WinAPI——谐振动的合成

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

#define NUM 1000
#define PI  3.14159

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

static int    cxClient, cyClient, xOffset, yOffset;
POINT        apt[NUM] ;
static int    A = 100 ;

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow)
{
    static TCHAR szAppName[] = TEXT("谐振动合成") ;
    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 0 ;
    }

    hwnd = CreateWindow(szAppName, TEXT("谐振动合成"), 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, 0, 0, PM_REMOVE))
        {
            if(msg.message == WM_QUIT)
                break ;
            TranslateMessage(&msg) ;
            DispatchMessage(&msg) ;
        }
        else 
        {
            Draw(hwnd) ;
        }
    }
    return msg.wParam ;
}

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

    switch(message)
    {
    case WM_SIZE :
        cxClient = LOWORD(lParam) ;
        cyClient = HIWORD(lParam) ;
        xOffset  = cxClient / 2 ;
        yOffset  = cyClient / 2 ;
        A = xOffset < yOffset ? xOffset : yOffset ;

        return 0 ;

    case WM_DESTROY :
        PostQuitMessage(0) ;
        return 0 ;
    }
    return DefWindowProc(hwnd, message, wParam, lParam) ;
}

void Draw(HWND hwnd)
{
    HDC            hdc ;
    PAINTSTRUCT ps ;
    RECT        rect ;
    int            t ;
    static double    w1 = 4, w2 = 5 ;                // w1 : w2 = 1 : 2
    static double    g = PI / 2 ;                    // 初相位之差

    hdc = GetDC(hwnd) ;

    apt[0].x = xOffset ;
    apt[0].y = yOffset + A * sin(g) ;
    MoveToEx(hdc, apt[0].x, apt[0].y, NULL) ;
    for(t = 1; t < NUM ; t++)
    {
        apt[t].x = xOffset + A * sin(t * 2 * w1 * w2 * PI /( NUM * w1 ));
        apt[t].y = yOffset + A * sin(t * 2 * w1 * w2 * PI /( NUM * w2 ) + g ) ;
        LineTo(hdc, apt[t].x, apt[t].y) ;
        MoveToEx(hdc, apt[t].x, apt[t].y, NULL) ;    
    }
//    Polyline(hdc, apt, NUM ) ;

    rect.bottom = cyClient ;
    rect.left    = 0 ;
    rect.right  = cxClient ;
    rect.top    = 0 ;

//    Sleep(1000) ;
//    w1 ++ ;
//    w2 ++ ;
//    g += PI / 4 ;
//    InvalidateRect(hwnd, &rect, TRUE) ;

    ReleaseDC(hwnd, hdc) ;
}