double xyz_angle ( SS_XYZ *xyz1, SS_XYZ *xyz2, SS_XYZ *xyz3 )

SS_XYZ *xyz1;     // address of a 3D point

SS_XYZ *xyz2;     // address of a 3D point

SS_XYZ *xyz3;     // address of a 3D point

Synopsis

#include "silver.h"

The xyz_angle function computes the angle formed by points xyz1 , xyz2 and xyz3 , where xyz1 is the central point. The angle returned is in radians and is in the range [0,π].

Parameters

xyz1 , xyz2 and xyz3 are all addresses of 3D points.

Return Value

xyz_angle returns the angle, measured in radians.