godot-cpp/include/godot/core/Plane.h

#ifndef PLANE_H
#define PLANE_H

#include "Vector3.h"

#include <cmath>

typedef float real_t; // @Todo move this to a global Godot.h

#define CMP_EPSILON 0.00001

namespace godot {



#define _PLANE_EQ_DOT_EPSILON 0.999
#define _PLANE_EQ_D_EPSILON 0.0001



enum ClockDirection {

	CLOCKWISE,
	COUNTERCLOCKWISE
};

class Plane {
public:
	Vector3 normal;
	real_t d;

	void set_normal(const Vector3& p_normal)
	{
		this->normal = p_normal;
	}

	Vector3 get_normal() const { return normal; } ///Point is coplanar, CMP_EPSILON for precision

	void normalize(); // down below

	Plane normalized() const; // down below

	/* Plane-Point operations */

	Vector3 center() const { return normal*d; }
	Vector3 get_any_point() const;
	Vector3 get_any_perpendicular_normal() const;

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

	/* intersections */

	bool intersect_3(const Plane &p_plane1, const Plane &p_plane2, Vector3 *r_result=0) const;
	bool intersects_ray(Vector3 p_from, Vector3 p_dir, Vector3* p_intersection)  const;
	bool intersects_segment(Vector3 p_begin, Vector3 p_end, Vector3* p_intersection)  const;

	Vector3 project(const Vector3& p_point) const {

		return p_point - normal * distance_to(p_point);
	}

	/* misc */

	Plane operator-() const { return Plane(-normal,-d); }
	bool is_almost_like(const Plane& p_plane) const;

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

	Plane() { d=0; }
	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) { }

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

};

void Plane::normalize() {

	real_t l = normal.length();
	if (l==0) {
		*this=Plane(0,0,0,0);
		return;
	}
	normal/=l;
	d/=l;
}

Plane Plane::normalized() const {

	Plane p = *this;
	p.normalize();
	return p;
}

Vector3 Plane::get_any_point() const {

	return get_normal()*d;
}

Vector3 Plane::get_any_perpendicular_normal() const {

	static const Vector3 p1 = Vector3(1,0,0);
	static const Vector3 p2 = Vector3(0,1,0);
	Vector3 p;

	if (::fabs(normal.dot(p1)) > 0.99) // if too similar to p1
		p=p2; // use p2
	else
		p=p1; // use p1

	p-=normal * normal.dot(p);
	p.normalize();

	return p;
}


/* intersections */

bool Plane::intersect_3(const Plane &p_plane1, const Plane &p_plane2, Vector3 *r_result) const {

	const Plane &p_plane0=*this;
	Vector3 normal0=p_plane0.normal;
	Vector3 normal1=p_plane1.normal;
	Vector3 normal2=p_plane2.normal;

	real_t denom=vec3_cross(normal0,normal1).dot(normal2);

	if (::fabs(denom)<=CMP_EPSILON)
		return false;

	if (r_result) {
		*r_result = 	( (vec3_cross(normal1, normal2) * p_plane0.d) +
			(vec3_cross(normal2, normal0) * p_plane1.d) +
			(vec3_cross(normal0, normal1) * p_plane2.d) )/denom;
	}

	return true;
}


bool Plane::intersects_ray(Vector3 p_from, Vector3 p_dir, Vector3* p_intersection)  const {

	Vector3 segment=p_dir;
	real_t den=normal.dot( segment );

	//printf("den is %i\n",den);
	if (::fabs(den)<=CMP_EPSILON) {

		return false;
	}

	real_t dist=(normal.dot( p_from ) - d) / den;
	//printf("dist is %i\n",dist);

	if (dist>CMP_EPSILON) { //this is a ray, before the emiting pos (p_from) doesnt exist

		return false;
	}

	dist=-dist;
	*p_intersection = p_from + segment * dist;

	return true;
}

bool Plane::intersects_segment(Vector3 p_begin, Vector3 p_end, Vector3* p_intersection)  const {

	Vector3 segment= p_begin - p_end;
	real_t den=normal.dot( segment );

	//printf("den is %i\n",den);
	if (::fabs(den)<=CMP_EPSILON) {

		return false;
	}

	real_t dist=(normal.dot( p_begin ) - d) / den;
	//printf("dist is %i\n",dist);

	if (dist<-CMP_EPSILON || dist > (1.0 +CMP_EPSILON)) {

		return false;
	}

	dist=-dist;
	*p_intersection = p_begin + segment * dist;

	return true;
}

/* misc */

bool Plane::is_almost_like(const Plane& p_plane) const {

	return (normal.dot( p_plane.normal ) > _PLANE_EQ_DOT_EPSILON && ::fabs(d-p_plane.d) < _PLANE_EQ_D_EPSILON);
}


Plane::operator String() const {

	// return normal.operator String() + ", " + rtos(d);
	return String(); // @Todo
}



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 _epsilon) const {

	real_t dist=normal.dot(p_point) - d;
	dist=::fabs(dist);
	return ( dist <= _epsilon);

}

Plane::Plane(const Vector3 &p_normal, real_t p_d) {

	normal=p_normal;
	d=p_d;
}

Plane::Plane(const Vector3 &p_point, const Vector3& p_normal) {

	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);


}

bool Plane::operator==(const Plane& p_plane) const {

	return normal==p_plane.normal && d == p_plane.d;
}

bool Plane::operator!=(const Plane& p_plane) const {

	return normal!=p_plane.normal || d != p_plane.d;

}




}

#endif // PLANE_H