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////////////////////////////////////////////////////////////////////////////////////////////////////

#include "plane.h"

#include <stdio.h>

Plane::Plane()

{

    // EMPTY!

}

Plane::Plane(const Plane& rfPlane) :

    m_kNormal(rfPlane.m_kNormal),

    m_fConstant(rfPlane.m_fConstant)

{

    // EMPTY!

}

Plane::Plane(const float3& rkNormal, float fConstant) :

    m_kNormal(rkNormal),

    m_fConstant(fConstant)

{

    // EMPTY!

}

Plane::Plane(const float3 &rkPoint, const float3 &rkNormal) :

    m_kNormal(rkNormal)

{

    m_fConstant = dot(rkNormal, rkPoint);

}

Plane::Plane(

    const float3& rfP0, 

    const float3& rfP1,

    const float3& rfP2)

{

    float3 fE0 = rfP1 - rfP0;

    float3 fE1 = rfP2 - rfP0;

    m_kNormal = normalize(cross(fE0, fE1));

    m_fConstant = dot(m_kNormal, rfP0);

}

Plane& 

Plane::operator= (const Plane& rfPlane)

{

    m_kNormal = rfPlane.m_kNormal;

    m_fConstant = rfPlane.m_fConstant;

    return *this;

}

int 

Plane::side (

    const float3& rkPoint) const

{

    float fDistance = distance(rkPoint);

    if (fDistance < 0.0f)

    {

        return -1;

    }

    if (fDistance > 0.0f)

    {

        return +1;

    }

    return 0;

}

float 

Plane::distance(

    const float3& rkPoint) const

{

    return dot(m_kNormal, rkPoint) - m_fConstant;

}

float

Plane::dotNormal(

    const float3 &rkNormal) const

{

    return dot(m_kNormal, rkNormal);

}

bool

Plane::findIntersection(

    float3 &rkIntersection,

    const float3 &rkPoint,

    const float3 &rkDir,

    float fZeroEpsilon) const

{

    if(dot(rkDir, m_kNormal) == 0.0f)

        return false;

    float fT = (m_fConstant - dot(m_kNormal, rkPoint)) / (dot(m_kNormal, rkDir));

    rkIntersection = rkPoint + rkDir * fT;

    return true;

}

bool

Plane::findIntersection(

    float &rfT,

    const float3 &rkPoint, 

    const float3 &rkDirection,

    float fEpsilon) const

{

    float fD = dot(rkDirection, m_kNormal);

    float fS = distance(rkPoint);

    if (fabs(fD) > fEpsilon)

    {

        rfT = -fS/fD;

//        printf("Plane: Intersection at %8.3f\n", rfT);

        return true;

    }

    if (fabs(fS) <= fEpsilon)

    {

        rfT = 0.0f;

//        printf("Plane: Intersection at %8.3f\n", rfT);

        return true;

    }

//    printf("Plane: No Intersection!\n", rfT);

    return false;

}

bool 

Plane::intersects(

    const float3 &rkPoint, 

    const float3 &rkDirection, 

    float fEpsilon) const

{

    float fD = dot(rkDirection, m_kNormal);

    if (fabs(fD) > fEpsilon)

    {

        return true;

    }

    fD = distance(rkPoint);

    if (fabs(fD) <= fEpsilon)

    {

        return true;

    }

    return false;

}