: A few packets from client to server were dropped by the network.
             Server recovered player's movement using backup commands.
CLIENTPRED:: Many packets from client to server were dropped by the network.
             Server ran out of backup commands and had to predict player's movement.
NODELTA::    Server sent an uncompressed frame. Typically occurs during
             a heavy lag, when a lot of packets are dropped by the network.
SUPPRESSED:: Server suppressed packets to client because rate limit was exceeded.
BADFRAME::   Server sent an invalid delta compressed frame.
OLDFRAME::   Server sent a delta compressed frame that is too old and
             can't be recovered.
OLDENT::     Server sent a delta compressed frame whose entities are too
             old and can't be recovered.
************************

scr_demobar::
    Toggles drawing of progress bar at the bottom of the screen during demo
    playback. Default value is 1.
      - 0 — do not draw demo bar
      - 1 — draw demo bar and demo completion percentage
      - 2 — draw demo bar, demo completion percentage and current demo time

scr_showpause::
    Toggles drawing of pause indicator on the screen. Default value is 1.
      - 0 — do not draw pause indicator
      - 1 — draw pic in center of the screen
      - 2 — draw text in demo bar (visible only during demo playback)

scr_scale::
    Scaling factor of the HUD elements. Takes effect in OpenGL mode only.
    Default value is 1. Automatically scales depending on current display
    resolution when set to 0.

scr_alpha::
    Opacity of the HUD elements. 0 is fully transparent, 1 is opaque. Default
    value is 1.

scr_font::
    Font used for drawing HUD text. Default value is "conchars".

scr_lag_draw::
    Toggles drawing of small (48x48 pixels) ping graph on the screen. Default
    value is 0.
      - 0 — do not draw graph
      - 1 — draw transparent graph
      - 2 — overlay graph on gray background

scr_lag_x::
    Absolute value of this cvar specifies horizontal placement of the ping graph,
    counted in pixels from the screen edge. Negative values align graph to the right
    edge of the screen instead of the left edge. Default value is -1.

scr_lag_y::
    Absolute value of this cvar specifies vertical placement of the ping graph,
    counted in pixels from the screen edge. Negative values align graph to the bottom
    edge of the screen intead of the top edge. Default value is -1.

scr_lag_min::
    Specifies ping graph offset by defining the minimum value that can be
    displayed. Default value is 0.

scr_lag_max::
    Specifies ping graph scale by defining the maximum value that can be
    displayed. Default value is 200.

scr_chathud::
    Toggles drawing of the last chat lines on the screen. Default value is 0.
      - 0 — do not draw chat lines
      - 1 — draw chat lines in normal color
      - 2 — draw chat lines in alternative color

scr_chathud_lines::
    Specifies number of the last chat lines drawn on the screen. Default value
    is 4. Maximum value is 32.

scr_chathud_time::
    Specifies visibility time of each chat line, counted in seconds. Default
    value is 0 (lines never fade out).

scr_chathud_x::
    Absolute value of this cvar specifies horizontal placement of the chat HUD,
    counted in pixels from the screen edge. Negative values align graph to the right
    edge of the screen instead of the left edge. Default value is 8.

scr_chathud_y::
    Absolute value of this cvar specifies vertical placement of the chat HUD,
    counted in pixels from the screen edge. Negative values align graph to the bottom
    edge of the screen intead of the top edge. Default value is -64.

ch_health::
    Enables dynamic crosshair coloring based on the health statistic seen in
    the player's HUD.  Default value is 0 (use static color).

ch_red::
ch_green::
ch_blue::
    These variables specify the color of crosshair image. Default values are 1
    (draw in white color). Ignored if ‘ch_health’ is enabled.

ch_alpha::
    Opacity level of crosshair image. Default value is 1 (fully opaque).

ch_scale::
    Scaling factor of the crosshair image. Default value is 1 (original size).

ch_x::
ch_y::
    These variables specify the crosshair image offset, counted in pixels from
    the default position in center of the game screen. Default values are 0
    (draw in center).

Video Modes
~~~~~~~~~~~

Hard coded list of the fullscreen video modes is gone from Q2PRO, you can
specify your own list in configuration files. Vertical refresh frequency _freq_
and bit depth _bpp_ can be specified individually for each mode.

Video mode change no longer requires ‘vid_restart’ and is nearly instant.  In
windowed mode, size as well as position of the main window can be changed
freely.

vid_modelist::
    Space separated list of fullscreen video modes. Both _freq_ and _bpp_
    parameters are optional. Full syntax is: 'WxH[@freq][:bpp] [...]'. Default
    value is "640x480 800x600 1024x768". On Linux, _freq_ parameter is currently
    ignored. Special keyword ‘desktop’ means to use default desktop video mode.

vid_fullscreen::
    If set to non zero _value_, run in the specified fullscreen mode. This way,
    _value_ acts as index into the list of video modes specified by
    ‘vid_modelist’. Default value is 0, which means to run in windowed mode.

vid_geometry::
    Size and optional position of the main window on virtual desktop.
    Full syntax is: `WxH[+X+Y]`. Default value is "640x480".

vid_flip_on_switch::
    On Windows, specifies if original video mode is automatically restored when
    switching from fullscreen Q2PRO to another application or desktop.  Default
    value is 0 (don't switch video modes).

vid_hwgamma::
    Instructs the video driver to use hardware gamma correction for
    implementing ‘vid_gamma’.  Default value is 0 (use software gamma).

.Setting video modes
====================
The following lines define 2 video modes: 640x480 and 800x600 at 75 Hz vertical refresh and
32 bit framebuffer depth, and select the last 800x600 mode.
--------------------
/set vid_modelist "640x480@75:32 800x600@75:32"
/set vid_fullscreen 2
--------------------
====================


Windows Specific
~~~~~~~~~~~~~~~~

