gtk/gdk/gdkvulkancontext.c

/* GDK - The GIMP Drawing Kit
 *
 * gdkvulkancontext-x11.c: X11 specific Vulkan wrappers
 *
 * Copyright © 2016  Benjamin Otte
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
 */

#include "config.h"

#include "gdkvulkancontextprivate.h"

#include <vulkan/vulkan.h>

#include "gdkdisplayprivate.h"
#include "gdkinternals.h"
#include "gdkintl.h"

typedef struct _GdkVulkanContextPrivate GdkVulkanContextPrivate;

struct _GdkVulkanContextPrivate {
  VkSurfaceKHR surface;
  VkSurfaceFormatKHR image_format;

  int swapchain_width, swapchain_height;
  VkSwapchainKHR swapchain;
};

G_DEFINE_QUARK (gdk-vulkan-error-quark, gdk_vulkan_error)

static void gdk_vulkan_context_initable_init (GInitableIface *iface);

G_DEFINE_ABSTRACT_TYPE_WITH_CODE (GdkVulkanContext, gdk_vulkan_context, GDK_TYPE_DRAW_CONTEXT,
                                  G_IMPLEMENT_INTERFACE (G_TYPE_INITABLE, gdk_vulkan_context_initable_init)
                                  G_ADD_PRIVATE (GdkVulkanContext))

#ifdef GDK_WINDOWING_VULKAN

const char *
gdk_vulkan_strerror (VkResult result)
{
  switch (result)
  {
    case VK_SUCCESS:
      return "Command successfully completed.";
    case VK_NOT_READY:
      return "A fence or query has not yet completed.";
    case VK_TIMEOUT:
      return "A wait operation has not completed in the specified time.";
    case VK_EVENT_SET:
      return "An event is signaled.";
    case VK_EVENT_RESET:
      return "An event is unsignaled.";
    case VK_INCOMPLETE:
      return "A return array was too small for the result.";
    case VK_SUBOPTIMAL_KHR:
      return "A swapchain no longer matches the surface properties exactly, but can still be used to present to the surface successfully.";
    case VK_ERROR_OUT_OF_HOST_MEMORY:
      return "A host memory allocation has failed.";
    case VK_ERROR_OUT_OF_DEVICE_MEMORY:
      return "A device memory allocation has failed.";
    case VK_ERROR_INITIALIZATION_FAILED:
      return "Initialization of an object could not be completed for implementation-specific reasons.";
    case VK_ERROR_DEVICE_LOST:
      return "The logical or physical device has been lost.";
    case VK_ERROR_MEMORY_MAP_FAILED:
      return "Mapping of a memory object has failed.";
    case VK_ERROR_LAYER_NOT_PRESENT:
      return "A requested layer is not present or could not be loaded.";
    case VK_ERROR_EXTENSION_NOT_PRESENT:
      return "A requested extension is not supported.";
    case VK_ERROR_FEATURE_NOT_PRESENT:
      return "A requested feature is not supported.";
    case VK_ERROR_INCOMPATIBLE_DRIVER:
      return "The requested version of Vulkan is not supported by the driver or is otherwise incompatible for implementation-specific reasons.";
    case VK_ERROR_TOO_MANY_OBJECTS:
      return "Too many objects of the type have already been created.";
    case VK_ERROR_FORMAT_NOT_SUPPORTED:
      return "A requested format is not supported on this device.";
    case VK_ERROR_FRAGMENTED_POOL:
      return "A requested pool allocation has failed due to fragmentation of the pool’s memory.";
    case VK_ERROR_SURFACE_LOST_KHR:
      return "A surface is no longer available.";
    case VK_ERROR_NATIVE_WINDOW_IN_USE_KHR:
      return "The requested window is already in use by Vulkan or another API in a manner which prevents it from being used again.";
    case VK_ERROR_OUT_OF_DATE_KHR:
      return "A surface has changed in such a way that it is no longer compatible with the swapchain.";
    case VK_ERROR_INCOMPATIBLE_DISPLAY_KHR:
      return "The display used by a swapchain does not use the same presentable image layout, or is incompatible in a way that prevents sharing an image.";
    default:
      return "Unknown Vulkan error.";
  }
}

