Question

I’ve been working on a DirectX application in C#, and I noticed that when I lock the workstation, the DirectX ‘Device’ becomes lost. After looking up the information about what to do upon when a device is lost (and when a DeviceLostException is thrown by Device.Present), I re-wrote the code to reset the Device. This simply meant that I made a call to Device.Reset.

Calling Device.Reset recovered the Device. No problem. But when I lost the device a second time (for example, when the computer was locked, went to sleep, or activated a screen-saver), an exception was thrown by Device.Reset.

The exception was InvalidCallException, which (according to the documentation) means something went wrong with the call. So I assumed it was a problem with the arguments to the function. So instead of passing the same copy of PresentParams that I used to create the Device, I created a new instance of PresentParams (at first using the copy constructor, and later by re-creating without it) and passed that to Device.Reset.

Doesn’t work. Device.Reset still dies with the InvalidCallException. Oh, and the message of the exception? ‘Error in application.’ Not helpful.

Can you point me in the direction of either a solution, or some documentation about how to get more debug information out of DirectX?

Answer 1

OK, I know how silly is seems to answer my own question, but I figured someone else might need this, eh?

The answer is: there were too many calls to the Dispose method of the VertexBuffers in the scene. The reason being that the internal Device reset-handlers were calling the Dispose method. And why was that happening? Because I had neglected to read the .NET DirectX SDK documentation regarding the Pool Enumeration, and was allocating the VertexBuffers using Pool.Default instead of Pool.Managed.

So obviously, after a few thousand badly done allocate-and-release cycles, something went wrong.

Oh, and how did I discover this? I attached a listener to VertexBuffer.Dispose which incremented a counter that I displayed on-screen. Imagine my suprise when I noticed this counter kept growing as I resized the window!