kicad/polygon/poly2tri/common/utils.h

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/*
* Poly2Tri Copyright (c) 2009-2010, Poly2Tri Contributors
* http://code.google.com/p/poly2tri/
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* * Neither the name of Poly2Tri nor the names of its contributors may be
* used to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef UTILS_H
#define UTILS_H
// Otherwise #defines like M_PI are undeclared under Visual Studio
#define _USE_MATH_DEFINES
#include <exception>
#include <math.h>
namespace p2t {
const double PI_3div4 = 3 * M_PI / 4;
const double PI_div2 = 1.57079632679489661923;
const double EPSILON = 1e-12;
enum Orientation {
CW, CCW, COLLINEAR
};
/**
* Forumla to calculate signed area<br>
* Positive if CCW<br>
* Negative if CW<br>
* 0 if collinear<br>
* <pre>
* A[P1,P2,P3] = (x1*y2 - y1*x2) + (x2*y3 - y2*x3) + (x3*y1 - y3*x1)
* = (x1-x3)*(y2-y3) - (y1-y3)*(x2-x3)
* </pre>
*/
Orientation Orient2d( Point& pa, Point& pb, Point& pc )
{
double detleft = (pa.x - pc.x) * (pb.y - pc.y);
double detright = (pa.y - pc.y) * (pb.x - pc.x);
double val = detleft - detright;
if( val > -EPSILON && val < EPSILON )
{
return COLLINEAR;
}
else if( val > 0 )
{
return CCW;
}
return CW;
}
/*
* bool InScanArea(Point& pa, Point& pb, Point& pc, Point& pd)
* {
* double pdx = pd.x;
* double pdy = pd.y;
* double adx = pa.x - pdx;
* double ady = pa.y - pdy;
* double bdx = pb.x - pdx;
* double bdy = pb.y - pdy;
*
* double adxbdy = adx * bdy;
* double bdxady = bdx * ady;
* double oabd = adxbdy - bdxady;
*
* if (oabd <= EPSILON) {
* return false;
* }
*
* double cdx = pc.x - pdx;
* double cdy = pc.y - pdy;
*
* double cdxady = cdx * ady;
* double adxcdy = adx * cdy;
* double ocad = cdxady - adxcdy;
*
* if (ocad <= EPSILON) {
* return false;
* }
*
* return true;
* }
*
*/
bool InScanArea( Point& pa, Point& pb, Point& pc, Point& pd )
{
double oadb = (pa.x - pb.x) * (pd.y - pb.y) - (pd.x - pb.x) * (pa.y - pb.y);
if( oadb >= -EPSILON )
{
return false;
}
double oadc = (pa.x - pc.x) * (pd.y - pc.y) - (pd.x - pc.x) * (pa.y - pc.y);
if( oadc <= EPSILON )
{
return false;
}
return true;
}
}
#endif