/* @(#)  Add gaussian noise with mean 0 and variance sigma to image
 * @(#)   The noise is generated by averaging 12 random numbers
 * @(#)  page 78 PIETGEN 1989 n = 12
 * @(#)  Input image is any, output is float
 * @(#)  If running on SYSTEM V CONSTANT should be replaced by 2**15 - 1
 * @(#)   Usage
 * @(#) 
 * @(#) int im_addgnoise(imin, imout, sigma)
 * @(#) IMAGE *imin, *imout;
 * @(#) double sigma;
 * @(#)  Returns 0 on success and -1 on error
 * @(#)
 *
 * Copyright 1990, N. Dessipris.
 *
 * File written on 2/12/1986
 * Author : N. Dessipris
 * Updated : 22/01/1991
 * 1/2/95 JC
 *	- junked!
 *	- now uses partial im_gaussnoise() and partial im_add() to do the
 *	  same job
 & 1/5/01 JC
 *	- oops, failed for not-1-band images
 */

/*

    This file is part of VIPS.
    
    VIPS is free software; you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program 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 program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

/*

    These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk

 */


#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <vips/intl.h>

#include <stdio.h>
#include <stdlib.h>

#include <vips/vips.h>

#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif /*WITH_DMALLOC*/

#define MAX_BANDS (200)

int
im_addgnoise( IMAGE *in, IMAGE *out, double sigma )
{
	IMAGE *noise[MAX_BANDS];
	IMAGE *nb;
	int i;

	if( in->Bands > MAX_BANDS ) {
		im_error( "im_addgnoise", _( "too many bands" ) );
		return( -1 );
	}

	/* Make n-band noise image.
	 */
	for( i = 0; i < in->Bands; i++ ) 
		if( !(noise[i] = im_open_local( out, "im_addgnoise:2", "p" )) ||
			im_gaussnoise( noise[i], in->Xsize, in->Ysize, 
				0.0, sigma ) )
			return( -1 );

	if( !(nb = im_open_local( out, "im_addgnoise:3", "p" )) ||
		im_gbandjoin( noise, out, in->Bands ) ||
		im_add( in, nb, out ) )
		return( -1 );

	return( 0 );
}