m_imu_3dof.h

Go to the documentation of this file.

// Copyright 2013, Fredrik Hultin.
// Copyright 2013, Jakob Bornecrantz.
// Copyright 2020, Collabora, Ltd.
// SPDX-License-Identifier: BSL-1.0
/*!
 * @file
 * @brief  A IMU fusion specially made for 3dof devices.
 * @author Jakob Bornecrantz <jakob@collabora.com>
 * @ingroup aux_math
 */
 
#pragma once
 
#include "xrt/xrt_defines.h"
 
 
#ifdef __cplusplus
extern "C" {
#endif
 
 
#define M_IMU_3DOF_USE_GRAVITY_DUR_300MS (1 << 0)
#define M_IMU_3DOF_USE_GRAVITY_DUR_20MS (1 << 1)
 
 
struct m_ff_vec3_f32;
 
enum m_imu_3dof_state
{
        M_IMU_3DOF_STATE_START = 0,
        M_IMU_3DOF_STATE_RUNNING = 1,
};
 
struct m_imu_3dof
{
        struct xrt_quat rot; //!< Orientation
 
        struct
        {
                uint64_t timestamp_ns;
                struct xrt_vec3 gyro;  //!< Angular velocity
                struct xrt_vec3 accel; //!< Acceleration
                double delta_ms;
                float accel_length;
                float gyro_length;
                float gyro_biased_length;
        } last;
 
        enum m_imu_3dof_state state;
 
        int flags;
 
        // Filter fifos for accelerometer and gyroscope.
        struct m_ff_vec3_f32 *word_accel_ff;
        struct m_ff_vec3_f32 *gyro_ff;
 
        // gravity correction
        struct
        {
                uint64_t level_timestamp_ns;
                struct xrt_vec3 error_axis;
                float error_angle;
                bool is_accel;
                bool is_rotating;
        } grav;
 
        // gyro bias correction
        struct
        {
                struct xrt_vec3 value;
                bool manually_fire;
        } gyro_bias;
};
 
void
m_imu_3dof_init(struct m_imu_3dof *f, int flags);
 
void
m_imu_3dof_reset(struct m_imu_3dof *f);
 
void
m_imu_3dof_close(struct m_imu_3dof *f);
 
void
m_imu_3dof_add_vars(struct m_imu_3dof *f, void *root, const char *prefix);
 
void
m_imu_3dof_update(struct m_imu_3dof *f,
                  uint64_t timestamp_ns,
                  const struct xrt_vec3 *accel,
                  const struct xrt_vec3 *gyro);
 
 
#ifdef __cplusplus
}
#endif