LIGHT

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
MODEL ENTITY KEYS
LIGHT ENTITY KEYS
AUTHOR
REPORTING BUGS
COPYRIGHT
SEE ALSO

NAME

light − Caclulate lightmap data for a Quake BSP file

SYNOPSIS

light [OPTION]... BSPFILE

DESCRIPTION

light reads a Quake .bsp file and calculates light and shadow information based on the entity definitions contained in the .bsp. The .bsp file is updated with the new light data upon completion, overwriting any existing lighting data.

OPTIONS

−threads n

Set number of threads explicitly. By default light will attempt to detect the number of CPUs/cores available.

−extra

Calculate extra samples (2x2) and average the results for smoother shadows.

−extra4

Calculate even more samples (4x4) and average the results for smoother shadows.

−light n

Set a global minimum light level for style 0 (default) lightmaps. Overrides default light level set in worldspawn.

−addmin

Changes the behaviour of minlight. Instead of increasing low light levels to the global minimum, add the global minimum light level to all style 0 lightmaps. This may help reducing the sometimes uniform minlight effect.

−dist n

Scales the fade distance of all lights by a factor of n. If n > 1 lights fade more quickly with distance and if n < 1, lights fade more slowly with distance and light reaches further.

−range n

Scales the brightness range of all lights without affecting their fade discance. Values of n > 0.5 makes lights brighter and n < 0.5 makes lights less bright. The same effect can be achieved on individual lights by adjusting both the "light" and "wait" attributes.

−gate n

Set a minimum light level, below which can be considered zero brightness. This can dramatically speed up processing when there are large numbers of lights with inverse or inverse square falloff. In most cases, values less than 1.0 will cause no discernable visual differences. Default 0.001.

−soft [n]

Perform post-processing on the lightmap which averages adjacent samples to smooth shadow edges. If n is specified, the algorithm will take ’n’ samples on each side of the sample point and replace the original value with the average. e.g. a value of 1 results in averaging a 3x3 square centred on the original sample. 2 implies a 5x5 square and so on. If −soft is specified, but n is omitted, a value will be the level of oversampling requested. If no oversampling, then the implied value is 1. −extra implies a value of 2 and −extra4 implies 3. Default 0 (off).

−anglescale | −anglesense

Set the scaling of sunlight brightness due to the angle of incidence with a surface (more detailed explanation in the "_anglescale" key below).

−lit

Force generation of a .lit file, even if your map does not have any coloured lights. By default, light will automatically generate the .lit file when needed.

MODEL ENTITY KEYS

Worldspawn Keys
The following keys can be added to the worldspawn entity:
"light" "n"

Set a global minimum light level of "n" across the whole map. This is an easy way to eliminate completely dark areas of the level, however you may lose some contrast as a result, so use with care. Default 0.

"_sunlight" "n"

Set the brightness of the sunlight coming from an unseen sun in the sky. Sky brushes (or more accurately bsp leafs with sky contents) will emit sunlight at an angle specified by the "_sun_mangle" key. Default 0.

"_sun_mangle" "x y z"

Specifies the direction of sunlight using yaw(x), pitch(y) and roll(z) in degrees. Yaw specifies the angle around the Z-axis from 0 to 359 degrees and pitch specifies the angle from 90 (straight up) to -90 (straight down). Roll has no effect, so use any value (e.g. 0). Default is straight down ("0 -90 0").

"_sunlight_color" "r g b"

Specify red(r), green(g) and blue(b) components for the colour of the sunlight. RGB component values are between 0 and 255. Default is white light ("255 255 255").

Model Entity Keys
The following keys can be used on any entity with a brush model:
"_minlight" "n"

Set the minimum light level for any surface of the brush model. Default 0.

"_mincolor" "r g b"

Specify red(r), green(g) and blue(b) components for the colour of the minlight. RGB component values are between 0 and 255. Default is white light ("255 255 255").

"_shadow" "n"

If n is 1, this model will cast shadows on other models and itself (i.e. "_shadow" implies "_shadowself"). Note that this doesn’t magically give Quake dynamic lighting powers, so the shadows will not move if the model moves. Default 0.

"_shadowself" "n"

If n is 1, this model will cast shadows on itself if one part of the model blocks the light from another model surface. This can be a better compromise for moving models than full shadowing. Default 0.

LIGHT ENTITY KEYS

Light entity keys can be used in any entity with a classname starting with the first five letters "light". E.g. "light", "light_globe", "light_flame_small_yellow", etc.
"light" "n"

Set the light intensity. Negative values are also allowed and will cause the entity to subtract light cast by other entities. Default 300.

"wait" "n"

Scale the fade distance of the light by "n". Values of n > 1 make the light fade more quickly with distance, and values < 1 make the light fade more slowly (and thus reach further). Default 1.

"delay" "n"

Select an attenuation formaula for the light:
0 => Linear attenuation (default)
1 => 1/x attenuation
2 => 1/(x^2) attenuation
3 => No attenuation (same brightness at any distance)
4 => "local minlight" - No attenuation and like minlight,
it won’t raise the lighting above it’s light value.
Unlike minlight, it will only affect surfaces within
line of sight of the entity.
5 => 1/(x^2) attenuation, but slightly more attenuated and
without the extra bright effect that "delay 2" has
near the source.

"_color" "r g b"

Specify red(r), green(g) and blue(b) components for the colour of the light. RGB component values are between 0 and 255. Default is white light ("255 255 255").

"target" "name"

Turns the light into a spotlight, with the direction of light being towards another entity with it’s "targetname" key set to "name".

"mangle" "x y z"

Turns the light into a spotlight and specifies the direction of light using yaw(x), pitch(y) and roll(z) in degrees. Yaw specifies the angle around the Z-axis from 0 to 359 degrees and pitch specifies the angle from 90 (straight up) to -90 (straight down). Roll has no effect, so use any value (e.g. 0). Often easier than the "target" method.

"angle" "n"

Specifies the angle in degrees for a spotlight cone. Default 40.

"_softangle" "n"

Specifies the angle in degrees for an inner spotlight cone (must be less than the "angle" cone. Creates a softer transition between the full brightness of the inner cone to the edge of the outer cone. Default 0 (disabled).

"targetname" "name"

Turns the light into a switchable light, toggled by another entity targeting it’s name.

"style" "n"

Set the animated light style. Default 0.

"_anglescale" "n" | "_anglesense" "n"

Sets a scaling factor for how much influence the angle of incidence of light on a surface has on the brightness of the surface. n must be between 0.0 and 1.0. Smaller values mean less attenuation, with zero meaning that angle of incidence has no effect at all on the brightness. Default 0.5.

AUTHOR

Written by Kevin Shanahan (aka Tyrann)
Based on source provided by id Software
http://disenchant.net

REPORTING BUGS

Please send bug reports to tyrann@disenchant.net.
Improvements to the documentation are welcome and encouraged.

COPYRIGHT

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

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

SEE ALSO

qbsp(1) vis(1) bspinfo(1) bsputil(1) quake(6)