dataNode.h

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/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file dataNode.h
 * @author drose
 * @date 2002-03-11
 */

#ifndef DATANODE_H
#define DATANODE_H

/*
 * The Data Graph.  The data graph is intended to hook up devices and their
 * inputs andor outputs in a clean interface.  It uses the same graph
 * relationship that is used to construct the scene graph, with the same sort
 * of nodes and NodePaths.  In a data graph, each node may potentially produce
 * andor consume data, and the arcs transmit data downward, from the root of
 * the graph to its leaves.  Thus, an input device such as a mouse might be
 * added to the graph near the root, and a tformer-style object that
 * interprets the mouse data as a trackball motion and outputs a matrix might
 * be the immediate child of the mouse, followed by an object that accepts a
 * matrix and sets it on some particular arc in the scene graph.  Each
 * different kind of DataNode defines its own set of input values and output
 * values, identified by name.  When a DataNode is attached to another
 * DataNode, the inputs of the child are automatically connected up to the
 * corresponding outputs of the parent, and an error message is issued if
 * there are no matching connections.
 */

#include "pandabase.h"

#include "pandaNode.h"
#include "pointerTo.h"

class DataGraphTraverser;
class DataNodeTransmit;

/**
 * The fundamental type of node for the data graph.  The DataNode class is
 * itself primarily intended as an abstract class; it defines no inputs and no
 * outputs.  Most kinds of data nodes will derive from this to specify the
 * inputs and outputs in the constructor.
 *
 * DataNode does not attempt to cycle its data with a PipelineCycler.  The
 * data graph is intended to be used only within a single thread.
 */
class EXPCL_PANDA_DGRAPH DataNode : public PandaNode {
PUBLISHED:
  INLINE explicit DataNode(const std::string &name);

protected:
  INLINE DataNode(const DataNode &copy);
public:
  virtual PandaNode *make_copy() const;

  void transmit_data(DataGraphTraverser *trav,
                     const DataNodeTransmit inputs[],
                     DataNodeTransmit &output);

  INLINE int get_num_inputs() const;
  INLINE int get_num_outputs() const;

PUBLISHED:
  void write_inputs(std::ostream &out) const;
  void write_outputs(std::ostream &out) const;
  void write_connections(std::ostream &out) const;

protected:
  int define_input(const std::string &name, TypeHandle data_type);
  int define_output(const std::string &name, TypeHandle data_type);

protected:
  // Inherited from PandaNode
  virtual void parents_changed();

  // Local to DataNode
  virtual void do_transmit_data(DataGraphTraverser *trav,
                                const DataNodeTransmit &input,
                                DataNodeTransmit &output);

private:
  void reconnect();

  class WireDef {
  public:
    TypeHandle _data_type;
    int _index;
  };

  typedef pmap<std::string, WireDef> Wires;

  Wires _input_wires;
  Wires _output_wires;

  class DataConnection {
  public:
    int _parent_index;
    int _output_index;
    int _input_index;
  };
  typedef pvector<DataConnection> DataConnections;
  DataConnections _data_connections;

public:
  virtual void write_datagram(BamWriter *manager, Datagram &dg);

protected:
  void fillin(DatagramIterator &scan, BamReader *manager);

public:
  static TypeHandle get_class_type() {
    return _type_handle;
  }
  static void init_type() {
    PandaNode::init_type();
    register_type(_type_handle, "DataNode",
                  PandaNode::get_class_type());
  }
  virtual TypeHandle get_type() const {
    return get_class_type();
  }
  virtual TypeHandle force_init_type() {init_type(); return get_class_type();}

private:
  static TypeHandle _type_handle;
};

#include "dataNode.I"

#endif