Table of contents

• NAME
• SYNOPSIS
• OPTIONS
• DESCRIPTION
• INPUT FILE
• SAMPLE INPUT FILE
• SEE ALSO
• AUTHOR

NAME

SYNOPSIS

[x] is a PLOT79 device library suffix letter.

OPTIONS

-d

Show hidden arcs with dotted lines.

-f

Draw on a full frame unit square, instead of in a viewport inside the default rectangular frame.

-g:#

Show grid lines delineating # horizontal and vertical cells. nn is the value of GHOR and GVER in spheres(1).

-i

Draw spheres from the input file to spheres, rather than the usual output file from spheres.

-l

Label arcs by their sequence numbers, with the label flush right to the beginning of the arc.

-p

Draw a plus at the center of each sphere.

DESCRIPTION

When the output device supports it, the visible sphere arcs are plotted in color, to enhance depth perception. The colors are defined by a file, rgb.dat, in the current directory, which contains a single initial comment line, followed by (index, values in free format, each starting a new line.

The index values must lie in the range 0 ... 255, although 0 ... 7 are permanently preassigned by the CORE system to black, red, green, yellow, blue, magenta, cyan, and white, in that order, and cannot be altered.

The (red, triples specify primary intensities on a scale of 0.0 ... 1.0.

The range of depth values wmin...wmax is mapped uniformly to the color range 8 ... MAXINDEX, where MAXINDEX is the largest color index found in the file.

The default rgb.dat file defines 256 colors in the rainbow order, red (front), orange, yellow, green, blue, indigo, and violet (back) (remember: Roy G. Biv). The human eye is less sensitive in the blue-violet part of the visible spectrum than in the green-yellow part, so using blue-violet colors for far distant spheres is quite effective at enhancing the illusion of depth.

If no color map file is provided, a monochrome image is produced.

INPUT FILE

The normal sphplt input file contains a one-line title, six window box extents in order umin, umax, vmin, vmax, wmin, wmax, followed by a list of visible arcs. Each arc starts a new line, and consists of (u,v,w,r) position and radius values, plus a starting and ending angle, measured counterclockwise in degrees from the u axis.

All numbers are specified in free-format Fortran list-directed input.

Window coordinates are always left-handed, u increasing to the right, v increasing vertically, and w increasing from front to back.

SAMPLE INPUT FILE

 10 Random Uniform Spheres
 -2.000E-01 1.200E+00 -2.000E-01  1.200E+00  0.000E+00  1.000E+00
5.64009E-01  9.10292E-01  6.53278E-01  1.99976E-01  36.565 135.711
5.64009E-01  9.10292E-01  6.53278E-01  1.99976E-01 254.019 315.613
4.74618E-01  3.60786E-01  2.82261E-01  1.99976E-01    .000 360.000
1.17690E-02  1.03040E-01  6.21902E-01  1.99976E-01    .000 360.000
2.69174E-01  9.19521E-01  5.39128E-01  1.99976E-01  25.841 239.187
8.67562E-01  8.89611E-01  3.04358E-01  1.99976E-01    .000 360.000
7.68893E-02  8.34062E-01  6.68417E-01  1.99976E-01  82.205 286.936
3.45574E-01  5.34611E-01  2.96911E-01  1.99976E-01   3.802  48.431
3.45574E-01  5.34611E-01  2.96911E-01  1.99976E-01 131.097 249.339
3.46771E-01  8.34916E-01  1.94115E-01  1.99976E-01    .000 360.000
1.89525E-01  4.70346E-01  7.88548E-01  1.99976E-01 125.010 298.758
3.15322E-01  5.55976E-01  5.86497E-01  1.99976E-01 128.987 240.066 

This particular file was generated by spheres from the sample file shown in its manual pages. The coordinate values differ from those in that file because they are window, rather than world, coordinates.

SEE ALSO

AUTHOR

Center for Scientific Computing

Department of Mathematics

220 South Physics Building

University of Utah

Salt Lake City, UT 84112

Tel: (801) 581-5254

FAX: (801) 581-4148

E-mail: <beebe@math.utah.edu>