The following variables are specific to the Windows port of Q2PRO.

win_noalttab::
    Disables the Alt-Tab key combination to prevent it from interfering with
    game when pressed. Default is 0 (don't disable).

win_disablewinkey::
    Disables the default Windows key action to prevent it from interfering with
    game when pressed. Default is 0 (don't disable).

win_noresize::
    Prevents the main window from resizing by dragging the border. Default is 0
    (allow resizing).

win_notitle::
    Hides the main window title bar. Default is 0 (show title bar).

win_alwaysontop::
    Puts the main window on top of other windows. Default is 0 (main window can
    be obscured by other windows).

win_xpfix::
    Temporary disables mouse acceleration setting applied by the OS. Only
    effective when legacy Windows mouse input is in use, otherwise ignored.
    Default value is 0 (don't modify OS setting).

win_rawmouse::
    Enables raw mouse input instead of legacy Windows mouse input. Default
    value is 1 (use raw input).


OpenGL Renderer
~~~~~~~~~~~~~~~

gl_gamma_scale_pics::
    Apply software gamma scaling not only to textures and skins, but to HUD
    pictures also. Default value is 0 (don't apply to pics).

gl_noscrap::
    By default, OpenGL renderer combines small HUD pictures into the single
    texture called scrap. This usually speeds up rendering a bit, and allows
    pixel precise rendering of non power of two sized images. If you don't like
    this optimization for some reason, this cvar can be used to disable it.
    Default value is 0 (optimize).

gl_bilerp_chars::
    Enables bilinear filtering of charset images. Default value is 0 (disabled).

gl_bilerp_pics::
    Enables bilinear filtering of HUD pictures. Default value is 1.
      - 0 — disabled for all pictures
      - 1 — enabled for large pictures that don't fit into the scrap
      - 2 — enabled for all pictures, including the scrap texture itself

gl_upscale_pcx::
    Enables upscaling of PCX images using HQ2x and HQ4x filters. This improves
    rendering quality when screen scaling is used. Default value is 0.
      - 0 — don't upscale
      - 1 — upscale 2x (takes 5x more memory)
      - 2 — upscale 4x (takes 21x more memory)

gl_texture_non_power_of_two::
    Enables use of non power-of-two sized textures without resampling on OpenGL
    3.0 and higher compliant hardware. Default value is 1.

gl_downsample_skins::
    Specifies if skins are downsampled just like world textures are. When
    disabled, ‘gl_round_down’, ‘gl_picmip’ cvars have no effect on skins.
    Default value is 1 (downsampling enabled).

gl_drawsky::
    Enable skybox texturing. 0 means to draw sky box in solid black color.
    Default value is 1 (enabled).

gl_fontshadow::
    Specifies font shadow width, in pixels, ranging from 0 to 2. Default value
    is 0 (no shadow).

gl_partscale::
    Specifies minimum size of particles. Default value is 2.

gl_partstyle::
    Specifies drawing style of particles. Default value is 0.
      - 0 — blend colors
      - 1 — saturate colors

gl_celshading::
    Enables drawing black contour lines around 3D models (aka ‘celshading’).
    Value of this variable specifies thickness of the lines drawn. Default
    value is 0 (celshading disabled).

gl_dotshading::
    Enables dotshading effect when drawing 3D models, which helps them look
    truly 3D-ish by simulating diffuse lighting from a fake light source.
    Default value is 1 (enabled).

gl_saturation::
    Enables grayscaling of world textures. 1 keeps original colors, 0 converts
    textures to grayscale format (this may save some video memory and speed up
    rendering a bit since textures are uploaded at 8 bit per pixel instead of
    24), any value in between reduces colorfulness. Default value is 1 (keep
    original colors).

gl_invert::
    Inverts colors of world textures. In combination with ‘gl_saturation 0’
    effectively makes textures look like black and white photo negative.
    Default value is 0 (do not invert colors).

gl_anisotropy::
    When set to 2 and higher, enables anisotropic filtering of world textures,
    if supported by your OpenGL implementation. Default value is 0 (anisotropic
    filtering disabled).

gl_brightness::
    Specifies a brightness value that is added to each pixel of world
    lightmaps. Positive values make lightmaps brighter, negative values make
    lightmaps darker.  Default value is 0 (keep original brightness).

gl_coloredlightmaps::
    Enables grayscaling of world lightmaps. 1 keeps original colors, 0 converts
    lightmaps to grayscale format, any value in between reduces colorfulness.
    Default value is 1 (keep original colors).

gl_modulate::
    Specifies a primary modulation factor that each pixel of world lightmaps is
    multiplied by. This cvar affects entity lighting as well.  Default value is
    1 (identity).

gl_modulate_world::
    Specifies an secondary modulation factor that each pixel of world lightmaps
    is multiplied by. This cvar does not affect entity lighting. Default value
    is 1 (identity).

gl_modulate_entities::
    Specifies an secondary modulation factor that entity lighting is multiplied
    by.  This cvar does not affect world lightmaps. Default value is 1
    (identity).

