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/*
* Triangle2D.cpp
*
* Copyright (C) 2008 Matthias Schiffer <matthias@gamezock.de>
*
* 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/>.
*/
#include "Triangle2D.h"
#include <cmath>
namespace ZoomEdit {
namespace Math {
float Triangle2D::area() const {
return std::fabs((vertices[0].getY() + vertices[1].getY())*(vertices[0].getX()-vertices[1].getX())
+ (vertices[1].getY() + vertices[2].getY())*(vertices[1].getX()-vertices[2].getX())
+ (vertices[2].getY() + vertices[0].getY())*(vertices[2].getX()-vertices[0].getX()))/2;
}
bool Triangle2D::contains(const Vertex2D &v) const {
for(int i = 0; i < 3; ++i) {
Vector2D v1 = vertices[(i+2)%3] - vertices[(i+1)%3];
Vector2D v2 = vertices[i] - vertices[(i+1)%3];
Vector2D vp = v - vertices[(i+1)%3];
if((v1.getX()*vp.getY()-vp.getX()*v1.getY())*(v1.getX()*v2.getY()-v2.getX()*v1.getY()) < 0)
return false;
}
return true;
}
}
}
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