PLYWriter.hpp

/*

  Static class for writing PLY files.

  Copyright (C) 2011  Tao Ju

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public License
  (LGPL) as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#ifndef PLYWRITER_H
#define PLYWRITER_H

class PLYWriter {
public:
	/// Constructor
	PLYWriter( ) { };

	/// Write ply header
	static void writeHeader ( FILE* fout, int numVert, int numFace ) {
		// Ply
		fprintf( fout, "ply\n" ) ;

		// Always big endian
		fprintf( fout, "format binary_big_endian 1.0\n" ) ;

		// vertex properties
		fprintf( fout, "element vertex %d\n", numVert ) ;
		fprintf( fout, "property float x\n" ) ;
		fprintf( fout, "property float y\n" ) ;
		fprintf( fout, "property float z\n" ) ;

		// face properties
		fprintf( fout, "element face %d\n", numFace ) ;
		fprintf( fout, "property list uchar int vertex_indices\n" ) ;

		// End
		fprintf( fout, "end_header\n" ) ;
	};
    // data written below is not ascii, but binary!
    
	/// Write vertex
	static void writeVertex ( FILE* fout, float vt[3] )
	{
		float nvt[3] ;
		for ( int i = 0 ; i < 3 ; i ++ )
		{
			nvt[i] = vt[i] ;
			flipBits32( &(nvt[i]) ) ;
		}
		fwrite( nvt, sizeof ( float ), 3, fout ) ;
	};

	/// Write face
	static void writeFace ( FILE* fout, int num, int fc[] )
	{
		unsigned char cnum = num ;
		fwrite( &cnum, sizeof( unsigned char ), 1, fout ) ;
		for ( int i = 0 ; i < num ; i ++ )
		{
			flipBits32( &(fc[i]) ) ;
		}
		fwrite( fc, sizeof ( int ), num, fout ) ;
	};

	static void flipBits32 ( void *x )
	{
		unsigned char *temp = (unsigned char *)x;
		unsigned char swap;
		
		swap = temp [ 0 ];
		temp [ 0 ] = temp [ 3 ];
		temp [ 3 ] = swap;

		swap = temp [ 1 ];
		temp [ 1 ] = temp [ 2 ];
		temp [ 2 ] = swap;
	};

};

#endif