sdl/test/testvulkan.c

/*
  Copyright (C) 1997-2023 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely.
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>

#include "SDL_test_common.h"

#if defined(__ANDROID__) && defined(__ARM_EABI__) && !defined(__ARM_ARCH_7A__)

int main(int argc, char *argv[])
{
    SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "No Vulkan support on this system\n");
    return 1;
}

#else

#define VK_NO_PROTOTYPES
#ifdef HAVE_VULKAN_H
#include <vulkan/vulkan.h>
#else
/* SDL includes a copy for building on systems without the Vulkan SDK */
#include "../src/video/khronos/vulkan/vulkan.h"
#endif
#include "SDL_vulkan.h"

#ifndef UINT64_MAX /* VS2008 */
#define UINT64_MAX 18446744073709551615
#endif

#define VULKAN_FUNCTIONS()                                              \
    VULKAN_DEVICE_FUNCTION(vkAcquireNextImageKHR)                       \
    VULKAN_DEVICE_FUNCTION(vkAllocateCommandBuffers)                    \
    VULKAN_DEVICE_FUNCTION(vkBeginCommandBuffer)                        \
    VULKAN_DEVICE_FUNCTION(vkCmdClearColorImage)                        \
    VULKAN_DEVICE_FUNCTION(vkCmdPipelineBarrier)                        \
    VULKAN_DEVICE_FUNCTION(vkCreateCommandPool)                         \
    VULKAN_DEVICE_FUNCTION(vkCreateFence)                               \
    VULKAN_DEVICE_FUNCTION(vkCreateImageView)                           \
    VULKAN_DEVICE_FUNCTION(vkCreateSemaphore)                           \
    VULKAN_DEVICE_FUNCTION(vkCreateSwapchainKHR)                        \
    VULKAN_DEVICE_FUNCTION(vkDestroyCommandPool)                        \
    VULKAN_DEVICE_FUNCTION(vkDestroyDevice)                             \
    VULKAN_DEVICE_FUNCTION(vkDestroyFence)                              \
    VULKAN_DEVICE_FUNCTION(vkDestroyImageView)                          \
    VULKAN_DEVICE_FUNCTION(vkDestroySemaphore)                          \
    VULKAN_DEVICE_FUNCTION(vkDestroySwapchainKHR)                       \
    VULKAN_DEVICE_FUNCTION(vkDeviceWaitIdle)                            \
    VULKAN_DEVICE_FUNCTION(vkEndCommandBuffer)                          \
    VULKAN_DEVICE_FUNCTION(vkFreeCommandBuffers)                        \
    VULKAN_DEVICE_FUNCTION(vkGetDeviceQueue)                            \
    VULKAN_DEVICE_FUNCTION(vkGetFenceStatus)                            \
    VULKAN_DEVICE_FUNCTION(vkGetSwapchainImagesKHR)                     \
    VULKAN_DEVICE_FUNCTION(vkQueuePresentKHR)                           \
    VULKAN_DEVICE_FUNCTION(vkQueueSubmit)                               \
    VULKAN_DEVICE_FUNCTION(vkResetCommandBuffer)                        \
    VULKAN_DEVICE_FUNCTION(vkResetFences)                               \
    VULKAN_DEVICE_FUNCTION(vkWaitForFences)                             \
    VULKAN_GLOBAL_FUNCTION(vkCreateInstance)                            \
    VULKAN_GLOBAL_FUNCTION(vkEnumerateInstanceExtensionProperties)      \
    VULKAN_GLOBAL_FUNCTION(vkEnumerateInstanceLayerProperties)          \
    VULKAN_INSTANCE_FUNCTION(vkCreateDevice)                            \
    VULKAN_INSTANCE_FUNCTION(vkDestroyInstance)                         \
    VULKAN_INSTANCE_FUNCTION(vkDestroySurfaceKHR)                       \
    VULKAN_INSTANCE_FUNCTION(vkEnumerateDeviceExtensionProperties)      \
    VULKAN_INSTANCE_FUNCTION(vkEnumeratePhysicalDevices)                \
    VULKAN_INSTANCE_FUNCTION(vkGetDeviceProcAddr)                       \
    VULKAN_INSTANCE_FUNCTION(vkGetPhysicalDeviceFeatures)               \
    VULKAN_INSTANCE_FUNCTION(vkGetPhysicalDeviceProperties)             \
    VULKAN_INSTANCE_FUNCTION(vkGetPhysicalDeviceQueueFamilyProperties)  \
    VULKAN_INSTANCE_FUNCTION(vkGetPhysicalDeviceSurfaceCapabilitiesKHR) \
    VULKAN_INSTANCE_FUNCTION(vkGetPhysicalDeviceSurfaceFormatsKHR)      \
    VULKAN_INSTANCE_FUNCTION(vkGetPhysicalDeviceSurfacePresentModesKHR) \
    VULKAN_INSTANCE_FUNCTION(vkGetPhysicalDeviceSurfaceSupportKHR)

#define VULKAN_DEVICE_FUNCTION(name)   static PFN_##name name = NULL;
#define VULKAN_GLOBAL_FUNCTION(name)   static PFN_##name name = NULL;
#define VULKAN_INSTANCE_FUNCTION(name) static PFN_##name name = NULL;
VULKAN_FUNCTIONS()
#undef VULKAN_DEVICE_FUNCTION
#undef VULKAN_GLOBAL_FUNCTION
#undef VULKAN_INSTANCE_FUNCTION
static PFN_vkGetInstanceProcAddr vkGetInstanceProcAddr = NULL;

