Provided by: radiance_4R1+20120125-1.1_amd64 bug

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)