Multiple windows, multiple threads

Original Post

Mar 20, 2009 at 11:17 AM

I have multiple windows using d3d9. I share one device between them all. Each one has its own swap chain. Some of them have 3d content ( SetRenderTarget() -> BeginScene() -> EndScene() -> Present() ) and some of them display video frames ( GetDC() -> Present() ). Well thats a general overview of what I have anyway. Now the 3d window is fine when there is no video playing. Can rotate the scene around very fast. When I play video in another window, the 3d scene usually doesn't render correctly. It occasionally does but most of the time it's missing large chunks. I am guessing this is to do with a lack of any critical sections in the code. I put one around all the 3d rendering block but it doesn't make much difference. Not sure what bits of d3d need to be locked and whether or not to use the D3DCREATE_MULTITHREADED flag when creating the device?

Evil Steve

382

Evil Steve

Mar 20, 2009 at 12:00 PM

If you access a single device from multiple threads, you need to use the D3DCREATE_MULTITHREADED flag. No exceptions.

flobadob

Author

flobadob

Mar 20, 2009 at 3:43 PM

OK thanks. I think I may have to do some of my own locking too? For instance from SetRenderTarget() right through to Present() on the 3d windows - or would that be SetRenderTarget() right through to EndScene()? What about GetDC on other surfaces, can they happen at the same time? I suspect that d3d9 will manage multiple calls to Present() at the same time?

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