ArduPlane: SET_SENSORS_OFFSETS support for third compass

ArduPlane/GCS_Mavlink.cpp

@@ -1391,17 +1391,21 @@ void GCS_MAVLINK::handleMessage(mavlink_message_t* msg)
             break;
 
         case MAV_CMD_PREFLIGHT_SET_SENSOR_OFFSETS:
-            if (is_equal(packet.param1,2.0f)) {
-                // save first compass's offsets
-                plane.compass.set_and_save_offsets(0, packet.param2, packet.param3, packet.param4);
-                result = MAV_RESULT_ACCEPTED;
-            }
-            if (is_equal(packet.param1,5.0f)) {
-                // save secondary compass's offsets
-                plane.compass.set_and_save_offsets(1, packet.param2, packet.param3, packet.param4);
-                result = MAV_RESULT_ACCEPTED;
+            {
+                uint8_t compassNumber = -1;
+                if (is_equal(packet.param1, 2.0f)) {
+                    compassNumber = 0;
+                } else if (is_equal(packet.param1, 5.0f)) {
+                    compassNumber = 1;
+                } else if (is_equal(packet.param1, 6.0f)) {
+                    compassNumber = 2;
+                }
+                if (compassNumber != (uint8_t) -1) {
+                    plane.compass.set_and_save_offsets(compassNumber, packet.param2, packet.param3, packet.param4);
+                    result = MAV_RESULT_ACCEPTED;
+                }
+                break;
             }
-            break;
 
         case MAV_CMD_COMPONENT_ARM_DISARM:
             if (is_equal(packet.param1,1.0f)) {