static void
gdk_vulkan_context_dispose (GObject *gobject)
{
  GdkVulkanContext *context = GDK_VULKAN_CONTEXT (gobject);
  GdkVulkanContextPrivate *priv = gdk_vulkan_context_get_instance_private (context);
  GdkDisplay *display;

  if (priv->swapchain != VK_NULL_HANDLE)
    {
      vkDestroySwapchainKHR (gdk_vulkan_context_get_device (context),
                             priv->swapchain,
                             NULL);
      priv->swapchain = VK_NULL_HANDLE;
    }

  if (priv->surface != VK_NULL_HANDLE)
    {
      vkDestroySurfaceKHR (gdk_vulkan_context_get_instance (context),
                           priv->surface,
                           NULL);
      priv->surface = VK_NULL_HANDLE;
    }

  /* display will be unset in gdk_draw_context_dispose() */
  display = gdk_draw_context_get_display (GDK_DRAW_CONTEXT (context));
  if (display)
    gdk_display_unref_vulkan (display);

  G_OBJECT_CLASS (gdk_vulkan_context_parent_class)->dispose (gobject);
}

static void
gdk_vulkan_context_class_init (GdkVulkanContextClass *klass)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

  gobject_class->dispose = gdk_vulkan_context_dispose;
}

static void
gdk_vulkan_context_init (GdkVulkanContext *self)
{
}

static gboolean
gdk_vulkan_context_check_swapchain (GdkVulkanContext  *context,
                                    GError           **error)
{
  GdkVulkanContextPrivate *priv = gdk_vulkan_context_get_instance_private (context);
  GdkWindow *window = gdk_draw_context_get_window (GDK_DRAW_CONTEXT (context));
  VkSurfaceCapabilitiesKHR capabilities;
  VkCompositeAlphaFlagBitsKHR composite_alpha;
  VkSwapchainKHR new_swapchain;
  VkResult res;

  if (gdk_window_get_width (window) == priv->swapchain_width &&
      gdk_window_get_height (window) == priv->swapchain_height)
    return TRUE;

  res = GDK_VK_CHECK (vkGetPhysicalDeviceSurfaceCapabilitiesKHR, gdk_vulkan_context_get_physical_device (context),
                                                                 priv->surface,
                                                                 &capabilities);
  if (res != VK_SUCCESS)
    {
      g_set_error (error, GDK_VULKAN_ERROR, GDK_VULKAN_ERROR_NOT_AVAILABLE,
                   "Could not query surface capabilities: %s", gdk_vulkan_strerror (res));
      return FALSE;
    }

  if (capabilities.supportedCompositeAlpha & VK_COMPOSITE_ALPHA_PRE_MULTIPLIED_BIT_KHR)
    composite_alpha = VK_COMPOSITE_ALPHA_PRE_MULTIPLIED_BIT_KHR;
  else if (capabilities.supportedCompositeAlpha & VK_COMPOSITE_ALPHA_POST_MULTIPLIED_BIT_KHR)
    composite_alpha = VK_COMPOSITE_ALPHA_POST_MULTIPLIED_BIT_KHR;
  else if (capabilities.supportedCompositeAlpha & VK_COMPOSITE_ALPHA_INHERIT_BIT_KHR)
    {
      /* let's hope the backend knows what it's doing */
      composite_alpha = VK_COMPOSITE_ALPHA_INHERIT_BIT_KHR;
    }
  else
    {
      GDK_NOTE (VULKAN, g_warning ("Vulkan swapchain doesn't do transparency. Using opaque swapchain instead."));
      composite_alpha = VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR;
    }

