(NDK) Added Listener component and system

Former-commit-id: 0553c4ad9a7e33608e9ab91bd4ca8812272a6293

SDK/src/NDK/Systems/ListenerSystem.cpp

@@ -0,0 +1,40 @@
+// Copyright (C) 2015 Jérôme Leclercq
+// This file is part of the "Nazara Development Kit"
+// For conditions of distribution and use, see copyright notice in Prerequesites.hpp
+
+#include <NDK/Systems/ListenerSystem.hpp>
+#include <Nazara/Audio/Audio.hpp>
+#include <NDK/Components/ListenerComponent.hpp>
+#include <NDK/Components/NodeComponent.hpp>
+
+namespace Ndk
+{
+	ListenerSystem::ListenerSystem()
+	{
+		Requires<ListenerComponent, NodeComponent>();
+	}
+
+	void ListenerSystem::Update(float elapsedTime)
+	{
+		unsigned int activeListenerCount = 0;
+
+		for (const Ndk::EntityHandle& entity : GetEntities())
+		{
+			// Le listener est-il actif ?
+			const ListenerComponent& listener = entity->GetComponent<ListenerComponent>();
+			if (!listener.IsActive())
+				continue;
+
+			const NodeComponent& node = entity->GetComponent<NodeComponent>();
+			NzAudio::SetListenerPosition(node.GetPosition(nzCoordSys_Global));
+			NzAudio::SetListenerRotation(node.GetRotation(nzCoordSys_Global));
+
+			activeListenerCount++;
+		}
+
+		if (activeListenerCount > 1)
+			NazaraWarning(NzString::Number(activeListenerCount) + " listeners were active in the same update loop");
+	}
+
+	SystemIndex ListenerSystem::systemIndex;
+}