Plane.h

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/*
   Copyright (c) 2018 DIVIDE-Studio
   Copyright (c) 2009 Ionut Cava
 
   This file is part of DIVIDE Framework.
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software
   and associated documentation files (the "Software"), to deal in the Software
   without restriction,
   including without limitation the rights to use, copy, modify, merge, publish,
   distribute, sublicense,
   and/or sell copies of the Software, and to permit persons to whom the
   Software is furnished to do so,
   subject to the following conditions:
 
   The above copyright notice and this permission notice shall be included in
   all copies or substantial portions of the Software.
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   IMPLIED,
   INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
   PARTICULAR PURPOSE AND NONINFRINGEMENT.
   IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
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 */
 
// This file is based on material originally from:
// Geometric Tools, LLC
// Copyright (c) 1998-2010
// Distributed under the Boost Software License, Version 1.0.
// http://www.boost.org/LICENSE_1_0.txt
// http://www.geometrictools.com/License/Boost/LICENSE_1_0.txt
// This code is HEAVILY inspired by Ogre3D and Torque3D
 
 
#pragma once
#ifndef DVD_CORE_MATH_PLANE_H_
#define DVD_CORE_MATH_PLANE_H_
 
#include "MathUtil.h"
 
namespace Divide {
 
template <typename T>
class Plane {
   public:
    enum class Side : I8 {
        NO_SIDE,
        POSITIVE_SIDE,
        NEGATIVE_SIDE
    };
 
    Plane(const Plane& rhs) noexcept
        : _normal(rhs._normal), _distance(rhs._distance)
    {
    }
 
    Plane(const vec3<T>& normal, T distance) noexcept 
        : _normal(normal), _distance(distance)
    {
    }
 
    Plane(const T a, const T b, const T c, const T distance) noexcept 
        : _normal(a, b, c), _distance(distance)
    {
    }
 
    Plane(const vec4<T>& plane) noexcept
        : _normal(plane.xyz()), _distance(plane.w)
    {
    }
 
    Plane(const vec3<T>& normal, const vec3<T>& point)
    {
        redefine(normal, point);
    }
 
    Plane(const vec3<T>& point0, const vec3<T>& point1, const vec3<T>& point2)
    {
        redefine(point0, point1, point2);
    }
 
    Plane() noexcept
        : Plane(0, 0, 0, 0)
    {
    }
    
    Plane& operator=(const Plane& other) noexcept {
        _normal.set(other._normal);
        _distance = other._distance;
 
        return *this;
    }
 
    [[nodiscard]] Side classifyPoint(const vec3<F32>& point) const noexcept {
        const F32 result = signedDistanceToPoint(point);
        return result > 0 ? Side::POSITIVE_SIDE
                   : result < 0 ? Side::NEGATIVE_SIDE : Side::NO_SIDE;
    }
 
    [[nodiscard]] T signedDistanceToPoint(const vec3<T>& point) const noexcept {
        return _normal.dot(point) + _distance;
    }
 
    [[nodiscard]] vec3<T> closestPointOnPlaneToPoint(const vec3<T>& point) const  {
        return (point - signedDistanceToPoint(point)) * _normal;
    }
 
    void set(const vec4<T>& equation) noexcept {
        set(equation.xyz, equation.w);
    }
 
    void set(const vec3<T>& normal, T distance) noexcept {
        _normal = normal;
        _distance = distance;
    }
 
    void set(T a, T b, T c, T distance) noexcept {
        set(vec3<T>(a, b, c), distance);
    }
 
    void redefine(const vec3<T>& point0, const vec3<T>& point1, const vec3<T>& point2) {
        const vec3<T> edge1 = point1 - point0;
        const vec3<T> edge2 = point2 - point0;
        _normal = edge1.cross(edge2);
        _normal.normalize();
        _distance = _normal.dot(point0);
    }
 
    void redefine(const vec3<T>& normal, const vec3<T>& point) {
        _normal = normal;
        _distance = _normal.dot(point);
    }
 
    bool operator==(const Plane& rhs) const noexcept {
        return COMPARE(rhs._distance, _distance) && rhs._normal == _normal;
    }
 
    bool operator!=(const Plane& rhs) const noexcept {
        return !COMPARE(rhs._distance, _distance) || rhs._normal != _normal;
    }
 
    bool compare(const Plane& rhs, F32 epsilon) {
        return COMPARE_TOLERANCE(rhs._distance, _distance, epsilon) && rhs._normal.compare(_normal, epsilon);
    }
 
    T normalize() noexcept {
        T length = _normal.length();
        if (length > static_cast<T>(0))
        {
            const F32 invLength = 1.f / length;
            _normal *= invLength;
            _distance *= invLength;
        }
        
        return length;
    }
 
     union {
          struct {
              vec3<T> _normal;
              T _distance;
          };
 
          vec4<T> _equation{0,0,0,0};
     };
};
 
template<size_t N>
using PlaneList = std::array<Plane<F32>, N>;
using PlaneDynamicList = vector<Plane<F32>>;
 
template<typename T>
FORCE_INLINE vec3<T> GetIntersection(const Plane<T>& a, const Plane<T>& b, const Plane<T>& c) noexcept {
    const T denom = Dot(Cross(a._normal, b._normal), c._normal);
    assert(!IS_ZERO(denom));
    return (-(a._distance * Cross(b._normal, c._normal)) -
              b._distance * Cross(c._normal, a._normal) -
              c._distance * Cross(a._normal, b._normal)) / denom;
}
}  // namespace Divide
 
#endif //DVD_CORE_MATH_PLANE_H_