X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=simgear%2Fmath%2FSGVec3.hxx;h=64ceac0a88ac141ed6273738c624779745b2573f;hb=7a52c2fa71355631a559d74e0860fa6c5efa424e;hp=f2b7406a647083cdc5d4422d81b08cde6ba51312;hpb=ce54997be569ebcac4222321e7ae3fecccd01324;p=simgear.git

diff --git a/simgear/math/SGVec3.hxx b/simgear/math/SGVec3.hxx
index f2b7406a..64ceac0a 100644
--- a/simgear/math/SGVec3.hxx
+++ b/simgear/math/SGVec3.hxx
@@ -53,12 +53,6 @@ public:
   { 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; }
-#ifndef NO_OPENSCENEGRAPH_INTERFACE
-  explicit SGVec3(const osg::Vec3f& d)
-  { data()[0] = d[0]; data()[1] = d[1]; data()[2] = d[2]; }
-  explicit SGVec3(const osg::Vec3d& d)
-  { data()[0] = d[0]; data()[1] = d[1]; data()[2] = d[2]; }
-#endif
 
   /// Access by index, the index is unchecked
   const T& operator()(unsigned i) const
@@ -100,11 +94,6 @@ public:
   T (&data(void))[3]
   { return _data; }
 
-#ifndef NO_OPENSCENEGRAPH_INTERFACE
-  osg::Vec3d osg() const
-  { return osg::Vec3d(data()[0], data()[1], data()[2]); }
-#endif
-
   /// Inplace addition
   SGVec3& operator+=(const SGVec3& v)
   { data()[0] += v(0); data()[1] += v(1); data()[2] += v(2); return *this; }
@@ -363,12 +352,18 @@ 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>
@@ -459,6 +454,18 @@ 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