/*
 * (C) 2003-2006 Gabest
 * (C) 2006-2022 see Authors.txt
 *
 * This file is part of MPC-BE.
 *
 * MPC-BE 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 3 of the License, or
 * (at your option) any later version.
 *
 * MPC-BE 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#pragma once

class Vector
{
public:
	float x, y, z;

	Vector() { x = y = z = 0.0f; }
	Vector(float x, float y, float z);
	void Set(float x, float y, float z);

	Vector Normal(const Vector& a, const Vector& b) const;
	float Angle(const Vector& a, const Vector& b) const;
	float Angle(const Vector& a) const;
	void Angle(float& u, float& v) const;   // returns spherical coords in radian, -M_PI_2 <= u <= M_PI_2, -M_PI <= v <= M_PI
	Vector Angle() const;                   // does like prev., returns 'u' in 'ret.x', and 'v' in 'ret.y'

	Vector Unit() const;
	Vector& Unitalize();
	float Length() const;
	float Sum() const;                      // x + y + z
	float CrossSum() const;                 // xy + xz + yz
	Vector Cross() const;                   // xy, xz, yz
	Vector Pow(float exp) const;

	Vector& Min(const Vector& a);
	Vector& Max(const Vector& a);
	Vector Abs() const;

	Vector Reflect(const Vector& n) const;
	Vector Refract(const Vector& n, float nFront, float nBack, float* nOut = nullptr) const;
	Vector Refract2(const Vector& n, float nFrom, float nTo, float* nOut = nullptr) const;

	Vector operator - () const;
	float& operator [](size_t i);

	float operator | (const Vector& v) const;   // dot
	Vector operator % (const Vector& v) const;  // cross

	bool operator == (const Vector& v) const;
	bool operator != (const Vector& v) const;

	Vector operator + (float d) const;
	Vector operator + (const Vector& v) const;
	Vector operator - (float d) const;
	Vector operator - (const Vector& v) const;
	Vector operator * (float d) const;
	Vector operator * (const Vector& v) const;
	Vector operator / (float d) const;
	Vector operator / (const Vector& v) const;
	Vector& operator += (float d);
	Vector& operator += (const Vector& v);
	Vector& operator -= (float d);
	Vector& operator -= (Vector& v);
	Vector& operator *= (float d);
	Vector& operator *= (const Vector& v);
	Vector& operator /= (float d);
	Vector& operator /= (const Vector& v);

	template<typename T> static float DegToRad(T angle) { return (float)(angle * M_PI / 180); }
};

class Ray
{
public:
	Vector p, d;

	Ray() {}
	Ray(const Vector& p, const Vector& d);
	void Set(const Vector& p, const Vector& d);

	float GetDistanceFrom(const Ray& r) const;      // r = plane
	float GetDistanceFrom(const Vector& v) const;   // v = point

	Vector operator [](float t) const;
};

class XForm
{
	class Matrix
	{
	public:
		float mat[4][4];

		Matrix();

		Matrix operator * (const Matrix& m) const;
		Matrix& operator *= (Matrix& m);
		bool operator == (const Matrix& m) const;
	} m;

	bool m_isWorldToLocal;

public:
	XForm() : m_isWorldToLocal(false) {}
	XForm(const Ray& r, const Vector& s, bool isWorldToLocal = true);

	void operator *= (const Vector& s);         // scale
	void operator += (const Vector& t);         // translate
	void operator <<= (const Vector& r);        // rotate

	void operator /= (const Vector& s);         // scale
	void operator -= (const Vector& t);         // translate
	void operator >>= (const Vector& r);        // rotate

	bool operator == (const XForm& x) const;    // compare
	bool operator != (const XForm& x) const;

	// transformations
	Vector operator < (const Vector& n) const;  // normal
	Vector operator << (const Vector& v) const; // vector
	Ray operator << (const Ray& r) const;       // ray
};
