AP_OSD: allow osd to be disabled

libraries/AP_OSD/AP_OSD.cpp

@@ -163,8 +163,14 @@ const AP_Param::GroupInfo AP_OSD::var_info[] = {
 
 extern const AP_HAL::HAL& hal;
 
+// singleton instance
+AP_OSD *AP_OSD::_singleton;
+
 AP_OSD::AP_OSD()
 {
+    if (_singleton != nullptr) {
+        AP_HAL::panic("AP_OSD must be singleton");
+    }
     AP_Param::setup_object_defaults(this, var_info);
     // default first screen enabled
     screen[0].enabled = 1;
@@ -176,6 +182,7 @@ AP_OSD::AP_OSD()
     osd_type.set_default(HAL_OSD_TYPE_DEFAULT);
 #endif
     previous_pwm_screen = -1;
+    _singleton = this;
 }
 
 void AP_OSD::init()
@@ -226,11 +233,14 @@ void AP_OSD::osd_thread()
 void AP_OSD::update_osd()
 {
     backend->clear();
-    stats();
-    update_current_screen();
 
-    screen[current_screen].set_backend(backend);
-    screen[current_screen].draw();
+    if (!_disable) {
+        stats();
+        update_current_screen();
+
+        screen[current_screen].set_backend(backend);
+        screen[current_screen].draw();
+    }
 
     backend->flush();
 }
@@ -386,3 +396,7 @@ void AP_OSD::set_nav_info(NavInfo &navinfo)
     // do this without a lock for now
     nav_info = navinfo;
 }
+
+AP_OSD *AP::osd() {
+    return AP_OSD::get_singleton();
+}

libraries/AP_OSD/AP_OSD.h

@@ -16,10 +16,15 @@
 
 #pragma once
 
+#include <AP_HAL/AP_HAL.h>
 #include <AP_Param/AP_Param.h>
 #include <AP_Math/AP_Math.h>
 #include <AP_BLHeli/AP_BLHeli.h>
 
+#ifndef OSD_ENABLED
+#define OSD_ENABLED 0
+#endif
+
 class AP_OSD_Backend;
 
 #define AP_OSD_NUM_SCREENS 4
@@ -196,6 +201,12 @@ public:
     AP_OSD(const AP_OSD &other) = delete;
     AP_OSD &operator=(const AP_OSD&) = delete;
 
+    // get singleton instance
+    static AP_OSD *get_singleton()
+    {
+        return _singleton;
+    }
+
     // init - perform required initialisation
     void init();
 
@@ -258,7 +269,14 @@ public:
     };
 
     void set_nav_info(NavInfo &nav_info);
-
+    // disable the display
+    void disable() {
+        _disable = true;
+    }
+    // enable the display
+    void enable() {
+        _disable = false;
+    }
 
 private:
     void osd_thread();
@@ -278,6 +296,7 @@ private:
     int8_t pre_fs_screen;
     bool was_armed;
     bool was_failsafe;
+    bool _disable;
 
     uint32_t last_update_ms;
     float last_distance_m;
@@ -286,4 +305,11 @@ private:
     float max_speed_mps;
     float max_current_a;
     float avg_current_a;
+
+    static AP_OSD *_singleton;
+};
+
+namespace AP
+{
+AP_OSD *osd();
 };