diff --git a/HelloTriangleApplication.cpp b/HelloTriangleApplication.cpp
index 5123d3d..732ad87 100644
--- a/HelloTriangleApplication.cpp
+++ b/HelloTriangleApplication.cpp
@@ -98,4 +98,114 @@ VkShaderModule HelloTriangleApplication::createShaderModule(const std::vector<ch
     }
 
     return shaderModule;
+}
+
+
+QueueFamilyIndices HelloTriangleApplication::findQueueFamilies(VkPhysicalDevice device)
+{
+    QueueFamilyIndices indices;
+
+    uint32_t queueFamilyCount = 0;
+    vkGetPhysicalDeviceQueueFamilyProperties(device, &queueFamilyCount, nullptr);
+
+    std::vector<VkQueueFamilyProperties> queueFamilies(queueFamilyCount);
+    vkGetPhysicalDeviceQueueFamilyProperties(device, &queueFamilyCount, queueFamilies.data());
+
+    int i = 0;
+    for (const auto &queueFamily : queueFamilies)
+    {
+        if (queueFamily.queueFlags & VK_QUEUE_GRAPHICS_BIT)
+        {
+            indices.graphicsFamily = i;
+        }
+
+        VkBool32 presentSupport = false;
+        vkGetPhysicalDeviceSurfaceSupportKHR(device, i, surface, &presentSupport);
+
+        if (presentSupport)
+        {
+            indices.presentFamily = i;
+        }
+
+        if (indices.isComplete())
+        {
+            break;
+        }
+
+        i++;
+    }
+
+    return indices;
+}
+
+std::vector<const char *> HelloTriangleApplication::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 HelloTriangleApplication::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;
+}
+
+
+std::vector<char> HelloTriangleApplication::readFile(const std::string& filename) {
+    std::ifstream file(filename, std::ios::ate | std::ios::binary);
+
+    if (!file.is_open()) {
+        throw std::runtime_error("failed to open file!");
+    }
+
+    size_t fileSize = (size_t) file.tellg();
+    std::vector<char> buffer(fileSize);
+
+    file.seekg(0);
+    file.read(buffer.data(), fileSize);
+
+    file.close();
+
+    return buffer;
+}
+
+VKAPI_ATTR VkBool32 VKAPI_CALL HelloTriangleApplication::debugCallback(VkDebugUtilsMessageSeverityFlagBitsEXT messageSeverity, VkDebugUtilsMessageTypeFlagsEXT messageType, const VkDebugUtilsMessengerCallbackDataEXT* pCallbackData, void* pUserData) 
+{
+    std::cerr << "validation layer: " << pCallbackData->pMessage << std::endl;
+
+    return VK_FALSE;
 }
\ No newline at end of file
diff --git a/PhysicalDevice.cpp b/PhysicalDevice.cpp
index 29937dc..0793eb6 100644
--- a/PhysicalDevice.cpp
+++ b/PhysicalDevice.cpp
@@ -40,4 +40,20 @@ bool HelloTriangleApplication::isDeviceSuitable(VkPhysicalDevice device) {
     }
 
     return indices.isComplete() && extensionsSupported && swapChainAdequate;
+}
+
+bool HelloTriangleApplication::checkDeviceExtensionSupport(VkPhysicalDevice device) {
+    uint32_t extensionCount;
+    vkEnumerateDeviceExtensionProperties(device, nullptr, &extensionCount, nullptr);
+
+    std::vector<VkExtensionProperties> availableExtensions(extensionCount);
+    vkEnumerateDeviceExtensionProperties(device, nullptr, &extensionCount, availableExtensions.data());
+
+    std::set<std::string> requiredExtensions(deviceExtensions.begin(), deviceExtensions.end());
+
+    for (const auto& extension : availableExtensions) {
+        requiredExtensions.erase(extension.extensionName);
+    }
+
+    return requiredExtensions.empty();
 }
\ No newline at end of file
diff --git a/main.cpp b/main.cpp
index bf6e044..e84514a 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,5 +1,6 @@
 #include "HelloTriangleApplication.h"
 
+
 int main() {
     HelloTriangleApplication app;