Panda3D
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queryContext.h
00001 // Filename: queryContext.h
00002 // Created by:  drose (27Mar06)
00003 //
00004 ////////////////////////////////////////////////////////////////////
00005 //
00006 // PANDA 3D SOFTWARE
00007 // Copyright (c) Carnegie Mellon University.  All rights reserved.
00008 //
00009 // All use of this software is subject to the terms of the revised BSD
00010 // license.  You should have received a copy of this license along
00011 // with this source code in a file named "LICENSE."
00012 //
00013 ////////////////////////////////////////////////////////////////////
00014 
00015 #ifndef QUERYCONTEXT_H
00016 #define QUERYCONTEXT_H
00017 
00018 #include "pandabase.h"
00019 #include "typedReferenceCount.h"
00020 
00021 class PreparedGraphicsObjects;
00022 
00023 ////////////////////////////////////////////////////////////////////
00024 //       Class : QueryContext
00025 // Description : This is a base class for queries that might require a
00026 //               round-trip to the graphics engine.  The idea is that
00027 //               when you ask the GSG to make a particular query, it
00028 //               returns a QueryContext, which does not necessarily
00029 //               have the answer right away (but it will eventually).
00030 //
00031 //               Unlike SavedContext, QueryContext is
00032 //               reference-counted.  It removes itself from the GSG
00033 //               when the last reference goes away.  You're
00034 //               responsible for keeping the pointer to the
00035 //               QueryContext as long as you are interested in the
00036 //               answer.
00037 ////////////////////////////////////////////////////////////////////
00038 class EXPCL_PANDA_GOBJ QueryContext : public TypedReferenceCount {
00039 public:
00040   INLINE QueryContext();
00041   virtual ~QueryContext();
00042 
00043   virtual bool is_answer_ready() const=0;
00044   virtual void waiting_for_answer();
00045 
00046 public:
00047   static TypeHandle get_class_type() {
00048     return _type_handle;
00049   }
00050   static void init_type() {
00051     TypedReferenceCount::init_type();
00052     register_type(_type_handle, "QueryContext",
00053                   TypedReferenceCount::get_class_type());
00054   }
00055   virtual TypeHandle get_type() const {
00056     return get_class_type();
00057   }
00058   virtual TypeHandle force_init_type() {init_type(); return get_class_type();}
00059 
00060 private:
00061   static TypeHandle _type_handle;
00062 };
00063 
00064 #include "queryContext.I"
00065 
00066 #endif
00067 
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