New event-driven goodness

src/control/EventBus.hpp

@@ -27,12 +27,16 @@
 #pragma once
 
 
-#include "Event.hpp"
+#include "TimeProvider.hpp"
 
+#include <chrono>
+#include <condition_variable>
+#include <cstdint>
 #include <deque>
+#include <functional>
 #include <limits>
-#include <memory>
 #include <queue>
+#include <thread>
 
 
 namespace RPGEdit {
@@ -40,35 +44,59 @@ namespace RPGEdit {
 namespace Control {
 
 class EventBus {
-private:
-	typedef std::pair<uint64_t, std::shared_ptr<Event>> event_entry;
+public:
+	typedef std::function<void ()> Event;
+	typedef std::pair<uint64_t, Event> EventEntry;
 
-	static bool compare_events(const event_entry &e1, const event_entry &e2) {
+private:
+	static bool compare_events(const EventEntry &e1, const EventEntry &e2) {
 		return e1.first > e2.first;
 	}
 
-	std::priority_queue<event_entry, std::deque<event_entry>, bool (*)(const event_entry &, const event_entry &)> events;
+	std::priority_queue<EventEntry, std::deque<EventEntry>, bool (*)(const EventEntry &, const EventEntry &)> events;
+
+	std::mutex mutex;
+	std::condition_variable cond;
 
 public:
 	EventBus() : events(compare_events) {
 	}
 
-	void enqueue(const std::shared_ptr<Event> &event, uint64_t time) {
-		events.push(std::pair<uint64_t, std::shared_ptr<Event>>(time, event));
+	void enqueue(const Event &event, uint64_t time) {
+		std::lock_guard<std::mutex> lock(mutex);
+		events.push(EventEntry(time, event));
+		cond.notify_one();
 	}
 
-	std::pair<uint64_t, std::shared_ptr<Event>> get(uint64_t time) {
-		if (events.empty())
-			return std::make_pair<uint64_t, std::shared_ptr<Event>>(std::numeric_limits<uint64_t>::max(), nullptr);
+	EventEntry get(TimeProvider *timeProvider) {
+		std::unique_lock<std::mutex> lock(mutex);
 
-		std::pair<uint64_t, std::shared_ptr<Event>> top = events.top();
+		while (true) {
+			if (events.empty()) {
+				cond.wait(lock);
+				continue;
+			}
+
+			EventEntry top = events.top();
+			uint64_t time = timeProvider->now();
+
+			if (top.first > time) {
+				cond.wait_for(lock, std::chrono::milliseconds(top.first - time));
+				continue;
+			}
 
-		if (top.first <= time) {
 			events.pop();
 			return top;
 		}
-		else
-			return std::pair<uint64_t, std::shared_ptr<Event>>(top.first, std::shared_ptr<Event>());
+	}
+
+	uint64_t peek() {
+		std::lock_guard<std::mutex> lock(mutex);
+
+		if (events.empty())
+			return std::numeric_limits<uint64_t>::max();
+
+		return events.top().first;
 	}
 };
 

src/control/InputHandler.hpp

@@ -26,10 +26,10 @@
 
 #pragma once
 
-#include <SDL.h>
-
 #include <cstdint>
+#include <functional>
 #include <unordered_set>
+#include <vector>
 
 
 namespace RPGEdit {
@@ -37,35 +37,36 @@ namespace RPGEdit {
 namespace Control {
 
 class InputHandler {
+public:
+	typedef std::function<void (uint16_t, bool, uint64_t)> Listener;
+
 private:
+	std::vector<Listener> listeners;
+
 	std::unordered_set<uint16_t> pressedKeys;
-	std::unordered_set<uint16_t> unhandledKeys;
 
 public:
-	void keyPressed(SDL_Scancode key) {
+	void registerListener(const Listener &listener) {
+		listeners.push_back(listener);
+	}
+
+	void keyPressed(uint16_t key, uint64_t time) {
 		pressedKeys.insert(key);
-		unhandledKeys.insert(key);
+
+		for (auto &listener : listeners)
+			listener(key, true, time);
 	}
 