/* Based on the headers found in
 * https://github.com/KhronosGroup/Vulkan-LoaderAndValidationLayers
 */
#if VK_HEADER_VERSION < 22
enum
{
    VK_ERROR_FRAGMENTED_POOL = -12,
};
#endif
#if VK_HEADER_VERSION < 38
enum
{
    VK_ERROR_OUT_OF_POOL_MEMORY_KHR = -1000069000
};
#endif

static const char *getVulkanResultString(VkResult result)
{
    switch ((int)result) {
#define RESULT_CASE(x) \
    case x:            \
        return #x
        RESULT_CASE(VK_SUCCESS);
        RESULT_CASE(VK_NOT_READY);
        RESULT_CASE(VK_TIMEOUT);
        RESULT_CASE(VK_EVENT_SET);
        RESULT_CASE(VK_EVENT_RESET);
        RESULT_CASE(VK_INCOMPLETE);
        RESULT_CASE(VK_ERROR_OUT_OF_HOST_MEMORY);
        RESULT_CASE(VK_ERROR_OUT_OF_DEVICE_MEMORY);
        RESULT_CASE(VK_ERROR_INITIALIZATION_FAILED);
        RESULT_CASE(VK_ERROR_DEVICE_LOST);
        RESULT_CASE(VK_ERROR_MEMORY_MAP_FAILED);
        RESULT_CASE(VK_ERROR_LAYER_NOT_PRESENT);
        RESULT_CASE(VK_ERROR_EXTENSION_NOT_PRESENT);
        RESULT_CASE(VK_ERROR_FEATURE_NOT_PRESENT);
        RESULT_CASE(VK_ERROR_INCOMPATIBLE_DRIVER);
        RESULT_CASE(VK_ERROR_TOO_MANY_OBJECTS);
        RESULT_CASE(VK_ERROR_FORMAT_NOT_SUPPORTED);
        RESULT_CASE(VK_ERROR_FRAGMENTED_POOL);
        RESULT_CASE(VK_ERROR_SURFACE_LOST_KHR);
        RESULT_CASE(VK_ERROR_NATIVE_WINDOW_IN_USE_KHR);
        RESULT_CASE(VK_SUBOPTIMAL_KHR);
        RESULT_CASE(VK_ERROR_OUT_OF_DATE_KHR);
        RESULT_CASE(VK_ERROR_INCOMPATIBLE_DISPLAY_KHR);
        RESULT_CASE(VK_ERROR_VALIDATION_FAILED_EXT);
        RESULT_CASE(VK_ERROR_OUT_OF_POOL_MEMORY_KHR);
        RESULT_CASE(VK_ERROR_INVALID_SHADER_NV);
#undef RESULT_CASE
    default:
        break;
    }
    return (result < 0) ? "VK_ERROR_<Unknown>" : "VK_<Unknown>";
}

typedef struct VulkanContext
{
    SDL_Window *window;
    VkInstance instance;
    VkDevice device;
    VkSurfaceKHR surface;
    VkSwapchainKHR swapchain;
    VkPhysicalDeviceProperties physicalDeviceProperties;
    VkPhysicalDeviceFeatures physicalDeviceFeatures;
    uint32_t graphicsQueueFamilyIndex;
    uint32_t presentQueueFamilyIndex;
    VkPhysicalDevice physicalDevice;
    VkQueue graphicsQueue;
    VkQueue presentQueue;
    VkSemaphore imageAvailableSemaphore;
    VkSemaphore renderingFinishedSemaphore;
    VkSurfaceCapabilitiesKHR surfaceCapabilities;
    VkSurfaceFormatKHR *surfaceFormats;
    uint32_t surfaceFormatsAllocatedCount;
    uint32_t surfaceFormatsCount;
    uint32_t swapchainDesiredImageCount;
    VkSurfaceFormatKHR surfaceFormat;
    VkExtent2D swapchainSize;
    VkCommandPool commandPool;
    uint32_t swapchainImageCount;
    VkImage *swapchainImages;
    VkCommandBuffer *commandBuffers;
    VkFence *fences;
} VulkanContext;

static SDLTest_CommonState *state;
static VulkanContext *vulkanContexts = NULL; // an array of state->num_windows items
static VulkanContext *vulkanContext = NULL;  // for the currently-rendering window

static void shutdownVulkan(SDL_bool doDestroySwapchain);

/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
static void quit(int rc)
{
    shutdownVulkan(SDL_TRUE);
    SDLTest_CommonQuit(state);
    exit(rc);
}

static void loadGlobalFunctions(void)
{
    vkGetInstanceProcAddr = SDL_Vulkan_GetVkGetInstanceProcAddr();
    if (!vkGetInstanceProcAddr) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "SDL_Vulkan_GetVkGetInstanceProcAddr(): %s\n",
                     SDL_GetError());
        quit(2);
    }

#define VULKAN_DEVICE_FUNCTION(name)
#define VULKAN_GLOBAL_FUNCTION(name)                                                   \
    name = (PFN_##name)vkGetInstanceProcAddr(VK_NULL_HANDLE, #name);                   \
    if (!name) {                                                                       \
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,                                     \
                     "vkGetInstanceProcAddr(VK_NULL_HANDLE, \"" #name "\") failed\n"); \
        quit(2);                                                                       \
    }
#define VULKAN_INSTANCE_FUNCTION(name)
    VULKAN_FUNCTIONS()
#undef VULKAN_DEVICE_FUNCTION
#undef VULKAN_GLOBAL_FUNCTION
#undef VULKAN_INSTANCE_FUNCTION
}

static void createInstance(void)
{
    VkApplicationInfo appInfo = { 0 };
    VkInstanceCreateInfo instanceCreateInfo = { 0 };
    const char **extensions = NULL;
    unsigned extensionCount = 0;
    VkResult result;

    appInfo.sType = VK_STRUCTURE_TYPE_APPLICATION_INFO;
    appInfo.apiVersion = VK_API_VERSION_1_0;
    instanceCreateInfo.sType = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO;
    instanceCreateInfo.pApplicationInfo = &appInfo;
    if (!SDL_Vulkan_GetInstanceExtensions(NULL, &extensionCount, NULL)) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "SDL_Vulkan_GetInstanceExtensions(): %s\n",
                     SDL_GetError());
        quit(2);
    }
    extensions = (const char **)SDL_malloc(sizeof(const char *) * extensionCount);
    if (extensions == NULL) {
        SDL_OutOfMemory();
        quit(2);
    }
    if (!SDL_Vulkan_GetInstanceExtensions(NULL, &extensionCount, extensions)) {
        SDL_free((void *)extensions);
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "SDL_Vulkan_GetInstanceExtensions(): %s\n",
                     SDL_GetError());
        quit(2);
    }
    instanceCreateInfo.enabledExtensionCount = extensionCount;
    instanceCreateInfo.ppEnabledExtensionNames = extensions;
    result = vkCreateInstance(&instanceCreateInfo, NULL, &vulkanContext->instance);
    SDL_free((void *)extensions);
    if (result != VK_SUCCESS) {
        vulkanContext->instance = VK_NULL_HANDLE;
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkCreateInstance(): %s\n",
                     getVulkanResultString(result));
        quit(2);
    }
}

