Merge pull request #25 from SHADE-DP/SP3-18-Events

SP3-18 SP3-108 Event/Messaging System

Ported over Events Manager from 200
Removed singleton design pattern
Removed event package design
Implemented event dynamic data

Instructions to use are in SHEventManager.h

SHADE_Engine/src/Common/SHCommonTypes.h

@@ -0,0 +1,28 @@
+/************************************************************************************//*!
+\file           SHCommonTypes.h
+\author         Tng Kah Wei, kahwei.tng, 390009620
+\par            email: kahwei.tng\@digipen.edu
+\date           Sep 8, 2022
+\brief			Contains the definitions of type alias for commonly used units for 
+                clarity and convenience.
+
+
+Copyright (C) 2022 DigiPen Institute of Technology.
+Reproduction or disclosure of this file or its contents without the prior written consent
+of DigiPen Institute of Technology is prohibited.
+*//*************************************************************************************/
+#pragma once
+
+namespace SHADE
+{
+	/*---------------------------------------------------------------------------------*/
+	/* Type Definitions                                                                */
+	/*---------------------------------------------------------------------------------*/	
+    /***********************************************************************************/
+    /*!
+      \brief
+        Type used to mark a value that is supposed to represent a size in bytes.
+    */
+    /***********************************************************************************/
+	using Byte = size_t;
+}

SHADE_Engine/src/Events/SHEvent.h

@@ -0,0 +1,22 @@
+/******************************************************************************
+ * \file    SHEvent.h
+ * \author  Loh Xiao Qi
+ * \brief   Event class declaration
+ * 
+ * \copyright Copyright (c) 2022 Digipen Institute of Technology. Reproduction
+ * or disclosure of this file or its contents without the prior written consent
+ * of Digipen Institute of Technology is prohibited.
+******************************************************************************/
+#pragma once
+
+#include "SHEventDefines.h"
+
+namespace SHADE
+{
+	struct SHEvent
+	{
+		SHEventIdentifier type;
+		SHEventDataPtr dataPtr;
+		SHEventHandle handle;
+	};
+}

SHADE_Engine/src/Events/SHEventDefines.h

@@ -0,0 +1,9 @@
+#pragma once
+#include "SHpch.h"
+
+typedef uint32_t SHEventIdentifier;
+typedef uint32_t SHEventHandle;
+typedef void* SHEventDataPtr;
+
+//Add your event identifiers here:
+constexpr SHEventIdentifier SH_EXAMPLE_EVENT{0};

