Creating the game loop

lib/wal/sources/Wal.cpp

@@ -5,8 +5,11 @@
 #include <chrono>
 #include "Wal.hpp"
 
+using namespace std::chrono_literals;
+
 namespace WAL
 {
+	std::chrono::nanoseconds WAL::_timestep = 8ms;
 
 	SceneManager &WAL::getSceneManger()
 	{
@@ -16,12 +19,49 @@ namespace WAL
 	void WAL::run()
 	{
 		auto lastTick = std::chrono::steady_clock::now();
+		std::chrono::nanoseconds dtime(0);
 
 		while (!this->_shouldClose) {
 			auto now = std::chrono::steady_clock::now();
-			auto dtime = now - lastTick;
+			dtime += now - lastTick;
 			lastTick = now;
-			// see https://gist.github.com/mariobadr/673bbd5545242fcf9482
+
+			this->_update(dtime);
+			while (dtime > WAL::_timestep) {
+				dtime -= WAL::_timestep;
+				this->_fixedUpdate();
+			}
+			this->_renderer->render();
+		}
+	}
+
+	void WAL::_update(std::chrono::nanoseconds dtime)
+	{
+		auto &entities = this->_scenes.getCurrent().getEntities();
+
+		for (auto &system : this->_systems) {
+			for (auto &entity : entities) {
+				auto &cmp = system->getComponent();
+				if (!entity.hasComponent(cmp))
+					continue;
+				// TODO handle dependencies.
+				system->onUpdate(entity, dtime);
+			}
+		}
+	}
+
+	void WAL::_fixedUpdate()
+	{
+		auto &entities = this->_scenes.getCurrent().getEntities();
+
+		for (auto &system : this->_systems) {
+			for (auto &entity : entities) {
+				auto &cmp = system->getComponent();
+				if (!entity.hasComponent(cmp))
+					continue;
+				// TODO handle dependencies.
+				system->onFixedUpdate(entity);
+			}
 		}
 	}
 }