From Mike Weiblen, support for geometry shaders, and osgeometryshaders example to demonstrate them.

include/osg/Shader

@@ -1,6 +1,7 @@
 /* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield 
  * Copyright (C) 2003-2005 3Dlabs Inc. Ltd.
  * Copyright (C) 2004-2005 Nathan Cournia
+ * Copyright (C) 2008 Zebra Imaging
  *
  * This application is open source and may be redistributed and/or modified   
  * freely and without restriction, both in commericial and non commericial
@@ -12,7 +13,7 @@
 */
 
 /* file:   include/osg/Shader
- * author: Mike Weiblen 2005-06-15
+ * author: Mike Weiblen 2008-01-02
 */
 
 #ifndef OSG_SHADER
@@ -46,6 +47,7 @@ class OSG_EXPORT Shader : public osg::Object
         enum Type {
             VERTEX = GL_VERTEX_SHADER,
             FRAGMENT = GL_FRAGMENT_SHADER,
+            GEOMETRY = GL_GEOMETRY_SHADER_EXT,
             UNDEFINED = -1
         };