Mount_Backend: add backend class

libraries/AP_Mount/AP_Mount_Backend.h

@@ -0,0 +1,66 @@
+// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
+/*
+   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/>.
+ */
+
+/*
+  Mount driver backend class. Each supported mount type
+  needs to have an object derived from this class.
+ */
+
+#ifndef __AP_MOUNT_BACKEND_H__
+#define __AP_MOUNT_BACKEND_H__
+
+#include <AP_Common.h>
+#include <AP_Mount.h>
+
+class AP_Mount_Backend
+{
+public:
+    // Constructor
+    AP_Mount_Backend(AP_Mount &frontend, uint8_t instance) :
+        _frontend(frontend),
+        _instance(instance)
+    {}
+
+    // Virtual destructor
+    virtual ~AP_Mount_Backend(void) {}
+
+    // init - performs any required initialisation for this instance
+    virtual void init() = 0;
+
+    // update mount position - should be called periodically
+    virtual void update() = 0;
+
+    // has_pan_control - returns true if this mount can control it's pan (required for multicopters)
+    virtual bool has_pan_control() const = 0;
+
+    // set_roi_target - sets target location that mount should attempt to point towards
+    virtual void set_roi_target(const struct Location &target_loc) = 0;
+
+    // configure_msg - process MOUNT_CONFIGURE messages received from GCS
+    virtual void configure_msg(mavlink_message_t* msg) {};
+
+    // control_msg - process MOUNT_CONTROL messages received from GCS
+    virtual void control_msg(mavlink_message_t* msg) {};
+
+    // status_msg - called to allow mounts to send their status to GCS via MAVLink
+    virtual void status_msg(mavlink_channel_t chan) {};
+
+protected:
+    AP_Mount    &_frontend; // reference to the front end which holds parameters
+    uint8_t     _instance;  // this instance's number
+};
+
+#endif // __AP_MOUNT_BACKEND_H__