static void
initEllipse(ellipse_t * ep, double cx, double cy, double a, double b,
double theta, double lambda1, double lambda2)
{
ep->cx = cx;
ep->cy = cy;
ep->a = a;
ep->b = b;
ep->theta = theta;
ep->eta1 = atan2(sin(lambda1) / b, cos(lambda1) / a);
ep->eta2 = atan2(sin(lambda2) / b, cos(lambda2) / a);
ep->cosTheta = cos(theta);
ep->sinTheta = sin(theta);
// make sure we have eta1 <= eta2 <= eta1 + 2*PI
ep->eta2 -= TWOPI * floor((ep->eta2 - ep->eta1) / TWOPI);
// the preceding correction fails if we have exactly eta2 - eta1 = 2*PI
// it reduces the interval to zero length
if ((lambda2 - lambda1 > M_PI) && (ep->eta2 - ep->eta1 < M_PI)) {
ep->eta2 += TWOPI;
}
computeFoci(ep);
computeEndPoints(ep);
computeBounds(ep);
/* Flatness parameters */
ep->f = (ep->a - ep->b) / ep->a;
ep->e2 = ep->f * (2.0 - ep->f);
ep->g = 1.0 - ep->f;
ep->g2 = ep->g * ep->g;
}
void Geom::Segment::set( Vector3 c, Vector3 d, double e )
{
Center = c;
Direction = d;
Extent = e;
computeEndPoints();
}