From de463e2fce3f2aee34b1444a55de99a33dff090b Mon Sep 17 00:00:00 2001
From: Lubosz Sarnecki <lubosz@gmail.com>
Date: Tue, 2 Feb 2021 23:20:49 +0100
Subject: [PATCH] Check if wl_display_connect succeeded before creating
 surface.

This prevents creating an invalid surface, as vkCreateWaylandSurfaceKHR
does not return an error if the `wl_display` is a nullptr in some
implementations (as seen on radv/mesa).

This fixes #93.

(cherry picked from commit 18a63a27eeb385c7d48d9551ba04ee4f6ba6f78e)
---
 vulkancapsviewer.cpp | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/vulkancapsviewer.cpp b/vulkancapsviewer.cpp
index 33ec715..5b06003 100644
--- a/vulkancapsviewer.cpp
+++ b/vulkancapsviewer.cpp
@@ -764,12 +764,19 @@ bool VulkanCapsViewer::initVulkan()
 
 #if defined(VK_USE_PLATFORM_WAYLAND_KHR)
         if (surface_extension == VK_KHR_WAYLAND_SURFACE_EXTENSION_NAME) {
-            VkWaylandSurfaceCreateInfoKHR surfaceCreateInfo = {};
-            surfaceCreateInfo.pNext = nullptr;
-            surfaceCreateInfo.sType = VK_STRUCTURE_TYPE_WAYLAND_SURFACE_CREATE_INFO_KHR;
-            surfaceCreateInfo.display = wl_display_connect(NULL);
-            surfaceCreateInfo.surface = nullptr;
-            surfaceResult = vkCreateWaylandSurfaceKHR(vulkanContext.instance, &surfaceCreateInfo, nullptr, &vulkanContext.surface);
+            struct wl_display* display = wl_display_connect(NULL);
+            if (display != NULL) {
+                VkWaylandSurfaceCreateInfoKHR surfaceCreateInfo = {
+                  .sType = VK_STRUCTURE_TYPE_WAYLAND_SURFACE_CREATE_INFO_KHR,
+                  .pNext = nullptr,
+                  .flags = 0,
+                  .display = display,
+                  .surface = nullptr
+                };
+                surfaceResult = vkCreateWaylandSurfaceKHR(vulkanContext.instance, &surfaceCreateInfo, nullptr, &vulkanContext.surface);
+            } else {
+                qDebug() << "Could not connect to Wayland display.";
+            }
         }
 #endif