DLight
From DoomWiki.org
DLight is a lightmap compilation utility by Samuel Villarreal (Kaiser). It allows lightmaps and shadows to be baked in a WAD file. Unlike dynamic light however, baked lights and shadows generated by DLight are static, but they can support surface based area lights.
Contents
History[edit]
DLight was worked on from 2013 to 2014. The utility was created to generate lightmaps for Doom64 EX and Strife: Veteran Edition. It is designed to be used with maps that are built with GL nodes. Several new map lumps containing lightmap data are added after compiling. If data exist in the GL_PVS lump as used in glVIS, then it will utilize it to further speed up compile time.
Currently, only Strife: Veteran Edition and Doom64 EX uses lightmaps. Other source ports will ignore these special lumps generated by DLight, though the lightmap data can be processed by any port supporting GL nodes.
The ZDRay lightmap compiler and node builder has its origins in DLight.
Features[edit]
- Support for area lights
- Max texture size 128x128
- General lightmap compiler - Can be used to bake maps for other games as well
DLightGUI[edit]
DLight is available as a command-line program, but can also be used with a GUI. Known as DLightGUI, it is capable of baking lightmaps as well as utilizing GL_PVS data by glVIS. DLightGUI was created in 2014.
Limitations[edit]
DLight (and thus DLightGUI) pose several restrictions, some of which are inherent on using an offline lightmap renderer:
- Baking lightmaps and shadows is a costly CPU-intensive process. If you have a complex map with hundreds of static lights, expect compilation time to be significant. Since DLight uses the CPU to calculate the lightmaps, dedicating more CPU cores to the baking process will decrease the compilation time.
- The total number of threads that can be utilized is currently 4 in the GUI, but the command-line program supports a maximum of 128 threads
- Multi-threaded baking is not very stable
- 3D floors are unsupported
- DLight configuration parameters are hardcoded
- Sunlight can be ignored, but DLight supports by default lighting from the sun
- DLight looks by default for a sky texture called F_SKY001. This is the sky texture for Strife.
- Hexen uses F_SKY
- All other Doom-engine games use F_SKY1
- Shadows are static, meaning that moving lifts or doors will not cast shadows
- DLight's raytracer isn't terribly advanced: it operates on the presumption that any object is either in shadow, or it isn't. Any indirect (bounced) lighting is thus ignored and not supported.
Usage[edit]
Before building lightmaps, the WAD file must first be pre-compiled with GL nodes using glBSP. Optionally, PVS data can be built using glVIS which can help speed up compile time. The input for DLight is as follows:
dlight -map ## [option1] [option2] ... [WAD file]}}
As of version 2.0, DLight can only compile one map at a time so the -map option is required.
Options[edit]
-map <1-99> Specify the map number to compile for
-samples <2, 4, 8, 16> Specify how many samples to build. Samples are
automatically rounded into powers of two. Higher
sample count will result in faster compile times
but results in poor quality lightmaps, while
lower values will generate better quality
lightmaps but results in longer compile times.
Using 8 or 16 is recommended.
-size <64, 128, 256> Specify the width and height of the lightmap
textures. Size is automatically rounded into
powers of two. Using 128 or 256 is recommended.
-threads <##> Specify how many threads to utilize for building
lightmaps. By default, the tool will try to
utilize 2 threads. (1 min, 128 max)
-help Displays list of options
-config <file path> Specify a configuration file to use. By default
it will try to find SVE.CFG
-writetga Dumps generated lightmaps as targa image files
-ambience <##> UNUSED
DLight configuration specification[edit]
DLight requires a .cfg configuration file to function. These files follow a specification which you can find below:
Format:
/*
multi-line comment
*/
// single line comment
block name
{
<property> <value>
}
integer a single whole number
float a number with decimals
vector a quoted string with 3 floating point or
integer numbers usually in the form of xyz
boolean either 0 or 1
Blocks:
mapdef
lightdef
surfaceLight
Mapdef block:
A mapdef defines the global sunlight behavior for a specified map.
Mapdef properties:
map <integer> The map number this mapdef block should
be assigned to
sun_direction <vector> A vector representing the direction in
which the direction of the sun is coming
from. Vector is normalized, meaning each
component ranges from 0.0 to 1.0 and is
measured in Doom axis coordinates
(e.g. x = left, y = forward, z = up)
Default vector: "0.45 0.3 0.9"
sun_color <vector> A vector representing the RGB color of
the sunlight. Values ranges from 0 to
255 Default vector: "255 255 255"
sun_ignore_tag <integer> If specified, any sector with this tag
will not be lit by sunlight and no
lightmaps will be generated for it.
Lightdef block:
A lightdef block allows to define a thing to emit light during
compile time.
Lightdef properties:
doomednum <integer> The doomednum of this thing in which
will generate lightmaps.
rgb <vector> A vector representing the RGB color of
the light
height <float> Sets an offset on the z-axis for the
origin of the light source.
radius <float> Specifies the radius of the light. A
larger radius will result in more
surfaces affected by this light.
Setting radius to -1 will tell DLight
to take the radius based on the
thing's angle value.
intensity <float> Specifies how strong the light source
is. A value of 4.0 is recommended in
Strife: Veteran Edition
falloff <float> Sets the falloff for this light
(expiremental)
ceiling If specified, then the origin of the
light will be relative to the ceiling
instead of the floor
SurfaceLight block:
A surfacelight block specifies a surface (either a wall or a flat) to
emit light during compile time.
SurfaceLight properties:
tag <integer> Tells Dlight to emit light from all
sectors/lines that contains this tag value.
rgb <vector> A vector representing the RGB color of
the light
cone_inner <float> Specifies the FOV (in degrees) of the main
source of light. Value ranges between 0 to
180 degrees. Smaller values results in
larger cone.
cone_outer <float> Specifies the FOV (in degrees) of the light
fading out from the inner cone.
distance <float> Specifies how much area to cover
intensity <float> Specifies how strong the light source is.
A value of 4.0 is recommended in
Strife: Veteran Edition
bIgnoreFloor <boolean> If 1, then floors will be ignored.
falloff <float> Sets the falloff for this light
(expiremental)
Map lump specification[edit]
DLight generates new lumps that contain the lightmap data. A port needs to have support for these lumps in order to recognize this data. The new lumps are as follows:
LM_MAP## Level marker
LM_CELLS Contains rgb information on how sprites
interacts with lightmaps.
LM_SUN Contains RGB and vector data for sunlight.
LM_SURFS Contains information for every surface
that is bounded to a lightmap. This
includes texture mapping (UV) data and
which lightmap block the surface is
mapped to.
LM_TXCRD Contains all UV texture coordinates for
each surface.
LM_LMAPS Contains raw RGB texture data that makes
up the lightmaps.
See also[edit]
External links[edit]
- DLight source code, at GitHub
- DLightGUI source code, at GitHub
- DLight configuration file specification More detailed usage of lightconfig.txt, at GitHub
- DLightGUI download, includes commandline and gui versions of DLight, at GitHub
- Doom Builder configuration files for DLight, at GitHub
