hotloading!!

src/CMakeLists.txt

@@ -27,5 +27,5 @@ SET(BGFX_BUILD_EXAMPLES OFF)
 add_subdirectory("${CMAKE_SOURCE_DIR}/dependency/bgfx.cmake")
 
 target_link_libraries(PuzGame bx bimg bgfx)
-target_link_libraries(PuzGameEngine bx)
-
+target_link_libraries(PuzGameEngine bx bimg bgfx)
+set_target_properties(PuzGame PROPERTIES OUTPUT_NAME "PuzGame2")

src/build.bat

@@ -1 +1 @@
-cmake --build cmake-build && .\cmake-build\PuzGameEngine.exe
+cmake --build cmake-build

src/engine/main.cpp

@@ -2,15 +2,44 @@
 #include <Windows.h> 
 #undef min
 #undef max
+
 #include <cstdio>
-#include <libloaderapi.h>
 #include <bx/string.h>
+#include <bgfx/bgfx.h>
 
 //#define VISUAL_STUDIO
 
 typedef void (*Startup)(void*);
 typedef void (*Update)();
 
+constexpr UINT WM_CUSTOM_DLL_CHANGE = WM_USER + 1;
+
+#ifdef VISUAL_STUDIO
+  const char* DLLPath = "Debug/PuzGame.dll";
+#else
+  const char* DLLPath = "libPuzGame.dll";
+#endif
+
+struct FileWatcherData
+{
+  bool Change = false;
+};
+
+struct DevelopmentData
+{
+  uint8_t FileChangeBuffer[1024]{0};
+  HMODULE GameLib = NULL;
+  HANDLE hDevDir = NULL;
+  FileWatcherData FileWatcher;
+};
+
+namespace
+{
+  DevelopmentData DevData;
+  Startup StartupFunc;
+  Update UpdateFunc;
+}
+
 LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam)
 {
   LRESULT Res = 0;
@@ -50,66 +79,139 @@ HWND InitWindow()
     DWORD err = GetLastError();
     printf("Failed to create window: %#x!\n", err);
   }
+
+  DevData.hDevDir = CreateFileW(L"cmake-build", FILE_LIST_DIRECTORY, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
+  if (DevData.hDevDir == NULL)
+  {
+    printf("Failed to monitor dev dir!\n");
+  }
+  
   return window;
 }
 
+unsigned long FileWatcherThread(void* data)
+{
+  DWORD bytesReturned = 0;
+  bool isRunning = DevData.hDevDir;
+  while (isRunning)
+  {
+    bx::memSet(DevData.FileChangeBuffer, 0, sizeof(DevData.FileChangeBuffer));
+    if (ReadDirectoryChangesW(DevData.hDevDir, DevData.FileChangeBuffer, sizeof(DevData.FileChangeBuffer), true, FILE_NOTIFY_CHANGE_FILE_NAME | FILE_NOTIFY_CHANGE_LAST_WRITE | FILE_NOTIFY_CHANGE_SIZE, &bytesReturned, NULL, NULL))
+    {
+      uint32_t offset = 0;
+      while (true)
+      {
+        FILE_NOTIFY_INFORMATION* notifyData = reinterpret_cast<FILE_NOTIFY_INFORMATION*>(&DevData.FileChangeBuffer[offset]);
+        wprintf(L"Change: %ls\n", notifyData->FileName);
+
+        if (notifyData->Action == FILE_ACTION_ADDED || notifyData->Action == FILE_ACTION_MODIFIED || notifyData->Action == FILE_ACTION_RENAMED_NEW_NAME)
+        {
+          if (wcscmp(notifyData->FileName, L"libPuzGame2.dll") == 0)
+          {
+            DevData.FileWatcher.Change = true;
+            printf("detected dll change!\n");
+          }
+        }
+      
+        if (notifyData->NextEntryOffset == 0) break;
+        offset += notifyData->NextEntryOffset;
+      }
+    }
+  }
+  printf("File watcher thread ended!\n");
+  return 0;
+}
+
+bool ReloadDLL()
+{
+  if (DevData.GameLib != NULL)
+  {
+    FreeLibrary(DevData.GameLib);
+  }
+  if (!CopyFile("cmake-build\\libPuzGame2.dll", "cmake-build\\libPuzGame.dll", false))
+  {
+    printf("Failed to copy game DLL!\n");
+  }
+  
+  HMODULE gameLibReloaded = LoadLibraryEx(DLLPath, NULL, 0);
+  if (gameLibReloaded == NULL)
+  {
+    printf("Failed to load game DLL from %s!\n", DLLPath);
+    return false;
+  }
+  DevData.GameLib = gameLibReloaded;
+  
+#ifdef VISUAL_STUDIO
+  Startup StartupReloaded = (Startup)GetProcAddress(DevData.GameLib, "?Setup@Game@@YAXPEAX@Z");
+#else
+  Startup StartupReloaded = (Startup)GetProcAddress(DevData.GameLib, "_ZN4Game5SetupEPv");
+#endif
+  if (StartupReloaded == NULL)
+  {
+    printf("Failed to load startup function from game DLL!\n");
+    return false;
+  }
+
+#ifdef VISUAL_STUDIO
+  Update UpdateReloaded = (Update)GetProcAddress(DevData.GameLib, "?Update@Game@@YAXXZ");
+#else
+  Update UpdateReloaded = (Update)GetProcAddress(DevData.GameLib, "_ZN4Game6UpdateEv");
+#endif
+  if (UpdateReloaded == NULL)
+  {
+    printf("Failed to load update function from game DLL!\n");
+    return false;
+  }
+
+  StartupFunc = StartupReloaded;
+  UpdateFunc = UpdateReloaded;
+
+  printf("Loaded Game DLL successfully!\n");
+  return true;
+}
+
 int main()
 {
   HWND window = InitWindow();
   if (window == NULL) return 1;
 
