GameEngine.h
========================================================================
// Game Event functions prototypes
BOOL GameInitialize( HINSTANCE hWindow );
void GameStart( HWND hWindow );
void GameEnd( );
void GameActivate( HWND hWindow );
void GameDeactivate( HWND hWindow );
void GamePaint( HDC hDC );
void GameCycle( );

// GameEngine Class
class GameEngine
{
      protected:
      // Define member vars
      static GameEngine*   m_pGameEngine;
      HINSTANCE            m_hInstance;
      HWND                 m_hWindow;
      TCHAR                m_szWindowClass[32];
      TCHAR                m_szTitle[32];
      WORD                 m_wIcon, m_wSmallIcon;
      int                  m_iWidth, m_iHeight;
      int                  m_iFrameDelay;
      BOOL                 m_bSleep;
      
      public:
      // Constructor
      GameEngine( HINSTANCE hInstance, LPTSTR szWindowClass, LPTSTR szTitle, WORD wIcon, WORD wSmallIcon, int iWidth = 640, int iHeight = 480 );
      
      // Destructor
      virtual ~GameEngine( );
      
      // General methods
      static GameEngine*   GetEngine( ) { return m_pGameEngine; };
      BOOL                 Initialize( int iCmdShow );
      LRESULT              HandleEvent( HWND hWindow, UINT msg, WPARAM wParam, LPARAM lParam );
      
      // Accessor methods
      HINSTANCE   GetInstance( ) { return m_hInstance; };
      HWND        GetWindow( ) { return m_hWindow; };
      void        SetWindow( HWND hWindow ) { m_hWindow = hWindow; };
      LPTSTR      GetTitle( ) { return m_szTitle; };
      WORD        GetIcon( ) { return m_wIcon; };
      WORD        GetSmallIcon( ) { return m_wSmallIcon; };
      int         GetWidth( ) { return m_iWidth; };
      int         GetHeight( ) { return m_iHeight; };
      int         GetFrameDelay( ) { return m_iFrameDelay; };
      void        SetFrameRate( int iFrameRate ) { m_iFrameDelay = 1000 / iFrameRate; };
      BOOL        GetSleep( ) { return m_bSleep; };
      void        SetSleep( BOOL bSleep ) { m_bSleep = bSleep; };
};

// Constructor
GameEngine::GameEngine( HINSTANCE hInstance, LPTSTR szWindowClass, LPTSTR szTitle, WORD wIcon, WORD wSmallIcon, int iWidth, int iHeight )
{
      // Set the member vars
      m_pGameEngine = this;
      m_hInstance = hInstance;
      m_hWindow = NULL;
      if( lstrlen( szWindowClass ) > 0 )
          lstrcpy( m_szWindowClass, szWindowClass );
      if( lstrlen( szTitle ) > 0 )
          lstrcpy( m_szTitle, szTitle );
      m_wIcon = wIcon;
      m_wSmallIcon = wSmallIcon;
      m_iWidth = iWidth;
      m_iHeight = iHeight;
      m_iFrameDelay = 50;
      m_bSleep = TRUE;
}

// Destructor
GameEngine::~GameEngine( )
{
}

// WinMain, the function that every windows app needs
int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow )
{
    MSG             msg;
    static int      iTickTrigger = 0;
    int             iTickCount;
    
    // Init game    
    if( GameInitialize( hInstance ) )
    {
        // Init game engine
        if( ! GameEngine::GetEngine( )->Initialize( iCmdShow ) )
            return FALSE;
            
        // Enter main msg loop
        while( TRUE )
        {
               if( PeekMessage( & msg, NULL, 0, 0, PM_REMOVE ) )
               {
                   // Process message
                   if( msg.message == WM_QUIT )
                       break;
                   TranslateMessage( & msg );
                   DispatchMessage( & msg );
               }
               else
               {
                   // Make sure the game engine isn't sleeping
                   if( ! GameEngine::GetEngine( )->GetSleep( ) )
                   {
                         // Check the tick count to see if a game cycle has elapsed
                         iTickCount = GetTickCount( );
                         if( iTickCount > iTickTrigger )
                         {
                             iTickTrigger = iTickCount + GameEngine::GetEngine( )->GetFrameDelay( );
                             GameCycle( );
                         }
                   }
               }
        }
        return ( int ) msg.wParam;
    }
    
    // End game
    GameEnd( );
    
    return TRUE;
}

// WndProc, just route all messages to HandleEvent
LRESULT CALLBACK WndProc( HWND hWindow, UINT msg, WPARAM wParam, LPARAM lParam )
{
        return GameEngine::GetEngine( )->HandleEvent( hWindow, msg, wParam, lParam );
}

// Function that creates the main window, etc. ( Normally done in WinMain() )
BOOL GameEngine::Initialize( int iCmdShow )
{
     // Create the windowclass
     WNDCLASSEX wndclass;
     wndclass.cbSize          = sizeof( wndclass );
     wndclass.style           = CS_HREDRAW | CS_VREDRAW;
     wndclass.lpfnWndProc     = WndProc;
     wndclass.cbClsExtra      = 0;
     wndclass.cbWndExtra      = 0;
     wndclass.hInstance       = m_hInstance;
     wndclass.hIcon           = LoadIcon( m_hInstance, MAKEINTRESOURCE( GetIcon( ) ) );
     wndclass.hIconSm         = LoadIcon( m_hInstance, MAKEINTRESOURCE( GetSmallIcon( ) ) );
     wndclass.hCursor         = LoadCursor( NULL, IDC_ARROW );
     wndclass.hbrBackground   = ( HBRUSH ) ( COLOR_WINDOW + 1 );
     wndclass.lpszMenuName    = NULL;
     wndclass.lpszClassName   = m_szWindowClass;
     