SHADE_Engine/src/Events/SHEventManager.cpp

@@ -0,0 +1,107 @@
+/******************************************************************************
+ * \file    SHEventManager.cpp
+ * \author  Loh Xiao Qi
+ * \brief   Function Implmentations for SHEventManager
+ * 
+ * \copyright	Copyright (c) 2021 Digipen Institute of Technology. Reproduction
+ *						or disclosure of this file or its contents without the prior
+ *						written consent of Digipen Institute of Technology is prohibited
+ ******************************************************************************/
+#include "SHpch.h"
+#include "SHEventManager.h"
+
+namespace SHADE
+{
+	std::unordered_map<SHEventIdentifier, ResponseVec> SHEventManager::packageReceiverRegistry;
+	std::unordered_map<SHEventHandle, SHEventDataPtr> SHEventManager::dataEventMap;
+
+	SHEventHandle SHEventManager::handleCounter{ 0 };
+	
+	/****************************************************************************
+	 * \param   ListenerConstPtr - Const pointer to listener that sent event.
+	 * \param   EventType - Templated type for every type of event
+
+	 * \brief		Receives event from the listeners.
+	****************************************************************************/
+	void SHEventManager::CatchEvent(SHEvent event)
+	{
+
+		// Do something with the event
+
+		Broadcast(event);
+	}
+
+	/****************************************************************************
+	 * \param   ResponseFunction - function pointer from receiver to be passed
+	 *					into event manager to be called when events are broadcasted.
+	 * \param   SHEventIdentifier - package type that corresponding subscriber is
+	 *					subscribing to.
+
+	 * \brief   Links a function pointer from a subscriber to a particular
+	 *					package type
+	****************************************************************************/
+	void SHEventManager::SubscribeTo(SHEventIdentifier pkgType, ReceiverPtr receiver)
+	{
+		RegisterReceiverToType(pkgType, receiver);
+	}
+
+	template<typename T>
+	T* SHEventManager::BroadcastEvent(T data, SHEventIdentifier eventType)
+	{
+		SHEventDataPtr ptr = new std::byte[sizeof(data)];
+
+		std::memcpy(ptr, &data, sizeof(data));
+
+		CatchEvent(
+		{
+				eventType,
+				ptr,
+				handleCounter++
+			}
+		);
+
+		return reinterpret_cast<T*>(ptr);
+	}
+
+	/****************************************************************************
+	 * \param   ReceiverPtr - Pointer to receiver
+	 * \param   ListenerConstPtr - Const pointer to listener that receiver is
+	 *					subscribing to.
+
+	 * \brief   Registers receiver as a subscriber to listener in the registry.
+	****************************************************************************/
+	void SHEventManager::RegisterReceiverToType(
+		SHEventIdentifier pkgType, ReceiverPtr receiver)
+	{
+		if (packageReceiverRegistry.contains(pkgType))
+		{
+			packageReceiverRegistry[pkgType].emplace_back(receiver);
+		}
+		else
+		{
+			packageReceiverRegistry.emplace(pkgType, std::vector{ receiver });
+		}
+	}
+
+	/****************************************************************************
+	 * \param   ListenerConstPtr - Const pointer to listener that sent event.
+	 * \param   EventType - Event data
+
+	 * \brief		Broadcast event to all receivers that are subscribed to this
+	 *					listener.
+	****************************************************************************/
+	void SHEventManager::Broadcast(SHEvent const& event)
+	{
+		ResponseVec& receivers{ packageReceiverRegistry[event.type] };
+		for (auto& receiver : receivers)
+		{
+			receiver->Receive(event);
+		}
+
+		//auto& funcs{ ackageReceiverRegistry[event.GetType()] };
+		//for (auto func : funcs)
+		//{
+		//	func(event.GetData());
+		//}
+	}
+}

