AP_Camera: add parameter CAMx_MNT_INST for associating camera with co…

…rresponding mount

libraries/AP_Camera/AP_Camera_Mount.cpp

@@ -10,7 +10,7 @@ bool AP_Camera_Mount::trigger_pic()
 {
     AP_Mount* mount = AP::mount();
     if (mount != nullptr) {
-        mount->take_picture(0);
+        mount->take_picture(get_mount_instance());
         return true;
     }
     return false;
@@ -22,7 +22,7 @@ bool AP_Camera_Mount::record_video(bool start_recording)
 {
     AP_Mount* mount = AP::mount();
     if (mount != nullptr) {
-        return mount->record_video(0, start_recording);
+        return mount->record_video(get_mount_instance(), start_recording);
     }
     return false;
 }
@@ -32,7 +32,7 @@ bool AP_Camera_Mount::set_zoom(ZoomType zoom_type, float zoom_value)
 {
     AP_Mount* mount = AP::mount();
     if (mount != nullptr) {
-        return mount->set_zoom(0, zoom_type, zoom_value);
+        return mount->set_zoom(get_mount_instance(), zoom_type, zoom_value);
     }
     return false;
 }
@@ -43,7 +43,7 @@ SetFocusResult AP_Camera_Mount::set_focus(FocusType focus_type, float focus_valu
 {
     AP_Mount* mount = AP::mount();
     if (mount != nullptr) {
-        return mount->set_focus(0, focus_type, focus_value);
+        return mount->set_focus(get_mount_instance(), focus_type, focus_value);
     }
     return SetFocusResult::FAILED;
 }
@@ -55,7 +55,7 @@ bool AP_Camera_Mount::set_tracking(TrackingType tracking_type, const Vector2f& p
 {
     AP_Mount* mount = AP::mount();
     if (mount != nullptr) {
-        return mount->set_tracking(0, tracking_type, p1, p2);
+        return mount->set_tracking(get_mount_instance(), tracking_type, p1, p2);
     }
     return false;
 }
@@ -66,7 +66,7 @@ bool AP_Camera_Mount::set_lens(uint8_t lens)
 {
     AP_Mount* mount = AP::mount();
     if (mount != nullptr) {
-        return mount->set_lens(0, lens);
+        return mount->set_lens(get_mount_instance(), lens);
     }
     return false;
 }
@@ -89,4 +89,14 @@ void AP_Camera_Mount::send_camera_settings(mavlink_channel_t chan) const
     }
 }
 
+// get correspoding mount instance for the camera
+uint8_t AP_Camera_Mount::get_mount_instance() const
+{
+    // instance 0 means default
+    if (_params.mount_instance.get() == 0) {
+        return _instance;
+    }
+    return _params.mount_instance.get() - 1;
+}
+
 #endif // AP_CAMERA_MOUNT_ENABLED

libraries/AP_Camera/AP_Camera_Mount.h

@@ -59,6 +59,9 @@ class AP_Camera_Mount : public AP_Camera_Backend
 
     // send camera settings message to GCS
     void send_camera_settings(mavlink_channel_t chan) const override;
+
+    // get correspoding mount instance for the camera
+    uint8_t get_mount_instance() const;
 };
 
 #endif // AP_CAMERA_MOUNT_ENABLED

libraries/AP_Camera/AP_Camera_Params.cpp

@@ -81,6 +81,12 @@ const AP_Param::GroupInfo AP_Camera_Params::var_info[] = {
     // @User: Standard
     AP_GROUPINFO("_OPTIONS", 10, AP_Camera_Params, options, 0),
 
+    // @Param: _MNT_INST
+    // @DisplayName: Camera Mount instance
+    // @Description: Mount instace to which camera is associated with. By default its 0 means camera and mount have identical instance numbers e.g. camera1 and mount1
+    // @User: Standard
+    AP_GROUPINFO("_MNT_INST", 11, AP_Camera_Params, mount_instance, 0),
+
     AP_GROUPEND
 
 };

libraries/AP_Camera/AP_Camera_Params.h

@@ -22,6 +22,7 @@ class AP_Camera_Params {
     AP_Int8 relay_on;           // relay value to trigger camera
     AP_Float interval_min;      // minimum time (in seconds) between shots required by camera
     AP_Int8 options;            // whether to start recording when armed and stop when disarmed
+    AP_Int8 mount_instance;     // mount instace to which camera is associated with
 
     // pin number for accurate camera feedback messages
     AP_Int8 feedback_pin;