From f1ea75bbe808871216be39aaa923fb37f01cba8b Mon Sep 17 00:00:00 2001
From: cignoni <paolo.cignoni@isti.cnr.it>
Date: Wed, 21 Apr 2004 14:22:27 +0000
Subject: [PATCH] Initial Commit

---
 vcg/space/intersection3.h | 70 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 vcg/space/intersection3.h

diff --git a/vcg/space/intersection3.h b/vcg/space/intersection3.h
new file mode 100644
index 00000000..5c8fa7e6
--- /dev/null
+++ b/vcg/space/intersection3.h
@@ -0,0 +1,70 @@
+/****************************************************************************
+* VCGLib                                                            o o     *
+* Visual and Computer Graphics Library                            o     o   *
+*                                                                _   O  _   *
+* Copyright(C) 2004                                                \/)\/    *
+* Visual Computing Lab                                            /\/|      *
+* ISTI - Italian National Research Council                           |      *
+*                                                                    \      *
+* All rights reserved.                                                      *
+*                                                                           *
+* This program is free software; you can redistribute it and/or modify      *   
+* it under the terms of the GNU General Public License as published by      *
+* the Free Software Foundation; either version 2 of the License, or         *
+* (at your option) any later version.                                       *
+*                                                                           *
+* This program is distributed in the hope that it will be useful,           *
+* but WITHOUT ANY WARRANTY; without even the implied warranty of            *
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the             *
+* GNU General Public License (http://www.gnu.org/licenses/gpl.txt)          *
+* for more details.                                                         *
+*                                                                           *
+****************************************************************************/
+/****************************************************************************
+  History
+
+$Log: not supported by cvs2svn $
+
+****************************************************************************/
+
+
+
+#ifndef __VCGLIB_INTERSECTION_3
+#define __VCGLIB_INTERSECTION_3
+
+#include <vcg/space/point3.h>
+
+namespace vcg {
+// sphere line
+
+template<class T>
+inline bool Intersection( const Sphere3<T> & sp, const Line3<T> & li, Point3<T> & p0,Point3<T> & p1 ){
+
+	// Per prima cosa si sposta il sistema di riferimento 
+	// fino a portare il centro della sfera nell'origine
+	Point3<T> neworig=li.Origin()-sp.Center();
+	// poi si risolve il sistema di secondo grado (con maple...)
+	 T t1 = li.Direction().x()*li.Direction().x();
+	 T t2 = li.Direction().y()*li.Direction().y();
+   T t3 = li.Direction().z()*li.Direction().z();
+   T t6 = neworig.y()*li.Direction().y();
+   T t7 = neworig.x()*li.Direction().x();
+   T t8 = neworig.z()*li.Direction().z();
+   T t15 = sp.Radius()*sp.Radius();
+   T t17 = neworig.z()*neworig.z();
+   T t19 = neworig.y()*neworig.y();
+   T t21 = neworig.x()*neworig.x();
+   T t28 = 2.0*t7*t6+2.0*t6*t8+2.0*t7*t8+t1*t15-t1*t17-t1*t19-t2*t21+t2*t15-t2*t17-t3*t21+t3*t15-t3*t19;
+	if(t28<0) return false;
+	T t29 = sqrt(t28);      
+	T val0 = 1/(t1+t2+t3)*(-t6-t7-t8+t29); 
+	T val1 = 1/(t1+t2+t3)*(-t6-t7-t8-t29);
+
+	p0=li.P(val0);
+	p1=li.P(val1);
+return true;
+}
+
+
+} // end namespace
+#endif
\ No newline at end of file