  res = GDK_VK_CHECK (vkCreateSwapchainKHR, gdk_vulkan_context_get_device (context),
                                            &(VkSwapchainCreateInfoKHR) {
                                                .sType = VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR,
                                                .pNext = NULL,
                                                .flags = 0,
                                                .surface = priv->surface,
                                                .minImageCount = 2,
                                                .imageFormat = priv->image_format.format,
                                                .imageColorSpace = priv->image_format.colorSpace,
                                                .imageExtent = capabilities.currentExtent,
                                                .imageArrayLayers = 1,
                                                .imageUsage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT,
                                                .imageSharingMode = VK_SHARING_MODE_EXCLUSIVE,
                                                .queueFamilyIndexCount = 1,
                                                .pQueueFamilyIndices = (uint32_t[1]) {
                                                    gdk_draw_context_get_display (GDK_DRAW_CONTEXT (context))->vk_queue_family_index
                                                },
                                                .preTransform = capabilities.currentTransform,
                                                .compositeAlpha = composite_alpha,
                                                .presentMode = VK_PRESENT_MODE_FIFO_KHR,
                                                .clipped = VK_FALSE,
                                                .oldSwapchain = priv->swapchain
                                            },
                                            NULL,
                                            &new_swapchain);

  if (priv->swapchain != VK_NULL_HANDLE)
    vkDestroySwapchainKHR (gdk_vulkan_context_get_device (context),
                           priv->swapchain,
                           NULL);

  if (res == VK_SUCCESS)
    {
      priv->swapchain_width = gdk_window_get_width (window);
      priv->swapchain_height = gdk_window_get_height (window);
      priv->swapchain = new_swapchain;
    }
  else
    {
      g_set_error (error, GDK_VULKAN_ERROR, GDK_VULKAN_ERROR_NOT_AVAILABLE,
                   "Could not create swapchain for this window: %s", gdk_vulkan_strerror (res));
      priv->swapchain = VK_NULL_HANDLE;
      priv->swapchain_width = 0;
      priv->swapchain_height = 0;
      return FALSE;
    }

  return TRUE;
}

static gboolean
gdk_vulkan_context_real_init (GInitable     *initable,
                              GCancellable  *cancellable,
                              GError       **error)
{
  GdkVulkanContext *context = GDK_VULKAN_CONTEXT (initable);
  GdkVulkanContextPrivate *priv = gdk_vulkan_context_get_instance_private (context);
  VkResult res;
  VkBool32 supported;
  uint32_t i;

  if (!gdk_display_ref_vulkan (gdk_draw_context_get_display (GDK_DRAW_CONTEXT (context)), error))
    return FALSE;

  res = GDK_VULKAN_CONTEXT_GET_CLASS (context)->create_surface (context, &priv->surface);
  if (res != VK_SUCCESS)
    {
      g_set_error (error, GDK_VULKAN_ERROR, GDK_VULKAN_ERROR_NOT_AVAILABLE,
                   "Could not create surface for this window: %s", gdk_vulkan_strerror (res));
      return FALSE;
    }

  res = GDK_VK_CHECK (vkGetPhysicalDeviceSurfaceSupportKHR, gdk_vulkan_context_get_physical_device (context),
                                                            gdk_vulkan_context_get_queue_family_index (context),
                                                            priv->surface,
                                                            &supported);
  if (res != VK_SUCCESS)
    {
      g_set_error (error, GDK_VULKAN_ERROR, GDK_VULKAN_ERROR_NOT_AVAILABLE,
                   "Could not check if queue family supports this window: %s", gdk_vulkan_strerror (res));
    }
  else if (!supported)
    {
      g_set_error (error, GDK_VULKAN_ERROR, GDK_VULKAN_ERROR_NOT_AVAILABLE,
                   "FIXME: Queue family does not support surface. Write code to try different queue family.");
    }
  else
    {
      uint32_t n_formats;
      GDK_VK_CHECK (vkGetPhysicalDeviceSurfaceFormatsKHR, gdk_vulkan_context_get_physical_device (context),
                                                          priv->surface,
                                                          &n_formats, NULL);
      VkSurfaceFormatKHR formats[n_formats];
      GDK_VK_CHECK (vkGetPhysicalDeviceSurfaceFormatsKHR, gdk_vulkan_context_get_physical_device (context),
                                                          priv->surface,
                                                          &n_formats, formats);
      for (i = 0; i < n_formats; i++)
        {
          if (formats[i].format == VK_FORMAT_B8G8R8A8_SRGB)
            break;
        }
      if (i == n_formats)
        {
          g_set_error_literal (error, GDK_VULKAN_ERROR, GDK_VULKAN_ERROR_NOT_AVAILABLE,
                               "No supported image format found.");
          goto out_surface;  
        }
      priv->image_format = formats[i];

      if (!gdk_vulkan_context_check_swapchain (context, error))
        goto out_surface;

      return TRUE;
    }

out_surface:
  vkDestroySurfaceKHR (gdk_vulkan_context_get_instance (context),
                       priv->surface,
                       NULL);
  priv->surface = VK_NULL_HANDLE;
  return FALSE;
}

static void
gdk_vulkan_context_initable_init (GInitableIface *iface)
{
  iface->init = gdk_vulkan_context_real_init;
}

