/* 
 * PROJECT: NyARToolkit
 * --------------------------------------------------------------------------------
 * This work is based on the original ARToolKit developed by
 *   Hirokazu Kato
 *   Mark Billinghurst
 *   HITLab, University of Washington, Seattle
 * http://www.hitl.washington.edu/artoolkit/
 *
 * 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;

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

/**
 * エッジ検出フィルタ 入力 BUFFERFORMAT_INT2D 出力 BUFFERFORMAT_INT2D
 */
public class NyARRasterFilter_Edge implements INyARRasterFilter
{
	public void doFilter(INyARRaster i_input, INyARRaster i_output) throws NyARException
	{
		assert (i_input.isEqualBufferType(NyARBufferType.INT1D_GRAY_8));
		assert (i_output.isEqualBufferType(NyARBufferType.INT1D_GRAY_8));
		assert (i_input.getSize().isEqualSize(i_output.getSize()) == true);

		int[] out_buf = (int[]) i_output.getBuffer();
		int[] in_buf = (int[]) i_input.getBuffer();

		int bp = 0;
		NyARIntSize size = i_output.getSize();
		for (int y = 1; y < size.h; y++) {
			int prev = 128;
			for (int x = 1; x < size.w; x++) {
				int w = in_buf[y* size.w+x];
				out_buf[y* size.w+x] = (Math.abs(w - prev) + Math.abs(w - in_buf[(y - 1)* size.w+x])) / 2;
				prev = w;
				bp += 3;
			}
		}
		return;
	}
}