     // Register the class with windows
     if( ! RegisterClassEx( & wndclass ) )
         return FALSE;
         
     // Calculate window size and position
     int iWindowWidth    = m_iWidth + GetSystemMetrics( SM_CXFIXEDFRAME ) * 2;
     int iWindowHeight   = m_iHeight + GetSystemMetrics( SM_CYFIXEDFRAME ) * 2 + GetSystemMetrics( SM_CYCAPTION );
     if( wndclass.lpszMenuName != NULL )
         iWindowHeight += GetSystemMetrics( SM_CYMENU );
     int iXWindowPos     = ( GetSystemMetrics( SM_CXSCREEN ) - iWindowWidth ) / 2;
     int iYWindowPos     = ( GetSystemMetrics( SM_CYSCREEN ) - iWindowHeight ) / 2;
     
     // Create the window
     m_hWindow = CreateWindow( m_szWindowClass, m_szTitle, WS_POPUPWINDOW | WS_CAPTION | WS_MINIMIZEBOX, iXWindowPos, iYWindowPos, iWindowWidth, iWindowHeight, NULL, NULL, m_hInstance, NULL );
     if( ! m_hWindow )
         return false;
     
     // Show & update the window
     ShowWindow( m_hWindow, iCmdShow );
     UpdateWindow( m_hWindow );
     
     return TRUE;
} 

// Function to handle Windows messages ( normally done in WndProc )
LRESULT GameEngine::HandleEvent( HWND hWindow, UINT msg, WPARAM wParam, LPARAM lParam )
{
        // Route Windows messages to game engine functions
        switch( msg )
        {
                case WM_CREATE:
                     // Set the window and start the game
                     SetWindow( hWindow );
                     GameStart( hWindow );
                     return 0;
                     
                case WM_ACTIVATE:
                     // Activate/deactivate the game and update sleep status
                     if( wParam != WA_INACTIVE )
                     {
                         GameActivate( hWindow );
                         SetSleep( FALSE );
                     }
                     else
                     {
                         GameDeactivate( hWindow );
                         SetSleep( TRUE );
                     }
                     return 0;
                     
                case WM_PAINT:
                     HDC           hDC;
                     PAINTSTRUCT   ps;
                     hDC = BeginPaint( hWindow, & ps );
                     
                     // Paint the game
                     GamePaint( hDC );
                     EndPaint( hWindow, & ps );
                     return 0;
               
               case WM_DESTROY:
                    // End the game, and exit app
                    GameEnd( );
                    PostQuitMessage( 0 );
                    return 0;
        }
        return DefWindowProc( hWindow, msg, wParam, lParam );
}                                   
==============================================================
Resource.h
==============================================================
// Define icons
#define IDI_SKELETON    1000
#define IDI_SKELETON_SM 1001
==============================================================
Skeleton.cpp
==============================================================
// Include the file that includes the headers ^^
#include "Skeleton.h"

// Init pointer
GameEngine* GameEngine::m_pGameEngine = NULL;

// Game Engine functions
BOOL GameInitialize( HINSTANCE hInstance )
{
     // Create the Game Engine
     _pGame = new GameEngine( hInstance, TEXT( "Game Skeleton" ), TEXT( "Game Skeleton" ), IDI_SKELETON, IDI_SKELETON_SM );
     if( _pGame == NULL )
         return FALSE;
         
     // Set the framerate
     _pGame->SetFrameRate( 15 );
     
     return TRUE;
}

void GameStart( HWND hWindow )
{
     // Seed the random number generator
     srand( GetTickCount( ) );
}

void GameEnd( )
{
     // Cleanup the game engine
     delete _pGame;
}

void GameActivate( HWND hWindow )
{
     HDC  hDC;
     RECT rect;
     
     // Draw activated in the window
     GetClientRect( hWindow, & rect );
     hDC = GetDC( hWindow );
     DrawText( hDC, TEXT( "Activated!" ), -1, & rect, DT_SINGLELINE | DT_CENTER | DT_VCENTER );
     ReleaseDC( hWindow, hDC );
}

void GameDeactivate( HWND hWindow )
{
     HDC  hDC;
     RECT rect;
     
     // Draw deactivated on the screen
     GetClientRect( hWindow, & rect );
     hDC = GetDC( hWindow );
     DrawText( hDC, TEXT( "Activated!" ), -1, & rect, DT_SINGLELINE | DT_CENTER | DT_VCENTER );
     ReleaseDC( hWindow, hDC );
}

void GamePaint( HDC hDC )
{
}

void GameCycle( )
{
     HDC   hDC;
     HWND  hWindow = _pGame->GetWindow( );
     
     // Draw the skeleton icon at random positions in the window
     hDC = GetDC( hWindow );
     DrawIcon( hDC, rand( ) % _pGame->GetWidth( ), rand( ) % _pGame->GetHeight( ), ( HICON ) ( WORD ) GetClassLong( hWindow, GCL_HICON ) );
     ReleaseDC( hWindow, hDC );
}
=========================================================
Skeleton.h
=========================================================
// Make sure its only included once
#pragma once

// Include headers
#include <windows.h>
#include "Resource.h"
#include "GameEngine.h"
#include <stdlib.h>

// Global vars
GameEngine* _pGame;
===========================================================
Resource.rc
===========================================================
// Include resource ID header
#include "Resource.h"

// Give the location of the iconfiles :)
IDI_SKELETON         ICON   "Skeleton.ico"
IDI_SKELETON_SM      ICON   "Skeleton_sm.ico"