.\" RCSid "$Id: rtpict.1,v 1.15 2023/12/12 17:18:27 greg Exp $"
.TH RTPICT 1 3/19/2018 RADIANCE
.SH NAME
rtpict - generate a RADIANCE picture, hyperspectral image, or layers using rtrace
.SH SYNOPSIS
.B rtpict
.B "-n nproc"
[
.B -co
][
.B "-o[vrxlLRXnNsmM] out_dir"
][
.B "-d ref_depth/unit"
]
[
.B "rpict options"
]
[
.B @file
]
.B octree
.SH DESCRIPTION
.I Rtpict
is a script that generates a picture or hyperspectral image
from the RADIANCE scene given in
.I octree
and sends it to the standard output, or to a file specified with the
.I \-o
option.
Most options and defaults are the same as
.I rpict(1),
although a few options are silently ignored, and the
.I rtrace(1)
.I \-co
boolean switch is supported.
Options incompatible with multi-processing may generate an error.
.PP
The
.I rtrace
tool is called with
.I vwrays(1)
to perform the actual work.
This enables the
.I \-n
option for multiprocessing on platforms that support it.
If the
.I \-n
option is not specified or is set to 1, then
.I rpict
is called directly.
There is no benefit in setting the number of processes to anything
greater than the number of virtual cores available on your machine.
Also, it is very important to set the
.I \-af
option if an irradiance cache is being generated;
otherwise, your speed-up will be far from linear.
.PP
If the
.I \-o
option has additional characters corresponding to output types from
.I rtrace,
it must be followed by the name of a directory that either exists or
will be created to contain image layers, one per output type.
The supported types are listed below, and do not include types that
are useless or have no convenient representation.
The table below shows the correspondence between output type and file name
in the specified directory:
.sp
.nf
v	radiance.hdr
r	r_refl.hdr
x	r_unrefl.hdr
l	d_effective.dpt
L	d_firstsurf.dpt
R	d_refl.dpt
X	d_unrefl.dpt
n	perturbed.nrm
N	unperturbed.nrm
s	surface.idx
m	modifier.idx
M	material.idx
.fi
.sp
Different encodings are associated with different data types.
Color data (from the 'v', 'r', and 'x' types) will be converted to
a flat RGBE picture by
.I pvalue(1),
unless the
.I \-co+
option is specified and
.I \-cs
is greater than 3.
In this case, a hyperspectral image will be generated for each
of the value types, converted by
.I rcomb(1)
and with its suffix set to ".hsr" rather than ".hdr".
Distances (from the 'l', 'L', 'R', and 'X' types) will be
converted to a 16-bit representation by
.I rcode_depth(1),
and the
.I \-d
option should be used to assign the reference (median) depth and world
units, which applies to the overall scene.
Surface normals (from the 'n' and 'N' types) will be converted
to a 32-bit representation by
.I rcode_norm(1).
Finally, identifiers (from the 's', 'm', and 'M' types) will be
converted to a 16-bit index format by
.I rcode_ident(1).
.PP
If the
.I \-i
option is used to turn on irradiane output, then the picture associated
with the 'v' type will be renamed
.I "irradiance.hdr"
or
.I "irradiance.hsr"
and some other output types become irrelevant
(i.e., 'r', 'x', 'R', and 'X').
If one or more of the associated output files already exists in the
destination directory, an error will be printed and the command will abort.
.SH EXAMPLES
To render a scene with four processes:
.IP "" .2i
rtpict -n 4 -vf mypers.vf -ab 1 -af scene.amb scene.oct > scene_pers.hdr
.PP
To render radiance, first surface distance, and normals in a layered image:
.IP "" .2i
rtpict -n 8 -vf fish.vf @render.opt -ovLn fisholay scene.oct
.PP
To render a hyperspectral irradiance image with 18 spectral samples:
.IP "" .2i
rtpict -vf inside.vf -i+ -cs 18 -co+ scene.oct > scene_inside.hsr
.SH AUTHOR
Greg Ward
.SH "SEE ALSO"
getinfo(1), mkpmap(1), oconv(1), pfilt(1), 
pvalue(1), rad(1), rcode_depth(1), rcode_norm(1), rcode_ident(1),
rcomb(1), rcrop(1), rmtxop(1),
rpiece(1), rpict(1), rsplit(1), rtrace(1), rvu(1), vwrays(1)