Direct3D9Ex Render System

[jpho]

I've seen that there are some forks that patch the D3D9 Rendersystem to create an D3D9Ex device instead.

E.g. here: https://bitbucket.org/JaredThirsk/ogre-d3d9ex/wiki/Home
and here: https://bitbucket.org/nryan/ogre

Is there any chance that mainline Ogre will include a way to choose D3D9Ex? 99% of the code is identical, so I believe it would probably be best to make some global config setting and pass a Parameter to the RenderSystem ctor in D3DPlugin.cpp.

Or what do you think? Clone the whole RenderSystem for the 10 or so lines changed to have clear separation?

[Wolfmanfx]

Its already added by mattan its a config option

[jpho]

Wow, great.

[sparkprime]

Why would one want to use this, out of interest?

[bstone]

For one thing it's simply faster on Windows Vista and later because DWM doesn't have to store the copy of your render surface and blit it every time during the final composition. D3D9Ex lets DWM work straight with your render surface. That also spares the memory for the otherwise required surface copy. That's what I know but maybe there's some other improvement.

[sparkprime]

So does this only make a difference in windowed mode or something like that?

[bstone]

Yeah, I'd think so.

[jpho]

Why would one want to use this, out of interest?

I need it to have efficient integration with WPF (Windows Presentation Foundation)-based User Interfaces. bstone's post above explains the technical background.

[bstone]

Huh, now I'm curious - is your project .net based? Using WPF in a C++ project is a sea of pain

[jpho]

We have the GUI and related code in C#, and the rendering part in C++. We use Ogre directly, that's also why we didn't use the MOGRE/Wpf integration stuff.

Using C++/CLR, it's quite easy and nice to interop.

[FlorianGeorge]

Would this also improve performance for blitting a RenderTexture to an Image via Ogre::RenderTarget::copyContentsToMemory and/or Ogre::HardwarePixelBuffer::blitToMemory?

[bstone]

Nope, the whole point is that DWM doesn't have to copy application's surface to memory for compositing. With D3D9Ex it can do that directly in the video memory.