-  char Buf[512];
-  GetCurrentDirectoryA(sizeof(Buf), Buf);
+  if (!ReloadDLL()) return 1;
 
-#ifdef VISUAL_STUDIO
-  const char* dllPath = "Debug/PuzGame.dll";
-#else
-  const char* dllPath = "libPuzGame.dll";
-#endif
-  HMODULE gameLibModule = LoadLibraryEx(dllPath, NULL, 0);
-  if (gameLibModule == NULL)
-  {
-    printf("Failed to load game DLL from %s!", dllPath);
-    return 1;
-  }
+  bgfx::Init init;
+  init.platformData.nwh = (void*)window;
+  init.platformData.ndt = nullptr;
+  init.platformData.type = bgfx::NativeWindowHandleType::Default;
+  init.resolution.width = 1920;
+  init.resolution.height = 1080;
+  init.resolution.reset = BGFX_RESET_VSYNC;
+  bgfx::init(init);  
   
-#ifdef VISUAL_STUDIO
-  Startup StartFunc = (Startup)GetProcAddress(gameLibModule, "?Setup@Game@@YAXPEAX@Z");
-#else
-  Startup StartFunc = (Startup)GetProcAddress(gameLibModule, "_ZN4Game5SetupEPv");
-#endif
-  if (StartFunc == NULL)
-  {
-    printf("Failed to load startup function from game DLL!\n");
-    return 1;
-  }
+  StartupFunc(window);
+  DWORD fileWatcherThreadId = 0;
+  CreateThread(NULL, 0, FileWatcherThread, NULL, 0, &fileWatcherThreadId);
   
-#ifdef VISUAL_STUDIO
-  Update UpdateFunc = (Update)GetProcAddress(gameLibModule, "?Update@Game@@YAXXZ");
-#else
-  Update UpdateFunc = (Update)GetProcAddress(gameLibModule, "_ZN4Game6UpdateEv");
-#endif
-  if (UpdateFunc == NULL)
-  {
-    printf("Failed to load update function from game DLL!\n");
-    return 1;
-  }
-
-  printf("Loaded Game DLL successfully!\n");
-  
-  StartFunc(window);
   bool isRunning = true;
   while (isRunning)
   {
-    MSG Message;
-    BOOL MessageResult = GetMessage(&Message, 0, 0, 0);
-    if (MessageResult > 0)
-    {
-      TranslateMessage(&Message);
-      DispatchMessageW(&Message);
+    MSG msg;
+    while (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
+		{
+			if (msg.message == WM_QUIT)
+			{
+			  
+			}
+
+			TranslateMessage(&msg);
+			DispatchMessage(&msg);
     }
-    // UpdateFunc();
-    // Sleep(1000.0);
+
+    if (DevData.FileWatcher.Change)
+    {
+      DevData.FileWatcher.Change = false;
+      ReloadDLL();
+    }
+    
+    UpdateFunc();
   }
   return 0;
 }

src/game/Log.cpp

@@ -1,10 +1,14 @@
 #include "Log.h"
-#include <cstdio>
+#include <bx/string.h>
 
-namespace Game
+namespace
 {
-  void Log(const char* text)
-  {
-    printf("%s\n", text);
-  }
+  char LineBuffer[1024]{0};
+}
+
+void Log(const char *format, ...)
+{
+  va_list args;
+  bx::snprintf(LineBuffer, sizeof(LineBuffer), "%s\n", format);
+  bx::printf(LineBuffer, args);
 }

src/game/Log.h

@@ -1,6 +1,3 @@
 #pragma once
 
-namespace Game
-{
-  void Log(const char* text);
-}
+void Log(const char *format, ...);

src/game/Setup.cpp

@@ -4,22 +4,19 @@
 
 namespace Game
 {
+  int32_t FrameCounter = 0;
+  
   void Setup(void* window)
   {
-    Log("Setup");
-    bgfx::Init init;
-    init.type = bgfx::RendererType::Direct3D12;
-    init.platformData.nwh = (void*)window;
-    init.platformData.ndt = nullptr;
-    init.platformData.type = bgfx::NativeWindowHandleType::Default;
-    init.resolution.width = 1920;
-    init.resolution.height = 1080;
-    init.resolution.reset = BGFX_RESET_VSYNC;
-    bgfx::init(init);
+    Log("Game Setup Start!");
   }
 
   void Update()
   {
-    Log("Update");
+    ++FrameCounter;
+    if (FrameCounter % 1000000 == 0)
+    {
+      Log("Frame!");
+    }
   }
 }