VkInstance
gdk_vulkan_context_get_instance (GdkVulkanContext *context)
{
  g_return_val_if_fail (GDK_IS_VULKAN_CONTEXT (context), NULL);

  return gdk_draw_context_get_display (GDK_DRAW_CONTEXT (context))->vk_instance;
}

VkPhysicalDevice
gdk_vulkan_context_get_physical_device (GdkVulkanContext *context)
{
  g_return_val_if_fail (GDK_IS_VULKAN_CONTEXT (context), NULL);

  return gdk_draw_context_get_display (GDK_DRAW_CONTEXT (context))->vk_physical_device;
}

VkDevice
gdk_vulkan_context_get_device (GdkVulkanContext *context)
{
  g_return_val_if_fail (GDK_IS_VULKAN_CONTEXT (context), NULL);

  return gdk_draw_context_get_display (GDK_DRAW_CONTEXT (context))->vk_device;
}

VkQueue
gdk_vulkan_context_get_queue (GdkVulkanContext *context)
{
  g_return_val_if_fail (GDK_IS_VULKAN_CONTEXT (context), NULL);

  return gdk_draw_context_get_display (GDK_DRAW_CONTEXT (context))->vk_queue;
}

uint32_t
gdk_vulkan_context_get_queue_family_index (GdkVulkanContext *context)
{
  g_return_val_if_fail (GDK_IS_VULKAN_CONTEXT (context), 0);

  return gdk_draw_context_get_display (GDK_DRAW_CONTEXT (context))->vk_queue_family_index;
}

VkFormat
gdk_vulkan_context_get_image_format (GdkVulkanContext *context)
{
  GdkVulkanContextPrivate *priv = gdk_vulkan_context_get_instance_private (context);

  g_return_val_if_fail (GDK_IS_VULKAN_CONTEXT (context), VK_FORMAT_UNDEFINED);

  return priv->image_format.format;
}

static gboolean
gdk_display_create_vulkan_device (GdkDisplay  *display,
                                  GError     **error)
{
  uint32_t i, j;

  uint32_t n_devices;
  GDK_VK_CHECK(vkEnumeratePhysicalDevices, display->vk_instance, &n_devices, NULL);
  VkPhysicalDevice devices[n_devices];
  GDK_VK_CHECK(vkEnumeratePhysicalDevices, display->vk_instance, &n_devices, devices);

  if (n_devices == 0)
    {
      /* Give a different error for 0 devices so people know their drivers suck. */
      g_set_error_literal (error, GDK_VULKAN_ERROR, GDK_VULKAN_ERROR_NOT_AVAILABLE,
                           "No Vulkan devices available.");
      return FALSE;
    }

  for (i = 0; i < n_devices; i++)
    {
      VkPhysicalDeviceProperties props;

      vkGetPhysicalDeviceProperties (devices[i], &props);

      GDK_NOTE (VULKAN, g_print ("Vulkan Device %u:\n", i));
      GDK_NOTE (VULKAN, g_print ("    %s (%u)\n", props.deviceName, props.deviceType));
      GDK_NOTE (VULKAN, g_print ("    vendor ID: 0x%Xu\n", props.vendorID));
      GDK_NOTE (VULKAN, g_print ("    device ID: 0x%Xu\n", props.deviceID));
      GDK_NOTE (VULKAN, g_print ("    API version %u.%u.%u\n",
                                 VK_VERSION_MAJOR (props.apiVersion),
                                 VK_VERSION_MINOR (props.apiVersion),
                                 VK_VERSION_PATCH (props.apiVersion)));
      GDK_NOTE (VULKAN, g_print ("    driver version %u.%u.%u\n",
                                 VK_VERSION_MAJOR (props.driverVersion),
                                 VK_VERSION_MINOR (props.driverVersion),
                                 VK_VERSION_PATCH (props.driverVersion)));

