calc_spline

calc_spline(3alleg4)             Allegro manual             calc_spline(3alleg4)



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

SYNOPSIS
       #include <allegro.h>


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

DESCRIPTION
       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.


SEE ALSO
       spline(3alleg4), exspline(3alleg4)



Allegro                           version 4.4.3             calc_spline(3alleg4)