From 2b3075626bd9e81ad9799e1c811dbec12a3deb35 Mon Sep 17 00:00:00 2001
From: Karen Webb <karen.r.webb@outlook.com>
Date: Tue, 26 Nov 2024 18:29:06 +0000
Subject: [PATCH] surface: Better support for linux surface backends (#225)

* surface: Better support for linux surface backends

Manually create X surface instead of being tied to the Qt platform in use
Don't rely on Qt's wayland/X libraries
Don't violate vulkan spec with null wayland surface

* Fix Build
---
 vulkanCapsViewer.pro |  4 +--
 vulkanDeviceInfo.h   |  4 ---
 vulkancapsviewer.cpp | 63 +++++++++++++++++++++++++++++++++++---------
 3 files changed, 52 insertions(+), 19 deletions(-)

diff --git a/vulkanCapsViewer.pro b/vulkanCapsViewer.pro
index 6b15e11..22bd705 100644
--- a/vulkanCapsViewer.pro
+++ b/vulkanCapsViewer.pro
@@ -27,12 +27,12 @@ linux:!android {
     LIBS += -lvulkan
     contains(DEFINES, X11) {
         message("Building for X11")
-        QT += x11extras
+        LIBS += -lxcb
         DEFINES += VK_USE_PLATFORM_XCB_KHR
     }
     contains(DEFINES, WAYLAND) {
         message("Building for Wayland")
-        QT += waylandclient
+        LIBS += -lwayland-client
         DEFINES += VK_USE_PLATFORM_WAYLAND_KHR
     }
     target.path = /usr/bin
diff --git a/vulkanDeviceInfo.h b/vulkanDeviceInfo.h
index 2b63a7f..a104712 100644
--- a/vulkanDeviceInfo.h
+++ b/vulkanDeviceInfo.h
@@ -51,10 +51,6 @@
 #include <sys/system_properties.h>
 #endif
 
-#ifdef VK_USE_PLATFORM_XCB_KHR
-#include <QX11Info>
-#endif
-
 #include "vulkanandroid.h"
 #if !defined(DISABLE_PROFILES)
 #include "vulkan_profiles.hpp"
diff --git a/vulkancapsviewer.cpp b/vulkancapsviewer.cpp
index 5a84545..9c87175 100644
--- a/vulkancapsviewer.cpp
+++ b/vulkancapsviewer.cpp
@@ -56,10 +56,6 @@
 #include <sys/utsname.h>
 #endif
 
-#ifdef VK_USE_PLATFORM_XCB_KHR
-#include <QX11Info>
-#endif
-
 #ifdef VK_USE_PLATFORM_WAYLAND_KHR
 #include <wayland-client.h>
 #endif
@@ -785,21 +781,62 @@ 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);
+            static const wl_registry_listener WAYLAND_LISTENER {
+                .global = [](void *data, wl_registry*, uint32_t name, const char* interface, uint32_t){
+                    if (!strcmp(interface, wl_compositor_interface.name)) {
+                        *static_cast<uint32_t *>(data) = name;
+                    }
+                },
+                .global_remove = [](void*, wl_registry*, uint32_t){
+
+                }
+            };
+
+            const auto wayland_display = wl_display_connect(nullptr);
+            const auto wayland_registry = wl_display_get_registry(wayland_display);
+            uint32_t wayland_compositor_name = 0;
+            wl_registry_add_listener(wayland_registry, &WAYLAND_LISTENER, &wayland_compositor_name);
+            wl_display_roundtrip(wayland_display);
+
+            if (wayland_compositor_name > 0) {
+                const auto wayland_compositor = static_cast<wl_compositor *>(
+                    wl_registry_bind(wayland_registry, wayland_compositor_name, &wl_compositor_interface, 1)
+                );
+                const auto wayland_surface = wl_compositor_create_surface(wayland_compositor);
+                VkWaylandSurfaceCreateInfoKHR surfaceCreateInfo = {};
+                surfaceCreateInfo.pNext = nullptr;
+                surfaceCreateInfo.sType = VK_STRUCTURE_TYPE_WAYLAND_SURFACE_CREATE_INFO_KHR;
+                surfaceCreateInfo.display = wayland_display;
+                surfaceCreateInfo.surface = wayland_surface;
+                surfaceResult = vkCreateWaylandSurfaceKHR(vulkanContext.instance, &surfaceCreateInfo, nullptr, &vulkanContext.surface);
+            }
         }
 #endif
-
 #if defined(VK_USE_PLATFORM_XCB_KHR)
         if (surface_extension == VK_KHR_XCB_SURFACE_EXTENSION_NAME) {
+            int xcb_screen_idx;
+            const auto xcb_connection = xcb_connect(nullptr, &xcb_screen_idx);
+            const auto xcb_setup = xcb_get_setup(xcb_connection);
+            auto xcb_screen = xcb_setup_roots_iterator(xcb_setup);
+            for (int i = 0; i < xcb_screen_idx; ++i) {
+                xcb_screen_next(&xcb_screen);
+            }
+            const auto xcb_window = xcb_generate_id(xcb_connection);
+            xcb_create_window(
+                xcb_connection,
+                xcb_screen.data->root_depth,
+                xcb_window,
+                xcb_screen.data->root,
+                0, 0,
+                800, 600, 0,
+                XCB_WINDOW_CLASS_INPUT_OUTPUT,
+                xcb_screen.data->root_visual,
+                0, nullptr);
+
             VkXcbSurfaceCreateInfoKHR surfaceCreateInfo = {};
             surfaceCreateInfo.sType = VK_STRUCTURE_TYPE_XCB_SURFACE_CREATE_INFO_KHR;
-            surfaceCreateInfo.connection = QX11Info::connection();
-            surfaceCreateInfo.window = static_cast<xcb_window_t>(this->winId());
+            surfaceCreateInfo.connection = xcb_connection;
+            surfaceCreateInfo.window = xcb_window;
             surfaceResult = vkCreateXcbSurfaceKHR(vulkanContext.instance, &surfaceCreateInfo, nullptr, &vulkanContext.surface);
         }
 #endif