      uint32_t n_queue_props;
      vkGetPhysicalDeviceQueueFamilyProperties (devices[i], &n_queue_props, NULL);
      VkQueueFamilyProperties queue_props[n_queue_props];
      vkGetPhysicalDeviceQueueFamilyProperties (devices[i], &n_queue_props, queue_props);

      for (j = 0; j < n_queue_props; j++)
        {
          GDK_NOTE (VULKAN, g_print ("    queue %u/%u: %s\n", j, n_queue_props, queue_props[j].queueFlags & VK_QUEUE_GRAPHICS_BIT ? "graphics" : "no graphics"));
          if (queue_props[j].queueFlags & VK_QUEUE_GRAPHICS_BIT)
            {
              GDK_NOTE (VULKAN, g_print ("    => trying this queue\n"));
              if (GDK_VK_CHECK (vkCreateDevice, devices[i],
                                                &(VkDeviceCreateInfo) {
                                                    VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO,
                                                    NULL,
                                                    0,
                                                    1,
                                                    &(VkDeviceQueueCreateInfo) {
                                                        .sType = VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO,
                                                        .queueFamilyIndex = j,
                                                        .queueCount = 1,
                                                        .pQueuePriorities = (float []) { 1.0f },
                                                    },
                                                    0,
                                                    NULL,
                                                    1,
                                                    (const char * const []) {
                                                       VK_KHR_SWAPCHAIN_EXTENSION_NAME,
                                                    },
                                                },
                                                NULL,
                                                &display->vk_device) != VK_SUCCESS)
                continue;

              display->vk_physical_device = devices[i];
              vkGetDeviceQueue(display->vk_device, j, 0, &display->vk_queue);
              display->vk_queue_family_index = j;
              return TRUE;
            }
        }
    }

  g_set_error_literal (error, GDK_VULKAN_ERROR, GDK_VULKAN_ERROR_NOT_AVAILABLE,
                       "Could not find a Vulkan device with the required features.");
  return FALSE;
}

static VkBool32
gdk_vulkan_debug_report (VkDebugReportFlagsEXT      flags,
                         VkDebugReportObjectTypeEXT objectType,
                         uint64_t                   object,
                         size_t                     location,
                         int32_t                    messageCode,
                         const char*                pLayerPrefix,
                         const char*                pMessage,
                         void*                      pUserData)
{
  if (flags & VK_DEBUG_REPORT_ERROR_BIT_EXT)
    {
      g_critical ("Vulkan: %s: %s\n", pLayerPrefix, pMessage);
    }
  else if (flags & VK_DEBUG_REPORT_WARNING_BIT_EXT)
    {
      g_critical ("Vulkan: %s: %s\n", pLayerPrefix, pMessage);
    }
  else if (flags & VK_DEBUG_REPORT_PERFORMANCE_WARNING_BIT_EXT)
    {
      g_warning ("Vulkan: %s: %s\n", pLayerPrefix, pMessage);
    }
  else if (flags & VK_DEBUG_REPORT_DEBUG_BIT_EXT)
    {
      g_debug ("Vulkan: %s: %s\n", pLayerPrefix, pMessage);
    }
  else
    {
      g_message ("Vulkan: %s: %s\n", pLayerPrefix, pMessage);
    }
  
  return VK_TRUE;
}

static gboolean
gdk_display_create_vulkan_instance (GdkDisplay  *display,
                                    GError     **error)
{
  uint32_t i;
  GPtrArray *used_extensions;
  GPtrArray *used_layers;
  gboolean validate = FALSE, have_debug_report = FALSE;
  VkResult res;

  if (GDK_DISPLAY_GET_CLASS (display)->vk_extension_name == NULL)
    {
      g_set_error (error, GDK_VULKAN_ERROR, GDK_VULKAN_ERROR_UNSUPPORTED,
                   "The %s backend has no Vulkan support.", G_OBJECT_TYPE_NAME (display));
      return FALSE;
    }

