void follow_vector ( SS_XYZ *p1, SS_XYZ *p2, double d, SS_XYZ *q )

SS_XYZ *p1;          // first point of vector

SS_XYZ *p2;          // second point of vector

double  d;           // distance

SS_XYZ *q;           // resulting point

Synopsis

#include "silver.h"

On the line defined by p1-p2, this function finds, for a positive value d, a point q that lies a distance d from p1 in the direction of p2.  For negative values of d, the function finds a point q opposite the direction of p2.

Parameters

p1, p2 are distinct points; d is any value.

Return Value

None .