API 더블 버퍼링

=========================================== main.cpp ===========================================
//글로벌(exturn 변수로 사용)
HWND hWnd;
HINSTANCE hInst;
HDC hdc;
HDC MemDC, StaDC;
HBITMAP MyBit;
int Cha_x, Cha_y;
 
 
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	int wmId, wmEvent;
	PAINTSTRUCT ps;
 
	switch (message) {
	case WM_COMMAND:
		wmId    = LOWORD(wParam);
		wmEvent = HIWORD(wParam);
 
		// 메뉴의 선택 영역을 구문 분석합니다.
		switch (wmId) {
		case IDM_ABOUT:
			DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
			break;
 
		case IDM_EXIT:
			DestroyWindow(hWnd);
			break;
 
		default:
			return DefWindowProc(hWnd, message, wParam, lParam);
		}
		break;
 
	case WM_CREATE:
		onCreate(hWnd,wParam,lParam);
		break;
 
	case WM_PAINT:
		hdc = BeginPaint(hWnd, &ps);
		onPaint(wParam,lParam);
		EndPaint(hWnd, &ps);
		break;
 
	case WM_TIMER:
		onTimer(wParam,lParam);
		break;
 
	case WM_MOUSEMOVE:
		onMouseMove(wParam,lParam);
		break;
 
	case WM_LBUTTONDOWN:
		onLButtonDown(wParam,lParam);
		break;
 
	case WM_LBUTTONUP:
		onLButtonUp(wParam,lParam);
		break;
 
	case WM_DESTROY:
		PostQuitMessage(0);
		break;
 
	default:
		return DefWindowProc(hWnd, message, wParam, lParam);
	}
	return 0;
}
 
=========================================== onCreate.cpp ===========================================
void onCreate(HWND hWnd,WPARAM wParam, LPARAM lParam)
{
	srand(time(NULL));
	SetTimer(hWnd, 1, 10, NULL);
	MyBit = LoadBitmap(hInst, MAKEINTRESOURCE(IDB_BITMAP1));
}
 
=========================================== onTimer.cpp ===========================================
void onTimer(WPARAM wParam, LPARAM lParam)
{
	InvalidateRect(hWnd, NULL, FALSE);
}
 
=========================================== onTimer.cpp ===========================================
exturn void DrawBitmap(int x, int y, HBITMAP Bit);
 
HBITMAP OldBit;
HPEN MyPen, OldPen;
HBRUSH MyBrush, OldBrush;
 
void onPaint(WPARAM wParam, LPARAM lParam)
{
	RECT crt;
	hdc = GetDC(hWnd);
 
	//글씨 및 그리기를 할 도화지
	GetClientRect(hWnd, &crt);
 
	FillRect(MemDC, &crt, GetSysColorBrush(COLOR_WINDOW));
	FillRect(StaDC, &crt, GetSysColorBrush(COLOR_WINDOW));
 
	// hdc에 그려 주기 위해 필요한 MemDC
	MemDC = CreateCompatibleDC( hdc );
	StaDC = CreateCompatibleDC( hdc );
 
	//onCreate에서 명령 >> MyBit = LoadBitmap(hInst, MAKEINTRESOURCE(IDB_BITMAP1));
	OldBit = (HBITMAP)SelectObject(StaDC, MyBit);
	BitBlt(MemDC, Cha_x, Cha_y, 25, 25, StaDC, 0, 0, SRCCOPY);
 
	DrawBitmap(0, 0, MyBit);
 
	SelectObject(hdc, OldBit);
 
	DeleteDC( StaDC );
	DeleteDC( MemDC );
	ReleaseDC(hWnd, hdc);
}
 
void DrawBitmap(int x, int y, HBITMAP Bit)
{
	HBITMAP OldBitmap;
	BITMAP bit;
	int bx, by;
 
	//MemDC = CreateCompatibleDC( hdc );
	OldBitmap = (HBITMAP)SelectObject( MemDC, Bit );
 
	GetObject( Bit, sizeof(BITMAP), &bit ); 
	bx = bit.bmWidth;
	by = bit.bmHeight;
 
	BitBlt( hdc, x, y, bx, by, MemDC, 0, 0, SRCCOPY );
 
	SelectObject( MemDC, OldBitmap );
	DeleteDC( MemDC );
	ReleaseDC( hWnd, hdc );
}