I'm following this Vulkan tutorial, and I'm trying to implement validation layers - here is my code:
#define GLFW_INCLUDE_VULKAN
#include <GLFW/glfw3.h>
#include <iostream>
#include <stdexcept>
#include <vector>
#include <cstring>
#include <cstdlib>
const uint32_t WIDTH = 800;
const uint32_t HEIGHT = 600;
const std::vector<const char*> validationLayers = {
"VK_LAYER_KHRONOS_validation"
};
#ifdef NDEBUG
const bool enableValidationLayers = false;
#else
const bool enableValidationLayers = true;
#endif
VkResult CreateDebugUtilsMessengerEXT(VkInstance instance, const VkDebugUtilsMessengerCreateInfoEXT* pCreateInfo, const VkAllocationCallbacks* pAllocator, VkDebugUtilsMessengerEXT* pDebugMessenger) {
auto func = (PFN_vkCreateDebugUtilsMessengerEXT) vkGetInstanceProcAddr(instance, "vkCreateDebugUtilsMessengerEXT");
if (func != nullptr) {
return func(instance, pCreateInfo, pAllocator, pDebugMessenger);
} else {
return VK_ERROR_EXTENSION_NOT_PRESENT;
}
}
void DestroyDebugUtilsMessengerEXT(VkInstance instance, VkDebugUtilsMessengerEXT debugMessenger, const VkAllocationCallbacks* pAllocator) {
auto func = (PFN_vkDestroyDebugUtilsMessengerEXT) vkGetInstanceProcAddr(instance, "vkDestroyDebugUtilsMessengerEXT");
if (func != nullptr) {
func(instance, debugMessenger, pAllocator);
}
}
class HelloTriangleApplication {
public:
void run() {
initWindow();
initVulkan();
mainLoop();
cleanup();
}
private:
GLFWwindow* window;
VkInstance instance;
VkDebugUtilsMessengerEXT debugMessenger;
void initWindow() {
glfwInit();
glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API);
glfwWindowHint(GLFW_RESIZABLE, GLFW_FALSE);
window = glfwCreateWindow(WIDTH, HEIGHT, "Vulkan", nullptr, nullptr);
}
void initVulkan() {
createInstance();
setupDebugMessenger();
}
void mainLoop() {
while (!glfwWindowShouldClose(window)) {
glfwPollEvents();
}
}
void cleanup() {
if (enableValidationLayers) {
DestroyDebugUtilsMessengerEXT(instance, debugMessenger, nullptr);
}
vkDestroyInstance(instance, nullptr);
glfwDestroyWindow(window);
glfwTerminate();
}
void createInstance() {
if (enableValidationLayers && !checkValidationLayerSupport()) {
throw std::runtime_error("validation layers requested, but not available!");
}
VkApplicationInfo appInfo{};
appInfo.sType = VK_STRUCTURE_TYPE_APPLICATION_INFO;
appInfo.pApplicationName = "Hello Triangle";
appInfo.applicationVersion = VK_MAKE_VERSION(1, 0, 0);
appInfo.pEngineName = "No Engine";
appInfo.engineVersion = VK_MAKE_VERSION(1, 0, 0);
appInfo.apiVersion = VK_API_VERSION_1_0;
VkInstanceCreateInfo createInfo{};
createInfo.sType = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO;
createInfo.pApplicationInfo = &appInfo;
auto extensions = getRequiredExtensions();
createInfo.enabledExtensionCount = static_cast<uint32_t>(extensions.size());
createInfo.ppEnabledExtensionNames = extensions.data();
VkDebugUtilsMessengerCreateInfoEXT debugCreateInfo{};
if (enableValidationLayers) {
createInfo.enabledLayerCount = static_cast<uint32_t>(validationLayers.size());
createInfo.ppEnabledLayerNames = validationLayers.data();
populateDebugMessengerCreateInfo(debugCreateInfo);
createInfo.pNext = (VkDebugUtilsMessengerCreateInfoEXT*) &debugCreateInfo;
} else {
createInfo.enabledLayerCount = 0;
createInfo.pNext = nullptr;
}
if (vkCreateInstance(&createInfo, nullptr, &instance) != VK_SUCCESS) {
throw std::runtime_error("failed to create instance!");
}
}
void populateDebugMessengerCreateInfo(VkDebugUtilsMessengerCreateInfoEXT& createInfo) {
createInfo = {};
createInfo.sType = VK_STRUCTURE_TYPE_DEBUG_UTILS_MESSENGER_CREATE_INFO_EXT;
createInfo.messageSeverity = VK_DEBUG_UTILS_MESSAGE_SEVERITY_VERBOSE_BIT_EXT | VK_DEBUG_UTILS_MESSAGE_SEVERITY_WARNING_BIT_EXT | VK_DEBUG_UTILS_MESSAGE_SEVERITY_ERROR_BIT_EXT;
