imstkEdgeEdgeCCDState.h

/*
** This file is part of the Interactive Medical Simulation Toolkit (iMSTK)
** iMSTK is distributed under the Apache License, Version 2.0.
** See accompanying NOTICE for details.
*/

#pragma once

#include "imstkMath.h"

namespace imstk
{
class EdgeEdgeCCDState
{
public:

    /*
                _o (xi1)
            _-*
        _-*
(xi) o*  (segment i)
     ^
     |
 (w0)|
     |
 (xj)o----------o (xj1)
        (segment j)
    */

    const Vec3d& xi, & xi1, & xj, & xj1;

    const Vec3d ei;  
    const Vec3d ej;  

    const Vec3d w0;  

    const Vec3d w;

    EdgeEdgeCCDState(const Vec3d& i0, const Vec3d& i1, const Vec3d& j0, const Vec3d& j1);

    const double si() const
    {
        return m_si;
    }

    const double sj() const
    {
        return m_sj;
    }

    const Vec3d& pi() const
    {
        return m_pi;
    }

    const Vec3d& pj() const
    {
        return m_pj;
    }

    Vec3d computeWBar();

    Vec3d computeWBar2() const;

    Vec3d computePi() const
    {
        return xi + ei * si();
    }

    Vec3d computePj() const
    {
        return xj + ej * sj();
    }

    void setThickness(double thickness)
    {
        m_thickness = thickness;
    }

    double thickness() const
    {
        return m_thickness;
    }

    void setTolerance(double eps)
    {
        m_epsilon = eps;
    }

    static int testCollision(const EdgeEdgeCCDState& prev, EdgeEdgeCCDState& curr, double& relativeTimeOfImpact);

private:

    double m_si; 
    double m_sj; 

    Vec3d m_pi;  
    Vec3d m_pj;  

    double m_epsilon = 1e-10;

    // Thickness of colliding LineMeshes.
    double m_thickness = 0.0016; // 0.0016

    double a() const
    {
        return ei.dot(ei);
    }

    double b() const
    {
        return ei.dot(ej);
    }

    double c() const
    {
        return ej.dot(ej);
    }

    double d() const
    {
        return ei.dot(w0);
    }

    double e() const
    {
        return ej.dot(w0);
    }

    double denom() const
    {
        return a() * c() - b() * b();
    }

    double computeSi() const;

    double computeSj() const;

    Vec3d shortestDistanceVector() const;
};
} // namespace imstk