TIP: An old trick to make entities look brighter in Quake 2 was setting
‘gl_modulate’ to a high value without issuing ‘vid_restart’ afterwards. This
way it was possible to keep ‘gl_modulate’ from applying to world lightmaps, but
only until the next map was loaded. In Q2PRO this trick is no longer needed
(and it won't work, since ‘gl_modulate’ is applied dynamically). To get the
similar effect, set the legacy ‘gl_modulate’ variable to 1, and configure
‘gl_modulate_world’ and ‘gl_modulate_entities’ to suit your needs.

gl_doublelight_entities::
    Specifies if combined modulation factor is applied to entity lighting one
    more time just before final lighting value is calculated, to simulate a bug
    (?) in the original Quake 2 renderer. Default value is 1 (apply twice).

.Entity lighting
****************
Entity lighting is calculated based on the color of the lightmap sample from
the world surface directly beneath the entity. This means any cvar affecting
lightmaps affects entity lighting as well (with exception of ‘gl_modulate_world’).
Cvars that have effect only on the entity lighting are ‘gl_modulate_entities’
and ‘gl_doublelight_entities’. Yet another cvar affecting entity lighting is
‘gl_dotshading’, which typically makes entities look a bit brighter. See also
‘cl_noglow’ cvar which removes the pulsing effect (glowing) on bonus entities.
****************

gl_dynamic::
    Controls dynamic lightmap updates. Default value is 2.
     - 0 — all dynamic lighting is disabled
     - 1 — all dynamic lighting is enabled
     - 2 — most dynamic lights are disabled, but lightmap updates are still
     allowed for switchable lights to work

NOTE: Dynamic lights may noticeably hurt rendering performance on some video
cards and drivers, therefore they are disabled by default.

gl_dlight_falloff::
    Makes dynamic lights look a bit smoother, opposed to original jagged Quake
    2 style.  Default value is 1 (enabled).

gl_fragment_program::
    Enables ‘GL_ARB_fragment_program’ extension, if supported by your OpenGL
    implementation.  Currently this extension is used only for warping effect
    when drawing liquid surfaces. Default value is 1 (enabled).

gl_vertex_buffer_object::
    Enables ‘GL_ARB_vertex_buffer_object’ extension, if supported by your
    OpenGL implementation. This extension allows world surfaces to be stored in
    high-performance video memory, which usually speeds up rendering. Default
    value is 1 (enabled).

gl_video_sync::
    On X11/GLX, enables ‘GLX_SGI_video_sync’ extension. This extension allows
    synchronizing rendering framerate to monitor vertical retrace frequency.
    Default value is 1 (enabled). See also ‘cl_async’ variable.

gl_colorbits::
    Specifies desired size of color buffer, in bits, requested from OpenGL
    implementation (should be typically 0, 24 or 32). Default value is 0
    (determine the best value automatically).

gl_depthbits::
    Specifies desired size of depth buffer, in bits, requested from OpenGL
    implementation (should be typically 0 or 24). Default value is 0
    (determine the best value automatically).

gl_stencilbits::
    Specifies desired size of stencil buffer, in bits, requested from OpenGL
    implementation (should be typically 0 or 8). Currently stencil buffer is
    used only for drawing projection shadows. Default value is 8. 0 means no
    stencil buffer requested.

gl_multisamples::
    Specifies number of samples per pixel used to implement multisample
    anti-aliasing, if supported by OpenGL implementation. Values 0 and 1 are
    equivalent and disable MSAA. Values from 2 to 32 enable MSAA. Default
    value is 0.

gl_texturebits::
    Specifies number of bits per texel used for internal texture storage
    (should be typically 0, 8, 16 or 32). Default value is 0 (choose the best
    internal format automatically).

gl_screenshot_format::
    Specifies image format ‘screenshot’ command uses. Possible values are
    "png", "jpg" and "tga". Default value is "jpg".

gl_screenshot_quality::
    Specifies image quality of JPG screenshots. Values range from 0 (worst
    quality) to 100 (best quality). Default value is 100.

gl_screenshot_compression::
    Specifies compression level of PNG screenshots. Values range from 0 (no
    compression) to 9 (best compression). Default value is 6.

r_override_textures::
    Enables automatic overriding of palettized textures (in WAL or PCX format)
    with truecolor replacements (in PNG, JPG or TGA format) by stripping off
    original file extension and searching for alternative filenames in the
    order specified by ‘r_texture_formats’ variable. Default value is 1
    (enabled).

r_texture_formats::
    Specifies the order in which truecolor texture replacements are searched.
    Default value is "pjt", which means to try ‘.png’ extension first, then
    ‘.jpg’, then ‘.tga’.

.MD2 model overrides
********************
When Q2PRO attempts to load an alias model from disk, it determines actual
model format by file contents, rather than by filename extension. Therefore, if
you wish to override MD2 model with MD3 replacement, simply rename the MD3
model to ‘tris.md2’ and place it in appropriate packfile to make sure it gets
loaded first.
********************


Downloads
~~~~~~~~~