-	void keyReleased(SDL_Scancode key) {
+	void keyReleased(uint16_t key, uint64_t time) {
 		pressedKeys.erase(key);
+
+		for (auto &listener : listeners)
+			listener(key, false, time);
 	}
 
-	void keyHandled(SDL_Scancode key) {
-		unhandledKeys.erase(key);
-	}
-
-	void resetHandled() {
-		unhandledKeys.clear();
-	}
-
-	bool isKeyPressed(SDL_Scancode key) {
+	bool isKeyPressed(uint16_t key) {
 		return pressedKeys.count(key);
 	}
-
-	bool isKeyUnhandled(SDL_Scancode key) {
-		return unhandledKeys.count(key);
-	}
 };
 
 }

src/control/MapContext.cpp

@@ -31,8 +31,8 @@ namespace RPGEdit {
 
 namespace Control {
 
-MapContext::MapContext(ImageLoader *imageLoader0, const std::shared_ptr<const Model::Map> &map0)
-	: imageLoader(imageLoader0), map(map0) {
+MapContext::MapContext(EventBus *eventBus0, InputHandler *inputHandler0, ImageLoader *imageLoader0, const std::shared_ptr<const Model::Map> &map0)
+	: eventBus(eventBus0), inputHandler(inputHandler0), imageLoader(imageLoader0), map(map0) {
 	const std::vector<std::string> &tileset = map->getTileset();
 
 	tiles.resize(tileset.size());
@@ -43,37 +43,61 @@ MapContext::MapContext(ImageLoader *imageLoader0, const std::shared_ptr<const Mo
 
 	for (const std::shared_ptr<Model::Entity> &entity : mapEntities)
 		entities[entity->getName()] = imageLoader->get("entity/" + entity->getName());
+
+	inputHandler->registerListener(
+		[this] (uint16_t key, bool pressed, uint64_t time) {
+			if (pressed)
+				keyPressed(key, time);
+		}
+	);
 }
 
-void MapContext::advance(InputHandler *inputHandler, uint32_t ticks) {
-	uint64_t totalTicksOld = totalTicks;
-	totalTicks += ticks;
+void MapContext::movePlayer(Model::Direction dir, uint64_t time) {
+	if (map->getPlayerEntity()->hasTransition())
+		return;
 
-	unsigned advance = totalTicks - totalTicksOld;
+	map->getPlayerEntity()->move(dir, time, time+250);
 
-	while (advance) {
-		advance = map->getPlayerEntity().advance(advance);
+	eventBus->enqueue(
+		[=] {
+			map->getPlayerEntity()->finishTransition();
+			movePlayerContinue(time+250);
+		},
+		time+250
+	);
+}
 
-		if (map->getPlayerEntity().hasTransition())
+void MapContext::movePlayerContinue(uint64_t time) {
+	if (inputHandler->isKeyPressed(SDL_SCANCODE_UP))
+		movePlayer(Model::NORTH, time);
+	else if (inputHandler->isKeyPressed(SDL_SCANCODE_RIGHT))
+		movePlayer(Model::EAST, time);
+	else if (inputHandler->isKeyPressed(SDL_SCANCODE_DOWN))
+		movePlayer(Model::SOUTH, time);
+	else if (inputHandler->isKeyPressed(SDL_SCANCODE_LEFT))
+		movePlayer(Model::WEST, time);
+}
+
+
+void MapContext::keyPressed(uint16_t key, uint64_t time) {
+	switch (key) {
+	case SDL_SCANCODE_UP:
+		movePlayer(Model::NORTH, time);
 		break;
 
