Add a compile time flag to disable the default HUD

The default HUD still relies on legacy OpenGL features, which makes it
incompatible with the GL core profile. A replacement involving Canvas
has been discussed before, but for now a toggle switch is enough to test
the core profile.

CMakeLists.txt

@@ -203,6 +203,7 @@ option(ENABLE_HID_INPUT  "Set to ON to build HID-based input code" ${EVENT_INPUT
 option(ENABLE_PLIB_JOYSTICK  "Set to ON to enable legacy joystick code (default)" ON)
 option(ENABLE_SWIFT      "Set to ON to build the swift module" ON)
 option(ENABLE_SENTRY     "Set to ON to build the Sentry.io crash reporting" ON)
+option(ENABLE_HUD        "Set to ON to build the default head-up display" ON)
 
 # Test-suite options.
 option(ENABLE_AUTOTESTING "Set to ON to execute the test suite after building the test_suite target (default)" ON)

src/Include/config_cmake.h.in

@@ -78,3 +78,5 @@
 #define SENTRY_API_KEY "@sentry_api_key@"
 
 #cmakedefine ENABLE_OSGXR
+
+#cmakedefine ENABLE_HUD

src/Instrumentation/CMakeLists.txt

@@ -34,17 +34,6 @@ set(SOURCES
     transponder.cxx
     turn_indicator.cxx
     vertical_speed_indicator.cxx
-    HUD/HUD.cxx
-    HUD/HUD_dial.cxx
-    HUD/HUD_gauge.cxx
-    HUD/HUD_instrument.cxx
-    HUD/HUD_label.cxx
-    HUD/HUD_ladder.cxx
-    HUD/HUD_misc.cxx
-    HUD/HUD_runway.cxx
-    HUD/HUD_scale.cxx
-    HUD/HUD_tape.cxx
-    HUD/HUD_tbi.cxx
     KLN89/kln89.cxx
     KLN89/kln89_page.cxx
     KLN89/kln89_page_act.cxx
@@ -97,8 +86,6 @@ set(HEADERS
     transponder.hxx
     turn_indicator.hxx
     vertical_speed_indicator.hxx
-    HUD/HUD.hxx
-    HUD/HUD_private.hxx
     KLN89/kln89.hxx
     KLN89/kln89_page.hxx
     KLN89/kln89_page_act.hxx
@@ -115,6 +102,26 @@ set(HEADERS
     KLN89/kln89_page_usr.hxx
     KLN89/kln89_page_vor.hxx
     KLN89/kln89_page_alt.hxx
+)
+
+if (ENABLE_HUD)
+    list(APPEND SOURCES
+        HUD/HUD.cxx
+        HUD/HUD_dial.cxx
+        HUD/HUD_gauge.cxx
+        HUD/HUD_instrument.cxx
+        HUD/HUD_label.cxx
+        HUD/HUD_ladder.cxx
+        HUD/HUD_misc.cxx
+        HUD/HUD_runway.cxx
+        HUD/HUD_scale.cxx
+        HUD/HUD_tape.cxx
+        HUD/HUD_tbi.cxx
     )
+    list(APPEND HEADERS
+        HUD/HUD.hxx
+        HUD/HUD_private.hxx
+    )
+endif()
 
 flightgear_component(Instruments "${SOURCES}" "${HEADERS}")

src/Main/fg_init.cxx

@@ -114,7 +114,9 @@
 #include <Environment/environment_mgr.hxx>
 #include <Environment/ephemeris.hxx>
 #include <FDM/fdm_shell.hxx>
+#ifdef ENABLE_HUD
 #include <Instrumentation/HUD/HUD.hxx>
+#endif
 #include <Navaids/NavDataCache.hxx>
 #include <Network/DNSClient.hxx>
 #include <Network/HTTPClient.hxx>
@@ -1081,7 +1083,9 @@ void fgCreateSubsystems(bool duringReset) {
     
     // SGSubsystemMgr::DISPLAY
     {
+#ifdef ENABLE_HUD
         mgr->add<HUD>();
+#endif
         mgr->add<flightgear::CockpitDisplayManager>();
 
         simgear::canvas::Canvas::setSystemAdapter(

src/Main/subsystemFactory.cxx

@@ -41,7 +41,9 @@
 #include <Environment/environment_mgr.hxx>
 #include <Environment/ephemeris.hxx>
 #include <Instrumentation/instrument_mgr.hxx>
-#include <Instrumentation/HUD/HUD.hxx>
+#ifdef ENABLE_HUD
+#  include <Instrumentation/HUD/HUD.hxx>
+#endif
 #include <Systems/system_mgr.hxx>
 #include <Autopilot/route_mgr.hxx>
 #include <Autopilot/autopilotgroup.hxx>
@@ -88,7 +90,9 @@ SGSubsystem* createSubsystemByName(const std::string& name)
     MAKE_SUB(Ephemeris, "ephemeris");
     MAKE_SUB(FGSystemMgr, "systems");
     MAKE_SUB(FGInstrumentMgr, "instrumentation");
+#ifdef ENABLE_HUD
     MAKE_SUB(HUD, "hud");
+#endif
     MAKE_SUB(flightgear::CockpitDisplayManager, "cockpit-displays");
     MAKE_SUB(FGRouteMgr, "route-manager");
     MAKE_SUB(FGIO, "io");

src/Viewer/renderer.cxx

@@ -96,7 +96,9 @@
 #include <GUI/gui.h>
 #include <GUI/Highlight.hxx>
 
-#include <Instrumentation/HUD/HUD.hxx>
+#ifdef ENABLE_HUD
+#  include <Instrumentation/HUD/HUD.hxx>
+#endif
 #include <Environment/precipitation_mgr.hxx>
 #include <Environment/environment_mgr.hxx>
 #include <Environment/ephemeris.hxx>
@@ -146,6 +148,7 @@ private:
   SGPropertyNode_ptr mConfigNode;
 };
 
+#ifdef ENABLE_HUD
 
 class SGHUDDrawable : public osg::Drawable {
 public:
@@ -194,6 +197,8 @@ public:
 private:
 };
 
+#endif
+
 class FGLightSourceUpdateCallback : public osg::NodeCallback {
 public:
 
@@ -726,9 +731,11 @@ FGRenderer::setupView( void )
 
     osg::Camera* guiCamera = getGUICamera(CameraGroup::getDefault());
     if (guiCamera) {
+#ifdef ENABLE_HUD
         osg::Geode* hudGeode = new osg::Geode;
         hudGeode->addDrawable(new SGHUDDrawable);
         guiCamera->addChild(hudGeode);
+#endif
 
 #if defined(HAVE_PUI)
         _puiCamera = new flightgear::PUICamera;