static void loadInstanceFunctions(void)
{
#define VULKAN_DEVICE_FUNCTION(name)
#define VULKAN_GLOBAL_FUNCTION(name)
#define VULKAN_INSTANCE_FUNCTION(name)                                           \
    name = (PFN_##name)vkGetInstanceProcAddr(vulkanContext->instance, #name);    \
    if (!name) {                                                                 \
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,                               \
                     "vkGetInstanceProcAddr(instance, \"" #name "\") failed\n"); \
        quit(2);                                                                 \
    }
    VULKAN_FUNCTIONS()
#undef VULKAN_DEVICE_FUNCTION
#undef VULKAN_GLOBAL_FUNCTION
#undef VULKAN_INSTANCE_FUNCTION
}

static void createSurface(void)
{
    if (!SDL_Vulkan_CreateSurface(vulkanContext->window,
                                  vulkanContext->instance,
                                  &vulkanContext->surface)) {
        vulkanContext->surface = VK_NULL_HANDLE;
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "SDL_Vulkan_CreateSurface(): %s\n", SDL_GetError());
        quit(2);
    }
}

static void findPhysicalDevice(void)
{
    uint32_t physicalDeviceCount = 0;
    VkPhysicalDevice *physicalDevices;
    VkQueueFamilyProperties *queueFamiliesProperties = NULL;
    uint32_t queueFamiliesPropertiesAllocatedSize = 0;
    VkExtensionProperties *deviceExtensions = NULL;
    uint32_t deviceExtensionsAllocatedSize = 0;
    uint32_t physicalDeviceIndex;
    VkResult result;

    result = vkEnumeratePhysicalDevices(vulkanContext->instance, &physicalDeviceCount, NULL);
    if (result != VK_SUCCESS) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkEnumeratePhysicalDevices(): %s\n",
                     getVulkanResultString(result));
        quit(2);
    }
    if (physicalDeviceCount == 0) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkEnumeratePhysicalDevices(): no physical devices\n");
        quit(2);
    }
    physicalDevices = (VkPhysicalDevice *)SDL_malloc(sizeof(VkPhysicalDevice) * physicalDeviceCount);
    if (physicalDevices == NULL) {
        SDL_OutOfMemory();
        quit(2);
    }
    result = vkEnumeratePhysicalDevices(vulkanContext->instance, &physicalDeviceCount, physicalDevices);
    if (result != VK_SUCCESS) {
        SDL_free(physicalDevices);
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkEnumeratePhysicalDevices(): %s\n",
                     getVulkanResultString(result));
        quit(2);
    }
    vulkanContext->physicalDevice = NULL;
    for (physicalDeviceIndex = 0; physicalDeviceIndex < physicalDeviceCount; physicalDeviceIndex++) {
        uint32_t queueFamiliesCount = 0;
        uint32_t queueFamilyIndex;
        uint32_t deviceExtensionCount = 0;
        SDL_bool hasSwapchainExtension = SDL_FALSE;
        uint32_t i;

        VkPhysicalDevice physicalDevice = physicalDevices[physicalDeviceIndex];
        vkGetPhysicalDeviceProperties(physicalDevice, &vulkanContext->physicalDeviceProperties);
        if (VK_VERSION_MAJOR(vulkanContext->physicalDeviceProperties.apiVersion) < 1) {
            continue;
        }
        vkGetPhysicalDeviceFeatures(physicalDevice, &vulkanContext->physicalDeviceFeatures);
        vkGetPhysicalDeviceQueueFamilyProperties(physicalDevice, &queueFamiliesCount, NULL);
        if (queueFamiliesCount == 0) {
            continue;
        }
        if (queueFamiliesPropertiesAllocatedSize < queueFamiliesCount) {
            SDL_free(queueFamiliesProperties);
            queueFamiliesPropertiesAllocatedSize = queueFamiliesCount;
            queueFamiliesProperties = (VkQueueFamilyProperties *)SDL_malloc(sizeof(VkQueueFamilyProperties) * queueFamiliesPropertiesAllocatedSize);
            if (queueFamiliesProperties == NULL) {
                SDL_free(physicalDevices);
                SDL_free(deviceExtensions);
                SDL_OutOfMemory();
                quit(2);
            }
        }
        vkGetPhysicalDeviceQueueFamilyProperties(physicalDevice, &queueFamiliesCount, queueFamiliesProperties);
        vulkanContext->graphicsQueueFamilyIndex = queueFamiliesCount;
        vulkanContext->presentQueueFamilyIndex = queueFamiliesCount;
        for (queueFamilyIndex = 0; queueFamilyIndex < queueFamiliesCount; queueFamilyIndex++) {
            VkBool32 supported = 0;

            if (queueFamiliesProperties[queueFamilyIndex].queueCount == 0) {
                continue;
            }

            if (queueFamiliesProperties[queueFamilyIndex].queueFlags & VK_QUEUE_GRAPHICS_BIT) {
                vulkanContext->graphicsQueueFamilyIndex = queueFamilyIndex;
            }

            result = vkGetPhysicalDeviceSurfaceSupportKHR(physicalDevice, queueFamilyIndex, vulkanContext->surface, &supported);
            if (result != VK_SUCCESS) {
                SDL_free(physicalDevices);
                SDL_free(queueFamiliesProperties);
                SDL_free(deviceExtensions);
                SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                             "vkGetPhysicalDeviceSurfaceSupportKHR(): %s\n",
                             getVulkanResultString(result));
                quit(2);
            }
            if (supported) {
                vulkanContext->presentQueueFamilyIndex = queueFamilyIndex;
                if (queueFamiliesProperties[queueFamilyIndex].queueFlags & VK_QUEUE_GRAPHICS_BIT) {
                    break; // use this queue because it can present and do graphics
                }
            }
        }

