plane.h

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/*  plane.h                                                               */
/**************************************************************************/
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#pragma once

#include "core/math/vector3.h"

class Variant;

struct [[nodiscard]] Plane {
	static const Plane PLANE_YZ;
	static const Plane PLANE_XZ;
	static const Plane PLANE_XY;

	Vector3 normal;
	real_t d = 0;

	void set_normal(const Vector3 &p_normal);
	_FORCE_INLINE_ Vector3 get_normal() const { return normal; }

	void normalize();
	Plane normalized() const;

	/* Plane-Point operations */

	_FORCE_INLINE_ Vector3 get_center() const { return normal * d; }
	Vector3 get_any_perpendicular_normal() const;

	_FORCE_INLINE_ bool is_point_over(const Vector3 &p_point) const; ///< Point is over plane
	_FORCE_INLINE_ real_t distance_to(const Vector3 &p_point) const;
	_FORCE_INLINE_ bool has_point(const Vector3 &p_point, real_t p_tolerance = CMP_EPSILON) const;

	/* intersections */

	bool intersect_3(const Plane &p_plane1, const Plane &p_plane2, Vector3 *r_result = nullptr) const;
	bool intersects_ray(const Vector3 &p_from, const Vector3 &p_dir, Vector3 *p_intersection) const;
	bool intersects_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 *p_intersection) const;

	// For Variant bindings.
	Variant intersect_3_bind(const Plane &p_plane1, const Plane &p_plane2) const;
	Variant intersects_ray_bind(const Vector3 &p_from, const Vector3 &p_dir) const;
	Variant intersects_segment_bind(const Vector3 &p_begin, const Vector3 &p_end) const;

	_FORCE_INLINE_ Vector3 project(const Vector3 &p_point) const {
		return p_point - normal * distance_to(p_point);
	}

	/* misc */

	constexpr Plane operator-() const { return Plane(-normal, -d); }
	bool is_equal_approx(const Plane &p_plane) const;
	bool is_same(const Plane &p_plane) const;
	bool is_equal_approx_any_side(const Plane &p_plane) const;
	bool is_finite() const;

	constexpr bool operator==(const Plane &p_plane) const;
	constexpr bool operator!=(const Plane &p_plane) const;
	explicit operator String() const;

	Plane() = default;
	constexpr Plane(real_t p_a, real_t p_b, real_t p_c, real_t p_d) :
			normal(p_a, p_b, p_c),
			d(p_d) {}

	constexpr Plane(const Vector3 &p_normal, real_t p_d = 0.0);
	_FORCE_INLINE_ Plane(const Vector3 &p_normal, const Vector3 &p_point);
	_FORCE_INLINE_ Plane(const Vector3 &p_point1, const Vector3 &p_point2, const Vector3 &p_point3, ClockDirection p_dir = CLOCKWISE);
};

inline constexpr Plane Plane::PLANE_YZ = { 1, 0, 0, 0 };
inline constexpr Plane Plane::PLANE_XZ = { 0, 1, 0, 0 };
inline constexpr Plane Plane::PLANE_XY = { 0, 0, 1, 0 };

bool Plane::is_point_over(const Vector3 &p_point) const {
	return (normal.dot(p_point) > d);
}

real_t Plane::distance_to(const Vector3 &p_point) const {
	return (normal.dot(p_point) - d);
}

bool Plane::has_point(const Vector3 &p_point, real_t p_tolerance) const {
	real_t dist = normal.dot(p_point) - d;
	dist = Math::abs(dist);
	return (dist <= p_tolerance);
}

constexpr Plane::Plane(const Vector3 &p_normal, real_t p_d) :
		normal(p_normal),
		d(p_d) {
}

Plane::Plane(const Vector3 &p_normal, const Vector3 &p_point) :
		normal(p_normal),
		d(p_normal.dot(p_point)) {
}

Plane::Plane(const Vector3 &p_point1, const Vector3 &p_point2, const Vector3 &p_point3, ClockDirection p_dir) {
	if (p_dir == CLOCKWISE) {
		normal = (p_point1 - p_point3).cross(p_point1 - p_point2);
	} else {
		normal = (p_point1 - p_point2).cross(p_point1 - p_point3);
	}

	normal.normalize();
	d = normal.dot(p_point1);
}

constexpr bool Plane::operator==(const Plane &p_plane) const {
	return normal == p_plane.normal && d == p_plane.d;
}

constexpr bool Plane::operator!=(const Plane &p_plane) const {
	return normal != p_plane.normal || d != p_plane.d;
}

template <>
struct is_zero_constructible<Plane> : std::true_type {};