From fede9a05fba44452121a831d79f34f0dcc9c4f49 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20Rydg=C3=A5rd?= <hrydgard@gmail.com>
Date: Tue, 30 May 2017 10:38:17 +0200
Subject: [PATCH] Only show the Vulkan setting if Vulkan might be available.

---
 Common/Vulkan/VulkanLoader.cpp | 35 +++++++++++++++++++++++++---------
 Common/Vulkan/VulkanLoader.h   |  3 +++
 UI/GameSettingsScreen.cpp      |  9 +++++----
 3 files changed, 34 insertions(+), 13 deletions(-)

diff --git a/Common/Vulkan/VulkanLoader.cpp b/Common/Vulkan/VulkanLoader.cpp
index 97ea7d4fa7..18df0c070b 100644
--- a/Common/Vulkan/VulkanLoader.cpp
+++ b/Common/Vulkan/VulkanLoader.cpp
@@ -195,16 +195,34 @@ static void *vulkanLibrary;
 #define LOAD_DEVICE_FUNC(instance, x) x = (PFN_ ## x)vkGetDeviceProcAddr(instance, #x); if (!x) {ILOG("Missing (device): %s", #x);}
 #define LOAD_GLOBAL_FUNC(x) x = (PFN_ ## x)dlsym(vulkanLibrary, #x); if (!x) {ILOG("Missing (global): %s", #x);}
 
-
-bool VulkanLoad() {
+bool VulkanMayBeAvailable() {
+	if (vulkanLibrary)
+		return true;
+	bool available = false;
 #ifndef _WIN32
-	vulkanLibrary = dlopen("libvulkan.so", RTLD_NOW | RTLD_LOCAL);
+	void *lib = dlopen("libvulkan.so", RTLD_NOW | RTLD_LOCAL);
+	available = lib != nullptr;
+	dlclose(lib);
 #else
 	// LoadLibrary etc
-	vulkanLibrary = LoadLibrary(L"vulkan-1.dll");
+	HINSTANCE lib = LoadLibrary(L"vulkan-1.dll");
+	available = lib != 0;
+	FreeLibrary(lib);
 #endif
+	return available;
+}
+
+bool VulkanLoad() {
 	if (!vulkanLibrary) {
-		return false;
+#ifndef _WIN32
+		vulkanLibrary = dlopen("libvulkan.so", RTLD_NOW | RTLD_LOCAL);
+#else
+		// LoadLibrary etc
+		vulkanLibrary = LoadLibrary(L"vulkan-1.dll");
+#endif
+		if (!vulkanLibrary) {
+			return false;
+		}
 	}
 
 	LOAD_GLOBAL_FUNC(vkCreateInstance);
@@ -391,13 +409,12 @@ void VulkanLoadDeviceFunctions(VkDevice device) {
 }
 
 void VulkanFree() {
+	if (vulkanLibrary) {
 #ifdef _WIN32
-	if (vulkanLibrary) {
 		FreeLibrary(vulkanLibrary);
-	}
 #else
-	if (vulkanLibrary) {
 		dlclose(vulkanLibrary);
-	}
 #endif
+		vulkanLibrary = nullptr;
+	}
 }
diff --git a/Common/Vulkan/VulkanLoader.h b/Common/Vulkan/VulkanLoader.h
index b6f8beaccf..67042c0c0c 100644
--- a/Common/Vulkan/VulkanLoader.h
+++ b/Common/Vulkan/VulkanLoader.h
@@ -191,6 +191,9 @@ extern PFN_vkQueuePresentKHR vkQueuePresentKHR;
 extern PFN_vkCreateDebugReportCallbackEXT vkCreateDebugReportCallbackEXT;
 extern PFN_vkDestroyDebugReportCallbackEXT vkDestroyDebugReportCallbackEXT;
 
+// Way to do a quick check before even attempting to load.
+bool VulkanMayBeAvailable();
+
 bool VulkanLoad();
 void VulkanLoadInstanceFunctions(VkInstance instance);
 void VulkanLoadDeviceFunctions(VkDevice device);
diff --git a/UI/GameSettingsScreen.cpp b/UI/GameSettingsScreen.cpp
index 15902fe0b9..263c626250 100644
--- a/UI/GameSettingsScreen.cpp
+++ b/UI/GameSettingsScreen.cpp
@@ -48,6 +48,7 @@
 #include "Common/KeyMap.h"
 #include "Common/FileUtil.h"
 #include "Common/OSVersion.h"
+#include "Common/Vulkan/VulkanLoader.h"
 #include "Core/Config.h"
 #include "Core/Host.h"
 #include "Core/System.h"
@@ -187,10 +188,10 @@ void GameSettingsScreen::CreateViews() {
 		renderingBackendChoice->HideChoice(2);  // D3D11
 	}
 #endif
-#if !defined(_WIN32) && !PPSSPP_PLATFORM(ANDROID)
-	// TODO: Add dynamic runtime check for Vulkan support on Android
-	renderingBackendChoice->HideChoice(3);
-#endif
+	if (!VulkanMayBeAvailable()) {
+		renderingBackendChoice->HideChoice(3);
+	}
+
 	static const char *renderingMode[] = { "Non-Buffered Rendering", "Buffered Rendering", "Read Framebuffers To Memory (CPU)", "Read Framebuffers To Memory (GPU)"};
 	PopupMultiChoice *renderingModeChoice = graphicsSettings->Add(new PopupMultiChoice(&g_Config.iRenderingMode, gr->T("Mode"), renderingMode, 0, ARRAY_SIZE(renderingMode), gr->GetName(), screenManager()));
 	renderingModeChoice->OnChoice.Add([=](EventParams &e) {