Implement the new shutdown path for libretro too

libretro/LibretroGLContext.cpp

@@ -42,3 +42,7 @@ void LibretroGLContext::DestroyDrawContext() {
 	LibretroHWRenderContext::DestroyDrawContext();
 	renderManager_ = nullptr;
 }
+
+void LibretroGLContext::NotifyEmuThreadExit() {
+   renderManager_->NotifyEmuThreadExit();
+}

libretro/LibretroGLContext.h

@@ -27,12 +27,15 @@ public:
 	}
 
 	void ThreadStart() override { renderManager_->ThreadStart(draw_); }
-	bool ThreadFrame(bool waitIfEmpty) override { return renderManager_->ThreadFrame(waitIfEmpty); }
+	bool ThreadFrame() override { return renderManager_->ThreadFrame(); }
 	void ThreadEnd() override { renderManager_->ThreadEnd(); }
 
 	GPUCore GetGPUCore() override { return GPUCORE_GLES; }
 	const char *Ident() override { return "OpenGL"; }
 
+   // Call from emu thread
+   void NotifyEmuThreadExit() override;
+
 private:
 	GLRenderManager *renderManager_ = nullptr;
 	bool glewInitDone = false;

libretro/LibretroGLCoreContext.cpp

@@ -44,3 +44,7 @@ void LibretroGLCoreContext::DestroyDrawContext() {
 	LibretroHWRenderContext::DestroyDrawContext();
 	renderManager_ = nullptr;
 }
+
+void LibretroGLCoreContext::NotifyEmuThreadExit() {
+   renderManager_->NotifyEmuThreadExit();
+}

libretro/LibretroGLCoreContext.h

@@ -21,9 +21,12 @@ public:
 	}
 
 	void ThreadStart() override { renderManager_->ThreadStart(draw_); }
-	bool ThreadFrame(bool waitIfEmpty) override { return renderManager_->ThreadFrame(waitIfEmpty); }
+	bool ThreadFrame() override { return renderManager_->ThreadFrame(); }
 	void ThreadEnd() override { renderManager_->ThreadEnd(); }
 
+   // Call from emu thread
+   void NotifyEmuThreadExit() override;
+
 	GPUCore GetGPUCore() override { return GPUCORE_GLES; }
 	const char *Ident() override { return "OpenGL Core"; }
 

libretro/LibretroGraphicsContext.h

@@ -96,9 +96,7 @@ extern retro_hw_context_type backend;
 
 enum class EmuThreadState {
 	DISABLED,
-	START_REQUESTED,
 	RUNNING,
-	PAUSE_REQUESTED,
 	PAUSED,
 	QUIT_REQUESTED,
 	STOPPED,

libretro/libretro.cpp

@@ -1384,34 +1384,32 @@ namespace Libretro {
       for (;;) {
          switch ((EmuThreadState)emuThreadState)
          {
-            case EmuThreadState::START_REQUESTED:
-               emuThreadState = EmuThreadState::RUNNING;
-               [[fallthrough]];
             case EmuThreadState::RUNNING:
                EmuFrame();
                break;
-            case EmuThreadState::PAUSE_REQUESTED:
-               emuThreadState = EmuThreadState::PAUSED;
-               [[fallthrough]];
             case EmuThreadState::PAUSED:
                sleep_ms(1, "libretro-paused");
                break;
-            default:
             case EmuThreadState::QUIT_REQUESTED:
+               ctx->NotifyEmuThreadExit();
                emuThreadState = EmuThreadState::STOPPED;
                return;
+            default:
+               _dbg_assert_(false);
+               return;
          }
       }
+      // Unreachable
    }
 
    void EmuThreadStart() {
       EmuThreadState state = emuThreadState;
       bool wasPaused = state == EmuThreadState::PAUSED;
 
-      if (state == EmuThreadState::RUNNING || state == EmuThreadState::START_REQUESTED || (emuThread.joinable() && !wasPaused))
+      if (state == EmuThreadState::RUNNING || (emuThread.joinable() && !wasPaused))
          return;
 
-      emuThreadState = EmuThreadState::START_REQUESTED;
+      emuThreadState = EmuThreadState::RUNNING;
 
       if (!wasPaused)
       {
@@ -1426,6 +1424,9 @@ namespace Libretro {
 
       emuThreadState = EmuThreadState::QUIT_REQUESTED;
 
+      // Eat remaining frames.
+      while (ctx->ThreadFrame()) {}
+
       emuThread.join();
       emuThread = std::thread();
       ctx->ThreadEnd();
@@ -1435,7 +1436,7 @@ namespace Libretro {
       if (emuThreadState != EmuThreadState::RUNNING)
          return;
 
-      emuThreadState = EmuThreadState::PAUSE_REQUESTED;
+      emuThreadState = EmuThreadState::PAUSED;
 
       // Is this safe?
       ctx->ThreadFrame(); // Eat 1 frame
@@ -1709,8 +1710,7 @@ void retro_run(void) {
 
    // Handle thread pumping.
    if (useEmuThread) {
-      if (emuThreadState == EmuThreadState::PAUSED ||
-          emuThreadState == EmuThreadState::PAUSE_REQUESTED) {
+      if (emuThreadState == EmuThreadState::PAUSED) {
          VsyncSwapIntervalDetect();
          ctx->SwapBuffers();
          return;