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#ifndef GMX_MATH_3DTRANSFORMS_H
#define GMX_MATH_3DTRANSFORMS_H

#include <cstdio>

#include "gromacs/math/vectypes.h"
#include "gromacs/utility/real.h"

/** Index for the fourth dimension for `vec4`. */
#define WW 3

/*! \brief
 * 4D vector type used in 3D transformations.
 *
 * In \Gromacs, only a limited set of 3D transformations are used, and all of
 * them operate on coordinates, so the fourth element is assumed to be one and
 * ignored in all contexts.
 */
typedef real vec4[4];

/*! \brief
 * 4D matrix type used in 3D transformations.
 */
typedef real mat4[4][4];

void gmx_mat4_copy(mat4 a, mat4 b);

void gmx_mat4_transform_point(mat4 m, const rvec x, vec4 v);

/*! \brief
 * Computes the product of two `mat4` matrices as A = B * C.
 *
 * Note that the order of operands is different from mmul() in vec.h!
 */
void gmx_mat4_mmul(mat4 A, mat4 B, mat4 C);

void gmx_mat4_init_unity(mat4 m);

void gmx_mat4_init_rotation(int axis, real angle, mat4 A);

void gmx_mat4_init_translation(real tx, real ty, real tz, mat4 A);

void gmx_mat4_print(FILE* fp, const char* s, mat4 A);

void gmx_vec4_print(FILE* fp, const char* s, vec4 a);

#endif
