Windows: Show instance counter only with peers.

Core/Instance.cpp

@@ -105,6 +105,14 @@ static bool UpdateInstanceCounter(void (*callback)(volatile InstanceInfo *)) {
 #endif
 }
 
+int GetInstancePeerCount() {
+	static int c = 0;
+	UpdateInstanceCounter([](volatile InstanceInfo *buf) {
+		c = buf->total;
+	});
+	return c;
+}
+
 // Get current number of instance of PPSSPP running.
 // Must be called only once during init.
 void InitInstanceCounter() {

Core/Instance.h

@@ -25,6 +25,7 @@ extern uint8_t PPSSPP_ID;
 
 void InitInstanceCounter();
 void ShutdownInstanceCounter();
+int GetInstancePeerCount();
 
 inline bool IsFirstInstance() {
 	return PPSSPP_ID == 1;

Windows/MainWindow.cpp

@@ -46,6 +46,7 @@
 #include "Core/Config.h"
 #include "Core/ConfigValues.h"
 #include "Core/Debugger/SymbolMap.h"
+#include "Core/Instance.h"
 #include "Core/MIPS/JitCommon/JitCommon.h"
 #include "Core/MIPS/JitCommon/JitBlockCache.h"
 #include "Windows/InputBox.h"
@@ -466,7 +467,11 @@ namespace MainWindow
 
 	void UpdateWindowTitle() {
 		// Seems to be fine to call now since we use a UNICODE build...
-		SetWindowText(hwndMain, windowTitle.c_str());
+		std::wstring title = windowTitle;
+		if (PPSSPP_ID >= 1 && GetInstancePeerCount() > 1) {
+			title.append(ConvertUTF8ToWString(StringFromFormat(" (instance: %d)", (int)PPSSPP_ID)));
+		}
+		SetWindowText(hwndMain, title.c_str());
 	}
 
 	void SetWindowTitle(const wchar_t *title) {
@@ -708,6 +713,7 @@ namespace MainWindow
 
 		case WM_ACTIVATE:
 			{
+				UpdateWindowTitle();
 				bool pause = true;
 				if (wParam == WA_ACTIVE || wParam == WA_CLICKACTIVE) {
 					WindowsRawInput::GainFocus();
@@ -741,6 +747,10 @@ namespace MainWindow
 			}
 			break;
 
+		case WM_SETFOCUS:
+			UpdateWindowTitle();
+			break;
+
 		case WM_ERASEBKGND:
 			// This window is always covered by DisplayWindow. No reason to erase.
 			return 1;

Windows/WindowsHost.cpp

@@ -170,9 +170,7 @@ void WindowsHost::SetWindowTitle(const char *message) {
 #ifdef _DEBUG
 	winTitle.append(L" (debug)");
 #endif
-	if (PPSSPP_ID >= 1) {
-		winTitle.append(ConvertUTF8ToWString(StringFromFormat(" (instance: %d)", (int)PPSSPP_ID)));
-	}
+	lastTitle_ = winTitle;
 
 	MainWindow::SetWindowTitle(winTitle.c_str());
 	PostMessage(mainWindow_, MainWindow::WM_USER_WINDOW_TITLE_CHANGED, 0, 0);
@@ -194,6 +192,12 @@ void WindowsHost::ShutdownSound() {
 
 void WindowsHost::UpdateUI() {
 	PostMessage(mainWindow_, MainWindow::WM_USER_UPDATE_UI, 0, 0);
+
+	int peers = GetInstancePeerCount();
+	if (PPSSPP_ID >= 1 && peers != lastNumInstances_) {
+		lastNumInstances_ = peers;
+		PostMessage(mainWindow_, MainWindow::WM_USER_WINDOW_TITLE_CHANGED, 0, 0);
+	}
 }
 
 void WindowsHost::UpdateMemView() {

Windows/WindowsHost.h

@@ -73,6 +73,8 @@ private:
 	HWND mainWindow_;
 	GraphicsContext *gfx_ = nullptr;
 	size_t numDinputDevices_ = 0;
+	std::wstring lastTitle_;
+	int lastNumInstances_ = 0;
 
 	std::list<std::unique_ptr<InputDevice>> input;
 };