-		if (inputHandler->isKeyPressed(SDL_SCANCODE_UP)) {
-			map->getPlayerEntity().move(Model::NORTH, 250);
-		}
-		else if (inputHandler->isKeyPressed(SDL_SCANCODE_RIGHT)) {
-			map->getPlayerEntity().move(Model::EAST, 250);
-		}
-		else if (inputHandler->isKeyPressed(SDL_SCANCODE_DOWN)) {
-			map->getPlayerEntity().move(Model::SOUTH, 250);
-		}
-		else if (inputHandler->isKeyPressed(SDL_SCANCODE_LEFT)) {
-			map->getPlayerEntity().move(Model::WEST, 250);
-		}
-		else {
+	case SDL_SCANCODE_RIGHT:
+		movePlayer(Model::EAST, time);
 		break;
+
+	case SDL_SCANCODE_DOWN:
+		movePlayer(Model::SOUTH, time);
+		break;
+
+	case SDL_SCANCODE_LEFT:
+		movePlayer(Model::WEST, time);
 	}
 }
-}
+
 
 }
 

src/control/MapContext.hpp

@@ -26,6 +26,7 @@
 
 #pragma once
 
+#include "EventBus.hpp"
 #include "ImageLoader.hpp"
 #include "InputHandler.hpp"
 #include "../model/Map.hpp"
@@ -41,6 +42,8 @@ namespace Control {
 
 class MapContext {
 private:
+	EventBus *const eventBus;
+	InputHandler *const inputHandler;
 	ImageLoader *const imageLoader;
 
 	std::shared_ptr<const Model::Map> map;
@@ -50,13 +53,15 @@ private:
 
 	uint64_t totalTicks = 0;
 
+	void movePlayer(Model::Direction dir, uint64_t time);
+	void movePlayerContinue(uint64_t time);
+	void keyPressed(uint16_t key, uint64_t time);
+
 public:
-	MapContext(ImageLoader *imageLoader0, const std::shared_ptr<const Model::Map> &map0);
+	MapContext(EventBus *eventBus0, InputHandler *inputHandler0, ImageLoader *imageLoader0, const std::shared_ptr<const Model::Map> &map0);
 
-	void advance(InputHandler *inputHandler, unsigned ticks);
-
-	Model::Position getViewPosition() {
-		return map->getPlayerEntity().getPosition();
+	Model::Position getViewPosition(uint64_t time) {
+		return map->getPlayerEntity()->getPosition(time);
 	}
 
 	std::shared_ptr<View::MapView> initView(const std::shared_ptr<View::Window> &window) {

src/control/RPGEdit.cpp

@@ -28,62 +28,99 @@
 #include "MapContext.hpp"
 #include "../view/MapView.hpp"
 
-#include <SDL.h>
-
-
-#define MIN_FRAME_DELAY 10
-
 
 namespace RPGEdit {
 
 namespace Control {
 
-bool RPGEdit::systemIter(unsigned ticks) {
-	int timeout = 0;
+bool RPGEdit::handleSystemEvent(const SDL_Event &event) {
+	uint64_t time = timeProvider.now();
 
-	SDL_Event event;
-	if (SDL_WaitEventTimeout(&event, timeout)) {
 	switch (event.type) {
 	case SDL_KEYDOWN:
-			inputHandler.keyPressed(event.key.keysym.scancode);
+		eventBus.enqueue([=] { inputHandler.keyPressed(event.key.keysym.scancode, time); }, time);
 		break;
 
 	case SDL_KEYUP:
-			inputHandler.keyReleased(event.key.keysym.scancode);
+		eventBus.enqueue([=] { inputHandler.keyReleased(event.key.keysym.scancode, time); }, time);
 		break;
 
 	case SDL_QUIT:
 		return false;
 	}
-	}
-
-	ctx->advance(&inputHandler, ticks);
-
-	Model::Position pos = ctx->getViewPosition();
-	mapView->render(pos.x, pos.y);
 
 	return true;
 }
 
 void RPGEdit::systemLoop() {
-	uint32_t ticks1 = SDL_GetTicks();
-	uint32_t ticks2 = ticks1;
+	const int MIN_FRAME_DELAY = 10;
 
