trigo.cpp

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/* *************************************************************************************
        Writer:         Sebastien Bloc
        Copyright:      2003-2004
        eMail:          sebastien.bloc@free.fr
        URL:            http://mignonsoft.free.fr

        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 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 General Public License for more details.
        http://www.gnu.org/copyleft/gpl.html
************************************************************************************* */

#include "trigo.h"

// borne a un angle de [0,2*PI[
double Bound2_PI(double angle)  
{
        int nbTours = (int)(angle/DOUBLE_PI);
        double angleRes = angle-nbTours*DOUBLE_PI;
        if (angleRes<0) angleRes = DOUBLE_PI+angleRes;
        return angleRes;
}

BOOL GetTrigoSens(POINT *pt)
{
        double angle1,angle2;
        int dx1=pt[1].x-pt[0].x;
        int dy1=pt[1].y-pt[0].y;
        int dx2=pt[2].x-pt[1].x;
        int dy2=pt[2].y-pt[1].y;
        angle1=atan2((double)dy1,(double)dx1);
        angle2=atan2((double)dy2,(double)dx2);
        return Bound2_PI(angle2-angle1)>PI?FALSE:TRUE;
}

BOOL GetTrigoSens(POINT *pt,int nbPoints)
{
        BOOL trigo=-2;
        for (int i=0;i<nbPoints-2;i++)
        {
                BOOL trigoCur = GetTrigoSens(pt+i);
                if (trigo==-2) trigo = trigoCur;
                if (trigoCur!=trigo) 
                        return -1;
        }
        return trigo;
}

void ChangeTrigoSens(POINT *pt,int nbPoints)
{
        POINT point;
        // si nb de point impaires, ne change rien
        for (int i=0,j=nbPoints-1;i<nbPoints/2;i++,j--)
        {
                point.x=pt[i].x;
                point.y=pt[i].y;
                pt[i].x=pt[j].x;
                pt[i].y=pt[j].y;
                pt[j].x=point.x;
                pt[j].y=point.y;
        }
}

int GetNearExp2(int num) 
{
        int numExp2;
        for (numExp2=1;numExp2<num;numExp2<<=1);
        return numExp2;
}

int IntFloorLog2(unsigned int x)
{
        int a=0;
        while (x>>=1) ++a;
        return a;
}

BOOL IsPow2(unsigned int x)
{
        return ((x>0) && ((x&(x-1))==0));
}

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