        if (vulkanContext->graphicsQueueFamilyIndex == queueFamiliesCount) { // no good queues found
            continue;
        }
        if (vulkanContext->presentQueueFamilyIndex == queueFamiliesCount) { // no good queues found
            continue;
        }
        result = vkEnumerateDeviceExtensionProperties(physicalDevice, NULL, &deviceExtensionCount, NULL);
        if (result != VK_SUCCESS) {
            SDL_free(physicalDevices);
            SDL_free(queueFamiliesProperties);
            SDL_free(deviceExtensions);
            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                         "vkEnumerateDeviceExtensionProperties(): %s\n",
                         getVulkanResultString(result));
            quit(2);
        }
        if (deviceExtensionCount == 0) {
            continue;
        }
        if (deviceExtensionsAllocatedSize < deviceExtensionCount) {
            SDL_free(deviceExtensions);
            deviceExtensionsAllocatedSize = deviceExtensionCount;
            deviceExtensions = SDL_malloc(sizeof(VkExtensionProperties) * deviceExtensionsAllocatedSize);
            if (deviceExtensions == NULL) {
                SDL_free(physicalDevices);
                SDL_free(queueFamiliesProperties);
                SDL_OutOfMemory();
                quit(2);
            }
        }
        result = vkEnumerateDeviceExtensionProperties(physicalDevice, NULL, &deviceExtensionCount, deviceExtensions);
        if (result != VK_SUCCESS) {
            SDL_free(physicalDevices);
            SDL_free(queueFamiliesProperties);
            SDL_free(deviceExtensions);
            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                         "vkEnumerateDeviceExtensionProperties(): %s\n",
                         getVulkanResultString(result));
            quit(2);
        }
        for (i = 0; i < deviceExtensionCount; i++) {
            if (SDL_strcmp(deviceExtensions[i].extensionName, VK_KHR_SWAPCHAIN_EXTENSION_NAME) == 0) {
                hasSwapchainExtension = SDL_TRUE;
                break;
            }
        }
        if (!hasSwapchainExtension) {
            continue;
        }
        vulkanContext->physicalDevice = physicalDevice;
        break;
    }
    SDL_free(physicalDevices);
    SDL_free(queueFamiliesProperties);
    SDL_free(deviceExtensions);
    if (!vulkanContext->physicalDevice) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Vulkan: no viable physical devices found");
        quit(2);
    }
}

static void createDevice(void)
{
    VkDeviceQueueCreateInfo deviceQueueCreateInfo[1] = { { 0 } };
    static const float queuePriority[] = { 1.0f };
    VkDeviceCreateInfo deviceCreateInfo = { 0 };
    static const char *const deviceExtensionNames[] = {
        VK_KHR_SWAPCHAIN_EXTENSION_NAME,
    };
    VkResult result;

    deviceQueueCreateInfo->sType = VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO;
    deviceQueueCreateInfo->queueFamilyIndex = vulkanContext->graphicsQueueFamilyIndex;
    deviceQueueCreateInfo->queueCount = 1;
    deviceQueueCreateInfo->pQueuePriorities = &queuePriority[0];

    deviceCreateInfo.sType = VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO;
    deviceCreateInfo.queueCreateInfoCount = 1;
    deviceCreateInfo.pQueueCreateInfos = deviceQueueCreateInfo;
    deviceCreateInfo.pEnabledFeatures = NULL;
    deviceCreateInfo.enabledExtensionCount = SDL_arraysize(deviceExtensionNames);
    deviceCreateInfo.ppEnabledExtensionNames = deviceExtensionNames;
    result = vkCreateDevice(vulkanContext->physicalDevice, &deviceCreateInfo, NULL, &vulkanContext->device);
    if (result != VK_SUCCESS) {
        vulkanContext->device = VK_NULL_HANDLE;
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "vkCreateDevice(): %s\n", getVulkanResultString(result));
        quit(2);
    }
}

static void loadDeviceFunctions(void)
{
#define VULKAN_DEVICE_FUNCTION(name)                                         \
    name = (PFN_##name)vkGetDeviceProcAddr(vulkanContext->device, #name);    \
    if (!name) {                                                             \
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,                           \
                     "vkGetDeviceProcAddr(device, \"" #name "\") failed\n"); \
        quit(2);                                                             \
    }
#define VULKAN_GLOBAL_FUNCTION(name)
#define VULKAN_INSTANCE_FUNCTION(name)
    VULKAN_FUNCTIONS()
#undef VULKAN_DEVICE_FUNCTION
#undef VULKAN_GLOBAL_FUNCTION
#undef VULKAN_INSTANCE_FUNCTION
}

#undef VULKAN_FUNCTIONS

static void getQueues(void)
{
    vkGetDeviceQueue(vulkanContext->device,
                     vulkanContext->graphicsQueueFamilyIndex,
                     0,
                     &vulkanContext->graphicsQueue);
    if (vulkanContext->graphicsQueueFamilyIndex != vulkanContext->presentQueueFamilyIndex) {
        vkGetDeviceQueue(vulkanContext->device,
                         vulkanContext->presentQueueFamilyIndex,
                         0,
                         &vulkanContext->presentQueue);
    } else {
        vulkanContext->presentQueue = vulkanContext->graphicsQueue;
    }
}

static void createSemaphore(VkSemaphore *semaphore)
{
    VkResult result;

    VkSemaphoreCreateInfo createInfo = { 0 };
    createInfo.sType = VK_STRUCTURE_TYPE_SEMAPHORE_CREATE_INFO;
    result = vkCreateSemaphore(vulkanContext->device, &createInfo, NULL, semaphore);
    if (result != VK_SUCCESS) {
        *semaphore = VK_NULL_HANDLE;
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkCreateSemaphore(): %s\n",
                     getVulkanResultString(result));
        quit(2);
    }
}

static void createSemaphores(void)
{
    createSemaphore(&vulkanContext->imageAvailableSemaphore);
    createSemaphore(&vulkanContext->renderingFinishedSemaphore);
}

static void getSurfaceCaps(void)
{
    VkResult result = vkGetPhysicalDeviceSurfaceCapabilitiesKHR(vulkanContext->physicalDevice, vulkanContext->surface, &vulkanContext->surfaceCapabilities);
    if (result != VK_SUCCESS) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkGetPhysicalDeviceSurfaceCapabilitiesKHR(): %s\n",
                     getVulkanResultString(result));
        quit(2);
    }

