Dx Windowed LAG

In windowed mode Dx7...so I am blting to a window's client rect....
My comp begins to lag like you wouldn't believe. I click close and it takes almost like two minutes to for the app to close...I am serious no bs.

The line which does this is when I Blt to the Primary, could, by any chance this be due to the fact I am also repainting the background of the window when WM_PAINT is called? does a Dx DD Blt send a WM_PAINT message???

This is my first attemp at Dx7 Windowed, and I pretty much went by code in the SDK for an app which switched between the modes.

Any idea's?

Foregt about WM_PAINT, has nothing to do with a DX app...

Then what on earth could be causng the extreme lag.

In windowed mode its laggy, way to laggy...100% cpu usage.
In full screen its nothing, not even noticable, no spikes in cpu usage.

GetClientRect(m_hwnd, &m_rWindow);
GetClientRect(m_hwnd, &m_rScreen);
ClientToScreen(m_hwnd, (POINT*)&m_rScreen.left);
ClientToScreen(m_hwnd, (POINT*)&m_rScreen.right);

Changed:

PHP Code:

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 hRet = Primary->Blt(&m_rScreen, BackBuffer, &m_rWindow, DDBLT_WAIT, NULL);    //Blt the Windowed buffer 


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To:

PHP Code:

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 hRet = Primary->Blt(&m_rScreen, BackBuffer, NULL, DDBLT_WAIT, NULL);    //Blt the Windowed buffer 


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No lag...so far. An incredible increase in speed.

Once again tho, Dx7 in windowed mode when I Blt to the Primary ie. the window does it send a WM_PAINT message?


Also, should the backbuffers width and hieght be the size of my window or full screen during windowed mode.