WinAPI——模拟正弦波

 /***************************
  *
  *  程序名称 ： 模拟正弦波
  *  作    者 ： doodle777
  *  版    本 ： 1.1
  *  日    期 ： 2012-10-19
  *  说    明 ： 1.1--解决了闪屏问题
  *
  ***************************/

 #include<Windows.h>
 #include<math.h>

 #define NUM 1000
 #define PI  3.14159

 LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM) ;
 void Draw(HWND, float, float) ;

 static int    cxClient, cyClient, xOffset, yOffset;
 POINT        apt[NUM] ;
 static int    A =  ;
 static float w = , g =  ;

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

     wndclass.cbClsExtra        = NULL ;
     wndclass.cbWndExtra        = NULL ;
     wndclass.hbrBackground    = (HBRUSH)GetStockObject(WHITE_BRUSH) ;
     wndclass.hCursor        = LoadCursor(NULL, IDC_ARROW) ;
     wndclass.hIcon            = LoadIcon(NULL, IDI_APPLICATION) ;
     wndclass.hInstance        = hInstance ;
     wndclass.lpfnWndProc    = WndProc ;
     wndclass.lpszClassName    = szAppName ;
     wndclass.lpszMenuName    = NULL ;
     wndclass.style            = CS_HREDRAW | CS_VREDRAW ;

     if(!RegisterClass(&wndclass))
     {
         MessageBox(NULL, TEXT("This Program Requires Windows NT !"), szAppName, MB_ICONERROR) ;
         return  ;
     }

     hwnd = CreateWindow(szAppName, TEXT("模拟正弦波(上下左右控制)"), WS_OVERLAPPEDWINDOW,
             CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,CW_USEDEFAULT,
             NULL, NULL, hInstance, NULL) ;
     ShowWindow(hwnd, iCmdShow) ;
     UpdateWindow(hwnd) ;

     while(TRUE)
     {
         if(PeekMessage(&msg, NULL, , , PM_REMOVE))
         {
             if(msg.message == WM_QUIT)
                 break ;
             TranslateMessage(&msg) ;
             DispatchMessage(&msg) ;
         }
         else
         {
             Draw(hwnd, w, g) ;
     //        w += 1 ;
     //        g += PI / 6 ;

         }
     }
     return msg.wParam ;
 }

 LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 {
     RECT        rect ;

     rect.bottom = cyClient ;
     rect.left    =  ;
     rect.right  = cxClient ;
     rect.top    =  ;

     switch(message)
     {
     case WM_SIZE :
         cxClient = LOWORD(lParam) ;
         cyClient = HIWORD(lParam) ;
         xOffset  = cxClient /  ;
         yOffset  = cyClient /  ;
         A = cyClient /  ;

         return  ;

     case WM_KEYDOWN :
         InvalidateRect(hwnd, &rect, TRUE) ;
         switch(wParam)
         {
         case VK_UP :
             g += PI /  ;
             break ;
         case VK_DOWN :
             g -= PI /  ;
             break ;
         case VK_LEFT :
             w -=  ;
             break ;
         case VK_RIGHT :
             w +=  ;
             break ;
         }
         return  ;

     case WM_DESTROY :
         PostQuitMessage() ;
         return  ;
     }
     return DefWindowProc(hwnd, message, wParam, lParam) ;
 }

 void Draw(HWND hwnd, float w, float g)
 {
     HDC            hdc ;
     PAINTSTRUCT ps ;
     int            t ;

     hdc = GetDC(hwnd) ;

     MoveToEx(hdc, , yOffset, NULL) ;
     LineTo(hdc, cxClient, yOffset) ;
     MoveToEx(hdc, xOffset, , NULL) ;
     LineTo(hdc, xOffset, cyClient) ; 

     apt[].x =  ;
     apt[].y = yOffset + A * sin(g) ;
     MoveToEx(hdc, apt[].x, apt[].y, NULL) ;
     for(t = ; t < NUM ; t++)
     {
         apt[t].x = cxClient * t / NUM ;
         apt[t].y = yOffset + A * sin(w * t / NUM  + g ) ;
         LineTo(hdc, apt[t].x, apt[t].y) ;
         MoveToEx(hdc, apt[t].x, apt[t].y, NULL) ;
     }

     ReleaseDC(hwnd, hdc) ;
 }