Provided by: allegro4-doc_4.4.3.1-1_all bug


       calc_spline  -  Calculates  a  series  of  values  along  a  Bezier  spline.  Allegro game
       programming library.


       #include <allegro.h>

       void calc_spline(const int points[8], int npts, int *x, int *y);


       Calculates a series of npts values along a Bezier spline, storing them in the output x and
       y  arrays.  The  Bezier  curve  is  specified by the four x/y control points in the points
       array: points[0] and points[1]  contain  the  coordinates  of  the  first  control  point,
       points[2]  and points[3] are the second point, etc. Control points 0 and 3 are the ends of
       the spline, and points 1 and 2 are guides. The curve probably won't pass through points  1
       and  2, but they affect the shape of the curve between points 0 and 3 (the lines p0-p1 and
       p2-p3 are tangents to the spline). The easiest way to think of it is that the curve starts
       at  p0, heading in the direction of p1, but curves round so that it arrives at p3 from the
       direction of p2.  In addition to their role as graphics primitives, spline curves  can  be
       useful for constructing smooth paths around a series of control points, as in exspline.c.


       spline(3alleg4), exspline(3alleg4)