    // check surface usage
    if (!(vulkanContext->surfaceCapabilities.supportedUsageFlags & VK_IMAGE_USAGE_TRANSFER_DST_BIT)) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "Vulkan surface doesn't support VK_IMAGE_USAGE_TRANSFER_DST_BIT\n");
        quit(2);
    }
}

static void getSurfaceFormats(void)
{
    VkResult result = vkGetPhysicalDeviceSurfaceFormatsKHR(vulkanContext->physicalDevice,
                                                           vulkanContext->surface,
                                                           &vulkanContext->surfaceFormatsCount,
                                                           NULL);
    if (result != VK_SUCCESS) {
        vulkanContext->surfaceFormatsCount = 0;
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkGetPhysicalDeviceSurfaceFormatsKHR(): %s\n",
                     getVulkanResultString(result));
        quit(2);
    }
    if (vulkanContext->surfaceFormatsCount > vulkanContext->surfaceFormatsAllocatedCount) {
        vulkanContext->surfaceFormatsAllocatedCount = vulkanContext->surfaceFormatsCount;
        SDL_free(vulkanContext->surfaceFormats);
        vulkanContext->surfaceFormats = (VkSurfaceFormatKHR *)SDL_malloc(sizeof(VkSurfaceFormatKHR) * vulkanContext->surfaceFormatsAllocatedCount);
        if (!vulkanContext->surfaceFormats) {
            vulkanContext->surfaceFormatsCount = 0;
            SDL_OutOfMemory();
            quit(2);
        }
    }
    result = vkGetPhysicalDeviceSurfaceFormatsKHR(vulkanContext->physicalDevice,
                                                  vulkanContext->surface,
                                                  &vulkanContext->surfaceFormatsCount,
                                                  vulkanContext->surfaceFormats);
    if (result != VK_SUCCESS) {
        vulkanContext->surfaceFormatsCount = 0;
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkGetPhysicalDeviceSurfaceFormatsKHR(): %s\n",
                     getVulkanResultString(result));
        quit(2);
    }
}

static void getSwapchainImages(void)
{
    VkResult result;

    SDL_free(vulkanContext->swapchainImages);
    vulkanContext->swapchainImages = NULL;
    result = vkGetSwapchainImagesKHR(vulkanContext->device, vulkanContext->swapchain, &vulkanContext->swapchainImageCount, NULL);
    if (result != VK_SUCCESS) {
        vulkanContext->swapchainImageCount = 0;
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkGetSwapchainImagesKHR(): %s\n",
                     getVulkanResultString(result));
        quit(2);
    }
    vulkanContext->swapchainImages = SDL_malloc(sizeof(VkImage) * vulkanContext->swapchainImageCount);
    if (!vulkanContext->swapchainImages) {
        SDL_OutOfMemory();
        quit(2);
    }
    result = vkGetSwapchainImagesKHR(vulkanContext->device,
                                     vulkanContext->swapchain,
                                     &vulkanContext->swapchainImageCount,
                                     vulkanContext->swapchainImages);
    if (result != VK_SUCCESS) {
        SDL_free(vulkanContext->swapchainImages);
        vulkanContext->swapchainImages = NULL;
        vulkanContext->swapchainImageCount = 0;
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkGetSwapchainImagesKHR(): %s\n",
                     getVulkanResultString(result));
        quit(2);
    }
}

static SDL_bool createSwapchain(void)
{
    uint32_t i;
    int w, h;
    VkSwapchainCreateInfoKHR createInfo = { 0 };
    VkResult result;

    // pick an image count
    vulkanContext->swapchainDesiredImageCount = vulkanContext->surfaceCapabilities.minImageCount + 1;
    if ((vulkanContext->swapchainDesiredImageCount > vulkanContext->surfaceCapabilities.maxImageCount) &&
        (vulkanContext->surfaceCapabilities.maxImageCount > 0)) {
        vulkanContext->swapchainDesiredImageCount = vulkanContext->surfaceCapabilities.maxImageCount;
    }

    // pick a format
    if ((vulkanContext->surfaceFormatsCount == 1) &&
        (vulkanContext->surfaceFormats[0].format == VK_FORMAT_UNDEFINED)) {
        // aren't any preferred formats, so we pick
        vulkanContext->surfaceFormat.colorSpace = VK_COLORSPACE_SRGB_NONLINEAR_KHR;
        vulkanContext->surfaceFormat.format = VK_FORMAT_R8G8B8A8_UNORM;
    } else {
        vulkanContext->surfaceFormat = vulkanContext->surfaceFormats[0];
        for (i = 0; i < vulkanContext->surfaceFormatsCount; i++) {
            if (vulkanContext->surfaceFormats[i].format == VK_FORMAT_R8G8B8A8_UNORM) {
                vulkanContext->surfaceFormat = vulkanContext->surfaceFormats[i];
                break;
            }
        }
    }

    // get size
    SDL_Vulkan_GetDrawableSize(vulkanContext->window, &w, &h);

    // Clamp the size to the allowable image extent.
    // SDL_Vulkan_GetDrawableSize()'s result it not always in this range (bug #3287)
    vulkanContext->swapchainSize.width = SDL_clamp((uint32_t)w,
                                                   vulkanContext->surfaceCapabilities.minImageExtent.width,
                                                   vulkanContext->surfaceCapabilities.maxImageExtent.width);

    vulkanContext->swapchainSize.height = SDL_clamp((uint32_t)h,
                                                    vulkanContext->surfaceCapabilities.minImageExtent.height,
                                                    vulkanContext->surfaceCapabilities.maxImageExtent.height);

    if (w == 0 || h == 0) {
        return SDL_FALSE;
    }

    getSurfaceCaps();

