From 4f1c64af05f09e3bd9cafe063721faa99a2b45d4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C5=82a=C5=BCej=20Szczygie=C5=82?= <mumei6102@gmail.com>
Date: Sat, 21 Oct 2023 00:30:44 +0200
Subject: [PATCH] Vulkan: Load libvulkan.so.1 if Qt can't find libvulkan.so

Closes #663
---
 src/qmplay2/vulkan/VulkanInstance.cpp | 36 +++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/src/qmplay2/vulkan/VulkanInstance.cpp b/src/qmplay2/vulkan/VulkanInstance.cpp
index 443dbedc2..9d33ef802 100644
--- a/src/qmplay2/vulkan/VulkanInstance.cpp
+++ b/src/qmplay2/vulkan/VulkanInstance.cpp
@@ -31,6 +31,10 @@
 #include <QLibrary>
 #include <QWindow>
 
+#if defined(Q_OS_UNIX) && !defined(Q_OS_MAC)
+#   include <QVersionNumber>
+#endif
+
 #if defined(Q_OS_WIN)
 #   include <QRegularExpression>
 #elif defined(Q_OS_LINUX)
@@ -266,8 +270,36 @@ void Instance::init()
         VK_KHR_GET_SURFACE_CAPABILITIES_2_EXTENSION_NAME,
     });
 
-    if (!m_qVulkanInstance->create())
-        throw vk::InitializationFailedError("Can't create Vulkan instance");
+#if defined(Q_OS_UNIX) && !defined(Q_OS_MAC)
+    const bool maybeSetEnvVar = (QVersionNumber::fromString(qVersion()) < QVersionNumber(6, 3, 0) || QGuiApplication::platformName().contains("wayland")) && !qEnvironmentVariableIsSet("QT_VULKAN_LIB");
+
+    QtMessageHandler oldMsgHandler = nullptr;
+    if (maybeSetEnvVar)
+        oldMsgHandler = qInstallMessageHandler(nullptr);
+#endif
+
+    bool ok = m_qVulkanInstance->create();
+
+#if defined(Q_OS_UNIX) && !defined(Q_OS_MAC)
+    if (maybeSetEnvVar && oldMsgHandler)
+        qInstallMessageHandler(oldMsgHandler);
+#endif
+
+    if (!ok)
+    {
+#if defined(Q_OS_UNIX) && !defined(Q_OS_MAC)
+        if (maybeSetEnvVar)
+        {
+            qputenv("QT_VULKAN_LIB", "libvulkan.so.1");
+            qDebug() << "Set QT_VULKAN_LIB to \"libvulkan.so.1\"";
+            ok = m_qVulkanInstance->create();
+        }
+        if (!ok)
+#endif
+        {
+            throw vk::InitializationFailedError("Can't create Vulkan instance");
+        }
+    }
 
 #ifdef QT_DEBUG
     if (!m_qVulkanInstance->layers().contains("VK_LAYER_KHRONOS_validation"))