125 lines
3.8 KiB
C++
125 lines
3.8 KiB
C++
/**********************************************************************
|
|
*
|
|
* GEOS - Geometry Engine Open Source
|
|
* http://geos.osgeo.org
|
|
*
|
|
* Copyright (C) 2012 Excensus LLC.
|
|
*
|
|
* This is free software; you can redistribute and/or modify it under
|
|
* the terms of the GNU Lesser General Licence as published
|
|
* by the Free Software Foundation.
|
|
* See the COPYING file for more information.
|
|
*
|
|
**********************************************************************
|
|
*
|
|
* Last port: triangulate/quadedge/TrianglePredicate.java r524
|
|
*
|
|
**********************************************************************/
|
|
|
|
#pragma once
|
|
|
|
#include <geos/export.h>
|
|
#include <geos/geom/Location.h>
|
|
|
|
namespace geos {
|
|
namespace geom {
|
|
class CoordinateXY;
|
|
}
|
|
}
|
|
|
|
namespace geos {
|
|
namespace triangulate {
|
|
namespace quadedge {
|
|
|
|
/** \brief
|
|
* Algorithms for computing values and predicates
|
|
* associated with triangles.
|
|
*
|
|
* For some algorithms extended-precision
|
|
* implementations are provided, which are more robust
|
|
* (i.e. they produce correct answers in more cases).
|
|
* Also, some more robust formulations of
|
|
* some algorithms are provided, which utilize
|
|
* normalization to the origin.
|
|
*
|
|
* @author JTS: Martin Davis
|
|
* @author Benjamin Campbell
|
|
*
|
|
*/
|
|
class GEOS_DLL TrianglePredicate {
|
|
public:
|
|
using CoordinateXY = geos::geom::CoordinateXY;
|
|
|
|
/**
|
|
* Tests if a point is inside the circle defined by
|
|
* the triangle with vertices a, b, c (oriented counter-clockwise).
|
|
* This test uses simple
|
|
* double-precision arithmetic, and thus may not be robust.
|
|
*
|
|
* @param a a vertex of the triangle
|
|
* @param b a vertex of the triangle
|
|
* @param c a vertex of the triangle
|
|
* @param p the point to test
|
|
* @return true if this point is inside the circle defined by the points a, b, c
|
|
*/
|
|
static geom::Location isInCircleNonRobust(
|
|
const CoordinateXY& a, const CoordinateXY& b, const CoordinateXY& c,
|
|
const CoordinateXY& p);
|
|
|
|
/**
|
|
* Tests if a point is inside the circle defined by
|
|
* the triangle with vertices a, b, c (oriented counter-clockwise).
|
|
* This test uses simple
|
|
* double-precision arithmetic, and thus is not 10% robust.
|
|
* However, by using normalization to the origin
|
|
* it provides improved robustness and increased performance.
|
|
* <p>
|
|
* Based on code by J.R.Shewchuk.
|
|
*
|
|
*
|
|
* @param a a vertex of the triangle
|
|
* @param b a vertex of the triangle
|
|
* @param c a vertex of the triangle
|
|
* @param p the point to test
|
|
* @return true if this point is inside the circle defined by the points a, b, c
|
|
*/
|
|
static geom::Location isInCircleNormalized(
|
|
const CoordinateXY& a, const CoordinateXY& b, const CoordinateXY& c,
|
|
const CoordinateXY& p);
|
|
|
|
private:
|
|
/**
|
|
* Computes twice the area of the oriented triangle (a, b, c), i.e., the area is positive if the
|
|
* triangle is oriented counterclockwise.
|
|
*
|
|
* @param a a vertex of the triangle
|
|
* @param b a vertex of the triangle
|
|
* @param c a vertex of the triangle
|
|
*/
|
|
static double triArea(const CoordinateXY& a,
|
|
const CoordinateXY& b, const CoordinateXY& c);
|
|
|
|
public:
|
|
/**
|
|
* Tests if a point is inside the circle defined by
|
|
* the triangle with vertices a, b, c (oriented counter-clockwise).
|
|
* This method uses more robust computation.
|
|
*
|
|
* @param a a vertex of the triangle
|
|
* @param b a vertex of the triangle
|
|
* @param c a vertex of the triangle
|
|
* @param p the point to test
|
|
* @return true if this point is inside the circle defined by the points a, b, c
|
|
*/
|
|
static geom::Location isInCircleRobust(
|
|
const CoordinateXY& a, const CoordinateXY& b, const CoordinateXY& c,
|
|
const CoordinateXY& p);
|
|
} ;
|
|
|
|
|
|
} // namespace geos.triangulate.quadedge
|
|
} // namespace geos.triangulate
|
|
} // namespace geos
|
|
|
|
|