#ifndef H_frame_conversions
#define H_frame_conversions

#include <Eigen/Dense>
#include <cmath>

/// @brief Converts a spherical vector [r, theta, phi] in ISO convention (theta=0 is Z+) to a cartesian vector.
Eigen::Vector3d sph2cart(const Eigen::Vector3d & sph);

/// @brief Converts a cartesian vector to a spherical vector [r, theta, phi] in ISO convention (theta=0 is Z+).
Eigen::Vector3d cart2sph(const Eigen::Vector3d & cart);

/// @brief Converts equirectangular coordinates to spherical coordinates. 
/// @param  i       Row in the equirectangular image.
/// @param  j       Column in the equirectangular image.
/// @param  width   Width of the equirectangular image.
/// @param  height  Height of the equirectangular image.
/// @return A spherical vector [r, theta, phi] in ISO convention (theta=0 is Z+).
Eigen::Vector3d equirectangular2sph(unsigned int i, unsigned int j, unsigned int width, unsigned int height);

/// @brief Converts spherical coordinates to pixel coordinates of an equirectangular image.
/// @param  p_sph    A spherical vector [r, theta, phi] in ISO convention (theta=0 is Z+).
/// @param  width    Width of the equirectangular image.
/// @param  height   Height of the equirectangular image.
/// @return A 2D vector of floating point numbers [i, j] representing the pixel coordinates of the equirectangular image.
Eigen::Vector2d sph2equirectangular_d(Eigen::Vector3d const& p_sph, unsigned int width, unsigned int height);

/// @brief Converts spherical coordinates to pixel coordinates of an equirectangular image.
/// @param  p_sph    A spherical vector [r, theta, phi] in ISO convention (theta=0 is Z+).
/// @param  width    Width of the equirectangular image.
/// @param  height   Height of the equirectangular image.
/// @return A 2D vector of integers [i, j] representing the pixel coordinates of the equirectangular image.
Eigen::Vector2i sph2equirectangular_i(Eigen::Vector3d const& p_sph, unsigned int width, unsigned int height);

#endif