Restarting java point cloud demo often fails to reacquire pose data - google-project-tango

(Wow did SO just select a lot of nonsequitor questions - joy of being on the edge :-)
I find that often when I'm trying to run this app multiple times from Android Studio, subsequent invocations that cause a resume, instead of a cold start (real cold, as in camera permission needed again), the app can no longer acquire pose data - it does get attitude and position data, but it never gets any point clouds because the onPoseAvailable callback in setTangoListeners never gets called again - often I have to reboot the device, sometimes googles app makes everything better, and other times I have to reboot.
I'm pretty sure this is because the proper actions vis connecting to and disconnecting from tango in the Pause and Resume logic is not quite right - however, even when the app is completely rebuilt and installed due to code changes, this irritating behavior remains (irritating) - Anyone have any experience with this ?

I think there are two possible reasons causing this issue, one is the above you mentioned(connect disconnect life cycles), the other one could be the IR frame out of sync issue, as mentioned in Project Tango known issues, as it says:
"Occasionally, or when under high CPU load, the depth flash may appear in the color image, or no depth points are returned. Let the device cool down and/or reboot"
One way to diagnose the problem is to observe the device's IR projector(see Project Tango Tablet Development Kit hardware section). First, launch a depth application, if everything works correctly, you will be able to see a sequence of really dim red flash coming from the IR projector, the red flash pulses around 3Hz. If the problem is connect fails, the IR projector won't give the red pulses. If it is depth out of sync, then you will see the red pulses, but no depth coming out (no callbacks).
Hope it helps.

Related

D3D9 Present returns D3DERR_DEVICELOST even in Windowed Mode(!)

Foreword
Since this appears to be a bug in the d3d9 Emulation on the Windows side, this would probably best addressed to Microsoft. If you know where I could get into contact with the DirectX Team, please tell me.
For the time being, I'm assuming that the only real chance we have is working around the bug.
What
We're investigating an inresponsiveness found in the Game Test Drive Unlimited 2.
Only when opening the Map and only when having an "RTX" Card (I think the most precise we got is GDDR6, because AMD also seems affected).
After long debugging, we found out, that it's not a simple fault of the game, but instead Present returning D3DERR_DEVICELOST even when having the game in Windowed Mode.
When the Game is in Fullscreen Mode, it properly does the required roundtrip over TestCooperativeLevel and Reset, but after the next frame is rendered, Present has lost the device again, causing the Hangup.
Now I'm looking for pointers on how to solve this issue. While it's probably some internal state corruption of some sorts, it's definitely triggered by an API Call only present when rendering the Map in that Game.
We will try to dig into d3d9.dll, but my suspicion is that the error code just comes from some Kernel/Driver Call, where our knowledge and tooling ends.
Ideally I'd like to fuzzy-find the drawcall by just hooking everything and omitting random apicalls, but I guess it's just not so easy and causes a lot more errors in most conditions.
Also note that an APITrace we did, showed D3D_OK for every single call including EndScene, up until Present, so it's not as simple as checking the return codes.
Trying to use Direct X 9 in Debug/Diagnostic Mode is also not really possible on Windows 10 anymore apparently, even when installing the SDK from June 2010
Thanks in Advance for any idea and maybe addresses to direct this problem to.

General tips in running a Unity3D-Animation on Microsoft Hololens

I'm going to have the task to make sure that an animation created for in Unity3D can be run on a Microsoft Hololens. I don't have any further information about the animation yet but I wanted to ask in advance if there are any big things i should keep in mind.
In the animation you're playing a "character" in first person mode, controlled by wasd or the arrow keys and you can look up, down, left, right with the mouse. There are (as known to me) no special interactions besides colliders.
And another question: is it easier to test the animation on the actual hololens or to use a hololens-emulator on my laptop?
I know it's a lot to ask right now without any code or stuff but I still hope that some of you can give me a little advide :)
In my experience it is difficult to say. The HoloLens, besides it is an awesome device with nice specs for that size, has quite limited graphical power. Try to minimize your model's vetices to a reasonable low amount (e.g. using Blender's decimate feature). Set down the quality in Unity's quality setting as proposed in the Dev-Guide.
For your emulation question: The emulator does not emulate the HoloLens' specs (like processor, memory...), but emulates input concepts etc., while running a Hyper-V virtual machine. So the performance in the emulator is dependent to your computer's hardware and is not related to the actual performance on a HoloLens.
Also take a look at the performance guidelines from Microsoft
I worked on HoloLens for a couple of projects. A few points that can be useful for you:
the first big thing I would keep in my mind is understanding if the character has to move in a VR environment. In this case HoloLens is almost useless because its lenses will allow you to see the surroundings [the real ones] distracting you from the virtual world. This is exactly what happens with their pre-installed HoloTour. Nice attempt but you will not totally feel in Roma or Machu Picchu
the second big thing that I would consider is the fact that - at least for the first release - HoloLens has a very limited field of view, that "amounts to the size of a monitor in front of you – equivalent to 15 inches" [source]. It is likely that - in a situation where the character will look in every direction - the objects that you put in the AR space will end up being cut or invisible
about testing: the emulator is really exceptional, I didn't find great differences between it and the real device. Of course if you already have the real HoloLens I would use that. But if not I would first develop and test on the emulator to understand if the project is worth the purchase

