Added new osg::AnimationPath which is contaner for a set of key frames for

defining an animation path.  To be used with osg::Transform etc.

src/osg/AnimationPath.cpp

@@ -0,0 +1,49 @@
+#include <osg/AnimationPath>
+
+using namespace osg;
+
+void AnimationPath::insert(double time,const Key& key)
+{
+    _timeKeyMap[time] = key;
+}
+
+bool AnimationPath::getMatrix(double time,Matrix& matrix)
+{
+    if (_timeKeyMap.empty()) return false;
+
+    TimeKeyMap::iterator second = _timeKeyMap.lower_bound(time);
+    if (second==_timeKeyMap.begin())
+    {
+        second->second.getMatrix(matrix);
+    }
+    else if (second!=_timeKeyMap.end())
+    {
+        TimeKeyMap::iterator first = second;
+        --first;        
+        
+        // we have both a lower bound and the next item.
+
+        // deta_time = second.time - first.time
+        double delta_time = second->first - first->first;
+
+        if (delta_time==0.0)
+            first->second.getMatrix(matrix);
+        else
+        {
+            Key key;
+            key.interpolate((time - first->first)/delta_time,
+                            first->second,
+                            second->second);
+            key.getMatrix(matrix);
+        }        
+    }
+    else // (second==_timeKeyMap.end())
+    {
+        _timeKeyMap.rbegin().base()->second.getMatrix(matrix);
+    }
+    return true;
+}
+
+bool AnimationPath::getInverse(double time,Matrix& matrix)
+{
+}