Vulkan: share library loading implementation

The macOS, Windows, and XCB implementations are identical
and can be moved to QBasicPlatformVulkanInstance.

Change-Id: Id84b27ffd87f86afe3798c4ad2743ba05e6190d3
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

2 files changed, 19 insertions, 0 deletions

diff --git a/src/platformsupport/vkconvenience/qbasicvulkanplatforminstance.cpp b/src/platformsupport/vkconvenience/qbasicvulkanplatforminstance.cpp
index d8b4e0a7e0..b9c5669b3f 100644
--- a/src/platformsupport/vkconvenience/qbasicvulkanplatforminstance.cpp
+++ b/src/platformsupport/vkconvenience/qbasicvulkanplatforminstance.cpp
@@ -82,6 +82,21 @@ QBasicPlatformVulkanInstance::~QBasicPlatformVulkanInstance()
         m_vkDestroyInstance(m_vkInst, nullptr);
 }
 
+void QBasicPlatformVulkanInstance::loadVulkanLibrary(const QString &defaultLibraryName)
+{
+    if (qEnvironmentVariableIsSet("QT_VULKAN_LIB"))
+        m_vulkanLib.setFileName(QString::fromUtf8(qgetenv("QT_VULKAN_LIB")));
+    else
+        m_vulkanLib.setFileName(defaultLibraryName);
+
+    if (!m_vulkanLib.load()) {
+        qWarning("Failed to load %s: %s", qPrintable(m_vulkanLib.fileName()), qPrintable(m_vulkanLib.errorString()));
+        return;
+    }
+
+    init(&m_vulkanLib);
+}
+
 void QBasicPlatformVulkanInstance::init(QLibrary *lib)
 {
     if (m_vkGetInstanceProcAddr)
diff --git a/src/platformsupport/vkconvenience/qbasicvulkanplatforminstance_p.h b/src/platformsupport/vkconvenience/qbasicvulkanplatforminstance_p.h
index 7395ee0323..566140b032 100644
--- a/src/platformsupport/vkconvenience/qbasicvulkanplatforminstance_p.h
+++ b/src/platformsupport/vkconvenience/qbasicvulkanplatforminstance_p.h
@@ -51,6 +51,7 @@
 // We mean it.
 //
 
+#include <QtCore/QLibrary>
 #include <qpa/qplatformvulkaninstance.h>
 
 QT_BEGIN_NAMESPACE
@@ -75,6 +76,7 @@ public:
     void destroySurface(VkSurfaceKHR surface) const;
 
 protected:
+    void loadVulkanLibrary(const QString &defaultLibraryName);
     void init(QLibrary *lib);
     void initInstance(QVulkanInstance *instance, const QByteArrayList &extraExts);
 
@@ -86,6 +88,8 @@ protected:
 private:
     void setupDebugOutput();
 
+    QLibrary m_vulkanLib;
+
     bool m_ownsVkInst;
     VkResult m_errorCode;
     QVulkanInfoVector<QVulkanLayer> m_supportedLayers;