These variables control automatic client downloads (both legacy UDP and HTTP
downloads).

allow_download::
    Globally allows or disallows client downloads. Remaining variables listed
    below are effective only when downloads are globally enabled. Default value
    is 1.
     - -1 — downloads are permanently disabled (once this value is set, it
       can't be modified)
     - 0 — downloads are disabled
     - 1 — downloads are enabled

allow_download_maps::
    Enables automatic downloading of maps. Default value is 1.

allow_download_models::
    Enables automatic downloading of non-player models, sprites and skins.
    Default value is 1.

allow_download_sounds::
    Enables automatic downloading of non-player sounds. Default value is 1.

allow_download_pics::
    Enables automatic downloading of HUD pictures. Default value is 1.

allow_download_players::
    Enables automatic downloading of player models, skins, sounds and icons.
    Default value is 1.

allow_download_textures::
    Enables automatic downloading of map textures. Default value is 1.


HTTP Downloads
~~~~~~~~~~~~~~

cl_http_downloads::
    Enables HTTP downloads, if server advertises download URL. Default value is
    1 (enabled).

cl_http_filelists::
    When a first file is about to be downloaded from HTTP server, send a
    filelist request, and download any additional files specified in the filelist.
    Filelists provide a ‘pushing’ mechanism for server operator to make sure
    all clients download complete set of data for the particular mod, instead
    of requesting files one-by-one. Default value is 1 (request filelists).

cl_http_max_connections::
    Maximum number of simultaneous connections to the HTTP server. Default
    value is 2.

cl_http_proxy::
    HTTP proxy server to use for downloads. Default value is empty (direct
    connection).


Locations
~~~~~~~~~

Client side location files provide a way to report player's position on the map
in team chat messages without depending on the game mod.  Locations are loaded
from ‘locs/<mapname>.loc’ file. Once location file is loaded, ‘loc_here’ and
‘loc_there’ macros will expand to the name of location closest to the given
position. Variables listed below control some aspects of location selection.

loc_trace::
    When enabled, location must be directly visible from the given position
    (not obscured by solid map geometry) in order to be selected. Default value
    is 0, which means any closest location will satisfy, even if it is placed
    behind the wall.

loc_dist::
    Maximum distance to the location, in world units, for it to be considered
    by the location selection algorithm. Default value is 500.

loc_draw::
    Enables visualization of location positions. Default value is 0 (disabled).


Mouse Input
~~~~~~~~~~~

in_direct::
    On Linux, enables Evdev interface for direct mouse input. Otherwise,
    standard input facilities provided by the window system are used. Default
    value is 1 (use direct input).

in_device::
    On Linux, specifies device file to use for direct mouse input. Normally, it
    should be one of ‘/dev/input/eventX’ files (reading permissions are
    required).  Default value is empty and needs to be filled by user.

in_grab::
    Specifies mouse grabbing policy in windowed mode. Normally, mouse is always
    grabbed in-game and released when console or menu is up. In addition to
    that, smart policy mode automatically releases the mouse when its input is
    not needed (playing a demo, or spectating a player). Default value is 1.
      - 0 — don't grab mouse
      - 1 — normal grabbing policy
      - 2 — smart grabbing policy

m_autosens::
    Enables automatic scaling of mouse sensitivity proportional to the current
    player field of view. Values between 90 and 179 specify the default FOV
    value to scale sensitivity from. Zero disables automatic scaling. Any other
    value assumes default FOV of 90 degrees. Default value is 0.

m_accel::
    Specifies mouse acceleration factor. Default value is 0 (acceleration
    disabled).

m_filter::
    When enabled, mouse movement is averaged between current and previous
    samples.  Default value is 0 (filtering disabled).

lirc_enable::
    On Linux, enables input from the LIRC daemon, which allows menu navigation
    and command execution from your infrared remote control device. Default
    value is 0 (disabled).

lirc_config::
    On Linux, specifies LIRC configuration file to use. Default value is empty,
    which means to use the default ‘~/.lircrc’ file. This variable may only be
    set from command line.  See README.lirc file for command syntax description.


Miscellaneous
~~~~~~~~~~~~~

cl_chat_notify::
    Specifies whether to display chat lines in the notify area. Default value
    is 1 (enabled).

