[vbox-dev] D3D support in custom frontend

Rūdolfs Bundulis rudolfs.bundulis at gmail.com
Mon Jan 26 11:00:49 UTC 2015

Hi Vadim,

Well since I also came to the the conclusion that the WinId could cause
this, I tried making a dummy window for each of the IFramebuffer instances,
but nothing changed. Though the windows do not have any logic in the
message loop, and I do not resize them when the resolutions change - maybe
this causes some errors. That is why I asked if any logs from the miniport
driver is available to see where does it actually crash. If I make a debug
VirtualBox build then would debug GAs work?

Best Regards,
Rudolfs Bundulis

2015-01-26 12:50 GMT+02:00 Vadim Galitsyn <vadim.galitsyn at oracle.com>:

> Hi Rudolfs,
> As far as I can understand, returning NULL WinID might cause the behaviour
> you are observing on Windows host (please note, I have not tried that
> locally, take it like a gesture). Seems, you also already have 3D host
> service running. Can you try to provide valid WinID to Main/src-client
> stuff as an experiment and see if things changed?
> Regarding to GAs, I am afraid you’ll have a BSOD in guest once you attempt
> to boot VM with debug GAs installed. We currently have some debug R0
> assertion there.
> Vadim
> On 26 Jan 2015, at 13:12, Rūdolfs Bundulis <rudolfs.bundulis at gmail.com>
> wrote:
> Hi Vadim,
> thanks for the pointers, I'll look up the code, I was already afraid that
> something is simply missing.
> To describe what I am doing:
> I am running a research project in University of Latvia where we are
> trying to use VirtualBox for large scale high resolution display wall
> construction - basically we run VirtualBox with a custom frontend that
> takes the video data from the VRAM, encodes it and streams over to a
> display wall, currently we've been able to run a 9600x5400 surface with
> Windows XPDM (we set this resolution as a hint and then internally split it
> to  5*5 1920x1080 displays) , which is really impressive, so thanks again
> for the great software. In terms of resolution I guess this is as far as
> the existing 256MB VRAM limit in VirtualBox can go (at least according to
> the calculations for framebuffer needs provided by Klaus Erspenlaub and
> mentioned in your code). Since the resolution limit is reached we are
> trying to address two more issues - 3D support and a weird unaligned stack
> crash in VBoxREM.dll with more than 1 CPU shared to the machine (for the
> second issue I need to do some more research as to where it is coming from
> before I ask any help here). As for the 3D - we'd basically want our
> software to function in the same way the VirtualBox QT client does, but
> currently it does not. Thanks for the pointer about the HGCM/OpenGL
> service, I'll check out that code and see what I can adapt.
> Our software basically uses the VirtualBox COM interface to create the
> needed machine, set the number of displays/resolutions, injects the
> IFramebuffer instances and powers up the machine via the IConsole
> interface. So I examined all the IFramebuffer implementations in VirtualBox
> frontends, and didn't see anything very special in the 3D related callbacks
> there. As for the log - I tried to compare the log of a session from our
> software with a session from the same machine under QT fronted where the 3D
> acceleration works. Basically there were no errors and differences, in both
> cases the logs contained the lines about OpenGL support (i guess this comes
> from the OpenGL capability test exe), I'll send both logs as soon as I get
> back to that machine but I doubt they'll give much help, since they don't
> have any errors, and in both of them the guest additions log line states
> that acceleration is supported. Basically the only thing that differs is
> that the D3D/OpenGL (we've tried both API's, since the test application is
> built on Unity it is trivial to force either mode) device creation fails on
> our frontend. That is why I asked about the get_WinId, I examined the
> miniport driver code and as far as I understood it uses the window id value
> to create a swap chain. Out frontend does not have an actual window, so I
> am always returning NULL, can this cause an error? I also saw that the
> miniport driver has a lot of WARN macros, is  the output visible anywhere?
> I tried using DebugView but that didn't help? Should I try building a debug
> version of guest additions to get some log information?
> Best Regards,
> Rudolfs Bundulis
> 2015-01-26 10:34 GMT+02:00 Vadim Galitsyn <vadim.galitsyn at oracle.com>:
>> Hi Rudolfs,
>> In order to provide 3D acceleration, VBox HGCM/OpenGL host service should
>> be running. It is currently a part of VirtualBoxVM process (ShCrOpenGL
>> thread). In order to provide 3D acceleration support for your frontend, I
>> am afraid, you need to adapt stuff from this thread for your code. And I am
>> afraid this might be not that easy (there is a bit of magic when VBox GUI
>> conversates w/ 3D stuff). Please refer to
>> src/VBox/HostServices/SharedOpenGL and src/VBox/GuestHost/OpenGL sources.
>> Btw, if you describe a little bit more why do you need this and what you
>> already have done, maybe I could explain you more things/steps you need to
>> do in order to reach the goal. VBox.log also might be helpful.
>> Vadim
>> > On 24 Jan 2015, at 14:14, Rūdolfs Bundulis <rudolfs.bundulis at gmail.com>
>> wrote:
>> >
>> > Hi,
>> >
>> > I'm having a bit of a hard time understanding why my custom framebuffer
>> cannot use the 3D acceleration feature. I have a Windows 7 guest machine
>> (3D acceleration enabled, guest additions installed) and a Unity demo
>> application. Under the default QT GUI the application launches fine, while
>> under my frontend Unity is not able to create the D3D device. First I
>> though that this could be due to incorrect implementation of IFramebuffer,
>> but when I looked at UIFrameBuffer::Notify3DEvent(ULONG uType, BYTE *pData)
>> in UIFrameBuffer.cpp there wasn't any special magic there. Are there any
>> hints to guide me towards understanding the cause of this? Is there any
>> tracing facilities for the guest miniport driver? Also, I don't have a
>> window handle for my frontend since there is no actual window. If I am
>> returning 0 in get_WinId in my framebuffer can that mess things up?
>> >
>> > Best Regards,
>> > Rudolfs Bundulis
>> > _______________________________________________
>> > vbox-dev mailing list
>> > vbox-dev at virtualbox.org
>> > https://www.virtualbox.org/mailman/listinfo/vbox-dev
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.virtualbox.org/pipermail/vbox-dev/attachments/20150126/c70dd1ce/attachment.html 

More information about the vbox-dev mailing list