Copter: FlightMode - convert DRIFT flight mode

ArduCopter/Copter.h

@@ -817,9 +817,6 @@ private:
     bool brake_init(bool ignore_checks);
     void brake_run();
     void brake_timeout_to_loiter_ms(uint32_t timeout_ms);
-    bool drift_init(bool ignore_checks);
-    void drift_run();
-    float get_throttle_assist(float velz, float pilot_throttle_scaled);
     bool flip_init(bool ignore_checks);
     void flip_run();
     bool guided_nogps_init(bool ignore_checks);
@@ -1067,6 +1064,8 @@ private:
 
     Copter::FlightMode_CIRCLE flightmode_circle{*this, circle_nav};
 
+    Copter::FlightMode_DRIFT flightmode_drift{*this};
+
     Copter::FlightMode_GUIDED flightmode_guided{*this};
 
     Copter::FlightMode_LAND flightmode_land{*this};

ArduCopter/FlightMode.h

@@ -577,3 +577,32 @@ private:
     // Loiter timer - Records how long we have been in loiter
     uint32_t _loiter_start_time = 0;
 };
+
+
+
+class FlightMode_DRIFT : public FlightMode {
+
+public:
+
+    FlightMode_DRIFT(Copter &copter) :
+        Copter::FlightMode(copter)
+        { }
+
+    virtual bool init(bool ignore_checks) override;
+    virtual void run() override; // should be called at 100hz or more
+
+    virtual bool requires_GPS() const override { return true; }
+    virtual bool has_manual_throttle() const override { return false; }
+    virtual bool allows_arming(bool from_gcs) const override { return true; };
+    virtual bool is_autopilot() const override { return false; }
+
+protected:
+
+    const char *name() const override { return "DRIFT"; }
+    const char *name4() const override { return "DRIF"; }
+
+private:
+
+    float get_throttle_assist(float velz, float pilot_throttle_scaled);
+
+};

ArduCopter/control_drift.cpp

@@ -27,9 +27,9 @@
 #endif
 
 // drift_init - initialise drift controller
-bool Copter::drift_init(bool ignore_checks)
+bool Copter::FlightMode_DRIFT::init(bool ignore_checks)
 {
-    if (position_ok() || ignore_checks) {
+    if (_copter.position_ok() || ignore_checks) {
         return true;
     }else{
         return false;
@@ -38,7 +38,7 @@ bool Copter::drift_init(bool ignore_checks)
 
 // drift_run - runs the drift controller
 // should be called at 100hz or more
-void Copter::drift_run()
+void Copter::FlightMode_DRIFT::run()
 {
     static float breaker = 0.0f;
     static float roll_input = 0.0f;
@@ -59,7 +59,7 @@ void Copter::drift_run()
     }
 
     // convert pilot input to lean angles
-    get_pilot_desired_lean_angles(channel_roll->get_control_in(), channel_pitch->get_control_in(), target_roll, target_pitch, aparm.angle_max);
+    get_pilot_desired_lean_angles(channel_roll->get_control_in(), channel_pitch->get_control_in(), target_roll, target_pitch, _copter.aparm.angle_max);
 
     // get pilot's desired throttle
     pilot_throttle_scaled = get_pilot_desired_throttle(channel_throttle->get_control_in());
@@ -108,7 +108,7 @@ void Copter::drift_run()
 }
 
 // get_throttle_assist - return throttle output (range 0 ~ 1) based on pilot input and z-axis velocity
-float Copter::get_throttle_assist(float velz, float pilot_throttle_scaled)
+float Copter::FlightMode_DRIFT::get_throttle_assist(float velz, float pilot_throttle_scaled)
 {
     // throttle assist - adjusts throttle to slow the vehicle's vertical velocity
     //      Only active when pilot's throttle is between 213 ~ 787

ArduCopter/flight_mode.cpp

@@ -103,7 +103,10 @@ bool Copter::set_mode(control_mode_t mode, mode_reason_t reason)
             break;
 
         case DRIFT:
-            success = drift_init(ignore_checks);
+            success = flightmode_drift.init(ignore_checks);
+            if (success) {
+                flightmode = &flightmode_drift;
+            }
             break;
 
         case SPORT:
@@ -212,10 +215,6 @@ void Copter::update_flight_mode()
 
     switch (control_mode) {
 
-        case DRIFT:
-            drift_run();
-            break;
-
         case SPORT:
             sport_run();
             break;
@@ -323,7 +322,6 @@ bool Copter::mode_requires_GPS()
     }
     switch (control_mode) {
         case SMART_RTL:
-        case DRIFT:
         case POSHOLD:
         case BRAKE:
         case AVOID_ADSB:
@@ -385,9 +383,6 @@ void Copter::notify_flight_mode()
 
     // set flight mode string
     switch (control_mode) {
-        case DRIFT:
-            notify.set_flight_mode_str("DRIF");
-            break;
         case SPORT:
             notify.set_flight_mode_str("SPRT");
             break;