cl_chat_sound::
    Specifies sound effect to play each time chat message is received. Default
    value is 1.
      - 0 — don't play chat sound
      - 1 — play normal sound (‘misc/talk.wav’)
      - 2 — play alternative sound (‘misc/talk1.wav’)

cl_chat_filter::
    Specifies if unprintable characters are filtered from incoming chat
    messages, to prevent common exploits like hiding player names. Default
    value is 0 (don't filter).

cl_noskins::
    Restricts which models and skins players can use. Default value is 0.
      - 0 — no restrictions, if skins exists, it will be loaded
      - 1 — do not allow any skins except of ‘male/grunt’
      - 2 — do not allow any skins except of ‘male/grunt’ and ‘female/athena’

TIP: With ‘cl_noskins’ set to 2, it is possible to keep just 2 model/skin pairs
(‘male/grunt’ and ‘female/athena’) to save memory and reduce map load times.
This will not affect model-based TDM gameplay, since any male skin will be
replaced by ‘male/grunt’ and any female skin will be replaced by
‘female/athena’.

cl_rollhack::
    Default OpenGL renderer in Quake 2 contained a bug that caused ‘roll’ angle
    of 3D models to be inverted during rotation.  Due to this bug, player
    models did lean in the opposite direction when strafing. New Q2PRO renderer
    doesn't have this bug, but since many players got used to it, Q2PRO is able
    to simulate original behavior. This cvar chooses in which direction player
    models will lean. Default value is 1 (invert ‘roll’ angle).

cl_adjustfov::
    Specifies if horizontal field of view is automatically adjusted for screens
    with aspect ratio different from 4/3. Default value is 0 (don't adjust FOV).

cl_demosnaps::
    Specifies time interval, in seconds, between saving ‘snapshots’ in memory
    during demo playback.  Snapshots enable backward seeking in demo (see ‘seek’
    command description), and speed up repeated forward seeks. Setting this
    variable to 0 disables snapshotting entirely. Default value is 10.

cl_demomsglen::
    Specifies default maximum message size used for demo recording. Default
    value is 1390.  See ‘record’ command description for more information on
    demo packet sizes.

cl_demowait::
    Specifies if demo playback is automatically paused at the last frame in
    demo file. Default value is 0 (finish playback).

cl_autopause::
    Specifies if single player game or demo playback is automatically paused
    once client console or menu is opened. Default value is 1 (pause game).

ui_open::
    Specifies if menu is automatically opened on startup, instead of full
    screen console. Default value is 1 (open menu).

ui_background::
    Specifies image to use as menu background. Default value is empty, which
    just fills the screen with solid black color.

ui_scale::
    Scaling factor of the UI widgets. Takes effect in OpenGL mode only. Default
    value is 1. Automatically scales depending on current display resolution
    when set to 0.

ui_sortdemos::
    Specifies default sorting order of entries in demo browser. Default value
    is 1.  Negate the values for descending sorting order instead of ascending.
        - 0 — don't sort
        - 1 — sort by name
        - 2 — sort by date
        - 3 — sort by size
        - 4 — sort by map
        - 5 — sort by POV

ui_listalldemos::
    List all demos, including demos in packs and demos in base directories.
    Default value is 0 (limit the search to physical files within the current
    game directory).

ui_sortservers::
    Specifies default sorting order of entries in server browser. Default value
    is 0.  Negate the values for descending sorting order instead of ascending.
        - 0 — don't sort
        - 1 — sort by hostname
        - 2 — sort by mod
        - 3 — sort by map
        - 4 — sort by players
        - 5 — sort by RTT

ui_colorservers::
    Enables highlighting of entries in server browser with different colors.
    Currently, this option grays out password protected and anticheat enforced
    servers. Default value is 0 (disabled).

ui_pingrate::
    Specifies the server pinging rate used by server browser, in packets per
    second. Default value is 0, which estimates the default pinging rate based
    on ‘rate’ client variable.

com_time_format::
    Time format used by ‘com_time’ macro. Default value is "%H.%M" on Win32 and
    "%H:%M" on UNIX. See strftime(3) for syntax description.

com_date_format::
    Date format used by ‘com_date’ macro. Default value is "%Y-%m-%d". See
    strftime(3) for syntax description.

Macros
------

Macros behave like automated console variables. When macro expansion is
performed, macros are searched first, then console variables.

