313 lines
8.5 KiB
C++
313 lines
8.5 KiB
C++
/**********************************************************************
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*
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* GEOS - Geometry Engine Open Source
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* http://geos.osgeo.org
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*
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* Copyright (C) 2012 Excensus LLC.
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*
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* This is free software; you can redistribute and/or modify it under
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* the terms of the GNU Lesser General Licence as published
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* by the Free Software Foundation.
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* See the COPYING file for more information.
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*
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**********************************************************************
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*
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* Last port: triangulate/quadedge/Vertex.java r705
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*
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**********************************************************************/
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#pragma once
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#include <cmath>
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#include <memory>
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#include <cstring>
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#include <geos/geom/Coordinate.h>
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#include <geos/algorithm/HCoordinate.h>
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#include <geos/triangulate/quadedge/TrianglePredicate.h>
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//fwd declarations
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namespace geos {
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namespace triangulate {
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namespace quadedge {
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class QuadEdge;
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}
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}
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}
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namespace geos {
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namespace triangulate { //geos.triangulate
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namespace quadedge { //geos.triangulate.quadedge
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/** \brief
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* Models a site (node) in a QuadEdgeSubdivision.
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*
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* The sites can be points on a line string representing a linear site.
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*
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* The vertex can be considered as a vector with a norm, length, inner product, cross
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* product, etc. Additionally, point relations (e.g., is a point to the left of a line, the circle
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* defined by this point and two others, etc.) are also defined in this class.
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*
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* It is common to want to attach user-defined data to the vertices of a subdivision.
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* One way to do this is to subclass `Vertex` to carry any desired information.
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*
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* @author JTS: David Skea
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* @author JTS: Martin Davis
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* @author Benjamin Campbell
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* */
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class GEOS_DLL Vertex {
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public:
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static const int LEFT = 0;
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static const int RIGHT = 1;
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static const int BEYOND = 2;
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static const int BEHIND = 3;
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static const int BETWEEN = 4;
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static const int ORIGIN = 5;
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static const int DESTINATION = 6;
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private:
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geom::Coordinate p;
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public:
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Vertex(double _x, double _y);
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Vertex(double _x, double _y, double _z);
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Vertex(const geom::Coordinate& _p);
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Vertex();
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~Vertex() {};
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inline double
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getX() const
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{
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return p.x;
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}
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inline double
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getY() const
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{
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return p.y;
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}
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inline double
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getZ() const
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{
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return p.z;
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}
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inline void
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setZ(double _z)
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{
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p.z = _z;
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}
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inline const geom::Coordinate&
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getCoordinate() const
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{
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return p;
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}
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inline bool
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equals(const Vertex& _x) const
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{
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return p.equals2D(_x.p);
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}
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inline bool
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equals(const Vertex& _x, double tolerance) const
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{
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if(p.distance(_x.getCoordinate()) < tolerance) {
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return true;
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}
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return false;
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}
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int classify(const Vertex& p0, const Vertex& p1);
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/**
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* Computes the cross product k = u X v.
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*
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* @param v a vertex
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* @return returns the magnitude of u X v
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*/
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inline double
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crossProduct(const Vertex& v) const
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{
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return (p.x * v.getY() - p.y * v.getX());
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}
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/**
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* Computes the inner or dot product
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*
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* @param v a vertex
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* @return returns the dot product u.v
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*/
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inline double
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dot(Vertex v) const
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{
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return (p.x * v.getX() + p.y * v.getY());
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}
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/**
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* Computes the scalar product c(v)
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*
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* @param c scaling factor
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* @return returns the scaled vector
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*/
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inline std::unique_ptr<Vertex>
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times(double c) const
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{
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return std::unique_ptr<Vertex>(new Vertex(c * p.x, c * p.y));
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}
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/* Vector addition */
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inline std::unique_ptr<Vertex>
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sum(Vertex v) const
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{
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return std::unique_ptr<Vertex>(new Vertex(p.x + v.getX(), p.y + v.getY()));
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}
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/* and subtraction */
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inline std::unique_ptr<Vertex>
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sub(const Vertex& v) const
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{
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return std::unique_ptr<Vertex>(new Vertex(p.x - v.getX(), p.y - v.getY()));
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}
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/* magnitude of vector */
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inline double
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magn() const
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{
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return (std::sqrt(p.x * p.x + p.y * p.y));
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}
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/* returns k X v (cross product). this is a vector perpendicular to v */
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inline std::unique_ptr<Vertex>
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cross() const
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{
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return std::unique_ptr<Vertex>(new Vertex(p.y, -p.x));
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}
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/** ************************************************************* */
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/***********************************************************************************************
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* Geometric primitives /
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**********************************************************************************************/
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/**
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* Tests if the vertex is inside the circle defined by
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* the triangle with vertices a, b, c (oriented counter-clockwise).
