$#include "Plane.h"

/// Surface in three-dimensional space.
class Plane
{
public:
    /// Construct undefined.
    Plane()
    {
    }
    
    /// Copy-construct from another plane.
    Plane(const Plane& plane) :
        normal_(plane.normal_),
        absNormal_(plane.absNormal_),
        intercept_(plane.intercept_)
    {
    }
    
    /// Construct from 3 vertices.
    Plane(const Vector3& v0, const Vector3& v1, const Vector3& v2)
    {
        Define(v0, v1, v2);
    }
    
    /// Construct from a normal vector and a point on the plane.
    Plane(const Vector3& normal, const Vector3& point)
    {
        Define(normal, point);
    }
    
    /// Define from 3 vertices.
    void Define(const Vector3& v0, const Vector3& v1, const Vector3& v2)
    {
        Vector3 dist1 = v1 - v0;
        Vector3 dist2 = v2 - v0;
        
        Define(dist1.CrossProduct(dist2).Normalized(), v0);
    }

    /// Define from a normal and a point.
    void Define(const Vector3& normal, const Vector3& point)
    {
        normal_ = normal;
        absNormal_ = normal.Abs();
        intercept_ = normal.DotProduct(point);
    }
    
    /// Return signed distance to a point.
    float Distance(const Vector3& point) const { return normal_.DotProduct(point) - intercept_; }
    
    /// Plane normal.
    Vector3 normal_ @ normal;
    /// Plane absolute normal.
    Vector3 absNormal_ @ absNormal;
    /// Plane intercept parameter.
    float intercept_ @ intercept;
};