X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=simgear%2Fmath%2FSGVec4.hxx;h=6030c48ba03e2ea331b43442cebfd2df509fdf1b;hb=3cd4c5566f8c418bc9bbb6026072eb0192027993;hp=335393fbeb6f94591d94e435eb4d61334030579e;hpb=ce54997be569ebcac4222321e7ae3fecccd01324;p=simgear.git

diff --git a/simgear/math/SGVec4.hxx b/simgear/math/SGVec4.hxx
index 335393fb..6030c48b 100644
--- a/simgear/math/SGVec4.hxx
+++ b/simgear/math/SGVec4.hxx
@@ -53,12 +53,6 @@ public:
   { data()[0] = d[0]; data()[1] = d[1]; data()[2] = d[2]; data()[3] = d[3]; }
   explicit SGVec4(const SGVec3<T>& v3, const T& v4 = 0)
   { data()[0] = v3[0]; data()[1] = v3[1]; data()[2] = v3[2]; data()[3] = v4; }
-#ifndef NO_OPENSCENEGRAPH_INTERFACE
-  explicit SGVec4(const osg::Vec4f& d)
-  { data()[0] = d[0]; data()[1] = d[1]; data()[2] = d[2]; data()[3] = d[3]; }
-  explicit SGVec4(const osg::Vec4d& d)
-  { data()[0] = d[0]; data()[1] = d[1]; data()[2] = d[2]; data()[3] = d[3]; }
-#endif
 
   /// Access by index, the index is unchecked
   const T& operator()(unsigned i) const
@@ -106,11 +100,6 @@ public:
   T (&data(void))[4]
   { return _data; }
 
-#ifndef NO_OPENSCENEGRAPH_INTERFACE
-  osg::Vec4d osg() const
-  { return osg::Vec4d(data()[0], data()[1], data()[2], data()[3]); }
-#endif
-
   /// Inplace addition
   SGVec4& operator+=(const SGVec4& v)
   { data()[0]+=v(0);data()[1]+=v(1);data()[2]+=v(2);data()[3]+=v(3);return *this; }
@@ -299,7 +288,12 @@ template<typename T>
 inline
 SGVec4<T>
 normalize(const SGVec4<T>& v)
-{ return (1/norm(v))*v; }
+{
+  T normv = norm(v);
+  if (normv <= SGLimits<T>::min())
+    return SGVec4<T>::zeros();
+  return (1/normv)*v;
+}
 
 /// Return true if exactly the same
 template<typename T>
@@ -394,6 +388,18 @@ T
 distSqr(const SGVec4<T>& v1, const SGVec4<T>& v2)
 { SGVec4<T> tmp = v1 - v2; return dot(tmp, tmp); }
 
+// calculate the projection of u along the direction of d.
+template<typename T>
+inline
+SGVec4<T>
+projection(const SGVec4<T>& u, const SGVec4<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