From 16206d18ab5688ac0b88e1e31c8855e97fa1101d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20Rydg=C3=A5rd?= <hrydgard@gmail.com>
Date: Wed, 5 Aug 2026 09:48:51 +0200
Subject: [PATCH] Simplify the EmuThread API again

---
 Core/EmuThread.cpp          | 10 +++++++++-
 Qt/QtMain.cpp               |  4 ----
 SDL/SDLMain.cpp             | 32 +++++++++++++++++++++-----------
 android/jni/app-android.cpp |  6 ------
 ios/ViewController.mm       |  3 ---
 5 files changed, 30 insertions(+), 25 deletions(-)

diff --git a/Core/EmuThread.cpp b/Core/EmuThread.cpp
index b176d93f74..01c82f80ca 100644
--- a/Core/EmuThread.cpp
+++ b/Core/EmuThread.cpp
@@ -84,11 +84,19 @@ std::thread EmuThread_Start(GraphicsContext *graphicsContext, Application *appli
 // This is useful when the render thread is in control.
 void EmuThread_RequestExit() {
 	INFO_LOG(Log::System, "EmuTread_RequestExit");
-	g_emuThreadState = EmuThreadState::QUIT_REQUESTED;
+	if (g_emuThreadState == EmuThreadState::RUNNING) {
+		g_emuThreadState = EmuThreadState::QUIT_REQUESTED;
+	} else {
+		INFO_LOG(Log::System, "EmuTread_RequestExit: g_emuThreadState was not RUNNING, so not requesting exit.");
+	}
 }
 
 void EmuThread_Join(GraphicsContext *graphicsContext, std::thread &emuThread) {
 	INFO_LOG(Log::System, "EmuTread_Join");
+	if (graphicsContext->NeedsSeparateEmuThread()) {
+		EmuThread_RequestExit();
+		while (graphicsContext->ThreadFrame()) {}
+	}
 	emuThread.join();
 	emuThread = std::thread();
 	graphicsContext->ThreadEnd();
diff --git a/Qt/QtMain.cpp b/Qt/QtMain.cpp
index 4371413141..2717fe5992 100644
--- a/Qt/QtMain.cpp
+++ b/Qt/QtMain.cpp
@@ -681,10 +681,6 @@ MainUI::MainUI(QWidget *parent)
 MainUI::~MainUI() {
 	INFO_LOG(Log::System, "MainUI::Destructor");
 	if (graphicsContext->NeedsSeparateEmuThread()) {
-		EmuThread_RequestExit();
-		while (graphicsContext->ThreadFrame()) {
-			// Wait for the emu thread to finish.
-		}
 		EmuThread_Join(graphicsContext, emuThread_);
 	}
 #if defined(MOBILE_DEVICE)
diff --git a/SDL/SDLMain.cpp b/SDL/SDLMain.cpp
index 904d809c53..4fc1998704 100644
--- a/SDL/SDLMain.cpp
+++ b/SDL/SDLMain.cpp
@@ -2215,16 +2215,23 @@ int main(int argc, char *argv[]) {
 		}
 	}
 
-	const bool mainThreadIsRender = graphicsContext->NeedsSeparateEmuThread();
-	if (!mainThreadIsRender) {
-		// TODO: This shouldn't be the EmuThread, but rather RunMainLoop?
-		std::thread emuThread = EmuThread_Start(graphicsContext, new NativeApplication(), [](GraphicsContext *graphicsContext){
-			NativeFrame(graphicsContext);
-			return true;
-		});
+	const bool needsSeparateEmuThread = graphicsContext->NeedsSeparateEmuThread();
+	if (!needsSeparateEmuThread) {
 		// Vulkan mode uses this.
-		// We should only be a message pump. This allows for lower latency
-		// input events, and so on. The spawned EmuThread runs emulation and rendering.
+
+		std::thread emuThread = std::thread([&] {
+			RunMainLoop(graphicsContext, new NativeApplication(), [&](GraphicsContext *graphicsContext) {
+				NativeFrame(graphicsContext);
+				bool keepRunning = !(g_QuitRequested || g_RestartRequested);
+				if (!keepRunning) {
+					INFO_LOG(Log::System, "EmuThread was requested to exit normally.");
+				}
+				return keepRunning;
+			});
+		});
+
+		// The SDL main thread only becomes a plain message pump. This allows for lower latency
+		// input events, and so on. The spawned main thread runs emulation and rendering.
 		while (true) {
 			SDL_Event event;
 			if (SDL_WaitEventTimeout(&event, 100)) {
@@ -2251,9 +2258,11 @@ int main(int argc, char *argv[]) {
 				}
 			}
 		}
-		EmuThread_Join(graphicsContext, emuThread);
+		INFO_LOG(Log::System, "Joining main thread...");
+		emuThread.join();
 	} else {
-		std::thread emuThread = EmuThread_Start(graphicsContext, new NativeApplication(), [](GraphicsContext *graphicsContext){
+		// OpenGL mode uses this path.
+		std::thread emuThread = EmuThread_Start(graphicsContext, new NativeApplication(), [&](GraphicsContext *graphicsContext){
 			NativeFrame(graphicsContext);
 			return true;
 		});
@@ -2291,6 +2300,7 @@ int main(int argc, char *argv[]) {
 				}
 			}
 		}
+		INFO_LOG(Log::System, "Requesting render thread exit...");
 		EmuThread_Join(graphicsContext, emuThread);
 	}
 
diff --git a/android/jni/app-android.cpp b/android/jni/app-android.cpp
index 6464b5da77..d622134f9c 100644
--- a/android/jni/app-android.cpp
+++ b/android/jni/app-android.cpp
@@ -903,9 +903,6 @@ extern "C" void Java_org_ppsspp_ppsspp_NativeApp_shutdown(JNIEnv *, jclass) {
 	if (renderer_inited && graphicsContext && graphicsContext->NeedsSeparateEmuThread()) {
 		// Only used in Java EGL path.
 		INFO_LOG(Log::System, "Joining emuthread.");
-		EmuThread_RequestExit();
-		// Eat up any remaining frames.
-		while (graphicsContext->ThreadFrame()) {}
 		EmuThread_Join(graphicsContext, g_emuThread);
 
 		INFO_LOG(Log::System, "EmuThread joined.");
@@ -973,9 +970,6 @@ extern "C" jboolean Java_org_ppsspp_ppsspp_NativeRenderer_displayInit(JNIEnv * e
 		// but the only mechanism for handling lost devices seems to be that onSurfaceCreated is called again,
 		// which ends up calling displayInit.
 		INFO_LOG(Log::G3D, "NativeApp.displayInit(): Second time, joining the emuthread and starting it up again.");
-		EmuThread_RequestExit();
-		// Eat up any remaining frames.
-		while (graphicsContext->ThreadFrame()) {}
 		EmuThread_Join(graphicsContext, g_emuThread);
 
 		graphicsContext->ShutdownSurface();
diff --git a/ios/ViewController.mm b/ios/ViewController.mm
index ea03d548bf..6383d9c08d 100644
--- a/ios/ViewController.mm
+++ b/ios/ViewController.mm
@@ -92,9 +92,6 @@ PPSSPPBaseViewController *sharedViewController;
 
 - (void)requestExitGLRenderLoop {
 	_assert_(g_emuThread.joinable());
-	EmuThread_RequestExit();
-	// Eat up any remaining frames.
-	while (graphicsContext->ThreadFrame()) {}
 	EmuThread_Join(graphicsContext, g_emuThread);
 	_assert_(!g_emuThread.joinable());
 }