From Farshid Lashkari, added function for querring whether a mode is a texture related mode or not.

include/osg/StateSet

@@ -486,6 +486,8 @@ class OSG_EXPORT StateSet : public Object
 
 };
 
+extern OSG_EXPORT bool isTextureMode(StateAttribute::GLMode mode);
+
 }
 
 #endif

src/osg/StateSet.cpp

@@ -73,6 +73,11 @@ static TextureGLModeSet& getTextureGLModeSet()
     return s_textureGLModeSet;
 }
 
+bool osg::isTextureMode(StateAttribute::GLMode mode)
+{
+    return getTextureGLModeSet().isTextureMode(mode);
+}
+
 StateSet::StateSet()
 {
     setDataVariance(osg::StateAttribute::STATIC);