Now have a blue screen.

vk_engine.h

@@ -5,25 +5,71 @@
 
 #include <vk_types.h>
 
+struct FrameData {
+  VkCommandPool _commandPool;
+  VkCommandBuffer _mainCommandBuffer;
+  VkSemaphore _swapchainSemaphore;
+  VkSemaphore _renderSemaphore;
+  VkFence _renderFence;
+};
+
+constexpr unsigned int FRAME_OVERLAP=2;
+
 class VulkanEngine {
 public:
+  // device selection
+  VkInstance _instance;
+  VkDebugUtilsMessengerEXT _debug_messenger;
+  VkPhysicalDevice _chosenGPU;
+  VkDevice _device;
+  VkSurfaceKHR _surface;
 
-	bool _isInitialized{ false };
-	int _frameNumber {0};
+  // swapchain
+  VkSwapchainKHR _swapchain;
+  VkFormat _swapchainImageFormat;
 
-	VkExtent2D _windowExtent{ 1700 , 900 };
+  std::vector<VkImage> _swapchainImages;
+  std::vector<VkImageView> _swapchainImageViews;
+  VkExtent2D _swapchainExtent;
 
-	struct SDL_Window* _window{ nullptr };
+  // frames/command buffer
+  int _frameNumber {0};
+  FrameData _frames[FRAME_OVERLAP];
 
-	//initializes everything in the engine
-	void init();
+  FrameData& get_current_frame() {
+    return _frames[_frameNumber % FRAME_OVERLAP];
+  }
 
-	//shuts down the engine
-	void cleanup();
+  VkQueue _graphicsQueue;
+  uint32_t _graphicsQueueFamily;
 
-	//draw loop
-	void draw();
+  // internal data
+  bool _isInitialized{ false };
 
-	//run main loop
-	void run();
+  VkExtent2D _windowExtent{ 1700 , 900 };
+
+  struct SDL_Window* _window{ nullptr };
+
+  static VulkanEngine& Get();
+
+  //initializes everything in the engine
+  void init();
+
+  //shuts down the engine
+  void cleanup();
+
+  //draw loop
+  void draw();
+
+  //run main loop
+  void run();
+
+private:
+  void init_vulkan();
+  void init_swapchain();
+  void init_commands();
+  void init_sync_structures();
+
+  void create_swapchain(uint32_t width, uint32_t height);
+  void destroy_swapchain();
 };