math: Add integer valued vector types.

[simgear.git] / simgear / math / SGVec2.hxx

diff --git a/simgear/math/SGVec2.hxx b/simgear/math/SGVec2.hxx
index 0409ee44695488c72c08babe25d7876b435282b7..0695cded19f232e7cc14b698e2f1c6892be2e0fe 100644 (file)
--- a/simgear/math/SGVec2.hxx
+++ b/simgear/math/SGVec2.hxx
@@ -1,4 +1,4 @@
-// Copyright (C) 2006  Mathias Froehlich - Mathias.Froehlich@web.de
+// Copyright (C) 2006-2009  Mathias Froehlich - Mathias.Froehlich@web.de
 //
 // This library is free software; you can redistribute it and/or
 // modify it under the terms of the GNU Library General Public
@@ -18,62 +18,11 @@
 #ifndef SGVec2_H
 #define SGVec2_H
 
-#if defined ( __CYGWIN__ )
-#include <ieeefp.h>
-#endif
-
-#include <osg/Vec2f>
-#include <osg/Vec2d>
-
-template<typename T>
-struct SGVec2Storage {
-  /// Readonly raw storage interface
-  const T (&data(void) const)[2]
-  { return _data; }
-  /// Readonly raw storage interface
-  T (&data(void))[2]
-  { return _data; }
-
-  void osg() const
-  { }
-
-private:
-  T _data[2];
-};
-
-template<>
-struct SGVec2Storage<float> : public osg::Vec2f {
-  /// Access raw data by index, the index is unchecked
-  const float (&data(void) const)[2]
-  { return osg::Vec2f::_v; }
-  /// Access raw data by index, the index is unchecked
-  float (&data(void))[2]
-  { return osg::Vec2f::_v; }
-
-  const osg::Vec2f& osg() const
-  { return *this; }
-  osg::Vec2f& osg()
-  { return *this; }
-};
-
-template<>
-struct SGVec2Storage<double> : public osg::Vec2d {
-  /// Access raw data by index, the index is unchecked
-  const double (&data(void) const)[2]
-  { return osg::Vec2d::_v; }
-  /// Access raw data by index, the index is unchecked
-  double (&data(void))[2]
-  { return osg::Vec2d::_v; }
-
-  const osg::Vec2d& osg() const
-  { return *this; }
-  osg::Vec2d& osg()
-  { return *this; }
-};
+#include <iosfwd>
 
 /// 2D Vector Class
 template<typename T>
-class SGVec2 : protected SGVec2Storage<T> {
+class SGVec2 {
 public:
   typedef T value_type;
 
@@ -96,9 +45,8 @@ public:
   /// make sure it has at least 2 elements
   explicit SGVec2(const T* d)
   { data()[0] = d[0]; data()[1] = d[1]; }
-  explicit SGVec2(const osg::Vec2f& d)
-  { data()[0] = d[0]; data()[1] = d[1]; }
-  explicit SGVec2(const osg::Vec2d& d)
+  template<typename S>
+  explicit SGVec2(const SGVec2<S>& d)
   { data()[0] = d[0]; data()[1] = d[1]; }
 
   /// Access by index, the index is unchecked
@@ -128,18 +76,12 @@ public:
   T& y(void)
   { return data()[1]; }
 
-  /// Get the data pointer
-  using SGVec2Storage<T>::data;
-
-  /// Readonly interface function to ssg's sgVec2/sgdVec2
-  const T (&sg(void) const)[2]
-  { return data(); }
-  /// Interface function to ssg's sgVec2/sgdVec2
-  T (&sg(void))[2]
-  { return data(); }
-
-  /// Interface function to osg's Vec2*
-  using SGVec2Storage<T>::osg;
+  /// Access raw data
+  const T (&data(void) const)[2]
+  { return _data; }
+  /// Access raw data
+  T (&data(void))[2]
+  { return _data; }
 
   /// Inplace addition
   SGVec2& operator+=(const SGVec2& v)
@@ -164,6 +106,9 @@ public:
   { return SGVec2(1, 0); }
   static SGVec2 e2(void)
   { return SGVec2(0, 1); }
+
+private:
+  T _data[2];
 };
 
 /// Unary +, do nothing ...
@@ -292,7 +237,12 @@ template<typename T>
 inline
 SGVec2<T>
 normalize(const SGVec2<T>& v)
-{ return (1/norm(v))*v; }
+{
+  T normv = norm(v);
+  if (normv <= SGLimits<T>::min())
+    return SGVec2<T>::zeros();
+  return (1/normv)*v;
+}
 
 /// Return true if exactly the same
 template<typename T>
@@ -379,6 +329,18 @@ T
 distSqr(const SGVec2<T>& v1, const SGVec2<T>& v2)
 { SGVec2<T> tmp = v1 - v2; return dot(tmp, tmp); }
 
+// calculate the projection of u along the direction of d.
+template<typename T>
+inline
+SGVec2<T>
+projection(const SGVec2<T>& u, const SGVec2<T>& d)
+{
+  T denom = dot(d, d);
+  T ud = dot(u, d);
+  if (SGLimits<T>::min() < denom) return u;
+  else return d * (dot(u, d) / denom);
+}
+
 #ifndef NDEBUG
 template<typename T>
 inline