.Macro expansion syntax
=======================
Each of the following examples are valid and produce the same output:
------------
/echo $loc_here
/echo $loc_here$
/echo ${loc_here}
/echo ${$loc_here}
------------
======================

[horizontal]
.List of client macros
cl_armor:: armor statistic seen in the HUD
cl_ammo:: ammo statistic seen in the HUD
cl_health:: health statistic seen in the HUD
cl_weaponmodel:: current weapon model
cl_timer:: time since level load
cl_demopos:: current position in demo, in _timespec_ syntax
cl_server:: address of the server client is connected to
cl_mapname:: name of the current map
loc_there:: name of the location player is looking at
loc_here:: name of the location player is standing at
cl_ping:: average round trip time to the server
cl_lag:: incoming packet loss percentage
cl_fps:: main client loop frame rate
         footnote:[This is not the framerate ‘cl_maxfps’ limits.
         Think of it as an input polling frame rate, or a ‘master’ framerate.]
cl_mps:: movement commands generation rate in movements per second
         footnote:[Can be also called ‘physics’ frame rate.
         This is what ‘cl_maxfps’ limits.]
cl_pps:: movement packets transmission rate in packets per second
cl_ups:: player velocity in world units per second
r_fps:: rendering frame rate
com_time:: current time formatted according to ‘com_time_format’
com_date:: current date formatted according to ‘com_date_format’
com_uptime:: engine uptime in short format
net_dnrate:: current download rate in bytes/sec
net_uprate:: current upload rate in bytes/sec
random:: expands to the random decimal digit

[horizontal]
.List of special macros
qt:: expands to double quote
sc:: expands to semicolon
$:: expands to dollar sign


Commands
--------

Client Demos
~~~~~~~~~~~~

demo [/]<filename[.ext]>::
    Begins demo playback. This command does not require file extension to be
    specified and supports filename autocompletion on TAB. Loads file from
    ‘demos/’ unless slash is prepended to _filename_, otherwise loads from the
    root of quake file system. Can be used to launch MVD playback as well, if
    MVD file type is detected, it will be automatically passed to the server
    subsystem. To stop demo playback, type ‘disconnect’.

seek [+-]<timespec>::
    Seeks the given amount of time during demo playback.  Prepend with ‘+’ to
    seek forward relative to current position, prepend with ‘-’ to seek
    backward relative to current position. Without prefix, seeks to an absolute
    position within the demo file. See below for _timespec_ syntax description.
    Initial forward seek may be slow, so be patient.

NOTE: The ‘seek’ command actually operates on demo frame numbers, not pure
server time.  Therefore, ‘seek +300’ does not exactly mean ‘skip 5 minutes of
server time’, but just means ‘skip 3000 demo frames’, which may account for
*more* than 5 minutes if there were dropped frames. For most demos, however,
correspondence between frame numbers and server time should be reasonably
close.

.Demo time specification
************************
Absolute or relative demo time can be specified in one of the following
formats:

* .FF, where FF are frames
* SS, where SS are seconds
* SS.FF, where SS are seconds, FF are frames
* MM:SS, where MM are minutes, SS are seconds
* MM:SS.FF, where MM are minutes, SS are seconds, FF are frames
************************

record [-hzes] <filename>::
    Begins demo recording into ‘demos/_filename_.dm2’, or prints some
    statistics if already recording. If neither ‘--extended’ nor ‘--standard’
    options are specified, this command uses maximum demo message size defined
    by ‘cl_demomsglen’ cvar.

        -h | --help::: display help message
        -z | --compress::: compress demo with gzip
        -e | --extended::: use extended packet size (4086 bytes)
        -s | --standard::: use standard packet size (1390 bytes)

TIP: With Q2PRO it is possible to record a demo while playing back another one.

stop::
    Stops demo recording and prints some statistics about recorded demo.

suspend::
    Pauses and resumes demo recording.

.Demo packet sizes
******************
Packet size options limit maximum demo message size and thus define
compatibility level of the recorded demo. Original Quake 2 supports just 1390
bytes (‘standard’ size), while Q2PRO and R1Q2 support message sizes up to 4086
bytes (‘extended’ size). When Q2PRO or R1Q2 protocols are in use, demo written
to disk is automatically downgraded to protocol 34. This can result in dropping
of large frames that don't fit into standard protocol 34 limit.  Demo packet
size can be extended to overcome this, but the resulting demo will be playable
only by Q2PRO and R1Q2 clients and will be incompatible with other Quake 2
clients or demo editing tools. By default, ‘standard’ packet size is used. This
default can be changed using ‘cl_demomsglen’ cvar.
******************


Cvar Operations
~~~~~~~~~~~~~~~

toggle <cvar> [value1 value2 ...]::
    If _values_ are omitted, toggle the specified _cvar_ between 0 and 1.
    If two or more _values_ are specified, cycle through them.

inc <cvar> [value]::
    If _value_ is omitted, add 1 to the value of _cvar_.
    Otherwise, add the specified floating point _value_.

dec <cvar> [value]::
    If _value_ is omitted, subtract 1 from the value of _cvar_.
    Otherwise, subtract the specified floating point _value_.

reset <cvar>::
    Reset the specified _cvar_ to it's default value.

resetall::
    Resets all cvars to their default values.

set <cvar> <value> [u|s|...]::
    If 2 arguments are given, sets the specified _cvar_ to _value_.  If 3
    arguments are given, and the last argument is ‘u’ or ‘s’, sets _cvar_ to
    _value_ and marks the _cvar_ with ‘userinfo’ or ‘serverinfo’ flags,
    respectively.  Otherwise, sets _cvar_ to _value_, which is handled as
    consisting from multiple tokens.

