Added convinience constructor.

include/osg/PolygonOffset

@@ -25,6 +25,8 @@ class SG_EXPORT PolygonOffset : public StateAttribute
 
         PolygonOffset();
 
+        PolygonOffset(float factor, float units);
+
         /** Copy constructor using CopyOp to manage deep vs shallow copy.*/
         PolygonOffset(const PolygonOffset& po,const CopyOp& copyop=CopyOp::SHALLOW_COPY):
             StateAttribute(po,copyop),

src/osg/PolygonOffset.cpp

@@ -15,12 +15,17 @@
 
 using namespace osg;
 
-PolygonOffset::PolygonOffset()
+PolygonOffset::PolygonOffset():
+    _factor(0.0f),
+    _units(0.0f)
 {
-    _factor = 0.0f;              // are these sensible defaut values?
-    _units = 0.0f;
 }
 
+PolygonOffset::PolygonOffset(float factor, float units):
+    _factor(factor),
+    _units(units)
+{
+}
 
 PolygonOffset::~PolygonOffset()
 {