    createInfo.sType = VK_STRUCTURE_TYPE_SWAPCHAIN_CREATE_INFO_KHR;
    createInfo.surface = vulkanContext->surface;
    createInfo.minImageCount = vulkanContext->swapchainDesiredImageCount;
    createInfo.imageFormat = vulkanContext->surfaceFormat.format;
    createInfo.imageColorSpace = vulkanContext->surfaceFormat.colorSpace;
    createInfo.imageExtent = vulkanContext->swapchainSize;
    createInfo.imageArrayLayers = 1;
    createInfo.imageUsage = VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT | VK_IMAGE_USAGE_TRANSFER_DST_BIT;
    createInfo.imageSharingMode = VK_SHARING_MODE_EXCLUSIVE;
    createInfo.preTransform = vulkanContext->surfaceCapabilities.currentTransform;
    createInfo.compositeAlpha = VK_COMPOSITE_ALPHA_OPAQUE_BIT_KHR;
    createInfo.presentMode = VK_PRESENT_MODE_FIFO_KHR;
    createInfo.clipped = VK_TRUE;
    createInfo.oldSwapchain = vulkanContext->swapchain;
    result = vkCreateSwapchainKHR(vulkanContext->device, &createInfo, NULL, &vulkanContext->swapchain);

    if (createInfo.oldSwapchain) {
        vkDestroySwapchainKHR(vulkanContext->device, createInfo.oldSwapchain, NULL);
    }

    if (result != VK_SUCCESS) {
        vulkanContext->swapchain = VK_NULL_HANDLE;
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkCreateSwapchainKHR(): %s\n",
                     getVulkanResultString(result));
        quit(2);
    }

    getSwapchainImages();
    return SDL_TRUE;
}

static void destroySwapchain(void)
{
    if (vulkanContext->swapchain) {
        vkDestroySwapchainKHR(vulkanContext->device, vulkanContext->swapchain, NULL);
        vulkanContext->swapchain = VK_NULL_HANDLE;
    }
    SDL_free(vulkanContext->swapchainImages);
    vulkanContext->swapchainImages = NULL;
}

static void destroyCommandBuffers(void)
{
    if (vulkanContext->commandBuffers) {
        vkFreeCommandBuffers(vulkanContext->device,
                             vulkanContext->commandPool,
                             vulkanContext->swapchainImageCount,
                             vulkanContext->commandBuffers);
        SDL_free(vulkanContext->commandBuffers);
        vulkanContext->commandBuffers = NULL;
    }
}

static void destroyCommandPool(void)
{
    if (vulkanContext->commandPool) {
        vkDestroyCommandPool(vulkanContext->device, vulkanContext->commandPool, NULL);
    }
    vulkanContext->commandPool = VK_NULL_HANDLE;
}

static void createCommandPool(void)
{
    VkResult result;
    VkCommandPoolCreateInfo createInfo = { 0 };
    createInfo.sType = VK_STRUCTURE_TYPE_COMMAND_POOL_CREATE_INFO;
    createInfo.flags = VK_COMMAND_POOL_CREATE_RESET_COMMAND_BUFFER_BIT | VK_COMMAND_POOL_CREATE_TRANSIENT_BIT;
    createInfo.queueFamilyIndex = vulkanContext->graphicsQueueFamilyIndex;
    result = vkCreateCommandPool(vulkanContext->device, &createInfo, NULL, &vulkanContext->commandPool);
    if (result != VK_SUCCESS) {
        vulkanContext->commandPool = VK_NULL_HANDLE;
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkCreateCommandPool(): %s\n",
                     getVulkanResultString(result));
        quit(2);
    }
}

static void createCommandBuffers(void)
{
    VkResult result;
    VkCommandBufferAllocateInfo allocateInfo = { 0 };
    allocateInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_ALLOCATE_INFO;
    allocateInfo.commandPool = vulkanContext->commandPool;
    allocateInfo.level = VK_COMMAND_BUFFER_LEVEL_PRIMARY;
    allocateInfo.commandBufferCount = vulkanContext->swapchainImageCount;
    vulkanContext->commandBuffers = (VkCommandBuffer *)SDL_malloc(sizeof(VkCommandBuffer) * vulkanContext->swapchainImageCount);
    result = vkAllocateCommandBuffers(vulkanContext->device, &allocateInfo, vulkanContext->commandBuffers);
    if (result != VK_SUCCESS) {
        SDL_free(vulkanContext->commandBuffers);
        vulkanContext->commandBuffers = NULL;
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkAllocateCommandBuffers(): %s\n",
                     getVulkanResultString(result));
        quit(2);
    }
}

static void createFences(void)
{
    uint32_t i;

    vulkanContext->fences = SDL_malloc(sizeof(VkFence) * vulkanContext->swapchainImageCount);
    if (!vulkanContext->fences) {
        SDL_OutOfMemory();
        quit(2);
    }
    for (i = 0; i < vulkanContext->swapchainImageCount; i++) {
        VkResult result;
        VkFenceCreateInfo createInfo = { 0 };
        createInfo.sType = VK_STRUCTURE_TYPE_FENCE_CREATE_INFO;
        createInfo.flags = VK_FENCE_CREATE_SIGNALED_BIT;
        result = vkCreateFence(vulkanContext->device, &createInfo, NULL, &vulkanContext->fences[i]);
        if (result != VK_SUCCESS) {
            for (; i > 0; i--) {
                vkDestroyFence(vulkanContext->device, vulkanContext->fences[i - 1], NULL);
            }
            SDL_free(vulkanContext->fences);
            vulkanContext->fences = NULL;
            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                         "vkCreateFence(): %s\n",
                         getVulkanResultString(result));
            quit(2);
        }
    }
}

static void destroyFences(void)
{
    uint32_t i;

    if (!vulkanContext->fences) {
        return;
    }

    for (i = 0; i < vulkanContext->swapchainImageCount; i++) {
        vkDestroyFence(vulkanContext->device, vulkanContext->fences[i], NULL);
    }
    SDL_free(vulkanContext->fences);
    vulkanContext->fences = NULL;
}

static void recordPipelineImageBarrier(VkCommandBuffer commandBuffer,
                                       VkAccessFlags sourceAccessMask,
                                       VkAccessFlags destAccessMask,
                                       VkImageLayout sourceLayout,
                                       VkImageLayout destLayout,
                                       VkImage image)
{
    VkImageMemoryBarrier barrier = { 0 };
    barrier.sType = VK_STRUCTURE_TYPE_IMAGE_MEMORY_BARRIER;
    barrier.srcAccessMask = sourceAccessMask;
    barrier.dstAccessMask = destAccessMask;
    barrier.oldLayout = sourceLayout;
    barrier.newLayout = destLayout;
    barrier.srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
    barrier.dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED;
    barrier.image = image;
    barrier.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
    barrier.subresourceRange.baseMipLevel = 0;
    barrier.subresourceRange.levelCount = 1;
    barrier.subresourceRange.baseArrayLayer = 0;
    barrier.subresourceRange.layerCount = 1;
    vkCmdPipelineBarrier(commandBuffer,
                         VK_PIPELINE_STAGE_TRANSFER_BIT,
                         VK_PIPELINE_STAGE_TRANSFER_BIT,
                         0,
                         0,
                         NULL,
                         0,
                         NULL,
                         1,
                         &barrier);
}