Can we use Dalvik with Tango

So I ran into the dreaded 'unfortunately....has stopped working' issue where art loads 2 classes and the debugger promptly tanks out - see this
So, in utter desperation, I switched from ART to Dalvik, half dreading a long session with ADB if the tablet got sour about the switch. Seemed to work. Tango works, albeit with a whole new set of head scratchers (flakier about getting XyzIj, flash is running, surface binding working, hell I can see the camera flashes in the surface showing the camera view - and if I try again and again, I do get tango point data :-)
Can I assume all the tango issues are of my own doing and keep using Dalvik, or must I switch back to ART and try to do all of my debugging through logcat ?
The answer to the question in title: Can we use Dalvik with Tango?
You should always use ART instead of Delvik on Tango, Delvik will work but NOT stable on Tango device, it might cause the issue you experienced like depth out-of-sync.
Same problem here,
What helps is switching to Dalvik for debugging non tango-related issues, but this really slows development process down, as all apps have to be optimized for each switch between debugging and testing session.

Periodic GPU performance problem

I have a WinForms application that uses XNA to animate 3D models in a control. The app have been doing just fine for months but recently I've started to experience periodic pauses in the animation. Setting out to investigate what is going on I have established these facts:
It happens on my machine only, other machines works fine
Removing everything from my render loop does not improve the problem
In 2. I didn't actually remove everything, I limited my loop to set the viewport on my GraphicsDevice and then do a GraphicsDevice.Present.
Trying to dig further I fired up PIX to capture some statistics. Screenshots of two PIX runs can be viewed here (Run6) and here (Run14). Run6 is using my original render loop and Run14 is using the bare-bones Present loop.
PIX tells me that the GPU is periodically doing something, and I assume this is causing the pauses. What could be the cause of this? Or how do I go about finding out what the GPU is actually doing?
Update: since I usually trust my code to be perfect (who's laughing?) I started a new XNA project from scratch to see if it exhibit the same behavior. So starting a new XNA 3.1 Windows Game project and running PIX I get this timeline. The same periodic pauses. So the problem must be lower in the stack, in XNA or Direct3D.
So PIX shows that the GPU is working on something, I can see the list of DX calls made within each frame and the timing calculations shows that the pause occurs during (or after) the IDirect3DDevice9::Present call.
Update 2: I had previously installed and uninstalled XNA 4.0 CTP on the problematic machine. I cannot be certain that this is related but I thought that perhaps a reinstall of the XNA Game Studio 3.1 bits could make a difference. Turns out it did.
The underlying question remains the same (and the bounty is still up): what could affect XNA 3.1 (or DirectX) to make it behave like this and is there any logging/tracing power tool for the DirectX and/or GPU level out there that could shed some light on what is going on?
Note: I'm using XNA 3.1 on a Windows 7 x64 dual-core machine with 8GB RAM.
Note2: also posted this question on the XNA Creators forums here.
You could try to see if you can find something with Xperf that is close to your periodically problem, do not run your application but keep the programs open that would normally run besides your application. You could also try to do it again with the application running but it could give a cluttered view.
Start the tracing, do this in an elevated prompt.
xperf -on BASE+LATENCY -stackWalk Profile
Wait for a fair amount of time to be sure that the problem is traced.
Stop the tracing and open it like this.
xperf -d trace.etl
xperfview trace.etl
Analyze by looking at the graphs and consulting tables of specific intervals and see if you can find something that is related to the problem, the highest chance on finding it would be in the DPC and Interrupts section. But it might as well be something odd at the CPU or I/O section. Good luck!
Also more information on Xperf and how to obtain it, hopefully this delivers results.
If not, you can alternatively try GPUView which has been used for improvements in DWM,
this is also included next to Xperf with the Windows Performance Toolkit so you can easily try both!
log v
... wait for a fair amount of time to be sure that the problem is traced ...
log
gpuview merged.etl
In the case that gpuview gets out of memory you can try to add "/limit 3" or remove the v.
Read the documentation of the tools if you are stuck somewhere.
Hmm ... this seems to be occurring on the GPU, however it sounds like a CPU garbage collection issue. Can you run the CLR profiler and see if you can see any spikes in GC activity that you can correlate to the slowdowns?
I agree that it sounds unlikely since you can clearly see it in PIX, but it might offer a clue as to the cause.
If it's only happening on your own machine, then could it be drivers? Forgive me for being skeptical, but it's a 64 bit machine after all :D
This looks like either a vsync issue or GPU in its last throes. Since going back to a different version fixed it, and the "bottleneck" is in IDirect3DDevice9::Present lets go with the former option.
I'm not familiar with XNA so I don't know how much of the workings of D3D are exposed, but do you know what your PresentationParameters are set to?
Specifically try setting the swap effect set to Discard.