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*
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* @param a a vertex of the triangle
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* @param b a vertex of the triangle
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* @param c a vertex of the triangle
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* @return true if this vertex is in the circumcircle of (a,b,c)
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*/
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bool isInCircle(const Vertex& a, const Vertex& b, const Vertex& c) const {
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return triangulate::quadedge::TrianglePredicate::isInCircleRobust(a.p, b.p, c.p, this->p) == geom::Location::INTERIOR;
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}
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/**
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* Tests whether the triangle formed by this vertex and two
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* other vertices is in CCW orientation.
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*
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* @param b a vertex
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* @param c a vertex
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* @returns true if the triangle is oriented CCW
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*/
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inline bool
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isCCW(const Vertex& b, const Vertex& c) const
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{
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// check if signed area is positive
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return (b.p.x - p.x) * (c.p.y - p.y)
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> (b.p.y - p.y) * (c.p.x - p.x);
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}
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bool rightOf(const QuadEdge& e) const;
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bool leftOf(const QuadEdge& e) const;
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private:
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static std::unique_ptr<algorithm::HCoordinate> bisector(const Vertex& a, const Vertex& b);
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inline double
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distance(const Vertex& v1, const Vertex& v2)
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{
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return std::sqrt(pow(v2.getX() - v1.getX(), 2.0) +
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pow(v2.getY() - v1.getY(), 2.0));
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}
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/**
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* Computes the value of the ratio of the circumradius to shortest edge. If smaller than some
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* given tolerance B, the associated triangle is considered skinny. For an equal lateral
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* triangle this value is 0.57735. The ratio is related to the minimum triangle angle theta by:
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* circumRadius/shortestEdge = 1/(2sin(theta)).
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*
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* @param b second vertex of the triangle
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* @param c third vertex of the triangle
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* @return ratio of circumradius to shortest edge.
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*/
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double circumRadiusRatio(const Vertex& b, const Vertex& c);
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/**
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* returns a new vertex that is mid-way between this vertex and another end point.
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*
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* @param a the other end point.
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* @return the point mid-way between this and that.
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*/
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std::unique_ptr<Vertex> midPoint(const Vertex& a);
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/**
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* Computes the centre of the circumcircle of this vertex and two others.
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*
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* @param b
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* @param c
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* @return the Coordinate which is the circumcircle of the 3 points.
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*/
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std::unique_ptr<Vertex> circleCenter(const Vertex& b, const Vertex& c) const;
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/**
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* For this vertex enclosed in a triangle defined by three vertices v0, v1 and v2, interpolate
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* a z value from the surrounding vertices.
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*/
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double interpolateZValue(const Vertex& v0, const Vertex& v1, const Vertex& v2) const;
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/**
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* Interpolates the Z-value (height) of a point enclosed in a triangle
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* whose vertices all have Z values.
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* The containing triangle must not be degenerate
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* (in other words, the three vertices must enclose a
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* non-zero area).
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*
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* @param p the point to interpolate the Z value of
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* @param v0 a vertex of a triangle containing the p
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* @param v1 a vertex of a triangle containing the p
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* @param v2 a vertex of a triangle containing the p
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* @return the interpolated Z-value (height) of the point
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*/
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static double interpolateZ(const geom::Coordinate& p, const geom::Coordinate& v0,
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const geom::Coordinate& v1, const geom::Coordinate& v2);
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/**
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* Computes the interpolated Z-value for a point p lying on the segment p0-p1
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*
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* @param p
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* @param p0
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* @param p1
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* @return the interpolated Z value
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*/
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static double interpolateZ(const geom::Coordinate& p, const geom::Coordinate& p0,
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const geom::Coordinate& p1);
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};
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inline bool
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operator<(const Vertex& v1, const Vertex& v2)
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{
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return v1.getCoordinate() < v2.getCoordinate();
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}
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} //namespace geos.triangulate.quadedge
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} //namespace geos.triangulate
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} //namespace geos
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