/*
   math/axis.cc
   This file is part of the Osirion project and is distributed under
   the terms of the GNU General Public License version 2
*/

// project headers
#include "math/axis.h"
#include "math/mathlib.h"

namespace math
{

Axis::Axis()
{
	clear();
}

Axis::Axis(const Axis & other)
{
	assign(other);
}

void Axis::clear()
{
	axis_vector[0] = Vector3f(1.0f, 0.0f, 0.0f);
	axis_vector[1] = Vector3f(0.0f, 1.0f, 0.0f);
	axis_vector[2] = Vector3f(0.0f, 0.0f, 1.0f);
}

void Axis::assign(const Axis & other)
{
	for (size_t i=0; i < 3; i++) {
		axis_vector[i].assign(other.axis_vector[i]);
	}
}

Axis & Axis::operator=(const Axis & other)
{
	assign(other);
	return *this;
}

// change heading, rotate around Z-axis (positive is left)
void Axis::change_direction(const float angle)
{
	float cosa = cosf(angle * M_PI / 180.0f);
	float sina = sinf(angle * M_PI / 180.0f);
	
	Vector3f forward = axis_vector[0] * cosa + axis_vector[1] * sina;
	Vector3f left = axis_vector[1] *cosa - axis_vector[0] * sina;
	
	axis_vector[0].assign(forward);
	axis_vector[1].assign(left);
}

// change pitch, rotate around negative Y-axis (positive is up)
void Axis::change_pitch(const float angle)
{
	float cosa = cosf(angle * M_PI / 180.0f);
	float sina = sinf(angle * M_PI / 180.0f);
	
	Vector3f forward = axis_vector[0] * cosa + axis_vector[2] * sina;
	Vector3f up = axis_vector[2] * cosa - axis_vector[0] * sina;
	
	axis_vector[0].assign(forward);
	axis_vector[2].assign(up);
}

// change roll, rotate around forward vector (positive is left)
void Axis::change_roll(const float angle)
{
	float cosa = cosf(angle * M_PI / 180.0f);
	float sina = sinf(angle * M_PI / 180.0f);
	
	Vector3f forward = axis_vector[2] * cosa + axis_vector[1] * sina;
	Vector3f up = axis_vector[1] * cosa - axis_vector[2] * sina;
	
	axis_vector[2].assign(forward);
	axis_vector[1].assign(up);
}

// perform a rotation about an arbitrary axis
/* notes:
	http://mathworld.wolfram.com/RotationFormula.html
*/
void Axis::rotate(Vector3f const &normal, float angle)
{
	float cosa = cosf(angle);
	float sina = sinf(angle);
	
	for (size_t i =0; i < 3; i++) {
		axis_vector[i] =
			axis_vector[i]*cosa +
			normal * dotproduct(normal, axis_vector[i]) * (1 - cosa) +
			crossproduct(axis_vector[i], normal)*sina;
	}
}

const Axis Axis::transpose() const
{
	Axis t;
	
	for (size_t i = 0; i < 3; i++)
		for (size_t j = 0; j < 3; j++)
			t.axis_vector[i][j] = axis_vector[j][i];
	return t;
}

const Axis Axis::operator*(const Axis &other) const
{
	Axis t;
	for (size_t i = 0; i < 3; i++)
		t.axis_vector[i] = (*this) * other.axis_vector[i];

	return t;
}

// write an axis to a std::ostream
std::ostream &operator<<(std::ostream & os, Axis const & axis)
{
	os << axis.forward() << " ";
	os << axis.left() << " ";
	os << axis.up();
	return os;
}

// read an axis from a std::istream
std::istream &operator>>(std::istream & is, Axis & axis)
{
	is >> axis[0];
	is >> axis[1];
	is >> axis[2];
	return is;
}

// local-to-global coordinates
Vector3f operator*(Axis const &axis, Vector3f const &vector)
{
	return (Vector3f(vector[0] * axis[0] + vector[1] * axis[1] + vector[2] * axis[2]));
}

}