#include <utils2d.h>
#include <plane.h>

Plane::Plane( const Vector3 &pt, const Vector3 &normal )
{
    a = normal.x;
    b = normal.y;
    c = normal.z;
    d = ( -a * pt.x ) - ( b * pt.y ) - ( c * pt.z );
}

Plane::~Plane( void )
{
}

bool Plane::closestIntersect( Vector3 *pos, Vector3 *norm,
                              const Vector3 &o,
                              const Vector3 &dir ) const
{
    double bot = ( (  a * dir.x ) + ( b * dir.y ) + ( c * dir.z ) );
    if( threshEqual( 0.0, bot, 0.00001 ) ) return false;

    double top = ( ( -a *   o.x ) - ( b *   o.y ) - ( c *   o.z ) - d );
    double t = top / bot;
    if( t <= 0.0 ) return false;

    *pos = o.add( dir.scalarMult( t ) );
    *norm = Vector3( a, b, c );

    return true;
}