Best practices for Alt-Tab support in a DirectX app?

When writing DirectX applications, obviously it's desirable to support the user suspending the application via Alt-Tab in a way that's fast and error-free. What is the best set of practices for ensuring this? Things that need to be addressed include:
The best methods of detecting when your application has been alt-tabbed out of and when it has been returned to.
What DirectX resources are lost when the user alt-tabs, and the best ways to cope with this.
Major things to do and things to avoid in application architecture for purposes of alt-tab support.
Any significant differences between major DirectX versions as they apply to the above.
Interesting tricks and gotchas are also good to hear about.
I will assume you are using C++ for the purposes of my answers, but if you can afford to use C#, XNA (http://creators.xna.com/) is an excellent game platform that handles all of these issues for you.
1]
This article is helpful for windows events in the window procedure to detect when a window loses or gains focus, you could handle this on your main window: http://www.functionx.com/win32/Lesson05.htm. Also, check out the WM_ACTIVATEAPP message here: http://msdn.microsoft.com/en-us/library/ms632614(VS.85).aspx
2]
The graphics device is lost when the application loses focus from full screen mode. Microsoft offers an article on how to handle this: http://msdn.microsoft.com/en-us/library/bb174717(VS.85).aspx This article also has a lost device tutorial: http://www.codesampler.com/dx9src/dx9src_6.htm
DirectInput can also have a device lost error state, here is a link about that: http://www.toymaker.info/Games/html/directinput.html
DirectSound can also have a device lost error state, this article has code that handles that: http://www.eastcoastgames.com/directx/chapter2.html
3]
I would make sure to never disable Alt-Tab. You probably want minimal CPU load while the application is not active because the user probably Alt-Tabbed because they want to do something else, so you could completely pause the application, or reduce the frames rendered per second. If the application is minimzed, you of course don't need to render anything either. After thinking about a network game, my best solution is that you should still reduce the frames rendered per second as well as the amount of network packets handled, possibly even throwing away many of the packets that come in until the game is re-activated.
4]
Honestly I would just stick to DirectX 9.0c (or DirectX 10 if you want to limit your target operating system to Vista and newer) if at all possible :)
Finally, the DirectX sdk has numerous tutorials and samples: http://www.microsoft.com/downloads/details.aspx?FamilyID=24a541d6-0486-4453-8641-1eee9e21b282&displaylang=en
We solved it by not using a fullscreen DirectX device at all - instead we used a full-screen window with the top-most flag to make it hide the task bar. If you Alt-Tab out of that, you can remove the flag and minimize the window. The texture resources are kept alive by the window.
However, this approach doesn't handle the device lost event happening due to 'lock screen', Ctrl+Alt+Delete, remote desktop connections, user switching or similar. But those don't need to be handled extremely fast or efficiently (at least that was the case in our application)
All serious D3D apps should be able to handle lost devices as this is something that can happen for a variety of reasons.
In DX10 under Vista there is a new "Timeout Detection and Recovery" feature that makes it common in my experience for graphics devices to be reset which would cause a lost device for your app. This seems to be improving as drivers mature but you need to handle it anyway.
In DX8 and 9 (and 10?) if you create your resources (vertex and index buffers and textures mainly) using D3DPOOL_MANAGED they will persist across lost devices and will not need reloading. This is because they are stored in system memory and the DX runtime copies to video memory automatically. However there is a performance cost due to the copying and this is not recommended for rapidly changing vertex data. Of course you would profile first to determine if there is a speed issue :-)

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