From c8bfdbd3b824fdd71bca1335a145aa19c42df1db Mon Sep 17 00:00:00 2001
From: Daniel Karbach <daniel.karbach@localhorst.tv>
Date: Mon, 6 Aug 2012 15:55:49 +0200
Subject: [PATCH] delayed state pushing/popping till the end of each loop

---
 src/app/Application.cpp | 42 +++++++++++++++++++++++++++--------------
 src/app/Application.h   | 24 +++++++++++++----------
 2 files changed, 42 insertions(+), 24 deletions(-)

diff --git a/src/app/Application.cpp b/src/app/Application.cpp
index d3b00a1..19aa06a 100644
--- a/src/app/Application.cpp
+++ b/src/app/Application.cpp
@@ -16,28 +16,41 @@ namespace app {
 Application::Application(sdl::InitScreen *screen, State *initialState)
 : screen(screen)
 , states()
-, last(SDL_GetTicks()) {
+, last(SDL_GetTicks())
+, toPop(0) {
 	assert(screen && "cannot create application without screen");
 	assert(initialState && "cannot create application without initial state");
 	RealPushState(initialState);
 }
 
-Application::~Application(void) {
+Application::~Application() {
 	PopAllStates();
 }
 
 
-State *Application::CurrentState(void) {
+State *Application::CurrentState() {
 	return states.top();
 }
 
+void Application::UpdateState() {
+	while (toPop > 0) {
+		RealPopState();
+		--toPop;
+	}
+	while (!toPush.empty()) {
+		State *s(toPush.front());
+		toPush.pop();
+		RealPushState(s);
+	}
+}
+
 void Application::ChangeState(State *s) {
-	RealPopState();
-	RealPushState(s);
+	PopState();
+	PushState(s);
 }
 
 void Application::PushState(State *s) {
-	RealPushState(s);
+	toPush.push(s);
 }
 
 void Application::RealPushState(State *s) {
@@ -45,35 +58,35 @@ void Application::RealPushState(State *s) {
 	s->EnterState(*this, screen->Screen());
 }
 
-void Application::PopState(void) {
-	RealPopState();
+void Application::PopState() {
+	++toPop;
 }
 
-void Application::RealPopState(void) {
+void Application::RealPopState() {
 	if (states.empty()) return;
 	states.top()->ExitState();
 	delete states.top();
 	states.pop();
 }
 
-void Application::Quit(void) {
+void Application::Quit() {
 	PopAllStates();
 }
 
-void Application::PopAllStates(void) {
+void Application::PopAllStates() {
 	while (!states.empty()) {
 		RealPopState();
 	}
 }
 
 
-void Application::Run(void) {
+void Application::Run() {
 	while (CurrentState()) {
 		Loop();
 	}
 }
 
-void Application::Loop(void) {
+void Application::Loop() {
 	Uint32 now(SDL_GetTicks());
 	Uint32 deltaT(now - last);
 	if (deltaT > 34) deltaT = 34;
@@ -83,10 +96,11 @@ void Application::Loop(void) {
 	Render();
 
 	last = now;
+	UpdateState();
 }
 
 
-void Application::HandleEvents(void) {
+void Application::HandleEvents() {
 	if (!CurrentState()) return;
 	input.ResetInteractiveState();
 	SDL_Event event;
diff --git a/src/app/Application.h b/src/app/Application.h
index f70dd69..dcc5e00 100644
--- a/src/app/Application.h
+++ b/src/app/Application.h
@@ -12,6 +12,7 @@
 #include "../sdl/InitScreen.h"
 
 #include <stack>
+#include <queue>
 #include <SDL.h>
 
 
@@ -23,39 +24,42 @@ class Application {
 
 public:
 	Application(sdl::InitScreen *screen, State *initialState);
-	~Application(void);
+	~Application();
 private:
 	Application(const Application &);
 	Application &operator =(const Application &);
 
 public:
-	void Run(void);
-	void Loop(void);
+	void Run();
+	void Loop();
 
 public:
 	void ChangeState(State *);
 	void PushState(State *);
-	void PopState(void);
-	void Quit(void);
+	void PopState();
+	void Quit();
 	Input &Buttons() { return input; }
 	const Input &Buttons() const { return input; }
 
 private:
-	State *CurrentState(void);
+	State *CurrentState();
+	void UpdateState();
 	void RealPushState(State *);
-	void RealPopState(void);
-	void PopAllStates(void);
+	void RealPopState();
+	void PopAllStates();
 
 private:
-	void HandleEvents(void);
+	void HandleEvents();
 	void UpdateWorld(Uint32 deltaT);
-	void Render(void);
+	void Render();
 
 private:
 	sdl::InitScreen *screen;
 	std::stack<State *> states;
+	std::queue<State *> toPush;
 	Input input;
 	Uint32 last;
+	int toPop;
 
 };
 
-- 
2.39.2