/* 
 * PROJECT: NyARToolkitCS(Extension)
 * --------------------------------------------------------------------------------
 * The NyARToolkitCS is C# 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>
 * 
 */
using System;
using System.Diagnostics;
using jp.nyatla.nyartoolkit.cs.core;

namespace jp.nyatla.nyartoolkit.cs.rpf
{

    /**
     * NyARReality用のエッジ検出フィルタ。
     * Roberts勾配の2乗値16倍に最大値制限をかけ、反転した値です。
     * 右端と左端の1ピクセルは、常に0が入ります。
     * X=|-1, 0|  Y=|0,-1|
     *   | 0, 1|    |1, 0|
     * V=sqrt(X^2+Y+2)/2
     */
    public class NegativeSqRoberts
    {
	    private IdoFilterImpl _do_filter_impl; 
	    public NegativeSqRoberts(int i_raster_type)
	    {
		    this.initInstance(i_raster_type);
	    }
	    public void initInstance(int i_raster_type)
	    {
		    switch (i_raster_type) {
		    case NyARBufferType.INT1D_GRAY_8:
			    this._do_filter_impl=new IdoFilterImpl_GRAY_8();
			    break;
		    default:
			    throw new NyARException();
		    }		
	    }
	    public void doFilter(INyARRaster i_input, INyARRaster i_output)
	    {
		    this._do_filter_impl.doFilter(i_input,i_output,i_input.getSize());
	    }
    	
	    interface IdoFilterImpl
	    {
		    void doFilter(INyARRaster i_input, INyARRaster i_output,NyARIntSize i_size);
	    }
	    private const int SH=4;
	    class IdoFilterImpl_GRAY_8 : IdoFilterImpl
	    {
		    public void doFilter(INyARRaster i_input, INyARRaster i_output,NyARIntSize i_size)
		    {
                Debug.Assert(i_input.isEqualBufferType(NyARBufferType.INT1D_GRAY_8));
                Debug.Assert(i_output.isEqualBufferType(NyARBufferType.INT1D_GRAY_8));
			    int[] in_ptr =(int[])i_input.getBuffer();
			    int[] out_ptr=(int[])i_output.getBuffer();
			    int width=i_size.w;
			    int idx=0;
			    int idx2=width;
			    int fx,fy;
			    int mod_p=(width-2)-(width-2)%4;
			    for(int y=i_size.h-2;y>=0;y--){
				    int p00=in_ptr[idx++];
				    int p10=in_ptr[idx2++];
				    int p01,p11;
				    int x=width-2;
				    for(;x>=mod_p;x--){
					    p01=in_ptr[idx++];p11=in_ptr[idx2++];
					    fx=p11-p00;fy=p10-p01;
    //					out_ptr[idx-2]=255-(((fx<0?-fx:fx)+(fy<0?-fy:fy))>>1);
					    fx=(fx*fx+fy*fy)>>SH;out_ptr[idx-2]=(fx>255?0:255-fx);
					    p00=p01;
					    p10=p11;
				    }
				    for(;x>=0;x-=4){
					    p01=in_ptr[idx++];p11=in_ptr[idx2++];
					    fx=p11-p00;
					    fy=p10-p01;
    //					out_ptr[idx-2]=255-(((fx<0?-fx:fx)+(fy<0?-fy:fy))>>1);
					    fx=(fx*fx+fy*fy)>>SH;out_ptr[idx-2]=(fx>255?0:255-fx);
					    p00=p01;p10=p11;
					    p01=in_ptr[idx++];p11=in_ptr[idx2++];
					    fx=p11-p00;
					    fy=p10-p01;
    //					out_ptr[idx-2]=255-(((fx<0?-fx:fx)+(fy<0?-fy:fy))>>1);
					    fx=(fx*fx+fy*fy)>>SH;out_ptr[idx-2]=(fx>255?0:255-fx);
					    p00=p01;p10=p11;
					    p01=in_ptr[idx++];p11=in_ptr[idx2++];
    					
					    fx=p11-p00;
					    fy=p10-p01;
    //					out_ptr[idx-2]=255-(((fx<0?-fx:fx)+(fy<0?-fy:fy))>>1);
					    fx=(fx*fx+fy*fy)>>SH;out_ptr[idx-2]=(fx>255?0:255-fx);
					    p00=p01;p10=p11;

					    p01=in_ptr[idx++];p11=in_ptr[idx2++];
					    fx=p11-p00;
					    fy=p10-p01;
    //					out_ptr[idx-2]=255-(((fx<0?-fx:fx)+(fy<0?-fy:fy))>>1);
					    fx=(fx*fx+fy*fy)>>SH;out_ptr[idx-2]=(fx>255?0:255-fx);
					    p00=p01;p10=p11;

				    }
				    out_ptr[idx-1]=255;
			    }
			    for(int x=width-1;x>=0;x--){
				    out_ptr[idx++]=255;
			    }
			    return;
		    }
	    }
    }
}