MRCutTrianglePredicates.h

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#pragma once
 
#include "MRPrecisePredicates3.h"
#include "MRVector.h"
#include "MRVector2.h"
#include <memory>
#include <optional>
 
namespace MR
{


struct MR_BIND_IGNORE PreciseCutPoint
{
    std::array<PreciseVertCoords, 2> seg;

    std::array<PreciseVertCoords, 3> tri;

    std::array<PreciseVertCoords, 2> wedge;

    std::array<PreciseVertCoords, 3> tri2;
 
    [[nodiscard]] bool isCrossing() const { return tri2[0].id.valid(); }
    [[nodiscard]] bool isVertex() const { return !seg[1].id.valid() && !isCrossing(); }
};

class MR_BIND_IGNORE CutTrianglePredicates
{
public:
    MRMESH_API CutTrianglePredicates();
    MRMESH_API CutTrianglePredicates( CutTrianglePredicates && ) noexcept;
    MRMESH_API CutTrianglePredicates & operator =( CutTrianglePredicates && ) noexcept;
    MRMESH_API ~CutTrianglePredicates();

    MRMESH_API void reset( const std::array<PreciseVertCoords, 3> & tri );

    MRMESH_API void addPoint( VertId v, const PreciseCutPoint & p );

    [[nodiscard]] MRMESH_API bool less( VertId p, VertId q ) const;

    [[nodiscard]] MRMESH_API std::optional<Vector2i> directionByPerturbation( VertId p, VertId q ) const;

    [[nodiscard]] MRMESH_API bool ccw( VertId a, VertId b, VertId c ) const;

    [[nodiscard]] MRMESH_API std::optional<bool> ccwByLines( VertId a, VertId b, VertId c ) const;

    [[nodiscard]] MRMESH_API std::optional<bool> ccwByPerturbation( VertId a, VertId b, VertId c ) const;

    [[nodiscard]] MRMESH_API bool ccwFromBehind( VertId b, VertId pivot ) const;

    [[nodiscard]] MRMESH_API bool failed() const;
 
private:
    struct Line
    {
        int side = -1; 
        std::array<PreciseVertCoords, 3> plane;
    };

    struct Impl;

    struct Shift;
 
    void addCrossing_( VertId v, const PreciseCutPoint & p );
    bool isCrossing_( VertId v ) const;
    int compareExact_( VertId p, VertId q, bool yFirst ) const;
    int exactOrient_( VertId a, VertId b, VertId c ) const;
    bool ccwExact_( VertId a, VertId b, VertId c ) const;
    int orientSlow_( VertId a, VertId b, VertId c ) const;
    std::optional<bool> ccwBySides_( VertId a, VertId b, VertId c ) const;
    std::optional<bool> ccwByPlanes_( VertId a, VertId b, VertId c ) const;
    std::optional<bool> ccwByShifts_( VertId a, VertId b, VertId c, const Line * line ) const;
    std::optional<Vector2i> coincidentDirection_( VertId p, VertId q ) const;
    std::optional<Vector2i> directionFromSide_( VertId p, VertId q ) const;
    std::optional<Vector2i> directionAlongCut_( VertId p, VertId q ) const;
    std::optional<Vector2i> perturbedDirection_( VertId p, VertId q, bool alike ) const;
    std::optional<Vector2i> shiftDirection_( VertId p, VertId q ) const;
    std::optional<Shift> shift_( VertId p ) const;
    std::optional<Line> commonLine_( VertId p, VertId q, bool withVertex ) const;
    Vector2i lineDirection_( const Line & l ) const;
    bool along_( const Vector2i & dir, VertId p, VertId q ) const;
    int sideOfPlane_( const std::array<PreciseVertCoords, 3> & plane, VertId x ) const;
    int crossingSideOfPlane_( const std::array<PreciseVertCoords, 3> & plane, VertId x ) const;
    void fail_() const;
 
    std::array<PreciseVertCoords, 3> tri_;
    Vector3i64 normal_;
    int kx_ = 0, ky_ = 1; 
    std::array<Vector2i, 3> sideDirs_; 
    Vector<Vector2d, VertId> approx_; 
    std::unique_ptr<Impl> impl_;
};

 
}