2034908d41 2012-05-20        kinaba: typedef long double LD;
2034908d41 2012-05-20        kinaba: typedef complex<LD> CMP;
2034908d41 2012-05-20        kinaba: 
2034908d41 2012-05-20        kinaba: bool line_circle(CMP la, CMP lb, CMP c, LD r, CMP* p1, CMP* p2)
2034908d41 2012-05-20        kinaba: {
2034908d41 2012-05-20        kinaba: 	CMP v = (lb-la) / abs(lb-la);
2034908d41 2012-05-20        kinaba: 	CMP o = (c-la) / v;
2034908d41 2012-05-20        kinaba: 	if( abs(o.imag()) > r )
2034908d41 2012-05-20        kinaba: 		return false;
2034908d41 2012-05-20        kinaba: 	LD dx = sqrt(r*r - o.imag()*o.imag());
2034908d41 2012-05-20        kinaba: 	*p1 = la + (o.real()-dx)*v;
2034908d41 2012-05-20        kinaba: 	*p2 = la + (o.real()+dx)*v;
2034908d41 2012-05-20        kinaba: 	return true;
2034908d41 2012-05-20        kinaba: }