double buffering

hi! i'm trying to make a double buffering to avoid the slow refresh
my code looks like this:

Code:

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void draw(HDC hdc)
{
        HDC dc = CreateCompatibleDC(hdc);
        HBITMAP hBitmap = CreateCompatibleBitmap (hdc, 400, 240);
        SelectObject(dc, hBitmap);

        /*draw all the stuff on dc*/

        BitBlt(hdc, 0, 0, 400, 240, dc, 0, 0, SRCCOPY);

        ReleaseDC(0, dc);
        DeleteObject(hBitmap);
        DeleteDC(dc);

        return;
}

---

where the hdc passed is the main hdc.
it draws but the refresh is slow. i know that is a working method because if i comment out BitBlt(hdc, 0, 0, 400, 240, dc, 0, 0, SRCCOPY); i get a black screen...

Your missing the part where "/*draw all the stuff on dc*/" is. That's probably where you're bogging down.

wooo! solved!
good double buffering script bad asking-to-refresh!
i was

Code:

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InvalidateRect(hWnd, NULL, TRUE);

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instead

Code:

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InvalidateRect(hWnd, NULL, FALSE);
UpdateWindow(hWnd);

---

well... i think is a good code... feel free to use and give suggestion! (i didn't find something that do this elsewhere o.o)
thanks for reply ;)

p.s. i'm working on windows mobile so this code runs over it too!

Quote:

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get a black screen[...]feel free to use and give suggestion!

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Just a little suggestion: If you have a message loop, and if you repaint the entire client area of your window, then you don't need Windows to paint a (black in your case) background. So you could write:

Code:

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      case WM_ERASEBKGND:
        return(1); // Prevent erasing the background to reduce flickering
        break;

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I read on msdn to pass FALSE as last parameter when I do:

Code:

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InvalidateRect(hWnd, NULL, FALSE);

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shouldn't this avoid the WM_ERASEBKGND message queuing?