Provided by: radiance_4R1+20120125-1.1_amd64 
NAME
rhpict - render a RADIANCE picture from a holodeck file
SYNOPSIS
rhpict [ options ] holodeck
DESCRIPTION
Rhpict generates one or more pictures from the RADIANCE holodeck file holodeck and sends them to the
standard output. The -o option may be used to specify an alternate output file. Other options specify
the viewing parameters and provide some control over the calculation.
The view as well as some of the other controls are shared in common with the rpict(1) command. The
options that are unique to rhpict are given first, followed by the more familiar ones.
-s Use the smooth resampling algorithm, which amounts to linear interpolation between ray samples
with additional edge detection along color and object boundaries. This is the default.
-r rf Use random resampling, where rf is a fraction from 0 to 1 indicating the desired degree of
randomness. A random fraction of 0 is not the same as smooth resampling, because there is no
linear interpolation, just Voronoi regions. Values greater than 1 produce interesting
underwater effects.
-x res Set the maximum x resolution to res.
-y res Set the maximum y resolution to res.
-pa rat Set the pixel aspect ratio (height over width) to rat. Either the x or the y resolution will
be reduced so that the pixels have this ratio for the specified view. If rat is zero, then the
x and y resolutions will adhere to the given maxima.
-pe expval
Set the exposure value for the output pictures to expval. Since filtering is performed by
rhpict, there is little sense in passing the output through pfilt(1), other than changing the
exposure. This option eliminates that need. The value may be specified either as a
multiplier, or as a number f-stops preceeded by a '+' or '-' character.
-vtt Set view type to t. If t is 'v', a perspective view is selected. If t is 'l', a parallel view
is used. A cylindrical panorma may be selected by setting t to the letter 'c'. This view is
like a standard perspective vertically, but projected on a cylinder horizontally (like a
soupcan's-eye view). Three fisheye views are provided as well; 'h' yields a hemispherical
fisheye view, 'a' results in angular fisheye distortion, and 's' results in a planisphere
(stereographic) projection. A hemispherical fisheye is a projection of the hemisphere onto a
circle. The maximum view angle for this type is 180 degrees. An angular fisheye view is
defined such that distance from the center of the image is proportional to the angle from the
central view direction. An angular fisheye can display a full 360 degrees. A planisphere
fisheye view maintains angular relationships between lines, and is commonly used for sun path
analysis. This is more commonly known as a "stereographic projection," but we avoid the term
here so as not to confuse it with a stereoscopic pair. A planisphere fisheye can display up to
(but not including) 360 degrees, although distortion becomes extreme as this limit is
approached. Note that there is no space between the view type option and its single letter
argument.
-vp x y z Set the view point to x y z . This is the focal point of a perspective view or the center of a
parallel projection.
-vd xd yd zd
Set the view direction vector to xd yd zd .
-vu xd yd zd
Set the view up vector (vertical direction) to xd yd zd .
-vh val Set the view horizontal size to val. For a perspective projection (including fisheye views),
val is the horizontal field of view (in degrees). For a parallel projection, val is the view
width in world coordinates.
-vv val Set the view vertical size to val.
-vo val Set the view fore clipping plane at a distance of val from the view point. The plane will be
perpendicular to the view direction for perspective and parallel view types. For fisheye view
types, the clipping plane is actually a clipping sphere, centered on the view point with radius
val. Objects in front of this imaginary surface will not be visible. This may be useful for
seeing through walls (to get a longer perspective from an exterior view point) or for
incremental rendering. A value of zero implies no foreground clipping. A negative value
produces some interesting effects, since it creates an inverted image for objects behind the
viewpoint. This possibility is provided mostly for the purpose of rendering stereographic
holograms.
-va val Set the view aft clipping plane at a distance of val from the view point. Like the view fore
plane, it will be perpendicular to the view direction for perspective and parallel view types.
For fisheye view types, the clipping plane is actually a clipping sphere, centered on the view
point with radius val. Objects behind this imaginary surface will not be visible. A value of
zero means no aft clipping, and is the only way to see infinitely distant objects such as the
sky.
-vs val Set the view shift to val. This is the amount the actual image will be shifted to the right of
the specified view. This is option is useful for generating skewed perspectives or rendering
an image a piece at a time. A value of 1 means that the rendered image starts just to the
right of the normal view. A value of -1 would be to the left. Larger or fractional values are
permitted as well.
-vl val Set the view lift to val. This is the amount the actual image will be lifted up from the
specified view, similar to the -vs option.
-vf file Get view parameters from file, which may be a picture or a file created by rvu (with the "view"
command).
-S seqstart
Instead of generating a single picture based only on the view parameters given on the command
line, this option causes rhpict to read view options from the standard input and for each line
containing a valid view specification, generate a corresponding picture. Seqstart is a
positive integer that will be associated with the first output frame, and incremented for
successive output frames. By default, each frame is concatenated to the output stream, but it
is possible to change this action using the -o option (described below). Multiple frames may
be later extracted from a single output stream using the ra_rgbe(1) command.
-o fspec Send the picture(s) to the file(s) given by fspec instead of the standard output. If this
option is used in combination with -S and fspec contains an integer field for printf(3) (eg.,
"%03d") then the actual output file name will include the current frame number.
-w Turn off warning messages.
EXAMPLE
rhpict -vp 10 5 3 -vd 1 -.5 0 scene.hdk > scene.hdr
rpict -S 1 -o frame%02d.hdr scene.hdk < keyframes.vf
AUTHOR
Greg Ward
SEE ALSO
getinfo(1), pfilt(1), pinterp(1), printf(3), ra_rgbe(1), rholo(1), rpict(1), rvu(1)
RADIANCE 3/10/99 RHPICT(1)