/* 
 * PROJECT: NyARToolkit(Extension)
 * --------------------------------------------------------------------------------
 * The NyARToolkit is Java edition ARToolKit class library.
 * Copyright (C)2008-2009 Ryo Iizuka
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * 
 * For further information please contact.
 *	http://nyatla.jp/nyatoolkit/
 *	<airmail(at)ebony.plala.or.jp> or <nyatla(at)nyatla.jp>
 * 
 */
package jp.nyatla.nyartoolkit.core.rasterfilter.gs;

import jp.nyatla.nyartoolkit.core.NyARException;
import jp.nyatla.nyartoolkit.core.raster.*;
import jp.nyatla.nyartoolkit.core.types.NyARBufferType;

/**
 * このインタフェイスは、Gaussianフィルタで画像を平滑化します。
 * カーネルサイズは3x3です。
 * <p>対応している画素形式は以下の通りです。
 * <li>{@link NyARBufferType#INT1D_GRAY_8}
 * </p>
 */
public interface INyARGsGaussianSmoothFilter
{
	public void doFilter(INyARGrayscaleRaster i_output) throws NyARException;
}

/**
 * 制限事項
 * このクラスは、in/out共にGS8の時のみ動作します。
 */
class NyARGsGaussianSmoothFilter_GS8 implements INyARGsGaussianSmoothFilter
{
	private INyARGrayscaleRaster _raster;
	public NyARGsGaussianSmoothFilter_GS8(INyARGrayscaleRaster i_raster)
	{
		assert i_raster.isEqualBufferType(NyARBufferType.INT1D_GRAY_8);
		this._raster=i_raster;
	}
	
	public void doFilter(INyARGrayscaleRaster i_output) throws NyARException
	{
		int[] in_ptr =(int[])this._raster.getBuffer();
		int width=this._raster.getWidth();
		int height=this._raster.getHeight();
		int col0,col1,col2;
		int bptr=0;
		switch(i_output.getBufferType()){
		case NyARBufferType.INT1D_GRAY_8:
			int[] out_ptr=(int[])i_output.getBuffer();
			bptr=0;
			//1行目
			col1=in_ptr[bptr  ]*2+in_ptr[bptr+width  ];
			col2=in_ptr[bptr+1]*2+in_ptr[bptr+width+1];
			out_ptr[bptr]=(col1*2+col2)/9;
			bptr++;
			for(int x=0;x<width-2;x++){
				col0=col1;
				col1=col2;
				col2=in_ptr[bptr+1]*2+in_ptr[bptr+width+1];
				out_ptr[bptr]=(col0+col1*2+col2)/12;
				bptr++;
			}			
			out_ptr[bptr]=(col1+col2)/9;
			bptr++;
			//2行目-末行-1
			for(int y=0;y<height-2;y++){
				//左端
				col1=in_ptr[bptr  ]*2+in_ptr[bptr-width  ]+in_ptr[bptr+width  ];
				col2=in_ptr[bptr+1]*2+in_ptr[bptr-width+1]+in_ptr[bptr+width+1];
				out_ptr[bptr]=(col1+col2)/12;
				bptr++;
				for(int x=0;x<width-2;x++){
					col0=col1;
					col1=col2;
					col2=in_ptr[bptr+1]*2+in_ptr[bptr-width+1]+in_ptr[bptr+width+1];
					out_ptr[bptr]=(col0+col1*2+col2)/16;
					bptr++;
				}
				//右端
				out_ptr[bptr]=(col1*2+col2)/12;
				bptr++;
			}
			//末行目
			col1=in_ptr[bptr  ]*2+in_ptr[bptr-width  ];
			col2=in_ptr[bptr+1]*2+in_ptr[bptr-width+1];
			out_ptr[bptr]=(col1+col2)/9;
			bptr++;
			for(int x=0;x<width-2;x++){
				col0=col1;
				col1=col2;
				col2=in_ptr[bptr+1]*2+in_ptr[bptr-width+1];
				out_ptr[bptr]=(col0+col1*2+col2)/12;
				bptr++;
			}			
			out_ptr[bptr]=(col1*2+col2)/9;
			bptr++;
			return;
		default:
			throw new NyARException();
		}
	}
}
