SITL: added is_lock_step_scheduled() API

used to fix panic on bad timing

libraries/SITL/SIM_Aircraft.cpp

@@ -330,6 +330,7 @@ void Aircraft::fill_fdm(struct sitl_fdm &fdm)
         // initialise home
         fdm.home = home;
     }
+    fdm.is_lock_step_scheduled = lock_step_scheduled;
     fdm.latitude  = location.lat * 1.0e-7;
     fdm.longitude = location.lng * 1.0e-7;
     fdm.altitude  = location.alt * 1.0e-2;

libraries/SITL/SIM_Aircraft.h

@@ -173,6 +173,7 @@ protected:
     float battery_voltage = -1.0f;
     float battery_current;
     float local_ground_level;            // ground level at local position
+    bool lock_step_scheduled;
 
     // battery model
     Battery battery;

libraries/SITL/SIM_BalanceBot.cpp

@@ -28,6 +28,7 @@ BalanceBot::BalanceBot(const char *frame_str) :
     skid_turn_rate(0.15708) // meters/sec
 {
     dcm.from_euler(0,0,0); // initial yaw, pitch and roll in radians
+    lock_step_scheduled = true;
     printf("Balance Bot Simulation Started\n");
 }
 

libraries/SITL/SIM_Blimp.cpp

@@ -28,6 +28,7 @@ Blimp::Blimp(const char *frame_str) :
 {
     frame_height = 0.0;
     ground_behavior = GROUND_BEHAVIOR_NONE;
+    lock_step_scheduled = true;
 }
 
 // calculate rotational and linear accelerations

libraries/SITL/SIM_Helicopter.cpp

@@ -52,6 +52,7 @@ Helicopter::Helicopter(const char *frame_str) :
     gas_heli = (strstr(frame_str, "-gas") != nullptr);
 
     ground_behavior = GROUND_BEHAVIOR_NO_MOVEMENT;
+    lock_step_scheduled = true;
 }
 
 /*

libraries/SITL/SIM_Multicopter.cpp

@@ -38,6 +38,7 @@ MultiCopter::MultiCopter(const char *frame_str) :
     frame_height = 0.1;
     num_motors = frame->num_motors;
     ground_behavior = GROUND_BEHAVIOR_NO_MOVEMENT;
+    lock_step_scheduled = true;
 }
 
 // calculate rotational and linear accelerations

libraries/SITL/SIM_Plane.cpp

@@ -37,7 +37,8 @@ Plane::Plane(const char *frame_str) :
     num_motors = 1;
 
     ground_behavior = GROUND_BEHAVIOR_FWD_ONLY;
-    
+    lock_step_scheduled = true;
+
     if (strstr(frame_str, "-heavy")) {
         mass = 8;
     }

libraries/SITL/SIM_QuadPlane.cpp

@@ -95,6 +95,7 @@ QuadPlane::QuadPlane(const char *frame_str) :
     frame->set_mass(mass);
 
     ground_behavior = GROUND_BEHAVIOR_NO_MOVEMENT;
+    lock_step_scheduled = true;
 }
 
 /*

libraries/SITL/SIM_Rover.cpp

@@ -41,6 +41,7 @@ SimRover::SimRover(const char *frame_str) :
     if (vectored_thrust) {
         printf("Vectored Thrust Rover Simulation Started\n");
     }
+    lock_step_scheduled = true;
 }
 
 

libraries/SITL/SIM_Sailboat.cpp

@@ -46,6 +46,7 @@ Sailboat::Sailboat(const char *frame_str) :
     sail_area(1.0)
 {
     motor_connected = (strcmp(frame_str, "sailboat-motor") == 0);
+    lock_step_scheduled = true;
 }
 
 // calculate the lift and drag as values from 0 to 1

libraries/SITL/SIM_SingleCopter.cpp

@@ -39,6 +39,7 @@ SingleCopter::SingleCopter(const char *frame_str) :
     */
     thrust_scale = (mass * GRAVITY_MSS) / hover_throttle;
     frame_height = 0.1;
+    lock_step_scheduled = true;
 }
 
 /*

libraries/SITL/SIM_Submarine.cpp

@@ -62,6 +62,7 @@ Submarine::Submarine(const char *frame_str) :
         thrusters = vectored_6dof_thrusters;
         n_thrusters = 8;
     }
+    lock_step_scheduled = true;
 }
 
 // calculate rotational and linear accelerations

libraries/SITL/SITL.h

@@ -81,6 +81,8 @@ struct sitl_fdm {
         float speed;
         float direction;
     } wind_vane_apparent;
+
+    bool is_lock_step_scheduled;
 };
 
 // number of rc output channels