Clearing the Windows Device Context

This is a discussion on Clearing the Windows Device Context within the Game Programming forums, part of the General Programming Boards category; What is the best way to clear the screen before redrawing if using a Windows Device Context as your drawing ...

  1. #1
    Call me AirBronto
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    Clearing the Windows Device Context

    What is the best way to clear the screen before redrawing if using a Windows Device Context as your drawing surface

  2. #2
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    Use the ClearScreen() fuction that is part of whatever API your using.

  3. #3
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    Can't you FillRect() or something like that?

  4. #4
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    If you are filling white or black you can use those flags in BitBlt as a quick fill. Otherwise, you can use this as a faster alternative to FillRect:

    Code:
    void PaintRect(HDC hdc, RECT *rect, COLORREF colour)
    {
      COLORREF oldcr = SetBkColor(hdc, colour);
      ExtTextOut(hdc, 0, 0, ETO_OPAQUE, rect, "", 0, 0);
      SetBkColor(hdc, oldcr);
    }
    "...the results are undefined, and we all know what "undefined" means: it means it works during development, it works during testing, and it blows up in your most important customers' faces." --Scott Meyers

  5. #5
    Call me AirBronto
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    yea fillrect works thanks sand man

  6. #6
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    Quote Originally Posted by loopshot
    yea fillrect works thanks sand man
    Nice guess wasn't it?

  7. #7
    Call me AirBronto
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    HA, here is one better than both of your suggestins
    Code:
    BOOL FloodFill(
      HDC hdc,          // handle to DC
      int nXStart,      // starting x-coordinate
      int nYStart,      // starting y-coordinate
      COLORREF crFill   // fill color
    );
    but thank you all for the help guys

  8. #8
    Super Moderator VirtualAce's Avatar
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    FloodFill() is not better than FillRect().

    FloodFill is more for filling areas with borders than it is for large areas. FillRect() simply creates a colored square the size of the rect specified. This is a much faster process. FloodFill() is a somewhat complex function and I wouldn't use it for what you want to do.

  9. #9
    Call me AirBronto
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    Thanks budda

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