Moved Impostor from osg to osgSim .osg plugin

src/osgPlugins/osgSim/IO_Impostor.cpp

@@ -0,0 +1,51 @@
+#include "osgSim/Impostor"
+
+#include "osgDB/Registry"
+#include "osgDB/Input"
+#include "osgDB/Output"
+
+using namespace osgSim;
+using namespace osgDB;
+
+// forward declare functions to use later.
+bool Impostor_readLocalData(osg::Object& obj, Input& fr);
+bool Impostor_writeLocalData(const osg::Object& obj, Output& fw);
+
+// register the read and write functions with the osgDB::Registry.
+RegisterDotOsgWrapperProxy g_ImpostorProxy
+(
+    new osgSim::Impostor,
+    "Impostor",
+    "Object Node Impostor LOD Group",
+    &Impostor_readLocalData,
+    &Impostor_writeLocalData
+);
+
+bool Impostor_readLocalData(osg::Object& obj, Input& fr)
+{
+    bool iteratorAdvanced = false;
+
+    Impostor& impostor = static_cast<Impostor&>(obj);
+
+    if (fr.matchSequence("ImpostorThreshold %f"))
+    {
+        float threshold;
+        fr[1].getFloat(threshold);
+        impostor.setImpostorThreshold(threshold);
+
+        iteratorAdvanced = true;
+        fr+=2;
+    }
+
+    return iteratorAdvanced;
+}
+
+
+bool Impostor_writeLocalData(const osg::Object& obj, Output& fw)
+{
+    const Impostor& impostor = static_cast<const Impostor&>(obj);
+
+    fw.indent() << "ImpostorThreshold "<< impostor.getImpostorThreshold() << std::endl;
+
+    return true;
+}