Add the ability to schedule scripts based on wallclock time (closes #1773)

src/scripting/scriptengine.cpp

@@ -572,6 +572,15 @@ void ScriptEngine::postSync(bool isMaster) {
             info.lastRun = now;
         }
     }
+
+    for (size_t i = 0; i < _scheduledScripts.size(); i++) {
+        const ScheduledScriptInfo& info = _scheduledScripts[i];
+        if (now > info.timestamp) {
+            runScript({ info.script });
+            _scheduledScripts.erase(_scheduledScripts.begin() + i);
+            i--;
+        }
+    }
 }
 
 void ScriptEngine::queueScript(Script script) {
@@ -636,6 +645,14 @@ void ScriptEngine::removeRepeatedScript(std::string_view identifier) {
     }
 }
 
+void ScriptEngine::scheduleScript(std::string script, double delay) {
+    double now =
+        global::sessionRecordingHandler->isSavingFramesDuringPlayback() ?
+        global::sessionRecordingHandler->currentApplicationInterpolationTime() :
+        global::windowDelegate->applicationTime();
+    _scheduledScripts.emplace_back(std::move(script), now + delay);
+}
+
 void ScriptEngine::addBaseLibrary() {
     ZoneScoped;
 
@@ -715,7 +732,8 @@ void ScriptEngine::addBaseLibrary() {
             codegen::lua::DirectoryForPath,
             codegen::lua::UnzipFile,
             codegen::lua::RegisterRepeatedScript,
-            codegen::lua::RemoveRepeatedScript
+            codegen::lua::RemoveRepeatedScript,
+            codegen::lua::ScheduleScript
         }
     };
     addLibrary(lib);

src/scripting/scriptengine_lua.inl

@@ -312,6 +312,15 @@ std::vector<std::filesystem::path> walkCommon(const std::filesystem::path& path,
     openspace::global::scriptEngine->removeRepeatedScript(identifier);
 }
 
+/**
+ * Schedules a `script` to be run in `delay` seconds. The delay is measured in wallclock
+ * time, which is seconds that occur in the real world, not in relation to the in-game
+ * time.
+ */
+[[codegen::luawrap]] void scheduleScript(std::string script, double delay) {
+    openspace::global::scriptEngine->scheduleScript(std::move(script), delay);
+}
+
 #include "scriptengine_lua_codegen.cpp"
 
 } // namespace