setu <cvar> <value> [...]::
    Sets the specified _cvar_ to _value_, and marks the cvar with ‘userinfo’
    flag. _Value_ may be composed from multiple tokens.

sets <cvar> <value> [...]::
    Sets the specified _cvar_ to _value_, and marks the cvar with ‘serverinfo’
    flag. _Value_ may be composed from multiple tokens.

seta <cvar> <value> [...]::
    Sets the specified _cvar_ to _value_, and marks the cvar with ‘archive’
    flag. _Value_ may be composed from multiple tokens.

cvarlist [-achlmnrstuvw:]::
    Display the list of registered cvars and their current values with
    filtering by cvar name or by cvar flags. If no options are given,
    all cvars are listed. Supported options are reproduced below.
        -a | --archive::: list archived cvars
        -c | --cheat::: list cheat protected cvars
        -h |--help::: display help message
        -l | --latched::: list latched cvars
        -m | --modified::: list modified cvars
        -n | --noset::: list command line cvars
        -r | --rom::: list read-only cvars
        -s | --serverinfo::: list serverinfo cvars
        -t | --custom::: list user-created cvars
        -u | --userinfo::: list userinfo cvars
        -v | --verbose::: display flags of each cvar
        -w | --wildcard=<string>::: list cvars matching wildcard _string_

macrolist::
    Display the list of registered macros and their current values.


Message Triggers
~~~~~~~~~~~~~~~~

Message triggers provide a form of automatic command execution when some game
event occurs.  Each trigger is composed from a _command_ string to execute and
a _match_ string.  When a non-chat message is received from server, a list
of message triggers is examined.  For each trigger, _match_ is macro expanded
and wildcard compared with the message, ignoring any unprintable characters. If
the message matches, _command_ is stuffed into the command buffer and executed.

trigger [<command> <match>]::
    Adds new message trigger. When called without arguments, prints a list of
    registered triggers.

untrigger [all] | [<command> <match>]::
    Removes the specified trigger. Specify _all_ to remove all triggers. When
    called without arguments, prints a list of registered triggers.


Chat Filters
~~~~~~~~~~~~

Chat filters allow messages from annoying players to be ignored.  Each chat
filter is composed from a _match_ string.  When a chat message is received from
server, a list of chat filters is examined.  For each filter, _match_ is
wildcard compared with the message, ignoring any unprintable characters.  If
the message matches, it is silently dropped.

ignoretext [match ...]::
    Adds new chat filter. When called without arguments, prints a list of
    registered filters.

unignoretext [all] | [match ...]::
    Removes the specified chat filter. Specify _all_ to remove all filters.
    When called without arguments, prints a list of registered filters.

ignorenick [nickname]::
    Automatically composes and adds two chat filters: ‘_nickname_: *’ and
    ‘(_nickname_): *’. This command supports nickname completion.  When called
    without arguments, prints a list of registered filters.

unignorenick [nickname]::
    Automatically composes and removes two chat filters: ‘_nickname_: *’ and
    ‘(_nickname_): *’. This command supports nickname completion. When called
    without arguments, prints a list of registered filters.


Draw Objects
~~~~~~~~~~~~

Draw objects provide a uniform way to display values of arbitrary cvars and
macros on the game screen.  By default, text is positioned relative to the top
left corner of the screen, which has coordinates (0, 0). Use negative values to
align text to the opposite edge, e.g. point with coordinates (-1, -1) is at the
bottom right corner of the screen. Absolute value of each coordinate specifies
the distance from the corresponding screen edge, counted in pixels.

draw <name> <x> <y> [color]::
    Add console variable or macro identified by _name_ (without the ‘$’ prefix)
    to the list of objects drawn on the screen at position (_x_, _y_), drawn
    in optional _color_.

undraw [all] | <name>::
    Remove object identified by _name_ from the list of objects drawn on the
    screen. Specify _all_ to remove all objects.

.Drawing FPS and a clock
========================
-------------------
/draw cl_fps -1 -1  // bottom right
/draw com_time 0 -1 // bottom left
-------------------
=======================


Screenshots
~~~~~~~~~~~

screenshot [format]::
    Standard command to take a screenshot. If _format_ argument is given,
    takes the screenshot in this format. Otherwise, takes in the format
    specified by ‘gl_screenshot_format’ variable. File name is picked up
    automatically from the ‘screenshots/quakeNNN.EXT’ template.

screenshotpng [filename] [compression]::
    Takes the screenshot in PNG format. If _filename_ argument is given, saves
    the screenshot into ‘screenshots/_filename_.png’. Otherwise, file name is
    picked up automatically. If _compression_ argument is given, saves with this
    compression level. Otherwise, saves with ‘gl_screenshot_compression’ level.

screenshotjpg [filename] [quality]::
    Takes the screenshot in JPG format. If _filename_ argument is given, saves
    the screenshot into ‘screenshots/_filename_.jpg’. Otherwise, file name is
    picked up automatically. If _quality_ argument is given, saves with this
    quality level. Otherwise, saves with ‘gl_screenshot_quality’ level.

screenshottga [filename]::
    Takes the screenshot in TGA format. If _filename_ argument is given, saves
    the screenshot into ‘screenshots/_filename_.tga’. Otherwise, file name is
    picked up automatically.


