Don't add empty PrimitiveSets (prevent undefined behaviour)

components/sceneutil/pathgridutil.cpp

@@ -85,6 +85,8 @@ namespace SceneUtil
 
         osg::ref_ptr<osg::Geometry> gridGeometry = new osg::Geometry();
 
+        if (PointIndexCount || EdgeIndexCount)
+        {
             osg::ref_ptr<osg::Vec3Array> vertices = new osg::Vec3Array(VertexCount);
             osg::ref_ptr<osg::Vec4Array> colors = new osg::Vec4Array(ColorCount);
             osg::ref_ptr<osg::DrawElementsUShort> pointIndices =
@@ -166,10 +168,12 @@ namespace SceneUtil
 
             gridGeometry->setVertexArray(vertices);
             gridGeometry->setColorArray(colors, osg::Array::BIND_PER_VERTEX);
+            if (PointIndexCount)
                 gridGeometry->addPrimitiveSet(pointIndices);
+            if (EdgeIndexCount)
                 gridGeometry->addPrimitiveSet(lineIndices);
             gridGeometry->getOrCreateStateSet()->setMode(GL_LIGHTING, osg::StateAttribute::OFF);
-
+        }
         return gridGeometry;
     }
 
@@ -184,6 +188,8 @@ namespace SceneUtil
 
         osg::ref_ptr<osg::Geometry> wireframeGeometry = new osg::Geometry();
 
+        if (IndexCount)
+        {
             osg::ref_ptr<osg::Vec3Array> vertices = new osg::Vec3Array(VertexCount);
             osg::ref_ptr<osg::Vec4Array> colors = new osg::Vec4Array(ColorCount);
             osg::ref_ptr<osg::DrawElementsUShort> indices =
@@ -221,7 +227,7 @@ namespace SceneUtil
             wireframeGeometry->setColorArray(colors, osg::Array::BIND_PER_VERTEX);
             wireframeGeometry->addPrimitiveSet(indices);
             wireframeGeometry->getOrCreateStateSet()->setMode(GL_LIGHTING, osg::StateAttribute::OFF);
-
+        }
         return wireframeGeometry;
     }