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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
#include <exception>
namespace p2t {
const double PI = 3.1415926535897932384626433832795029;
const double PI_2 = 2 * PI;
const double PI_3div4 = 3 * PI / 4;
const double EPSILON = 1e-15;
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;
}
}
#endif
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