extentReader.h

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/******************************************************************************
** Copyright (c) 2005 MAK Technologies, Inc.
** All rights reserved.
******************************************************************************/
/******************************************************************************
** $RCSfile: extentReader.h,v $ $Revision: 1.5 $ $State: Exp $
******************************************************************************/
#ifndef extentReader_H_
#define extentReader_H_

//
// \file extentReader.h
// \brief Contains the DtExtentReader class declaration.
//

#include "gdb/gdbDefines.h"
#include "gdb/terrainReader.h"

class DtExtentInitializer;
class DtTerrainInitializer;
class DtTerrainDatabase;
class DtFilename;


//
// The DtExtentReader class is responsible for creating a simple terrain with
// the coordinate system and extent specified in the initializer.  Note that
// the default is to create a geodetic terrain with the maximum extents defined
// for the initializer.
class DT_DLL_gdb DtExtentReader : public DtTerrainReader
{
public:
   DtExtentReader();

   virtual ~DtExtentReader();

private:
   // Copy constructor and Assignment operator not implemented. This class is
   // not copyable or assignable
   DtExtentReader(const DtExtentReader& original);
   const DtExtentReader& operator=(const DtExtentReader& original);
   
public:
   // Loads terrain database file named filename, returning the data in 
   // terrain.  The terrain pointer passed in must be initialized before calling 
   // loadTerrain.
   virtual bool loadTerrain(const DtFilename& filename, DtTerrainDatabase* terrain);

   // Loads terrain database file named filename, returning the data in 
   // terrain.  The initializer object is used to pass in additional information
   // about the terrain to be loaded.  The terrain pointer passed in must be 
   // initialized before calling loadTerrain.
   virtual bool loadTerrain(const DtFilename& filename, DtTerrainDatabase* terrain, 
      const DtTerrainInitializer* initializer);

   bool loadTerrain(DtTerrainDatabase& terrainDb, 
      const DtExtentInitializer& extentInitializer);

   bool createCoordinateSystem(DtTerrainDatabase& terrainDb, 
      const DtExtentInitializer& extentInitializer);
   
   // Creates two terrain triangles formed from the specified extent.  The 
   // altitude of the vertices is determined by the altitude of the left, back, 
   // bottom vertex and the right, front, upper vertex.  These are used as the 
   // SW and NE vertices respectively.  The altitude of the SE vertex matches 
   // the altitude of the SW vertex and the altitude of the NW vertex equals the
   // altitude of the NE vertex.
   // 
   // (NW) *----------* (NE)
   //      |\         |
   //      | \        |
   //      |  \       |
   //      |   \      |
   //      |    \     |
   //      |     \    |
   //      |      \   |
   //      |       \  |
   //      |        \ |
   //      |         \|
   // (SW) *----------* (SE)
   //
   bool createTerrain(DtTerrainDatabase& terrainDb, 
      const DtExtentInitializer& extentInitializer);
   
   // Returns "extent"
   virtual const DtString dataType() const;

   // Returns only the coordinate system that would define this database.  Should not load
   // any polygonal or vector information
   virtual Coordinate_System* coordinateSystem(const DtFilename& filename);

   static DtTerrainReader* create();

   virtual int optionalFileFlags(const DtFilename& filename)
   {
      return 0;
   }

protected:
   bool testInvariant() const;

private:
};

inline const DtString DtExtentReader::dataType() const
{
   return "extent";
}


#endif