diff --git a/include/osg/GLExtensions b/include/osg/GLExtensions
index a5df2de42..721e747a2 100644
--- a/include/osg/GLExtensions
+++ b/include/osg/GLExtensions
@@ -626,7 +626,25 @@ class OSG_EXPORT GLExtensions : public osg::Referenced
         // MultiDrawArrays
         void (GL_APIENTRY * glMultiDrawArrays) (GLenum mode, const GLint * first, const GLsizei * count, GLsizei primcount);
 
+        // ViewportArray
+        bool isViewportArraySupported;
 
+        void (GL_APIENTRY * glViewportArrayv) (GLuint first, GLsizei count, const GLfloat * v);
+        void (GL_APIENTRY * glViewportIndexedf) (GLuint index, GLfloat x, GLfloat y, GLfloat w, GLfloat h);
+        void (GL_APIENTRY * glViewportIndexedfv) (GLuint index, const GLfloat * v);
+        void (GL_APIENTRY * glScissorArrayv) (GLuint first, GLsizei count, const GLint * v);
+        void (GL_APIENTRY * glScissorIndexed) (GLuint index, GLint left, GLint bottom, GLsizei width, GLsizei height);
+        void (GL_APIENTRY * glScissorIndexedv) (GLuint index, const GLint * v);
+        void (GL_APIENTRY * glDepthRangeArrayv) (GLuint first, GLsizei count, const GLclampd * v);
+        void (GL_APIENTRY * glDepthRangeIndexed) (GLuint index, GLclampd n, GLclampd f);
+        void (GL_APIENTRY * glGetFloati_v) (GLenum target, GLuint index, GLfloat *data);
+        void (GL_APIENTRY * glGetDoublei_v) (GLenum target, GLuint index, GLdouble *data);
+
+        //introduced by other OpenGL extensions such as EXT_draw_buffers2
+        void (GL_APIENTRY * glGetIntegerIndexedvEXT) (GLenum target, GLuint index, int * v);
+        void (GL_APIENTRY * glEnableIndexedEXT) (GLenum target, GLuint index);
+        void (GL_APIENTRY * glDisableIndexedEXT) (GLenum target, GLuint index);
+        GLboolean (GL_APIENTRY * glIsEnabledIndexedEXT) (GLenum target, GLuint index);
 };
 
 
diff --git a/src/osg/GLExtensions.cpp b/src/osg/GLExtensions.cpp
index 274376362..da6899328 100644
--- a/src/osg/GLExtensions.cpp
+++ b/src/osg/GLExtensions.cpp
@@ -1103,6 +1103,25 @@ GLExtensions::GLExtensions(unsigned int contextID)
 
     // MultiDrawArrays
     setGLExtensionFuncPtr(glMultiDrawArrays, "glMultiDrawArrays", "glMultiDrawArraysEXT", validContext);
+
+    // ViewportArray
+    isViewportArraySupported = validContext && (isGLExtensionOrVersionSupported(contextID, "GL_ARB_viewport_array", 4.1f));
+
+    osg::setGLExtensionFuncPtr(glViewportArrayv, "glViewportArrayv", validContext);
+    osg::setGLExtensionFuncPtr(glViewportIndexedf, "glViewportIndexedf", validContext);
+    osg::setGLExtensionFuncPtr(glViewportIndexedfv, "glViewportIndexedfv", validContext);
+    osg::setGLExtensionFuncPtr(glScissorArrayv, "glScissorArrayv", validContext);
+    osg::setGLExtensionFuncPtr(glScissorIndexed, "glScissorIndexed", validContext);
+    osg::setGLExtensionFuncPtr(glScissorIndexedv, "glScissorIndexedv", validContext);
+    osg::setGLExtensionFuncPtr(glDepthRangeArrayv, "glDepthRangeArrayv", validContext);
+    osg::setGLExtensionFuncPtr(glDepthRangeIndexed, "glDepthRangeIndexed", validContext);
+    osg::setGLExtensionFuncPtr(glGetFloati_v, "glGetFloati_v", validContext);
+    osg::setGLExtensionFuncPtr(glGetDoublei_v, "glGetDoublei_v", validContext);
+    osg::setGLExtensionFuncPtr(glGetIntegerIndexedvEXT, "glGetIntegerIndexedvEXT", validContext);
+    osg::setGLExtensionFuncPtr(glEnableIndexedEXT, "glEnableIndexedEXT", validContext);
+    osg::setGLExtensionFuncPtr(glDisableIndexedEXT, "glDisableIndexedEXT", validContext);
+    osg::setGLExtensionFuncPtr(glIsEnabledIndexedEXT, "glIsEnabledIndexedEXT", validContext);
+
 }