add ComputeDispatch class

revoke glDispatch in PCProgram::useProgram
update example

src/osgWrappers/serializers/osg/ComputeDispatch.cpp

@@ -0,0 +1,36 @@
+#include <osg/ComputeDispatch>
+#include <osgDB/ObjectWrapper>
+#include <osgDB/InputStream>
+#include <osgDB/OutputStream>
+
+// _numGroupsX/Y/Z
+static bool checkComputeGroups( const osg::ComputeDispatch& attr )
+{
+    GLint numX = 0, numY = 0, numZ = 0;
+    attr.getComputeGroups( numX, numY, numZ );
+    return numX>0 && numY>0 && numZ>0;
+}
+
+static bool readComputeGroups( osgDB::InputStream& is, osg::ComputeDispatch& attr )
+{
+    GLint numX = 0, numY = 0, numZ = 0;
+    is >> numX >> numY >> numZ;
+    attr.setComputeGroups( numX, numY, numZ );
+    return true;
+}
+
+static bool writeComputeGroups( osgDB::OutputStream& os, const osg::ComputeDispatch& attr )
+{
+    GLint numX = 0, numY = 0, numZ = 0;
+    attr.getComputeGroups( numX, numY, numZ );
+    os << numX << numY << numZ << std::endl;
+    return true;
+}
+
+REGISTER_OBJECT_WRAPPER( ComputeDispatch,
+                         new osg::ComputeDispatch,
+                         osg::ComputeDispatch,
+                         "osg::Object osg::Node osg::Drawable osg::ComputeDispatch" )
+{
+        ADD_USER_SERIALIZER( ComputeGroups );  // _numGroupsX/Y/Z
+}