diff --git a/include/osg/GL2Extensions b/include/osg/GL2Extensions
index 7feac7b64..16b5f0bab 100644
--- a/include/osg/GL2Extensions
+++ b/include/osg/GL2Extensions
@@ -102,12 +102,6 @@ typedef char GLchar;
 #define GL_FLOAT_MAT2                     0x8B5A
 #define GL_FLOAT_MAT3                     0x8B5B
 #define GL_FLOAT_MAT4                     0x8B5C
-#define GL_SAMPLER_1D                     0x8B5D
-#define GL_SAMPLER_2D                     0x8B5E
-#define GL_SAMPLER_3D                     0x8B5F
-#define GL_SAMPLER_CUBE                   0x8B60
-#define GL_SAMPLER_1D_SHADOW              0x8B61
-#define GL_SAMPLER_2D_SHADOW              0x8B62
 #define GL_DELETE_STATUS                  0x8B80
 #define GL_COMPILE_STATUS                 0x8B81
 #define GL_LINK_STATUS                    0x8B82
@@ -128,6 +122,16 @@ typedef char GLchar;
 #define GL_STENCIL_BACK_REF               0x8CA3
 #define GL_STENCIL_BACK_VALUE_MASK        0x8CA4
 #define GL_STENCIL_BACK_WRITEMASK         0x8CA5
+
+#define GL_SAMPLER_2D                     0x8B5E
+#define GL_SAMPLER_CUBE                   0x8B60
+#endif
+
+#if !defined(GL_SAMPLER_1D)
+#define GL_SAMPLER_1D                     0x8B5D
+#define GL_SAMPLER_3D                     0x8B5F
+#define GL_SAMPLER_1D_SHADOW              0x8B61
+#define GL_SAMPLER_2D_SHADOW              0x8B62
 #endif
 
 #ifndef GL_VERSION_2_1