Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages


home | help
calc_spline(3)			Allegro	manual			calc_spline(3)

       calc_spline  - Calculates a series of values along a Bezier spline. Al-
       legro 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 se-
       ries of control points, as in exspline.c.

       spline(3), exspline(3)

Allegro				 version 4.4.3			calc_spline(3)


Want to link to this manual page? Use this URL:

home | help