createInfo.messageType = VK_DEBUG_UTILS_MESSAGE_TYPE_GENERAL_BIT_EXT | VK_DEBUG_UTILS_MESSAGE_TYPE_VALIDATION_BIT_EXT | VK_DEBUG_UTILS_MESSAGE_TYPE_PERFORMANCE_BIT_EXT;
createInfo.pfnUserCallback = debugCallback;
}
void setupDebugMessenger() {
if (!enableValidationLayers) return;
VkDebugUtilsMessengerCreateInfoEXT createInfo;
populateDebugMessengerCreateInfo(createInfo);
if (CreateDebugUtilsMessengerEXT(instance, &createInfo, nullptr, &debugMessenger) != VK_SUCCESS) {
throw std::runtime_error("failed to set up debug messenger!");
}
}
std::vector<const char*> getRequiredExtensions() {
uint32_t glfwExtensionCount = 0;
const char** glfwExtensions;
glfwExtensions = glfwGetRequiredInstanceExtensions(&glfwExtensionCount);
std::vector<const char*> extensions(glfwExtensions, glfwExtensions + glfwExtensionCount);
if (enableValidationLayers) {
extensions.push_back(VK_EXT_DEBUG_UTILS_EXTENSION_NAME);
}
return extensions;
}
bool checkValidationLayerSupport() {
uint32_t layerCount;
vkEnumerateInstanceLayerProperties(&layerCount, nullptr);
std::vector<VkLayerProperties> availableLayers(layerCount);
vkEnumerateInstanceLayerProperties(&layerCount, availableLayers.data());
for (const char* layerName : validationLayers) {
bool layerFound = false;
for (const auto& layerProperties : availableLayers) {
if (strcmp(layerName, layerProperties.layerName) == 0) {
layerFound = true;
break;
}
}
if (!layerFound) {
return false;
}
}
return true;
}
static VKAPI_ATTR VkBool32 VKAPI_CALL debugCallback(VkDebugUtilsMessageSeverityFlagBitsEXT messageSeverity, VkDebugUtilsMessageTypeFlagsEXT messageType, const VkDebugUtilsMessengerCallbackDataEXT* pCallbackData, void* pUserData) {
std::cerr << "validation layer: " << pCallbackData->pMessage << std::endl;
return VK_FALSE;
}
};
int main() {
HelloTriangleApplication app;
try {
app.run();
} catch (const std::exception& e) {
std::cerr << e.what() << std::endl;
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}
But when I run it, I get a black window (as expected), but I also get a cryptic error message:
validation layer: /usr/lib/i386-linux-gnu/libvulkan_intel.so: wrong ELF class: ELFCLASS32
validation layer: /usr/lib/i386-linux-gnu/libvulkan_lvp.so: wrong ELF class: ELFCLASS32
validation layer: /usr/lib/i386-linux-gnu/libvulkan_radeon.so: wrong ELF class: ELFCLASS32
If I remove the validation layers, this error message doesn't occur.
I also believe it has something to do with instance creation, because if I remove the
createInfo.pNext = (VkDebugUtilsMessengerCreateInfoEXT*) &debugCreateInfo;
line the error message disappears.
The vkcube demo works, so I'm not sure what's causing this specific code to fail.
Also: I'm using Nvidia as my driver. I followed the installation process shown in here.
The short answer is that those are harmless messages coming from the Vulkan loader and can be ignored.
The loader "hooks" your validation layer debug callback and uses it to send messages. The loader does a "trial" load of all installed Vulkan drivers on your system in order to determine which ones to report during device enumeration. Apparently, it can't or doesn't determine if a driver module has an incompatible ELF class before loading it and so can encounter this sort of error during this process.
See this loader code change for more background and discussion. It looks like the severity of this message was lowered to INFO level over a year ago. Your debug callback appears to be configured to not report INFO level messages. So, I don't know if you are running an older loader or I'm not reading your debug callback setup correctly. See also issues 262 and 644 in the same Vulkan Loader repository.
You can clean this up by filtering out these messages in your debug callback.
If your loader is over a year old and your debug callback is indeed not reporting INFO messages, then upgrading to a newer loader should also help.