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64 lines
2.0 KiB
C++
64 lines
2.0 KiB
C++
#ifndef INTELLITRIANGULATION_H
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#define INTELLITRIANGULATION_H
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#include <QPoint>
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#include <vector>
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/*!
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* \brief The Triangle struct holds the 3 vertices of a triangle.
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*/
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struct Triangle {
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QPoint A,B,C;
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};
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namespace IntelliTriangulation {
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/*!
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* \brief A function to get the 2*area of a traingle, using its determinat.
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* \param p1 - The Point to check its side.
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* \param p2 - The first Point of the spanning Line
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* \param p3 - The second Point of the spanning line.
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* \return Returns the area of the traingle*2
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*/
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inline float sign(QPoint& p1, QPoint& p2, QPoint& p3){
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return (p1.x() - p3.x()) * (p2.y() - p3.y()) - (p2.x() - p3.x()) * (p1.y() - p3.y());
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}
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/*!
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* \brief A function to check if a given point is in a triangle.
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* \param tri - The triangle to check, if it contains the point.
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* \param P - The point to check if it is in the triangle.
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* \return Returns true if the point is in the triangle, false otheriwse
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*/
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inline bool isInTriangle(Triangle& tri, QPoint& P){
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float val1, val2, val3;
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bool neg, pos;
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val1 = IntelliTriangulation::sign(P,tri.A,tri.B);
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val2 = IntelliTriangulation::sign(P,tri.B,tri.C);
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val3 = IntelliTriangulation::sign(P,tri.C,tri.A);
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neg = (val1<0.f) || (val2<0.f) || (val3<0.f);
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pos = (val1>0.f) || (val2>0.f) || (val3>0.f);
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return !(neg && pos);
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}
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/*!
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* \brief A function to split a polygon in its spanning traingles by using Meisters Theorem of graph theory by clipping ears of a planar graph.
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* \param polyPoints - The Vertices of the polygon.
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* \return Returns a Container of disjoint Triangles, which desribe the polygon area.
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*/
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std::vector<Triangle> calculateTriangles(std::vector<QPoint> polyPoints);
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/*!
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* \brief A function to check if a point lies in a polygon by checking its spanning triangles.
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* \param triangles - The spanning triangles of the planar polygon.
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* \param point - The point to checl, if it lies in the polygon.
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* \return Returns true if the point lies in the üpolygon, otherwise false.
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*/
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bool isInPolygon(std::vector<Triangle> &triangles, QPoint &point);
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}
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#endif
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