ardupilot/libraries/AP_Proximity/AP_Proximity.h

/*
   This program 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.

   This program 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

#include <AP_Common/AP_Common.h>
#include <AP_HAL/AP_HAL.h>
#include <AP_Param/AP_Param.h>
#include <AP_Math/AP_Math.h>
#include <AP_SerialManager/AP_SerialManager.h>


#define PROXIMITY_MAX_INSTANCES             1   // Maximum number of proximity sensor instances available on this platform
#define PROXIMITY_YAW_CORRECTION_DEFAULT    22  // default correction for sensor error in yaw
#define PROXIMITY_MAX_IGNORE                6   // up to six areas can be ignored

class AP_Proximity_Backend;

class AP_Proximity
{
public:
    friend class AP_Proximity_Backend;

    AP_Proximity(AP_SerialManager &_serial_manager);

    // Proximity driver types
    enum Proximity_Type {
        Proximity_Type_None  = 0,
        Proximity_Type_SF40C = 1,
        Proximity_Type_MAV   = 2,
        Proximity_Type_SITL  = 10,
    };

    enum Proximity_Status {
        Proximity_NotConnected = 0,
        Proximity_NoData,
        Proximity_Good
    };

    // detect and initialise any available proximity sensors
    void init(void);

    // update state of all proximity sensors. Should be called at high rate from main loop
    void update(void);

    // return sensor orientation and yaw correction
    uint8_t get_orientation(uint8_t instance) const;
    int16_t get_yaw_correction(uint8_t instance) const;

    // return sensor health
    Proximity_Status get_status(uint8_t instance) const;
    Proximity_Status get_status() const;

    // Return the number of proximity sensors
    uint8_t num_sensors(void) const {
        return num_instances;
    }

    // get distance in meters in a particular direction in degrees (0 is forward, clockwise)
    // returns true on successful read and places distance in distance
    bool get_horizontal_distance(uint8_t instance, float angle_deg, float &distance) const;
    bool get_horizontal_distance(float angle_deg, float &distance) const;

    // get boundary points around vehicle for use by avoidance
    //   returns nullptr and sets num_points to zero if no boundary can be returned
    const Vector2f* get_boundary_points(uint8_t instance, uint16_t& num_points) const;
    const Vector2f* get_boundary_points(uint16_t& num_points) const;

    // get distance and angle to closest object (used for pre-arm check)
    //   returns true on success, false if no valid readings
    bool get_closest_object(float& angle_deg, float &distance) const;

    // get number of objects, angle and distance - used for non-GPS avoidance
    uint8_t get_object_count() const;
    bool get_object_angle_and_distance(uint8_t object_number, float& angle_deg, float &distance) const;

    // structure holding distances in 8 directions
    struct Proximity_Distance_Array {
        uint8_t orientation[8]; // orientation (i.e. rough direction) of the distance (see MAV_SENSOR_ORIENTATION)
        float distance[8];      // distance in meters
    };

    // get distances in 8 directions. used for sending distances to ground station
    bool get_distances(Proximity_Distance_Array &prx_dist_array) const;

    // get maximum and minimum distances (in meters) of primary sensor
    float distance_max() const;
    float distance_min() const;

    // handle mavlink DISTANCE_SENSOR messages
    void handle_msg(mavlink_message_t *msg);

    // The Proximity_State structure is filled in by the backend driver
    struct Proximity_State {
        uint8_t                 instance;   // the instance number of this proximity sensor
        enum Proximity_Status   status;     // sensor status
    };

    //
    // support for upwardward facing sensors
    //

    // get distance upwards in meters. returns true on success
    bool get_upward_distance(uint8_t instance, float &distance) const;
    bool get_upward_distance(float &distance) const;

    // parameter list
    static const struct AP_Param::GroupInfo var_info[];

private:
    Proximity_State state[PROXIMITY_MAX_INSTANCES];
    AP_Proximity_Backend *drivers[PROXIMITY_MAX_INSTANCES];
    uint8_t primary_instance:3;
    uint8_t num_instances:3;
    AP_SerialManager &serial_manager;

    // parameters for all instances
    AP_Int8  _type[PROXIMITY_MAX_INSTANCES];
    AP_Int8  _orientation[PROXIMITY_MAX_INSTANCES];
    AP_Int16 _yaw_correction[PROXIMITY_MAX_INSTANCES];
    AP_Int16 _ignore_angle_deg[PROXIMITY_MAX_IGNORE];   // angle (in degrees) of area that should be ignored by sensor (i.e. leg shows up)
    AP_Int8 _ignore_width_deg[PROXIMITY_MAX_IGNORE];    // width of beam (in degrees) that should be ignored

    void detect_instance(uint8_t instance);
    void update_instance(uint8_t instance);  
};