From 3c50e995eee993c62e21dff69efebf5811571254 Mon Sep 17 00:00:00 2001
From: BearOso <bearoso@gmail.com>
Date: Fri, 24 Mar 2023 14:39:31 -0500
Subject: [PATCH] Win32: Allow the Vulkan driver to fail at the loader stage.

---
 vulkan/vulkan_context.cpp | 31 ++++++++++++++++++++-----------
 win32/win32_display.cpp   | 36 ++++++++++++++++++++++++------------
 2 files changed, 44 insertions(+), 23 deletions(-)

diff --git a/vulkan/vulkan_context.cpp b/vulkan/vulkan_context.cpp
index 1c5b4a6b..1166e0d5 100644
--- a/vulkan/vulkan_context.cpp
+++ b/vulkan/vulkan_context.cpp
@@ -12,17 +12,6 @@ static std::unique_ptr<vk::DynamicLoader> dl;
 
 Context::Context()
 {
-    if (!dl)
-    {
-        dl = std::make_unique<vk::DynamicLoader>();
-        if (!dl->success())
-            return;
-    }
-
-    auto vkGetInstanceProcAddr =
-        dl->getProcAddress<PFN_vkGetInstanceProcAddr>("vkGetInstanceProcAddr");
-
-    VULKAN_HPP_DEFAULT_DISPATCHER.init(vkGetInstanceProcAddr);
 }
 
 Context::~Context()
@@ -44,8 +33,28 @@ Context::~Context()
     device.destroy();
 }
 
+static bool load_loader()
+{
+    if (dl)
+        return true;
+
+    dl = std::make_unique<vk::DynamicLoader>();
+    if (!dl->success())
+    {
+        dl.reset();
+        return false;
+    }
+
+    auto vkGetInstanceProcAddr =
+        dl->getProcAddress<PFN_vkGetInstanceProcAddr>("vkGetInstanceProcAddr");
+
+    VULKAN_HPP_DEFAULT_DISPATCHER.init(vkGetInstanceProcAddr);
+    return true;
+}
+
 static vk::UniqueInstance create_instance_preamble(const char *wsi_extension)
 {
+    load_loader();
     if (!dl || !dl->success())
         return vk::UniqueInstance();
 
diff --git a/win32/win32_display.cpp b/win32/win32_display.cpp
index 1252f083..09ad97ca 100644
--- a/win32/win32_display.cpp
+++ b/win32/win32_display.cpp
@@ -98,15 +98,6 @@ void WinChangeWindowSize(unsigned int newWidth, unsigned int newHeight)
 	S9xDisplayOutput->ChangeRenderSize(newWidth,newHeight);
 }
 
-static void FlushMessageQueue()
-{
-	for (MSG msg; PeekMessage(&msg, GUI.hWnd, 0, 0, PM_NOREMOVE);)
-	{
-		GetMessage(&msg, GUI.hWnd, 0, 0);
-		DispatchMessage(&msg);
-	}
-}
-
 /*  WinDisplayReset
 initializes the currently selected display output and
 reinitializes the core graphics rendering
@@ -115,10 +106,10 @@ returns true if successful, false otherwise
 */
 bool WinDisplayReset(void)
 {
+	const TCHAR* driverNames[] = { TEXT("DirectDraw"), TEXT("Direct3D"), TEXT("OpenGL"), TEXT("Vulkan") };
 	static bool VulkanUsed = false;
 	static bool OpenGLUsed = false;
 	S9xDisplayOutput->DeInitialize();
-	FlushMessageQueue();
 
 	switch(GUI.outputMethod) {
 		default:
@@ -137,7 +128,6 @@ bool WinDisplayReset(void)
 				break;
 			}
 			S9xDisplayOutput = &OpenGL;
-			OpenGLUsed = true;
 			break;
 		case VULKAN:
 			if (OpenGLUsed)
@@ -146,7 +136,6 @@ bool WinDisplayReset(void)
 				break;
 			}
 			S9xDisplayOutput = &VulkanDriver;
-			VulkanUsed = true;
 			break;
 	}
 
@@ -155,10 +144,33 @@ bool WinDisplayReset(void)
 	if (!initialized) {
 		S9xDisplayOutput->DeInitialize();
 		Sleep(500);
+
+		auto oldDriverName = driverNames[GUI.outputMethod];
+
+		if (GUI.outputMethod == VULKAN)
+		{
+			GUI.outputMethod = OPENGL;
+			S9xDisplayOutput = &OpenGL;
+		}
+		else
+		{
+			GUI.outputMethod = DIRECT3D;
+			S9xDisplayOutput = &Direct3D;
+		}
+
+		auto newDriverName = driverNames[GUI.outputMethod];
+		TCHAR msg[512];
+		_stprintf(msg, TEXT("Couldn't load selected driver: %s. Trying %s."), oldDriverName, newDriverName);
+		MessageBox(GUI.hWnd, msg, TEXT("Snes9x Display Driver"), MB_OK | MB_ICONERROR);
+
 		initialized = S9xDisplayOutput->Initialize(GUI.hWnd);
 	}
 
 	if (initialized) {
+		if (S9xDisplayOutput == &VulkanDriver)
+			VulkanUsed = true;
+		if (S9xDisplayOutput == &OpenGL)
+			OpenGLUsed = true;
 		S9xGraphicsDeinit();
 		S9xSetWinPixelFormat();
 		S9xGraphicsInit();