static void rerecordCommandBuffer(uint32_t frameIndex, const VkClearColorValue *clearColor)
{
    VkCommandBuffer commandBuffer = vulkanContext->commandBuffers[frameIndex];
    VkImage image = vulkanContext->swapchainImages[frameIndex];
    VkCommandBufferBeginInfo beginInfo = { 0 };
    VkImageSubresourceRange clearRange = { 0 };

    VkResult result = vkResetCommandBuffer(commandBuffer, 0);
    if (result != VK_SUCCESS) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkResetCommandBuffer(): %s\n",
                     getVulkanResultString(result));
        quit(2);
    }
    beginInfo.sType = VK_STRUCTURE_TYPE_COMMAND_BUFFER_BEGIN_INFO;
    beginInfo.flags = VK_COMMAND_BUFFER_USAGE_SIMULTANEOUS_USE_BIT;
    result = vkBeginCommandBuffer(commandBuffer, &beginInfo);
    if (result != VK_SUCCESS) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkBeginCommandBuffer(): %s\n",
                     getVulkanResultString(result));
        quit(2);
    }
    recordPipelineImageBarrier(commandBuffer,
                               0,
                               VK_ACCESS_TRANSFER_WRITE_BIT,
                               VK_IMAGE_LAYOUT_UNDEFINED,
                               VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
                               image);
    clearRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
    clearRange.baseMipLevel = 0;
    clearRange.levelCount = 1;
    clearRange.baseArrayLayer = 0;
    clearRange.layerCount = 1;
    vkCmdClearColorImage(commandBuffer, image, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL, clearColor, 1, &clearRange);
    recordPipelineImageBarrier(commandBuffer,
                               VK_ACCESS_TRANSFER_WRITE_BIT,
                               VK_ACCESS_MEMORY_READ_BIT,
                               VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL,
                               VK_IMAGE_LAYOUT_PRESENT_SRC_KHR,
                               image);
    result = vkEndCommandBuffer(commandBuffer);
    if (result != VK_SUCCESS) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkEndCommandBuffer(): %s\n",
                     getVulkanResultString(result));
        quit(2);
    }
}

static void destroySwapchainAndSwapchainSpecificStuff(SDL_bool doDestroySwapchain)
{
    if (vkDeviceWaitIdle != NULL) {
        vkDeviceWaitIdle(vulkanContext->device);
    }
    destroyFences();
    destroyCommandBuffers();
    destroyCommandPool();
    if (doDestroySwapchain) {
        destroySwapchain();
    }
}

static SDL_bool createNewSwapchainAndSwapchainSpecificStuff(void)
{
    destroySwapchainAndSwapchainSpecificStuff(SDL_FALSE);
    getSurfaceCaps();
    getSurfaceFormats();
    if (!createSwapchain()) {
        return SDL_FALSE;
    }
    createCommandPool();
    createCommandBuffers();
    createFences();
    return SDL_TRUE;
}

static void initVulkan(void)
{
    int i;

    SDL_Vulkan_LoadLibrary(NULL);

    vulkanContexts = (VulkanContext *)SDL_calloc(state->num_windows, sizeof(VulkanContext));
    if (vulkanContexts == NULL) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Out of memory!");
        quit(2);
    }

    for (i = 0; i < state->num_windows; ++i) {
        vulkanContext = &vulkanContexts[i];
        vulkanContext->window = state->windows[i];
        loadGlobalFunctions();
        createInstance();
        loadInstanceFunctions();
        createSurface();
        findPhysicalDevice();
        createDevice();
        loadDeviceFunctions();
        getQueues();
        createSemaphores();
        createNewSwapchainAndSwapchainSpecificStuff();
    }
}

static void shutdownVulkan(SDL_bool doDestroySwapchain)
{
    if (vulkanContexts) {
        int i;
        for (i = 0; i < state->num_windows; ++i) {
            vulkanContext = &vulkanContexts[i];
            if (vulkanContext->device && vkDeviceWaitIdle) {
                vkDeviceWaitIdle(vulkanContext->device);
            }

            destroySwapchainAndSwapchainSpecificStuff(doDestroySwapchain);

            if (vulkanContext->imageAvailableSemaphore && vkDestroySemaphore) {
                vkDestroySemaphore(vulkanContext->device, vulkanContext->imageAvailableSemaphore, NULL);
            }

            if (vulkanContext->renderingFinishedSemaphore && vkDestroySemaphore) {
                vkDestroySemaphore(vulkanContext->device, vulkanContext->renderingFinishedSemaphore, NULL);
            }

            if (vulkanContext->device && vkDestroyDevice) {
                vkDestroyDevice(vulkanContext->device, NULL);
            }

            if (vulkanContext->surface && vkDestroySurfaceKHR) {
                vkDestroySurfaceKHR(vulkanContext->instance, vulkanContext->surface, NULL);
            }

            if (vulkanContext->instance && vkDestroyInstance) {
                vkDestroyInstance(vulkanContext->instance, NULL);
            }

            SDL_free(vulkanContext->surfaceFormats);
        }
        SDL_free(vulkanContexts);
        vulkanContexts = NULL;
    }