Locations
~~~~~~~~~

loc_add <name ...>::
    Adds new location with the specified name at current player position.

loc_delete::
    Deletes location closest to player position.

loc_update <name ...>::
    Changes name of location closest to player position.

loc_write::
    Saves current location list into ‘locs/<mapname>.loc’ file.

NOTE: Edit locations on a local server and don't forget to execute ‘loc_write’
command once you are finished. Otherwise all changes to location list will be
lost on map change or disconnect.


Miscellaneous
~~~~~~~~~~~~~

vid_restart::
    Perform complete shutdown and reinitialization of the renderer and video
    subsystem. Rarely needed.

fs_restart::
    Flush all media registered by the client (textures, models, sounds, etc),
    restart the file system and reload the current level.

r_reload::
    Flush and reload all media registered by the renderer (textures and models).
    Weaker form of ‘fs_restart’.

TIP: In Q2PRO, you don't have to issue ‘vid_restart’ after changing most of the
settings, a ‘fs_restart’ or ‘r_reload’ usually suffice. This helps to avoid
main window recreation and changing video modes back and forth, and is much
faster.

passive::
    Toggle passive connection mode. When enabled, client waits for the first
    ‘passive_connect’ packet from server and starts usual connection procedure
    once this packet is received. This command is useful for connecting to
    servers behind NATs or firewalls. See ‘pickclient’ [[server]] command for
    more details.

serverstatus [address]::
    Request the status string from the server at specified _address_,
    display server info and list of players sorted by frags. If connected
    to the server, _address_ may be omitted, in this case current server is
    queried.

followip [count]::
    Attempts to connect to the IP address recently seen in chat messages.
    Optional _count_ argument specifies how far to go back in message history
    (it should be positive integer).  If _count_ is omitted, then the most
    recent IP address is used.


Incompatibilities
-----------------

Q2PRO client tries to be compatible with other Quake 2 ports, including
original Quake 2 release. Compatibility, however, is defined in terms of full
file format and network protocol compatibility. Q2PRO is not meant to be a
direct replacement of your regular Quake 2 client. Some features are
implemented differently in Q2PRO, some may be not implemented at all. You may
need to review your config and adapt it for Q2PRO. This section tries to
document most of these incompatibilities so that when something doesn't work as
it used to be you know where to look. The following list may be incomplete.

- Q2PRO has a built-in renderer and doesn't support run-time loading of external
  renderers.  Thus, ‘vid_ref’ cvar has been made read-only and exists only for
  informational purpose.

- Default value of ‘intensity’ variable has been changed from 2 to 1. This means
  textures will appear darker by default.

- Default value of ‘gl_dynamic’ variable has been changed from 1 to 2. This means
  dynamic lights will be disabled by default.

- Changes to ‘gl_modulate’ variable in Q2PRO take effect immediately. To set
  separate modulation factors for world lightmaps and entities please use
  ‘gl_modulate_world’ and ‘gl_modulate_entities’ variables.

- Default value of R1GL-specific ‘gl_dlight_falloff’ variable has been changed
  from 0 to 1.

- ‘gl_particle_*’ series of variables are gone, as well as
  ‘gl_ext_pointparameters’ and R1GL-specific ‘gl_ext_point_sprite’. For
  controlling size of particles, which are always drawn as textured triangles,
  Q2PRO supports it's own ‘gl_partscale’ variable.

- ‘ip’ variable has been renamed to ‘net_ip’.

- ‘clientport’ variable has been renamed to ‘net_clientport’, and
  ‘ip_clientport’ alias is no longer supported.

- ‘demomap’ command has been removed in favor of ‘demo’ and ‘mvdplay’.

- Q2PRO works only with virtual paths constrained to the quake file system.
  All paths are normalized before use so that it is impossible to go past virtual
  filesystem root using ‘../’ components.  This means commands like these are
  equivalent and all reference the same file: ‘exec ../global.cfg’, ‘exec
  /global.cfg’, ‘exec global.cfg’.  If you have any config files in your Quake 2
  directory root, you should consider moving them into ‘baseq2/’ to make them
  accessible.

- Likewise, ‘link’ command syntax has been changed to work with virtual paths
  constrained to the quake file system. All arguments to ‘link’ are normalized.

- Cinematics are not supported.

- Joysticks are not supported.

- Single player savegame format has been rewritten from scratch for better
  robustness and portability. Only the ‘baseq2’ game library included in Q2PRO
  distribution has been converted to use the new improved savegame format. Q2PRO
  will refuse to load and save games in old format for security reasons.

- CD music is not supported.

