Bài quả banh di chuyển

Version 1: 1 quả banh di chuyển.
Chú ý: Hàm GetClientRect
The GetClientRect function retrieves the coordinates of a window's client area. The client coordinates specify the upper-left and lower-right corners of the client area. Because client coordinates are relative to the upper-left corner of a window's client area, the coordinates of the upper-left corner are (0,0).

// Single_Bound_Version1.cpp : Defines the entry point for the application.
//

#include "stdafx.h"
#include "resource.h"

#define MAX_LOADSTRING 100

// Global Variables:
HINSTANCE hInst;        // current instance
TCHAR szTitle[MAX_LOADSTRING];        // The title bar text
TCHAR szWindowClass[MAX_LOADSTRING];        // The title bar text
//-----------Khai bao Single Ball-----------
enum {ID_MOVE_TIMER=1, ID_CHANGE_COLOR=2};
// Foward declarations of functions included in this code module:
ATOM    MyRegisterClass(HINSTANCE hInstance);
BOOL    InitInstance(HINSTANCE, int);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK About(HWND, UINT, WPARAM, LPARAM);

int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
{
  // TODO: Place code here.
 MSG msg;
 HACCEL hAccelTable;

 // Initialize global strings
 LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
 LoadString(hInstance, IDC_SINGLE_BOUND_VERSION1, szWindowClass, MAX_LOADSTRING);
 MyRegisterClass(hInstance);

 // Perform application initialization:
 if (!InitInstance (hInstance, nCmdShow)) 
 {
  return FALSE;
 }

 hAccelTable = LoadAccelerators(hInstance, (LPCTSTR)IDC_SINGLE_BOUND_VERSION1);

 // Main message loop:
 while (GetMessage(&msg, NULL, 0, 0)) 
 {
  if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg)) 
  {
   TranslateMessage(&msg);
   DispatchMessage(&msg);
  }
 }

 return msg.wParam;
}



//
//  FUNCTION: MyRegisterClass()
//
//  PURPOSE: Registers the window class.
//
//  COMMENTS:
//
//    This function and its usage is only necessary if you want this code
//    to be compatible with Win32 systems prior to the 'RegisterClassEx'
//    function that was added to Windows 95. It is important to call this function
//    so that the application will get 'well formed' small icons associated
//    with it.
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
 WNDCLASSEX wcex;

 wcex.cbSize = sizeof(WNDCLASSEX); 

 wcex.style   = CS_HREDRAW | CS_VREDRAW;
 wcex.lpfnWndProc = (WNDPROC)WndProc;
 wcex.cbClsExtra  = 0;
 wcex.cbWndExtra  = 0;
 wcex.hInstance  = hInstance;
 wcex.hIcon   = LoadIcon(hInstance, (LPCTSTR)IDI_SINGLE_BOUND_VERSION1);
 wcex.hCursor  = LoadCursor(NULL, IDC_ARROW);
 wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
 wcex.lpszMenuName = (LPCSTR)IDC_SINGLE_BOUND_VERSION1;
 wcex.lpszClassName = szWindowClass;
 wcex.hIconSm  = LoadIcon(wcex.hInstance, (LPCTSTR)IDI_SMALL);

 return RegisterClassEx(&wcex);
}

//
//   FUNCTION: InitInstance(HANDLE, int)
//
//   PURPOSE: Saves instance handle and creates main window
//
//   COMMENTS:
//
//        In this function, we save the instance handle in a global variable and
//        create and display the main program window.
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
   HWND hWnd;

   hInst = hInstance; // Store instance handle in our global variable

   hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);

   if (!hWnd)
   {
      return FALSE;
   }

   ShowWindow(hWnd, nCmdShow);
   UpdateWindow(hWnd);

   return TRUE;
}

//
//  FUNCTION: WndProc(HWND, unsigned, WORD, LONG)
//
//  PURPOSE:  Processes messages for the main window.
//
//  WM_COMMAND - process the application menu
//  WM_PAINT - Paint the main window
//  WM_DESTROY - post a quit message and return
//
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
 int wmId, wmEvent;
 PAINTSTRUCT ps;
 HDC hdc;
 TCHAR szHello[MAX_LOADSTRING];
 LoadString(hInst, IDS_HELLO, szHello, MAX_LOADSTRING);
 //----------Khai bao cac bien trong bai Single Ball---------------
 static int x=40, y=50, rBall=10, dx=5, dy=5, nCrIdx;
 static COLORREF aColorTab[]={RGB(0xff,0xff,0xff),RGB(0,0xff,0),RGB(0xff,0,0),RGB(0,0,0xff),RGB(0xff,0xff,0),RGB(0xff,0,0xff),RGB(0,0xff,0xff)};
 static int nColors= sizeof(aColorTab)/sizeof(aColorTab[0]);
 //*********The End khai bao bien***************
 switch (message) 
 {
  case WM_CREATE:
   SetTimer(hWnd,ID_MOVE_TIMER,10,NULL);
   SetTimer(hWnd,ID_CHANGE_COLOR,1000,NULL);
   break;
  case WM_COMMAND:
   wmId    = LOWORD(wParam); 
   wmEvent = HIWORD(wParam); 
   // Parse the menu selections:
   switch (wmId)
   {
    case IDM_ABOUT:
       DialogBox(hInst, (LPCTSTR)IDD_ABOUTBOX, hWnd, (DLGPROC)About);
       break;
    case IDM_EXIT:
       DestroyWindow(hWnd);
       break;
    default:
       return DefWindowProc(hWnd, message, wParam, lParam);
   }
   break;
  case WM_TIMER:
   switch(wParam)
   {
    case ID_MOVE_TIMER:
     RECT rClient, r;
     GetClientRect(hWnd, &rClient);
     r.left=x-rBall-abs(dx);
     r.right=x+rBall+abs(dx);
     r.top=y-rBall-abs(dy);
     r.bottom=y+rBall+abs(dy);
     x=x+dx;
     y=y+dy;
     if(x+rBall > rClient.right && dx>0) dx = -dx;
     if(x-rBall < 0 && dx<0) dx = -dx;
     if(y+rBall > rClient.bottom && dy>0) dy=-dy;
     if(y-rBall < 0 && dy<0) dy=-dy;
     InvalidateRect(hWnd, &r,TRUE);
     break;
    case ID_CHANGE_COLOR:
     ++nCrIdx %=nColors;
     break;
   }
   break;
  case WM_PAINT:
   hdc = BeginPaint(hWnd, &ps);
   // TODO: Add any drawing code here...
   RECT rt;
   GetClientRect(hWnd, &rt);
   DrawText(hdc, szHello, strlen(szHello), &rt, DT_CENTER);
   //---------Ve qua banh----------
   HBRUSH hbr;
   hbr=CreateSolidBrush(aColorTab[nCrIdx]);
   SelectObject(hdc,hbr);
   Ellipse(hdc,x-rBall,y-rBall,x+rBall,y+rBall);
   DeleteObject(hbr);
   EndPaint(hWnd, &ps);
   break;
  case WM_DESTROY:
   KillTimer(hWnd, ID_MOVE_TIMER);
   KillTimer(hWnd, ID_CHANGE_COLOR);
   PostQuitMessage(0);
   break;
  default:
   return DefWindowProc(hWnd, message, wParam, lParam);
   }
   return 0;
}

// Mesage handler for about box.
LRESULT CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
 switch (message)
 {
  case WM_INITDIALOG:
    return TRUE;

  case WM_COMMAND:
   if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL) 
   {
    EndDialog(hDlg, LOWORD(wParam));
    return TRUE;
   }
   break;
 }
    return FALSE;
}