1 files changed, 105 insertions, 0 deletions
diff --git a/tdescreensaver/kdesavers/vec3.cpp b/tdescreensaver/kdesavers/vec3.cpp
new file mode 100644
index 00000000..c66730e5
--- /dev/null
+++ b/tdescreensaver/kdesavers/vec3.cpp
@@ -0,0 +1,105 @@
+//============================================================================
+//
+// 3-dim real vector class
+// $Id$
+// Copyright (C) 2004 Georg Drenkhahn
+//
+// This file is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License version 2 as published by the
+// Free Software Foundation.
+//
+//============================================================================
+
+#include <math.h>
+#if !defined(NAN)
+static inline double nan__()
+{
+    static const unsigned int one = 1;
+    static const bool BigEndian = (*((unsigned char *) &one) == 0);
+
+    static const unsigned char be_nan_bytes[] = { 0x7f, 0xf8, 0, 0, 0, 0, 0, 0 };
+    static const unsigned char le_nan_bytes[] = { 0, 0, 0, 0, 0, 0, 0xf8, 0x7f };
+
+    return *( ( const double * )( BigEndian ? be_nan_bytes : le_nan_bytes ) );
+}
+#   define NAN (::nan__())
+#endif
+
+#include <config.h>
+
+#ifdef HAVE_NUMERIC_LIMITS
+#include <limits>
+#endif
+
+#include <cerrno>
+#include "vec3.h"
+
+template<typename T>
+vec3<T>& vec3<T>::normalize()
+{
+   T n = norm(*this);
+   if (n != 0)
+   {
+      (*this) /= n;
+   }
+   else
+   {
+      errno = EDOM;             // indicate domain error
+      // TODO: throw an exception?
+   }
+   return *this;
+}
+
+template<typename T>
+vec3<T>& vec3<T>::rotate(const vec3<T>& r)
+{
+   T phi = norm(r);
+   if (phi != 0)
+   {
+      // part of vector which is parallel to r
+      vec3<T> par(r*(*this)/(r*r) * r);
+      // part of vector which is perpendicular to r
+      vec3<T> perp(*this - par);
+      // rotation direction, size of perp
+      vec3<T> rotdir(norm(perp) * normalized(crossprod(r,perp)));
+      *this = par + cos(phi)*perp + sin(phi)*rotdir;
+   }
+   return *this;
+}
+
+/*--- static member functions ---*/
+
+template<typename T>
+T vec3<T>::cos_angle(const vec3<T>& a, const vec3<T>& b)
+{
+   T den = norm(a) * norm(b);
+   T ret = 0;
+   // if |a|=0 or |b|=0 then angle is not defined.  We return NAN in this case.
+   if (den != 0.0)
+   {
+      ret = a*b/den;
+   }
+   else
+   {
+      errno = EDOM;             // indicate domain error
+#ifdef HAVE_NUMERIC_LIMITS
+      // TODO test
+      ret = std::numeric_limits<T>::quiet_NaN();
+#else
+      ret = NAN;                // return NAN from ISO C99
+#endif
+   }
+   return ret;
+}
+
+template<typename T>
+T vec3<T>::angle(const vec3<T>& a, const vec3<T>& b, const vec3<T>& c)
+{
+   // if |a|=0 or |b|=0 then angle is not defined.  We return NAN in this case.
+   T ang = vec3<T>::angle(a,b);
+   return (crossprod(a,b)*c<0) ?
+      T(2.*M_PI)-ang : ang;
+}
+
+// explicite instantiation
+template class vec3<double>;