Add environment variables for customizing Vulkan

QT_VULKAN_INSTANCE_EXTENSIONS to specify additional
instance extensions.
QT_VULKAN_INSTANCE_LAYERS to specify additional
instance layers.
QT_VULKAN_DEVICE_EXTENSIONS to specify additional
device extensions.

These will apply to all QVulkanWindows and everything
that uses RHI, including Qt Quick with the Vulkan RHI
backend.

Task-number: QTBUG-80499
Change-Id: I912495affa987d62a9823d55d06d6a8209f6adc6
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

1 files changed, 11 insertions, 0 deletions

diff --git a/src/gui/rhi/qrhivulkan.cpp b/src/gui/rhi/qrhivulkan.cpp
index 21ae142b1d..c540e9fa85 100644
--- a/src/gui/rhi/qrhivulkan.cpp
+++ b/src/gui/rhi/qrhivulkan.cpp
@@ -501,6 +501,17 @@ bool QRhiVulkan::create(QRhi::Flags flags)
             }
         }
 
+        QByteArrayList envExtList;
+        if (qEnvironmentVariableIsSet("QT_VULKAN_DEVICE_EXTENSIONS")) {
+            envExtList = qgetenv("QT_VULKAN_DEVICE_EXTENSIONS").split(';');
+            for (auto ext : requestedDevExts)
+                envExtList.removeAll(ext);
+            for (const QByteArray &ext : envExtList) {
+                if (!ext.isEmpty())
+                    requestedDevExts.append(ext.constData());
+            }
+        }
+
         VkDeviceCreateInfo devInfo;
         memset(&devInfo, 0, sizeof(devInfo));
         devInfo.sType = VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO;