Added scene selector in the SettingsEngine, in the GUI under Global Properties.

Has placeholder functionality for what's coming in the next commit.

src/engine/settingsengine.cpp

@@ -25,17 +25,57 @@
 #include <openspace/engine/settingsengine.h>
 
 #include <openspace/engine/openspaceengine.h>
+#include <openspace/engine/configurationmanager.h>
 #include <openspace/engine/wrapper/windowwrapper.h>
+#include <openspace/scene/scene.h>
+
+#include <ghoul/ghoul.h>
+#include <ghoul/filesystem/filesystem.h>
 
 namespace openspace {
 
-SettingsEngine::SettingsEngine() :
-    _eyeSeparation("eyeSeparation", "Eye Separation" , 0.f, 0.f, 10.f)
+SettingsEngine::SettingsEngine()
+    : _eyeSeparation("eyeSeparation", "Eye Separation" , 0.f, 0.f, 10.f)
+    , _scenes("scenes", "Scene", properties::OptionProperty::DisplayType::DROPDOWN)
 {
+    setName("Global Properties");
+}
+
+void SettingsEngine::initialize() {
+    initEyeSeparation();
+    initSceneFiles();
+}
+
+
+void SettingsEngine::initEyeSeparation() {
     addProperty(_eyeSeparation);
-    setName("Global");
+
+    // Set interaction to change the window's (SGCT's) eye separation
     _eyeSeparation.onChange(
-        [this](){ OsEng.windowWrapper().setEyeSeparationDistance(_eyeSeparation); });
+        [this]() { OsEng.windowWrapper().setEyeSeparationDistance(_eyeSeparation); });
+}
+
+void SettingsEngine::initSceneFiles() {
+    addProperty(_scenes);
+
+    // Load all matching files in the Scene
+    // TODO: match regex with either with new ghoul readFiles or local code
+    std::string sceneDir = "${SCENE}";
+    std::vector<std::string> scenes = ghoul::filesystem::Directory(sceneDir).readFiles();
+    for (std::size_t i = 0; i < scenes.size(); ++i) {
+        _scenes.addOption(i, scenes[i]);
+    }
+
+    // Set interaction to change ConfigurationManager and schedule the load
+    _scenes.onChange(
+        [this]() {
+            std::string sceneFile = _scenes.getDescriptionByValue(_scenes);
+            OsEng.configurationManager().setValue(
+                ConfigurationManager::KeyConfigScene, sceneFile);
+            std::cout << "For a relatively atomic commit, just pretending to load "
+                << sceneFile << std::endl;
+        }
+    );
 }
 
 }