plane.h

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/*
 Copyright (C) 2001-2006, William Joseph.
 All Rights Reserved.

 This file is part of GtkRadiant.

 GtkRadiant is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.

 GtkRadiant is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with GtkRadiant; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#if !defined(INCLUDED_MATH_PLANE_H)
#define INCLUDED_MATH_PLANE_H

#include "math/matrix.h"

class Plane3
{
    public:
        double a, b, c, d;

        Plane3 ()
        {
        }
        Plane3 (double _a, double _b, double _c, double _d) :
            a(_a), b(_b), c(_c), d(_d)
        {
        }
        template<typename Element>
        Plane3 (const BasicVector3<Element>& normal, double dist) :
            a(normal.x()), b(normal.y()), c(normal.z()), d(dist)
        {
        }

        BasicVector3<double>& normal ()
        {
            return reinterpret_cast<BasicVector3<double>&> (*this);
        }
        const BasicVector3<double>& normal () const
        {
            return reinterpret_cast<const BasicVector3<double>&> (*this);
        }
        double& dist ()
        {
            return d;
        }
        const double& dist () const
        {
            return d;
        }
};

inline Plane3 plane3_normalised (const Plane3& plane)
{
    double rmagnitude = 1.0 / sqrt(plane.a * plane.a + plane.b * plane.b + plane.c * plane.c);
    return Plane3(plane.a * rmagnitude, plane.b * rmagnitude, plane.c * rmagnitude, plane.d * rmagnitude);
}

inline Plane3 plane3_translated (const Plane3& plane, const Vector3& translation)
{
    Plane3 transformed;
    transformed.a = plane.a;
    transformed.b = plane.b;
    transformed.c = plane.c;
    transformed.d = -((-plane.d * transformed.a + translation.x()) * transformed.a + (-plane.d * transformed.b
            + translation.y()) * transformed.b + (-plane.d * transformed.c + translation.z()) * transformed.c);
    return transformed;
}

inline Plane3 plane3_transformed (const Plane3& plane, const Matrix4& transform)
{
    Plane3 transformed;
    transformed.a = transform[0] * plane.a + transform[4] * plane.b + transform[8] * plane.c;
    transformed.b = transform[1] * plane.a + transform[5] * plane.b + transform[9] * plane.c;
    transformed.c = transform[2] * plane.a + transform[6] * plane.b + transform[10] * plane.c;
    transformed.d = -((-plane.d * transformed.a + transform[12]) * transformed.a + (-plane.d * transformed.b
            + transform[13]) * transformed.b + (-plane.d * transformed.c + transform[14]) * transformed.c);
    return transformed;
}

inline Plane3 plane3_inverse_transformed (const Plane3& plane, const Matrix4& transform)
{
    return Plane3(transform[0] * plane.a + transform[1] * plane.b + transform[2] * plane.c + transform[3] * plane.d,
            transform[4] * plane.a + transform[5] * plane.b + transform[6] * plane.c + transform[7] * plane.d,
            transform[8] * plane.a + transform[9] * plane.b + transform[10] * plane.c + transform[11] * plane.d,
            transform[12] * plane.a + transform[13] * plane.b + transform[14] * plane.c + transform[15] * plane.d);
}

inline Plane3 plane3_flipped (const Plane3& plane)
{
    return Plane3(-plane.normal(), -plane.dist());
}

const double c_PLANE_NORMAL_EPSILON = 0.0001f;
const double c_PLANE_DIST_EPSILON = 0.02;

inline bool plane3_equal (const Plane3& self, const Plane3& other)
{
    return vector3_equal_epsilon(self.normal(), other.normal(), c_PLANE_NORMAL_EPSILON) && float_equal_epsilon(
            self.dist(), other.dist(), c_PLANE_DIST_EPSILON);
}

inline bool plane3_opposing (const Plane3& self, const Plane3& other)
{
    return plane3_equal(self, plane3_flipped(other));
}

inline bool plane3_valid (const Plane3& self)
{
    return float_equal_epsilon(self.normal().dot(self.normal()), 1.0, 0.01);
}

template<typename Element>
inline Plane3 plane3_for_points (const BasicVector3<Element>& p0, const BasicVector3<Element>& p1, const BasicVector3<
        Element>& p2)
{
    Plane3 self;
    self.normal() = (p1 - p0).crossProduct(p2 - p0).getNormalised();
    self.dist() = p0.dot(self.normal());
    return self;
}

template<typename Element>
inline Plane3 plane3_for_points (const BasicVector3<Element> planepts[3])
{
    return plane3_for_points(planepts[2], planepts[1], planepts[0]);
}

#endif