HAL_SITL: enable --gimbal option

instantiates a MAVLink gimbal

libraries/AP_HAL_SITL/SITL_State.cpp

@@ -89,6 +89,9 @@ void SITL_State::_sitl_setup(void)
         _update_compass(0, 0, 0);
         _update_gps(0, 0, 0, 0, 0, 0, false);
 #endif
+        if (enable_gimbal) {
+            gimbal = new Gimbal(_sitl->state);
+        }
     }
 
     if (_synthetic_clock_mode) {
@@ -312,6 +315,10 @@ void SITL_State::_fdm_input_local(void)
     // get FDM output from the model
     sitl_model->fill_fdm(_sitl->state);
 
+    if (gimbal != NULL) {
+        gimbal->update();
+    }
+
     // update simulation time
     hal.scheduler->stop_clock(_sitl->state.timestamp_us);
 

libraries/AP_HAL_SITL/SITL_State.h

@@ -22,7 +22,7 @@
 #include "../AP_OpticalFlow/AP_OpticalFlow.h"
 #include "../AP_Terrain/AP_Terrain.h"
 #include "../SITL/SITL.h"
-#include "../SITL/SIM_Multicopter.h"
+#include "../SITL/SIM_Gimbal.h"
 
 class HAL_SITL;
 
@@ -191,6 +191,10 @@ private:
     // internal SITL model
     Aircraft *sitl_model;
 
+    // simulated gimbal
+    bool enable_gimbal;
+    Gimbal *gimbal;
+
     // TCP address to connect uartC to
     const char *_client_address;
 };

libraries/AP_HAL_SITL/SITL_cmdline.cpp

@@ -41,6 +41,7 @@ void SITL_State::_usage(void)
            "\t--console          use console instead of TCP ports\n"
            "\t--instance N       set instance of SITL (adds 10*instance to all port numbers)\n"
            "\t--speedup SPEEDUP  set simulation speedup\n"
+           "\t--gimbal           enable simulated MAVLink gimbal\n"
         );
 }
 
@@ -84,7 +85,8 @@ void SITL_State::_parse_command_line(int argc, char * const argv[])
     _instance = 0;
 
     enum long_options {
-        CMDLINE_CLIENT=0
+        CMDLINE_CLIENT=0,
+        CMDLINE_GIMBAL
     };
 
     const struct GetOptLong::option options[] = {
@@ -99,6 +101,7 @@ void SITL_State::_parse_command_line(int argc, char * const argv[])
         {"home",            true,   0, 'O'},
         {"model",           true,   0, 'M'},
         {"client",          true,   0, CMDLINE_CLIENT},
+        {"gimbal",          false,  0, CMDLINE_GIMBAL},
         {0, false, 0, 0}
     };
 
@@ -145,6 +148,9 @@ void SITL_State::_parse_command_line(int argc, char * const argv[])
         case CMDLINE_CLIENT:
             _client_address = gopt.optarg;
             break;
+        case CMDLINE_GIMBAL:
+            enable_gimbal = true;
+            break;
         default:
             _usage();
             exit(1);