pllightsource - Sets the 3D position of the light source
pllightsource(x, y, z)
Sets the 3D position of the light source for use with plsurf3d(3plplot) and plsurf3dl(3plplot)
Redacted form: pllightsource(x, y, z)
This function is used in example 8.
Many developers (who are credited at http://plplot.org/credits.php) have contributed to PLplot over its long history.
PLplot documentation at http://plplot.org/documentation.php.