// VisStream.h

#ifndef VisStream_H
#define VisStream_H

// Base class for visualization.
//
// All visualization streams should inherit from this base.
// We expect two kinds of subclasses:
// 1. concrete implementing the methods here for a particular
//    visualization system
// 2. abstract adding methods for streaming objects associated
//    with a specific package or system
//
// The stream follows the open inventor/VRML hierarchial scene
// model.  The method add_child may be used to generate a new
// separator (equals new stream) at the current point in the
// stream.
//
// VisColor objects may be streamed to define the default color
// for objects streamed later.
//

#include <string>

class VisColor;

class VisStream {

public:

  // Destructor.
  virtual ~VisStream();

  // Add a substream and return a reference to it.
  virtual VisStream& add_child() =0;

  // Set the default color.
  // RGB model is assumed.
  virtual void set_color(const VisColor& col) =0;

  // Write contents to a file.
  // This file can be processed by an open inventor viewer.
  virtual void write(std::string filename) =0;

};

inline
VisStream& operator<<(VisStream& stream, const VisColor& col) {
  stream.set_color(col);
  return stream;
}

#endif