  uint32_t n_extensions;
  GDK_VK_CHECK (vkEnumerateInstanceExtensionProperties, NULL, &n_extensions, NULL);
  VkExtensionProperties extensions[n_extensions];
  GDK_VK_CHECK (vkEnumerateInstanceExtensionProperties, NULL, &n_extensions, extensions);

  used_extensions = g_ptr_array_new ();
  g_ptr_array_add (used_extensions, (gpointer) VK_KHR_SURFACE_EXTENSION_NAME); 
  g_ptr_array_add (used_extensions, (gpointer) GDK_DISPLAY_GET_CLASS (display)->vk_extension_name); 

  for (i = 0; i < n_extensions; i++)
    {
      GDK_NOTE (VULKAN, g_print ("Extension available: %s v%u.%u.%u\n",
                                 extensions[i].extensionName,
                                 VK_VERSION_MAJOR (extensions[i].specVersion),
                                 VK_VERSION_MINOR (extensions[i].specVersion),
                                 VK_VERSION_PATCH (extensions[i].specVersion)));

      if (g_str_equal (extensions[i].extensionName, VK_EXT_DEBUG_REPORT_EXTENSION_NAME))
        {
          g_ptr_array_add (used_extensions, (gpointer) VK_EXT_DEBUG_REPORT_EXTENSION_NAME);
          have_debug_report = TRUE;
        }
    }

  uint32_t n_layers;
  GDK_VK_CHECK (vkEnumerateInstanceLayerProperties, &n_layers, NULL);
  VkLayerProperties layers[n_layers];
  GDK_VK_CHECK (vkEnumerateInstanceLayerProperties, &n_layers, layers);

  used_layers = g_ptr_array_new ();

  for (i = 0; i < n_layers; i++)
    {
      GDK_NOTE (VULKAN, g_print ("Layer available: %s v%u.%u.%u (%s)\n",
                                 layers[i].layerName,
                                 VK_VERSION_MAJOR (layers[i].specVersion),
                                 VK_VERSION_MINOR (layers[i].specVersion),
                                 VK_VERSION_PATCH (layers[i].specVersion),
                                 layers[i].description));
      if ((_gdk_vulkan_flags & GDK_VULKAN_VALIDATE) &&
          g_str_equal (layers[i].layerName, "VK_LAYER_LUNARG_standard_validation"))
        {
          g_ptr_array_add (used_layers, (gpointer) "VK_LAYER_LUNARG_standard_validation");
          validate = TRUE;
        }
    }

  if ((_gdk_vulkan_flags & GDK_VULKAN_VALIDATE) && !validate)
    {
      g_warning ("Vulkan validation layers were requested, but not found. Running without.");
    }

  res = GDK_VK_CHECK (vkCreateInstance, &(VkInstanceCreateInfo) {
                                             .sType = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO,
                                             .pNext = NULL,
                                             .flags = 0,
                                             .pApplicationInfo = &(VkApplicationInfo) {
                                                 .sType = VK_STRUCTURE_TYPE_APPLICATION_INFO,
                                                 .pNext = NULL,
                                                 .pApplicationName = g_get_application_name (),
                                                 .applicationVersion = 0,
                                                 .pEngineName = "GTK+",
                                                 .engineVersion = VK_MAKE_VERSION (GDK_MAJOR_VERSION, GDK_MINOR_VERSION, GDK_MICRO_VERSION),
                                                 .apiVersion = VK_API_VERSION_1_0
                                             },
                                             .enabledLayerCount = used_layers->len,
                                             .ppEnabledLayerNames = (const char * const *) used_layers->pdata,
                                             .enabledExtensionCount = used_extensions->len,
                                             .ppEnabledExtensionNames = (const char * const *) used_extensions->pdata
                                         },
                                         NULL,
                                         &display->vk_instance);
  g_ptr_array_free (used_layers, TRUE);
  g_ptr_array_free (used_extensions, TRUE);

  if (res != VK_SUCCESS)
    {
      g_set_error (error, GDK_VULKAN_ERROR, GDK_VULKAN_ERROR_UNSUPPORTED,
                   "Could not create a Vulkan instance: %s", gdk_vulkan_strerror (res));
      return FALSE;
    }