SHADE_Engine/src/Events/SHEventManager.h

@@ -0,0 +1,116 @@
+/******************************************************************************
+ * \file    SHEventManager.h
+ * \author  Loh Xiao Qi
+ * \brief   Class declaration for event manager.
+ * 
+ * \copyright Copyright (c) 2022 Digipen Institute of Technology. Reproduction
+ * or disclosure of this file or its contents without the prior written consent
+ * of Digipen Institute of Technology is prohibited.
+******************************************************************************/
+#pragma once
+
+#include "SHEvent.h"
+#include "SHEventReceiver.h"
+#include <unordered_map>
+#include <functional>
+
+/******************************************************************************
+	INSTRUCTIONS FOR USE:
+	On broadcaster side:
+		1. Create a struct/class to contain the data that you would need to send
+			 in the event.
+		2. Create unique event identifier in SHEventDefines.h, follow the example
+			 provided.
+		3. When ready to send the event, call
+			 SHEventManager::BroadcastEvent<ExampleClass>(exampleClass, EVENT_IDENTIFIER);
+
+		Headers required: SHEventManager.h
+
+	On Receiver side:
+		1. Create a function with the signature:
+			 SHEventHandle FunctionName(SHEvent);
+		2. In the init function of the class, copy the below in and replace the
+			 necessary:
+
+			 std::shared_ptr<SHEventReceiverSpec<ReceiverClass>> thisReceiver{
+				std::make_shared<SHEventReceiverSpec<ReceiverClass>>(this, &ReceiverClass::ReceiveFunction)
+			 };
+			 ReceiverPtr receiver = std::dynamic_pointer_cast<SHEventReceiver>(thisReceiver);
+			 SHEventManager::SubscribeTo(EVENT_IDENTIFIER, receiver);
+
+			 ReceiverClass is the class that the receiver is in. E.g., SHPhysicsSystem
+
+		3. Note: The EventIdentifier should match all that is defined in
+			 SHEventDefines.h so check there. When the receiver catches the event, it
+			 needs to know the struct that the broadcaster is using to cast the void*
+			 properly.
+
+		Headers required: SHEventManager.h, SHEventReceiver.h
+
+	If you have any questions/suggestions for improvement lmk.
+******************************************************************************/
+
+namespace SHADE
+{
+	using ResponseFunction = std::function<SHEventHandle(SHEvent)>;
+	using ReceiverPtr = std::shared_ptr<SHEventReceiver>;
+	using ResponseVec = std::vector<ReceiverPtr>;
+	using StaticResponseVec = std::vector<ResponseFunction>;
+
+	using EventManagerListener = std::function<void(SHEvent)>;
+
+	class SHEventManager
+	{
+	public:
+
+		/****************************************************************************
+		 * \param   ListenerConstPtr - Const pointer to listener that sent event.
+		 * \param   EventType - Templated type for every type of event
+
+		 * \brief		Receives event from the listeners.
+		****************************************************************************/
+		static void CatchEvent(SHEvent);
+
+		/****************************************************************************
+		 * \param   ResponseFunction - function pointer from receiver to be passed
+		 *					into event manager to be called when events are broadcasted.
+		 * \param   SHPackageType - package type that corresponding subscriber is
+		 *					subscribing to.
+		
+		 * \brief   Links a function pointer from a subscriber to a particular
+		 *					package type
+		****************************************************************************/
+		static void SubscribeTo(SHEventIdentifier, ReceiverPtr);
+
+		template<typename T>
+		static T* BroadcastEvent(T data, SHEventIdentifier eventType);
+
+	private:
+
+		// Registry for broadcasters and subscribers
+		static std::unordered_map<SHEventIdentifier,	ResponseVec> packageReceiverRegistry;
+		static std::unordered_map<SHEventHandle, SHEventDataPtr> dataEventMap;
+
+		static SHEventHandle handleCounter;
+
+		/****************************************************************************
+		 * \param   ListenerConstPtr - Const pointer to listener that sent event.
+		 * \param   EventType - Event data
+
+		 * \brief		Broadcast event to all receivers that are subscribed to this
+		 *					listener.
+		****************************************************************************/
+		static void Broadcast(SHEvent const&);
+
+		/****************************************************************************
+		 * \param   ReceiverPtr - Pointer to receiver
+		 * \param   ListenerConstPtr - Const pointer to listener that receiver is
+		 *					subscribing to.
+
+		 * \brief   Registers receiver as a subscriber to listener in the registry.
+		****************************************************************************/
+		static void RegisterReceiverToType(SHEventIdentifier, ReceiverPtr);
+
+	};
+
+}

SHADE_Engine/src/Events/SHEventReceiver.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include "SHEvent.h"
+
+namespace SHADE
+{
+	class SHEventReceiver
+	{
+	private:
+	public:
+		virtual void Receive(SHEvent) = 0;
+	};
+
+	template<typename T>
+	class SHEventReceiverSpec : public SHEventReceiver
+	{
+	private:
+		T* object;
+		SHEventHandle(T::*callback)(SHEvent);
+
+	public:
+		SHEventReceiverSpec(T* obj, void(T::* cb)(SHEventDataPtr))
+			:SHEventReceiver(), object{ obj }, callback{ cb }
+		{
+
+		}
+
+		void Receive(SHEvent evt) override
+		{
+			(object->*callback)(evt);
+		}
+	};
+}

SHADE_Engine/src/SHpch.h

@@ -30,5 +30,6 @@
 #include <functional>
 #include <sstream>
 #include <iomanip>
+#include <cstddef>
 
-#include "SHCommonTypes.h"
+#include "Common/SHCommonTypes.h"