From 908df199d0782d161e83d75dd7a7d9aab29ff9e7 Mon Sep 17 00:00:00 2001
From: Paul Olav Tvete <paul.tvete@qt.io>
Date: Fri, 13 Dec 2019 14:18:11 +0100
Subject: 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>
---
 src/gui/rhi/qrhivulkan.cpp                               | 11 +++++++++++
 src/gui/vulkan/qvulkanwindow.cpp                         |  9 +++++++++
 .../vkconvenience/qbasicvulkanplatforminstance.cpp       | 16 ++++++++++++++++
 3 files changed, 36 insertions(+)

(limited to 'src')

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;
diff --git a/src/gui/vulkan/qvulkanwindow.cpp b/src/gui/vulkan/qvulkanwindow.cpp
index ed73a77683..e211863f21 100644
--- a/src/gui/vulkan/qvulkanwindow.cpp
+++ b/src/gui/vulkan/qvulkanwindow.cpp
@@ -689,6 +689,15 @@ void QVulkanWindowPrivate::init()
     QVulkanInfoVector<QVulkanExtension> supportedExtensions = q->supportedDeviceExtensions();
     QByteArrayList reqExts = requestedDevExtensions;
     reqExts.append("VK_KHR_swapchain");
+
+    QByteArray envExts = qgetenv("QT_VULKAN_DEVICE_EXTENSIONS");
+    if (!envExts.isEmpty()) {
+        QByteArrayList envExtList =  envExts.split(';');
+        for (auto ext : reqExts)
+            envExtList.removeAll(ext);
+        reqExts.append(envExtList);
+    }
+
     for (const QByteArray &ext : reqExts) {
         if (supportedExtensions.contains(ext))
             devExts.append(ext.constData());
diff --git a/src/platformsupport/vkconvenience/qbasicvulkanplatforminstance.cpp b/src/platformsupport/vkconvenience/qbasicvulkanplatforminstance.cpp
index 68340a3173..6f6ba58319 100644
--- a/src/platformsupport/vkconvenience/qbasicvulkanplatforminstance.cpp
+++ b/src/platformsupport/vkconvenience/qbasicvulkanplatforminstance.cpp
@@ -214,6 +214,22 @@ void QBasicPlatformVulkanInstance::initInstance(QVulkanInstance *instance, const
         for (const QByteArray &ext : extraExts)
             m_enabledExtensions.append(ext);
 
+        QByteArray envExts = qgetenv("QT_VULKAN_INSTANCE_EXTENSIONS");
+        if (!envExts.isEmpty()) {
+            QByteArrayList envExtList =  envExts.split(';');
+            for (auto ext : m_enabledExtensions)
+                envExtList.removeAll(ext);
+            m_enabledExtensions.append(envExtList);
+        }
+
+        QByteArray envLayers = qgetenv("QT_VULKAN_INSTANCE_LAYERS");
+        if (!envLayers.isEmpty()) {
+            QByteArrayList envLayerList = envLayers.split(';');
+            for (auto ext : m_enabledLayers)
+                envLayerList.removeAll(ext);
+            m_enabledLayers.append(envLayerList);
+        }
+
         // No clever stuff with QSet and friends: the order for layers matters
         // and the user-provided order must be kept.
         for (int i = 0; i < m_enabledLayers.count(); ++i) {
-- 
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