/*---------------------------------------
   BOUNCE.C -- Programme de balle qui rebondit
               (c) Charles Petzold, 1998
  ---------------------------------------*/

#include <windows.h>
#define ID_TIMER    1

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdLine, int iCmdShow)
{
     static TCHAR szAppName[] = TEXT ("Bounce") ;
     HWND         hwnd ;
     MSG          msg ;
     WNDCLASS     wndclass ;

     wndclass.style         = CS_HREDRAW | CS_VREDRAW ;
     wndclass.lpfnWndProc   = WndProc ;
     wndclass.cbClsExtra    = 0 ;
     wndclass.cbWndExtra    = 0 ;
     wndclass.hInstance     = hInstance ;
     wndclass.hIcon         = LoadIcon (NULL, IDI_APPLICATION) ;
     wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW) ;
     wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
     wndclass.lpszMenuName  = NULL ;
     wndclass.lpszClassName = szAppName ;
     
     if (!RegisterClass (&wndclass))
     {
          MessageBox (NULL, TEXT ("Ce programme fonctionne exclusivement sous Windows NT !"),
                      szAppName, MB_ICONERROR) ;
          return 0 ;
     }
     
     hwnd = CreateWindow (szAppName, TEXT ("La balle qui rebondit"),
                          WS_OVERLAPPEDWINDOW,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          CW_USEDEFAULT, CW_USEDEFAULT,
                          NULL, NULL, hInstance, NULL) ;
     
     ShowWindow (hwnd, iCmdShow) ;
     UpdateWindow (hwnd) ;
     while (GetMessage (&msg, NULL, 0, 0))
     {
          TranslateMessage (&msg) ;
          DispatchMessage (&msg) ;
     }
     return msg.wParam ;
}

LRESULT CALLBACK WndProc (HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam)
{
     static HBITMAP hBitmap ;
     static int     cxClient, cyClient, xCenter, yCenter, cxTotal, cyTotal,
                    cxRadius, cyRadius, cxMove, cyMove, xPixel, yPixel ;
     HBRUSH         hBrush ;
     HDC            hdc, hdcMem ;
     int            iScale ;
     
     switch (iMsg)
     {
     case WM_CREATE:
          hdc = GetDC (hwnd) ;
          xPixel = GetDeviceCaps (hdc, ASPECTX) ;
          yPixel = GetDeviceCaps (hdc, ASPECTY) ;
          ReleaseDC (hwnd, hdc) ;
          
          SetTimer (hwnd, ID_TIMER, 50, NULL) ;
          return 0 ;
          
     case WM_SIZE:
          xCenter = (cxClient = LOWORD (lParam)) / 2 ;
          yCenter = (cyClient = HIWORD (lParam)) / 2 ;
          
          iScale = min (cxClient * xPixel, cyClient * yPixel) / 16 ;
          
          cxRadius = iScale / xPixel ;
          cyRadius = iScale / yPixel ;
          
          cxMove = max (1, cxRadius / 2) ;
          cyMove = max (1, cyRadius / 2) ;
          
          cxTotal = 2 * (cxRadius + cxMove) ;
          cyTotal = 2 * (cyRadius + cyMove) ;
          
          if (hBitmap)
               DeleteObject (hBitmap) ;
          hdc = GetDC (hwnd) ;
          hdcMem = CreateCompatibleDC (hdc) ;
          hBitmap = CreateCompatibleBitmap (hdc, cxTotal, cyTotal) ;
          ReleaseDC (hwnd, hdc) ;
          
          SelectObject (hdcMem, hBitmap) ;
          Rectangle (hdcMem, -1, -1, cxTotal + 1, cyTotal + 1) ;
          
          hBrush = CreateHatchBrush (HS_DIAGCROSS, 0L) ;
          SelectObject (hdcMem, hBrush) ;
          SetBkColor (hdcMem, RGB (255, 0, 255)) ;
          Ellipse (hdcMem, cxMove, cyMove, cxTotal - cxMove, cyTotal - cyMove) ;
          DeleteDC (hdcMem) ;
          DeleteObject (hBrush) ;
          return 0 ;
          
     case WM_TIMER:
          if (!hBitmap)
               break ;
          
          hdc = GetDC (hwnd) ;
          hdcMem = CreateCompatibleDC (hdc) ;
          SelectObject (hdcMem, hBitmap) ;
          
          BitBlt (hdc, xCenter - cxTotal / 2,
                       yCenter - cyTotal / 2, cxTotal, cyTotal,
                  hdcMem, 0, 0, SRCCOPY) ;
          
          ReleaseDC (hwnd, hdc) ;
          DeleteDC (hdcMem) ;
          
          xCenter += cxMove ;
          yCenter += cyMove ;
          
          if ((xCenter + cxRadius >= cxClient) || (xCenter - cxRadius <= 0))
               cxMove = -cxMove ;
          
          if ((yCenter + cyRadius >= cyClient) || (yCenter - cyRadius <= 0))
               cyMove = -cyMove ;
          
          return 0 ;
          
     case WM_DESTROY:
          if (hBitmap)
               DeleteObject (hBitmap) ;
          KillTimer (hwnd, ID_TIMER) ;
          PostQuitMessage (0) ;
          return 0 ;
     }
     return DefWindowProc (hwnd, iMsg, wParam, lParam) ;
}