  if (have_debug_report)
    {
      PFN_vkCreateDebugReportCallbackEXT vkCreateDebugReportCallbackEXT;
      
      vkCreateDebugReportCallbackEXT = (PFN_vkCreateDebugReportCallbackEXT) vkGetInstanceProcAddr (display->vk_instance, "vkCreateDebugReportCallbackEXT" );
      GDK_VK_CHECK (vkCreateDebugReportCallbackEXT, display->vk_instance,
                                                    &(VkDebugReportCallbackCreateInfoEXT) {
                                                        .sType = VK_STRUCTURE_TYPE_DEBUG_REPORT_CALLBACK_CREATE_INFO_EXT,
                                                        .pNext = NULL,
                                                        .flags = VK_DEBUG_REPORT_INFORMATION_BIT_EXT
                                                               | VK_DEBUG_REPORT_WARNING_BIT_EXT
                                                               | VK_DEBUG_REPORT_PERFORMANCE_WARNING_BIT_EXT
                                                               | VK_DEBUG_REPORT_ERROR_BIT_EXT
                                                               | VK_DEBUG_REPORT_DEBUG_BIT_EXT,
                                                        .pfnCallback = gdk_vulkan_debug_report,
                                                        .pUserData = NULL
                                                    },
                                                    NULL,
                                                    &display->vk_debug_callback);
    }

  if (!gdk_display_create_vulkan_device (display, error))
    {
      if (display->vk_debug_callback != VK_NULL_HANDLE)
        {
          PFN_vkDestroyDebugReportCallbackEXT vkDestroyDebugReportCallbackEXT;

          vkDestroyDebugReportCallbackEXT = (PFN_vkDestroyDebugReportCallbackEXT) vkGetInstanceProcAddr (display->vk_instance, "vkDestroyDebugReportCallbackEXT");
          vkDestroyDebugReportCallbackEXT (display->vk_instance,
                                           display->vk_debug_callback,
                                           NULL);
          display->vk_debug_callback = VK_NULL_HANDLE;
        }
      vkDestroyInstance (display->vk_instance, NULL);
      display->vk_instance = VK_NULL_HANDLE;
      return FALSE;
    }

  return TRUE;
}

gboolean
gdk_display_ref_vulkan (GdkDisplay *display,
                        GError     **error)
{
  if (display->vulkan_refcount == 0)
    {
      if (!gdk_display_create_vulkan_instance (display, error))
        return FALSE;
    }

  display->vulkan_refcount++;
    
  return TRUE;
}

void
gdk_display_unref_vulkan (GdkDisplay *display)
{
  g_return_if_fail (GDK_IS_DISPLAY (display));
  g_return_if_fail (display->vulkan_refcount > 0);

  display->vulkan_refcount--;
  if (display->vulkan_refcount > 0)
    return;
  
  vkDestroyDevice (display->vk_device, NULL);
  display->vk_device = VK_NULL_HANDLE;
  if (display->vk_debug_callback != VK_NULL_HANDLE)
    {
      PFN_vkDestroyDebugReportCallbackEXT vkDestroyDebugReportCallbackEXT;

      vkDestroyDebugReportCallbackEXT = (PFN_vkDestroyDebugReportCallbackEXT) vkGetInstanceProcAddr (display->vk_instance, "vkDestroyDebugReportCallbackEXT");
      vkDestroyDebugReportCallbackEXT (display->vk_instance,
                                       display->vk_debug_callback,
                                       NULL);
      display->vk_debug_callback = VK_NULL_HANDLE;
    }
  vkDestroyInstance (display->vk_instance, NULL);
  display->vk_instance = VK_NULL_HANDLE;
}

#else /* GDK_WINDOWING_VULKAN */

static void
gdk_vulkan_context_class_init (GdkVulkanContextClass *klass)
{
}

static void
gdk_vulkan_context_init (GdkVulkanContext *self)
{
}

static void
gdk_vulkan_context_initable_init (GInitableIface *iface)
{
}

#endif /* GDK_WINDOWING_VULKAN */