RHPICT(1)                                                            RHPICT(1)



NNAAMMEE
       rhpict - render a RADIANCE picture from a holodeck file

SSYYNNOOPPSSIISS
       rrhhppiicctt [ ooppttiioonnss ] hhoollooddeecckk

DDEESSCCRRIIPPTTIIOONN
       _R_h_p_i_c_t  generates  one or more pictures from the RADIANCE holodeck file
       _h_o_l_o_d_e_c_k 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  _r_p_i_c_t_(_1_) command.  The options that are unique to _r_h_p_i_c_t are
       given first, followed by the more familiar ones.

       --ss        Use the smooth resampling algorithm, which amounts to  linear
                 interpolation between ray samples with additional edge detec-
                 tion along color and object boundaries.  This is the default.

       --rr _r_f     Use  random  resampling,  where  _r_f is a fraction from 0 to 1
                 indicating the desired degree of randomness.  A random  frac-
                 tion 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.

       --xx _r_e_s    Set the maximum x resolution to _r_e_s_.

       --yy _r_e_s    Set the maximum y resolution to _r_e_s_.

       --ppaa _r_a_t   Set  the  pixel  aspect  ratio  (height  over  width) to _r_a_t_.
                 Either the x or the y resolution will be reduced so that  the
                 pixels  have  this  ratio  for the specified view.  If _r_a_t is
                 zero, then the x and y resolutions will adhere to  the  given
                 maxima.

       --ppee _e_x_p_v_a_l
                 Set  the  exposure  value  for the output pictures to _e_x_p_v_a_l_.
                 Since filtering is performed by _r_h_p_i_c_t_, there is little sense
                 in  passing  the output through _p_f_i_l_t_(_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.

       --vvtt_t      Set view type to _t_.  If _t  is  'v',  a  perspective  view  is
                 selected.  If _t is 'l', a parallel view is used.  A cylindri-
                 cal panorma may be selected by setting _t to the  letter  'c'.
                 This view is like a standard perspective vertically, but pro-
                 jected 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  fish-
                 eye  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.

       --vvpp _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.

       --vvdd _x_d _y_d _z_d
                 Set the view direction vector to _x_d _y_d _z_d _.

       --vvuu _x_d _y_d _z_d
                 Set the view up vector (vertical direction) to _x_d _y_d _z_d _.

       --vvhh _v_a_l   Set the view horizontal size to _v_a_l_.  For a perspective  pro-
                 jection  (including  fisheye  views),  _v_a_l  is the horizontal
                 field of view (in degrees).  For a parallel  projection,  _v_a_l
                 is the view width in world coordinates.

       --vvvv _v_a_l   Set the view vertical size to _v_a_l_.

       --vvoo _v_a_l   Set  the  view  fore clipping plane at a distance of _v_a_l from
                 the view point.  The plane will be perpendicular to the  view
                 direction for perspective and parallel view types.  For fish-
                 eye view types, the clipping plane  is  actually  a  clipping
                 sphere,  centered on the view point with radius _v_a_l_.  Objects
                 in front of this imaginary surface will not be visible.  This
                 may  be useful for seeing through walls (to get a longer per-
                 spective from an exterior view point) or for incremental ren-
                 dering.   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  ren-
                 dering stereographic holograms.

       --vvaa _v_a_l   Set the view aft clipping plane at a distance of _v_a_l from the
                 view point.  Like the view fore plane, it will be perpendicu-
                 lar  to  the view direction for perspective and parallel view
                 types.  For fisheye view types, the clipping plane  is  actu-
                 ally  a  clipping  sphere,  centered  on  the view point with
                 radius _v_a_l_.  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.

       --vvss _v_a_l   Set  the  view  shift  to _v_a_l_.  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 nor-
                 mal view.  A value of -1 would be to  the  left.   Larger  or
                 fractional values are permitted as well.

       --vvll _v_a_l   Set  the  view  lift  to  _v_a_l_.  This is the amount the actual
                 image will be lifted up from the specified view,  similar  to
                 the _-_v_s option.

       --vvff _f_i_l_e  Get  view  parameters  from _f_i_l_e_, which may be a picture or a
                 file created by rvu (with the "view" command).

       --SS _s_e_q_s_t_a_r_t
                 Instead of generating a single picture based only on the view
                 parameters  given  on  the  command  line, this option causes
                 _r_h_p_i_c_t to read view options from the standard input  and  for
                 each  line  containing a valid view specification, generate a
                 corresponding picture.  _S_e_q_s_t_a_r_t is a positive  integer  that
                 will  be  associated  with the first output frame, and incre-
                 mented 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 _r_a___r_g_b_e_(_1_) command.

       --oo _f_s_p_e_c  Send the picture(s) to the file(s) given by _f_s_p_e_c instead  of
                 the  standard  output.  If this option is used in combination
                 with _-_S and _f_s_p_e_c contains an  integer  field  for  _p_r_i_n_t_f_(_3_)
                 (eg.,  "%03d")  then the actual output file name will include
                 the current frame number.

       --ww        Turn off warning messages.

EEXXAAMMPPLLEE
       rhpict -vp 10 5 3 -vd 1 -.5 0 scene.hdk > scene.hdr

       rpict -S 1 -o frame%02d.hdr scene.hdk < keyframes.vf

AAUUTTHHOORR
       Greg Ward

SSEEEE AALLSSOO
       getinfo(1),  pfilt(1),  pinterp(1),  printf(3),  ra_rgbe(1),  rholo(1),
       rpict(1), rvu(1)



RADIANCE                            3/10/99                          RHPICT(1)
