Create an AsyncEvent

include/simpleengine/async_event.h

@@ -0,0 +1,74 @@
+//
+// Created by SeanOMik on 3/12/2021.
+// Github: https://github.com/SeanOMik
+// Email: seanomik@gmail.com
+//
+
+#ifndef SIMPLEENGINE_ASYNC_EVENT_H
+#define SIMPLEENGINE_ASYNC_EVENT_H
+
+#include "event.h"
+
+#include <functional>
+#include <future>
+#include <thread>
+#include <iostream>
+
+namespace simpleengine {
+    class AsyncEvent : public simpleengine::Event {
+    public:
+        explicit AsyncEvent(sf::RenderWindow* window = nullptr) : simpleengine::Event(window) {
+            update_thread = std::thread( [this]() {
+                while (!quit) {
+                    std::unique_lock<std::mutex> unique_lock(mutex);
+                    cond_var.wait(unique_lock);
+
+                    // After waiting check if we're quiting and if we need to stop this thread.
+                    if (quit) break;
+            
+                    AsyncUpdate(tick_delta_time);
+                }
+            });
+        }
+
+        virtual ~AsyncEvent() {
+            quit = true;
+
+            // Notify the async updating thread that we're quiting.
+            {
+                std::unique_lock<std::mutex> unique_lock(mutex);
+                cond_var.notify_all();
+            }
+
+            // Quit the async updating thread if its still running.
+            if (update_thread.joinable()) {
+                update_thread.join();
+            }
+        };
+
+        const bool& WantsToQuit() {
+            return quit;
+        }
+
+        // Abstract methods
+        virtual void CheckForQuit() = 0; // Ran every Update to check if we're gonna quit.
+        virtual void Quiting() {} // Ran when a State is about to be destroyed.
+        
+        virtual void AsyncUpdate(const float delta_time) = 0;
+
+        virtual void Update(const float& delta_time) final {
+            std::unique_lock<std::mutex> unique_lock(mutex);
+            tick_delta_time = delta_time;
+            cond_var.notify_all();
+        }
+
+        virtual void Render(sf::RenderTarget* target) = 0;
+    protected:
+        std::mutex mutex;
+        std::condition_variable cond_var;
+        std::thread update_thread;
+        float tick_delta_time;
+    };
+}
+
+#endif //SIMPLEENGINE_ASYNC_EVENT_H