    SDL_Vulkan_UnloadLibrary();
}

static SDL_bool render(void)
{
    uint32_t frameIndex;
    VkResult result;
    double currentTime;
    VkClearColorValue clearColor = { { 0 } };
    VkPipelineStageFlags waitDestStageMask = VK_PIPELINE_STAGE_TRANSFER_BIT;
    VkSubmitInfo submitInfo = { 0 };
    VkPresentInfoKHR presentInfo = { 0 };
    int w, h;

    if (!vulkanContext->swapchain) {
        SDL_bool retval = createNewSwapchainAndSwapchainSpecificStuff();
        if (!retval) {
            SDL_Delay(100);
        }
        return retval;
    }
    result = vkAcquireNextImageKHR(vulkanContext->device,
                                   vulkanContext->swapchain,
                                   UINT64_MAX,
                                   vulkanContext->imageAvailableSemaphore,
                                   VK_NULL_HANDLE,
                                   &frameIndex);
    if (result == VK_ERROR_OUT_OF_DATE_KHR) {
        return createNewSwapchainAndSwapchainSpecificStuff();
    }

    if ((result != VK_SUBOPTIMAL_KHR) && (result != VK_SUCCESS)) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkAcquireNextImageKHR(): %s\n",
                     getVulkanResultString(result));
        quit(2);
    }
    result = vkWaitForFences(vulkanContext->device, 1, &vulkanContext->fences[frameIndex], VK_FALSE, UINT64_MAX);
    if (result != VK_SUCCESS) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "vkWaitForFences(): %s\n", getVulkanResultString(result));
        quit(2);
    }
    result = vkResetFences(vulkanContext->device, 1, &vulkanContext->fences[frameIndex]);
    if (result != VK_SUCCESS) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "vkResetFences(): %s\n", getVulkanResultString(result));
        quit(2);
    }
    currentTime = (double)SDL_GetPerformanceCounter() / SDL_GetPerformanceFrequency();
    clearColor.float32[0] = (float)(0.5 + 0.5 * SDL_sin(currentTime));
    clearColor.float32[1] = (float)(0.5 + 0.5 * SDL_sin(currentTime + M_PI * 2 / 3));
    clearColor.float32[2] = (float)(0.5 + 0.5 * SDL_sin(currentTime + M_PI * 4 / 3));
    clearColor.float32[3] = 1;
    rerecordCommandBuffer(frameIndex, &clearColor);
    submitInfo.sType = VK_STRUCTURE_TYPE_SUBMIT_INFO;
    submitInfo.waitSemaphoreCount = 1;
    submitInfo.pWaitSemaphores = &vulkanContext->imageAvailableSemaphore;
    submitInfo.pWaitDstStageMask = &waitDestStageMask;
    submitInfo.commandBufferCount = 1;
    submitInfo.pCommandBuffers = &vulkanContext->commandBuffers[frameIndex];
    submitInfo.signalSemaphoreCount = 1;
    submitInfo.pSignalSemaphores = &vulkanContext->renderingFinishedSemaphore;
    result = vkQueueSubmit(vulkanContext->graphicsQueue, 1, &submitInfo, vulkanContext->fences[frameIndex]);

    if (result != VK_SUCCESS) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "vkQueueSubmit(): %s\n", getVulkanResultString(result));
        quit(2);
    }
    presentInfo.sType = VK_STRUCTURE_TYPE_PRESENT_INFO_KHR;
    presentInfo.waitSemaphoreCount = 1;
    presentInfo.pWaitSemaphores = &vulkanContext->renderingFinishedSemaphore;
    presentInfo.swapchainCount = 1;
    presentInfo.pSwapchains = &vulkanContext->swapchain;
    presentInfo.pImageIndices = &frameIndex;
    result = vkQueuePresentKHR(vulkanContext->presentQueue, &presentInfo);
    if ((result == VK_ERROR_OUT_OF_DATE_KHR) || (result == VK_SUBOPTIMAL_KHR)) {
        return createNewSwapchainAndSwapchainSpecificStuff();
    }

    if (result != VK_SUCCESS) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                     "vkQueuePresentKHR(): %s\n",
                     getVulkanResultString(result));
        quit(2);
    }
    SDL_Vulkan_GetDrawableSize(vulkanContext->window, &w, &h);
    if (w != (int)vulkanContext->swapchainSize.width || h != (int)vulkanContext->swapchainSize.height) {
        return createNewSwapchainAndSwapchainSpecificStuff();
    }
    return SDL_TRUE;
}

int main(int argc, char **argv)
{
    int done;
    SDL_DisplayMode mode;
    SDL_Event event;
    Uint32 then, now, frames;
    int dw, dh;

    /* Enable standard application logging */
    SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);

    /* Initialize test framework */
    state = SDLTest_CommonCreateState(argv, SDL_INIT_VIDEO);
    if (state == NULL) {
        return 1;
    }

    /* Set Vulkan parameters */
    state->window_flags |= SDL_WINDOW_VULKAN;
    state->skip_renderer = 1;

    if (!SDLTest_CommonDefaultArgs(state, argc, argv) || !SDLTest_CommonInit(state)) {
        SDLTest_CommonQuit(state);
        return 1;
    }

    SDL_GetCurrentDisplayMode(0, &mode);
    SDL_Log("Screen BPP    : %" SDL_PRIu32 "\n", SDL_BITSPERPIXEL(mode.format));
    SDL_GetWindowSize(state->windows[0], &dw, &dh);
    SDL_Log("Window Size   : %d,%d\n", dw, dh);
    SDL_Vulkan_GetDrawableSize(state->windows[0], &dw, &dh);
    SDL_Log("Draw Size     : %d,%d\n", dw, dh);
    SDL_Log("\n");

    initVulkan();

    /* Main render loop */
    frames = 0;
    then = SDL_GetTicks();
    done = 0;
    while (!done) {
        /* Check for events */
        frames++;
        while (SDL_PollEvent(&event)) {
            /* Need to destroy the swapchain before the window created
             * by SDL.
             */
            if (event.type == SDL_WINDOWEVENT_CLOSE) {
                destroySwapchainAndSwapchainSpecificStuff(SDL_TRUE);
            }
            SDLTest_CommonEvent(state, &event, &done);
        }

        if (!done) {
            int i;
            for (i = 0; i < state->num_windows; ++i) {
                if (state->windows[i]) {
                    vulkanContext = &vulkanContexts[i];
                    render();
                }
            }
        }
    }

    /* Print out some timing information */
    now = SDL_GetTicks();
    if (now > then) {
        SDL_Log("%2.2f frames per second\n", ((double)frames * 1000) / (now - then));
    }

    shutdownVulkan(SDL_TRUE);
    SDLTest_CommonQuit(state);
    return 0;
}

#endif