Make the GameGlobalShaderConstantSetter use the settings callback (8% perf improvement in game loop)

Amend the settings callback to support userdata

src/fontengine.cpp

@@ -36,7 +36,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 FontEngine* g_fontengine = NULL;
 
 /** callback to be used on change of font size setting */
-static void font_setting_changed(const std::string) {
+static void font_setting_changed(const std::string, void *userdata) {
 	g_fontengine->readSettings();
 }
 

src/game.cpp

@@ -809,15 +809,31 @@ class GameGlobalShaderConstantSetter : public IShaderConstantSetter
 	bool *m_force_fog_off;
 	f32 *m_fog_range;
 	Client *m_client;
+	bool m_fogEnabled;
 
 public:
+
+	void onSettingsChange(const std::string &name)
+	{
+		if (name == "enable_fog")
+			m_fogEnabled = g_settings->getBool("enable_fog");
+	}
+
+	static void SettingsCallback(const std::string name, void *userdata)
+	{
+		reinterpret_cast<GameGlobalShaderConstantSetter*>(userdata)->onSettingsChange(name);
+	}
+
 	GameGlobalShaderConstantSetter(Sky *sky, bool *force_fog_off,
 			f32 *fog_range, Client *client) :
 		m_sky(sky),
 		m_force_fog_off(force_fog_off),
 		m_fog_range(fog_range),
 		m_client(client)
-	{}
+	{
+		g_settings->registerChangedCallback("enable_fog", SettingsCallback, this);
+	}
+
 	~GameGlobalShaderConstantSetter() {}
 
 	virtual void onSetConstants(video::IMaterialRendererServices *services,
@@ -840,7 +856,7 @@ public:
 		// Fog distance
 		float fog_distance = 10000 * BS;
 
-		if (g_settings->getBool("enable_fog") && !*m_force_fog_off)
+		if (m_fogEnabled && !*m_force_fog_off)
 			fog_distance = *m_fog_range;
 
 		services->setPixelShaderConstant("fogDistance", &fog_distance, 1);

src/settings.cpp

@@ -965,15 +965,15 @@ void Settings::clearNoLock()
 
 
 void Settings::registerChangedCallback(std::string name,
-	setting_changed_callback cbf)
+	setting_changed_callback cbf, void *userdata)
 {
-	m_callbacks[name].push_back(cbf);
+	m_callbacks[name].push_back(std::make_pair(cbf,userdata));
 }
 
 
 void Settings::doCallbacks(const std::string name)
 {
-	std::vector<setting_changed_callback> tempvector;
+	std::vector<std::pair<setting_changed_callback,void*> > tempvector;
 	{
 		JMutexAutoLock lock(m_mutex);
 		if (m_callbacks.find(name) != m_callbacks.end())
@@ -982,9 +982,9 @@ void Settings::doCallbacks(const std::string name)
 		}
 	}
 
-	std::vector<setting_changed_callback>::iterator iter;
+	std::vector<std::pair<setting_changed_callback, void*> >::iterator iter;
 	for (iter = tempvector.begin(); iter != tempvector.end(); iter++)
 	{
-		(*iter)(name);
+		(iter->first)(name,iter->second);
 	}
 }

src/settings.h

@@ -32,7 +32,7 @@ class Settings;
 struct NoiseParams;
 
 /** function type to register a changed callback */
-typedef void (*setting_changed_callback)(const std::string);
+typedef void (*setting_changed_callback)(const std::string, void *userdata);
 
 enum ValueType {
 	VALUETYPE_STRING,
@@ -204,7 +204,7 @@ public:
 	void clear();
 	void updateValue(const Settings &other, const std::string &name);
 	void update(const Settings &other);
-	void registerChangedCallback(std::string name, setting_changed_callback cbf);
+	void registerChangedCallback(std::string name, setting_changed_callback cbf, void *userdata = NULL);
 
 private:
 
@@ -215,7 +215,7 @@ private:
 
 	std::map<std::string, SettingsEntry> m_settings;
 	std::map<std::string, SettingsEntry> m_defaults;
-	std::map<std::string, std::vector<setting_changed_callback> > m_callbacks;
+	std::map<std::string, std::vector<std::pair<setting_changed_callback,void*> > > m_callbacks;
 	// All methods that access m_settings/m_defaults directly should lock this.
 	mutable JMutex m_mutex;
 };