-	while (systemIter(ticks2 - ticks1)) {
-		ticks1 = ticks2;
-		ticks2 = SDL_GetTicks();
+	uint32_t lastFrameTicks = SDL_GetTicks();
+
+	while (true) {
+		uint32_t diff = SDL_GetTicks() - lastFrameTicks;
+		int timeout = std::max(MIN_FRAME_DELAY - int(diff), 0);
+
+		SDL_Event event;
+		if (SDL_WaitEventTimeout(&event, timeout)) {
+			if (!handleSystemEvent(event))
+				return;
+
+			continue;
+		}
+
+		lastFrameTicks = SDL_GetTicks();
+
+		{
+			std::unique_lock<std::mutex> lock(modelMutex);
+
+			uint64_t time = timeProvider.now();
+
+			while (time >= handledTime) {
+				modelCond.wait(lock);
+				time = timeProvider.now();
+			}
+
+			Model::Position pos = ctx->getViewPosition(time);
+			mapView->render(pos.x, pos.y, time);
+		}
+
+		SDL_RenderPresent(window->getRenderer());
+	}
+}
+
+void RPGEdit::eventLoop() {
+	while (true) {
+		EventBus::EventEntry event = eventBus.get(&timeProvider);
+
+		if (!event.second)
+			return;
+
+		{
+			std::lock_guard<std::mutex> lock(modelMutex);
+
+			event.second();
+
+			handledTime = eventBus.peek();
+			modelCond.notify_one();
+		}
 	}
 }
 
 void RPGEdit::run() {
 	std::shared_ptr<Model::Map> map = Model::Map::load("test");
 
-	ctx = std::make_shared<MapContext>(&tileLoader, map);
+	ctx = std::make_shared<MapContext>(&eventBus, &inputHandler, &tileLoader, map);
 
 	window = std::make_shared<View::Window>();
 	mapView = ctx->initView(window);
 
+	eventThread = std::thread([this] { eventLoop(); });
+
 	systemLoop();
+
+	eventBus.enqueue(EventBus::Event(), timeProvider.now());
+	eventThread.join();
 }
 
 }

src/control/RPGEdit.hpp

@@ -30,8 +30,10 @@
 #include "InputHandler.hpp"
 #include "MapContext.hpp"
 
+#include <condition_variable>
 #include <memory>
 #include <mutex>
+#include <thread>
 
 
 namespace RPGEdit {
@@ -40,6 +42,8 @@ namespace Control {
 
 class RPGEdit {
 private:
+	TimeProvider timeProvider;
+
 	EventBus eventBus;
 	InputHandler inputHandler;
 	ImageLoader tileLoader;
@@ -49,11 +53,20 @@ private:
 	std::shared_ptr<View::Window> window;
 	std::shared_ptr<View::MapView> mapView;
 
-	std::mutex modelLock;
+	std::thread eventThread;
+	std::mutex modelMutex;
+	std::condition_variable modelCond;
+	uint64_t handledTime = std::numeric_limits<uint64_t>::max();
 
-	bool systemIter(unsigned ticks);
+	void enqueueNow(const EventBus::Event &event) {
+		eventBus.enqueue(event, timeProvider.now());
+	}
+
+	bool handleSystemEvent(const SDL_Event &event);
 	void systemLoop();
 
+	void eventLoop();
+
 public:
 	void run();
 };

src/control/TimeProvider.hpp

@@ -26,16 +26,34 @@
 
 #pragma once
 
+#include <SDL.h>
+
+#include <cstdint>
+#include <mutex>
+
 
 namespace RPGEdit {
 
 namespace Control {
 
-class Event {
-public:
-	virtual void handle() = 0;
+class TimeProvider {
+private:
+	uint64_t time;
+	std::mutex mutex;
 
-	virtual ~Event() {}
+public:
+	TimeProvider() {
+		time = SDL_GetTicks();
+	}
+
+	uint64_t now() {
+		std::lock_guard<std::mutex> lock(mutex);
+
+		uint32_t ticks = SDL_GetTicks() - uint32_t(time);
+		time += ticks;
+
+		return time;
+	}
 };
 
 }

src/model/Entity.hpp

@@ -46,8 +46,8 @@ private:
 	Position pos;
 	Direction direction;
 
