Add Lua functions to print cluster id (closes #704)

include/openspace/engine/wrapper/sgctwindowwrapper.h

@@ -65,6 +65,7 @@ public:
     bool hasGuiWindow() const override;
     bool isGuiWindow() const override;
     bool isMaster() const override;
+    int clusterId() const override;
     bool isUsingSwapGroups() const override;
     bool isSwapGroupMaster() const override;
 

include/openspace/engine/wrapper/windowwrapper.h

@@ -207,6 +207,13 @@ public:
      */
     virtual bool isMaster() const;
 
+    /**
+     * Returns the unique identifier of this OpenSpace instance within the current cluster
+     * configuration. If this instance is not part of a cluster, this value is always 0.
+     * \return The cluster identifier of this OpenSpace instance
+     */
+    virtual int clusterId() const;
+
     /**
     * Returns <code>true</code> if the current rendering window is using swap groups.
     */

src/engine/openspaceengine.cpp

@@ -1564,6 +1564,23 @@ scripting::LuaLibrary OpenSpaceEngine::luaLibrary() {
                 {},
                 "string, string",
                 "Removes a tag (second argument) from a scene graph node (first argument)"
+            },
+            {
+                "isMaster",
+                &luascriptfunctions::isMaster,
+                {},
+                "",
+                "Returns whether the current OpenSpace instance is the master node of a "
+                "cluster configuration. If this instance is not part of a cluster, this "
+                "function also returns 'true'."
+            },
+            {
+                "clusterId",
+                &luascriptfunctions::clusterId,
+                {},
+                "Returns the zero-based identifier for this OpenSpace instance in a "
+                "cluster configuration. If this instance is not part of a cluster, this "
+                "identifier is always 0."
             }
         },
         {

src/engine/openspaceengine_lua.inl

@@ -262,4 +262,16 @@ int downloadFile(lua_State* L) {
     return 0;
 }
 
+int isMaster(lua_State* L) {
+    ghoul::lua::checkArgumentsAndThrow(L, 0, "lua::isMaster");
+    ghoul::lua::push(L, OsEng.windowWrapper().isMaster());
+    return 1;
+}
+
+int clusterId(lua_State* L) {
+    ghoul::lua::checkArgumentsAndThrow(L, 0, "lua::clusterId");
+    ghoul::lua::push(L, OsEng.windowWrapper().clusterId());
+    return 1;
+}
+
 } // namespace openspace::luascriptfunctions

src/engine/wrapper/sgctwindowwrapper.cpp

@@ -217,6 +217,10 @@ bool SGCTWindowWrapper::isMaster() const {
     return sgct::Engine::instance()->isMaster();
 }
 
+int SGCTWindowWrapper::clusterId() const {
+    return sgct_core::ClusterManager::instance()->getThisNodeId();
+}
+
 bool SGCTWindowWrapper::isSwapGroupMaster() const {
     return sgct::Engine::instance()->getCurrentWindowPtr()->isSwapGroupMaster();
 }

src/engine/wrapper/windowwrapper.cpp

@@ -145,6 +145,10 @@ bool WindowWrapper::isMaster() const {
     return false;
 }
 
+int WindowWrapper::clusterId() const {
+    return 0;
+}
+
 bool WindowWrapper::isSwapGroupMaster() const {
     return false;
 }