VB: Drawing in a game

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Hi, Im trying to display a text message inside a game, it works but it flickers real bad. Programs like FRAPS or XFIRE also draw inside a game but then without the flickering. Whats the best way to make this kind function without the text flickering all the time? The one that Im using now (which flickers) is this one:

Public Function DrawText(hwnd As Long, strText As String, x As Long, y As Long)
    Dim hDC As Long
    
    hDC = GetDC(hwnd)
    If hDC = 0 Then Exit Function

    SetBkMode hDC, vbTransparent 'Transparent background
    SetTextColor hDC, 0 'Textcolor to black
    TextOut hDC, x + 1, y + 1, strText, Len(strText) 'Make shadow
    TextOut hDC, x + 2, y + 2, strText, Len(strText) 'Make shadow
    SetTextColor hDC, RGB(0, 255, 0) 'Set text color to green
    TextOut hDC, x, y, strText, Len(strText) 'Write the text

    UpdateWindow hwnd
    ReleaseDC hwnd, hDC
End Function

Thanks.