-	unsigned transition = 0;
-	unsigned step = 0;
+	uint64_t transitionStart = 0;
+	uint64_t transitionEnd = 0;
 
 	Position translate(Direction dir, float amount) const {
 		Position p = pos;
@@ -81,9 +81,14 @@ public:
 		return name;
 	}
 
-	Position getPosition() const {
-		if (transition)
-			return translate(direction, (float)step / transition);
+	Position getPosition(uint64_t time) const {
+		if (hasTransition())
+			if (time <= transitionStart)
+				return pos;
+			else if (time >= transitionEnd)
+				return translate(direction, 1);
+			else
+				return translate(direction, float(time-transitionStart)/float(transitionEnd-transitionStart));
 		else
 			return pos;
 	}
@@ -92,43 +97,28 @@ public:
 		return direction;
 	}
 
-	void moveTo(float newX, float newY) {
-		pos.x = newX;
-		pos.y = newY;
+	void moveTo(Position newPos) {
+		pos = newPos;
+		transitionStart = transitionEnd = 0;
 	}
 
-	void move(Direction dir, unsigned steps = 0) {
-		if (transition)
+	void move(Direction dir, uint64_t start, uint64_t end) {
+		if (hasTransition())
 			return;
 
 		direction = dir;
 
-		if (steps)
-			transition = steps;
-		else
-			pos = translate(direction, 1);
+		transitionStart = start;
+		transitionEnd = end;
+	}
+
+	void finishTransition() {
+		if (hasTransition())
+			moveTo(translate(direction, 1));
 	}
 
 	bool hasTransition() const {
-		return transition;
-	}
-
-	unsigned advance(unsigned ticks) {
-		if (!transition)
-			return ticks;
-
-		step += ticks;
-
-		if (step >= transition) {
-			ticks = step - transition;
-			transition = step = 0;
-			pos = translate(direction, 1);
-
-			return ticks;
-		}
-		else {
-			return 0;
-		}
+		return transitionEnd;
 	}
 };
 

src/model/Map.cpp

@@ -46,7 +46,7 @@ std::shared_ptr<Map> Map::load(__attribute__((unused)) const std::string &name)
 	}
 
 	map->playerEntity = std::make_shared<Entity>("square");
-	map->playerEntity->moveTo(6, 6);
+	map->playerEntity->moveTo(Model::Position{6, 6});
 
 	map->entities.push_back(map->playerEntity);
 

src/model/Map.hpp

@@ -67,8 +67,8 @@ public:
 		return entities;
 	}
 
-	Entity & getPlayerEntity() const {
-		return *playerEntity;
+	const std::shared_ptr<Entity> & getPlayerEntity() const {
+		return playerEntity;
 	}
 
 	size_t getWidth() const {

src/view/MapView.cpp

@@ -79,7 +79,7 @@ MapView::~MapView() {
 		SDL_DestroyTexture(entity.second);
 }
 
-void MapView::render(float centerX, float centerY) {
+void MapView::render(float centerX, float centerY, uint64_t time) {
 	SDL_RenderClear(window->getRenderer());
 
 	std::pair<int, int> viewport = window->getViewport();
@@ -120,7 +120,7 @@ void MapView::render(float centerX, float centerY) {
 	}
 
 	for (const std::shared_ptr<Model::Entity> &entity : map->getEntities()) {
-		Model::Position pos = entity->getPosition();
+		Model::Position pos = entity->getPosition(time);
 		Model::Direction dir = entity->getDirection();
 
 		SDL_Rect src = {
@@ -139,8 +139,6 @@ void MapView::render(float centerX, float centerY) {
 
 		SDL_RenderCopy(window->getRenderer(), entityTextures[entity->getName()], &src, &dst);
 	}
-
-	SDL_RenderPresent(window->getRenderer());
 }
 
 }

src/view/MapView.hpp

@@ -55,7 +55,7 @@ public:
 			 const std::map<std::string, SDL_Surface *> &entities);
 	~MapView();
 
-	void render(float centerX, float centerY);
+	void render(float centerX, float centerY, uint64_t time);
 };
 
 }