math: Add integer valued vector types.

[simgear.git] / simgear / math / SGVec3.hxx

diff --git a/simgear/math/SGVec3.hxx b/simgear/math/SGVec3.hxx
index bed95dadd540c30cf5b08d4fe88aabd072b3a10a..dbc8af543bf9a5d39a933be30d55e32b9dfc9c43 100644 (file)
--- a/simgear/math/SGVec3.hxx
+++ b/simgear/math/SGVec3.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
@@ -18,61 +18,19 @@
 #ifndef SGVec3_H
 #define SGVec3_H
 
-#include <osg/Vec3f>
-#include <osg/Vec3d>
-
-template<typename T>
-struct SGVec3Storage {
-  /// Readonly raw storage interface
-  const T (&data(void) const)[3]
-  { return _data; }
-  /// Readonly raw storage interface
-  T (&data(void))[3]
-  { return _data; }
-
-  void osg() const
-  { }
-
-private:
-  T _data[3];
-};
-
-template<>
-struct SGVec3Storage<float> : public osg::Vec3f {
-  /// Access raw data by index, the index is unchecked
-  const float (&data(void) const)[3]
-  { return osg::Vec3f::_v; }
-  /// Access raw data by index, the index is unchecked
-  float (&data(void))[3]
-  { return osg::Vec3f::_v; }
-
-  const osg::Vec3f& osg() const
-  { return *this; }
-  osg::Vec3f& osg()
-  { return *this; }
-};
-
-template<>
-struct SGVec3Storage<double> : public osg::Vec3d {
-  /// Access raw data by index, the index is unchecked
-  const double (&data(void) const)[3]
-  { return osg::Vec3d::_v; }
-  /// Access raw data by index, the index is unchecked
-  double (&data(void))[3]
-  { return osg::Vec3d::_v; }
-
-  const osg::Vec3d& osg() const
-  { return *this; }
-  osg::Vec3d& osg()
-  { return *this; }
-};
+#include <iosfwd>
 
 /// 3D Vector Class
 template<typename T>
-class SGVec3 : protected SGVec3Storage<T> {
+class SGVec3 {
 public:
   typedef T value_type;
 
+#ifdef __GNUC__
+// Avoid "_data not initialized" warnings (see comment below).
+#   pragma GCC diagnostic ignored "-Wuninitialized"
+#endif
+
   /// Default constructor. Does not initialize at all.
   /// If you need them zero initialized, use SGVec3::zeros()
   SGVec3(void)
@@ -85,6 +43,12 @@ public:
       data()[i] = SGLimits<T>::quiet_NaN();
 #endif
   }
+
+#ifdef __GNUC__
+  // Restore warning settings.
+#   pragma GCC diagnostic warning "-Wuninitialized"
+#endif
+
   /// Constructor. Initialize by the given values
   SGVec3(T x, T y, T z)
   { data()[0] = x; data()[1] = y; data()[2] = z; }
@@ -92,9 +56,8 @@ public:
   /// make sure it has at least 3 elements
   explicit SGVec3(const T* d)
   { data()[0] = d[0]; data()[1] = d[1]; data()[2] = d[2]; }
-  explicit SGVec3(const osg::Vec3f& d)
-  { data()[0] = d[0]; data()[1] = d[1]; data()[2] = d[2]; }
-  explicit SGVec3(const osg::Vec3d& d)
+  template<typename S>
+  explicit SGVec3(const SGVec3<S>& d)
   { data()[0] = d[0]; data()[1] = d[1]; data()[2] = d[2]; }
   explicit SGVec3(const SGVec2<T>& v2, const T& v3 = 0)
   { data()[0] = v2[0]; data()[1] = v2[1]; data()[2] = v3; }
@@ -132,18 +95,12 @@ public:
   T& z(void)
   { return data()[2]; }
 
-  /// Get the data pointer
-  using SGVec3Storage<T>::data;
-
-  /// Readonly interface function to ssg's sgVec3/sgdVec3
-  const T (&sg(void) const)[3]
-  { return data(); }
-  /// Interface function to ssg's sgVec3/sgdVec3
-  T (&sg(void))[3]
-  { return data(); }
-
-  /// Interface function to osg's Vec3*
-  using SGVec3Storage<T>::osg;
+  /// Readonly raw storage interface
+  const T (&data(void) const)[3]
+  { return _data; }
+  /// Readonly raw storage interface
+  T (&data(void))[3]
+  { return _data; }
 
   /// Inplace addition
   SGVec3& operator+=(const SGVec3& v)
@@ -177,6 +134,9 @@ public:
   /// Constructor. Initialize by a geocentric coordinate
   /// Note that this conversion is relatively expensive to compute
   static SGVec3 fromGeoc(const SGGeoc& geoc);
+
+private:
+  T _data[3];
 };
 
 template<>
@@ -261,6 +221,15 @@ SGVec3<T>
 operator*(const SGVec3<T>& v, S s)
 { return SGVec3<T>(s*v(0), s*v(1), s*v(2)); }
 
+/// multiplication as a multiplicator, that is assume that the first vector
+/// represents a 3x3 diagonal matrix with the diagonal elements in the vector.
+/// Then the result is the product of that matrix times the second vector.
+template<typename T>
+inline
+SGVec3<T>
+mult(const SGVec3<T>& v1, const SGVec3<T>& v2)
+{ return SGVec3<T>(v1(0)*v2(0), v1(1)*v2(1), v1(2)*v2(2)); }
+
 /// component wise min
 template<typename T>
 inline
@@ -391,12 +360,18 @@ perpendicular(const SGVec3<T>& v)
   }
 }
 
-/// The euclidean norm of the vector, that is what most people call length
+/// Construct a unit vector in the given direction.
+/// or the zero vector if the input vector is zero.
 template<typename T>
 inline
 SGVec3<T>
 normalize(const SGVec3<T>& v)
-{ return (1/norm(v))*v; }
+{
+  T normv = norm(v);
+  if (normv <= SGLimits<T>::min())
+    return SGVec3<T>::zeros();
+  return (1/normv)*v;
+}
 
 /// Return true if exactly the same
 template<typename T>
@@ -487,6 +462,18 @@ T
 distSqr(const SGVec3<T>& v1, const SGVec3<T>& v2)
 { SGVec3<T> tmp = v1 - v2; return dot(tmp, tmp); }
 
+// calculate the projection of u along the direction of d.
+template<typename T>
+inline
+SGVec3<T>
+projection(const SGVec3<T>& u, const SGVec3<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