From bb4fca593b0e7a74f1f271d98c404cd4bf6b5bae Mon Sep 17 00:00:00 2001
From: Alexander Bock <alexander.bock@me.com>
Date: Mon, 6 Mar 2017 15:06:54 -0500
Subject: [PATCH] Automatically register core classes on first access to
 DocumentationEngine

---
 include/openspace/documentation/documentationengine.h |  2 ++
 src/documentation/documentationengine.cpp             | 10 ++++++++--
 src/engine/openspaceengine.cpp                        |  2 --
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/include/openspace/documentation/documentationengine.h b/include/openspace/documentation/documentationengine.h
index 4841c3efc4..41400602fb 100644
--- a/include/openspace/documentation/documentationengine.h
+++ b/include/openspace/documentation/documentationengine.h
@@ -92,6 +92,8 @@ public:
 private:
     /// The list of all Documentation%s that are stored by the DocumentationEngine
     std::vector<Documentation> _documentations;
+
+    static DocumentationEngine* _instance;
 };
 
 } // namespace documentation
diff --git a/src/documentation/documentationengine.cpp b/src/documentation/documentationengine.cpp
index 2f90737a73..2f48183dd1 100644
--- a/src/documentation/documentationengine.cpp
+++ b/src/documentation/documentationengine.cpp
@@ -25,6 +25,7 @@
 #include <openspace/documentation/documentationengine.h>
 
 #include <openspace/openspace.h>
+#include <openspace/documentation/core_registration.h>
 #include <openspace/documentation/verifier.h>
 
 #include <ghoul/misc/assert.h>
@@ -48,6 +49,8 @@ namespace {
 namespace openspace {
 namespace documentation {
 
+DocumentationEngine* DocumentationEngine::_instance = nullptr;
+
 DocumentationEngine::DuplicateDocumentationException::DuplicateDocumentationException(
                     Documentation documentation)
     : ghoul::RuntimeError(fmt::format(
@@ -59,8 +62,11 @@ DocumentationEngine::DuplicateDocumentationException::DuplicateDocumentationExce
 {}
 
 DocumentationEngine& DocumentationEngine::ref() {
-    static DocumentationEngine engine;
-    return engine;
+    if (_instance == nullptr) {
+        _instance = new DocumentationEngine;
+        registerCoreClasses(*_instance);
+    }
+    return *_instance;
 }
 
 std::string generateTextDocumentation(const Documentation& d, int& indentLevel) {
diff --git a/src/engine/openspaceengine.cpp b/src/engine/openspaceengine.cpp
index e911816cec..32389d5649 100644
--- a/src/engine/openspaceengine.cpp
+++ b/src/engine/openspaceengine.cpp
@@ -229,8 +229,6 @@ void OpenSpaceEngine::create(int argc, char** argv,
     LDEBUG("Creating OpenSpaceEngine");
     _engine = new OpenSpaceEngine(std::string(argv[0]), std::move(windowWrapper));
 
-    registerCoreClasses(DocEng);
-
     // Query modules for commandline arguments
     _engine->gatherCommandlineArguments();