DirectX in Windows 7 (11) and Windows 8 (11.1) - windows

In Windows 8, when you minimize a game and switch to it back again, then the game will be displayed very fast. It looks like that the screen was ready even before you told your PC to show the game. When you do the same in Windows 7, then it will take a second till you see the game. This time it looks like Direct X was suspended and the Video card needs time to prepare the screen.
So the question is, does Windows 8 render the game in the background and does Windows 7 begin to render when it is going to be displayed? Or is this because a change in the Windows API?

Do you use the same hardware and DirectX run time library for your test? I don't think that's a OS related performance issue, since most of DirectX program/game will stop rendering when they were minimized in order to release CPU time to other programs

Related

Reduce blink windows phone 7 flash

What is the best approach to set a Windows Phone 7 led to torch mode? I have used http://www.locked.nl/wp7-flashlight-getting-started but using reflection and/or the VideoCaptureDevice is not allowed. (only works on dev phone)
I have used the AutoFocusCompleted event and have tried a task (taskfactory.new) and regular task. My latest attempt uses the DispatcherTimer.
So what is the best approach to keep calling Focus and/or FocusAtPoint to minimize the blinking and get the closest to a constant light.
Windows Phone 7 - Camera Flash App Not Functioning

How to detect if Windows 8 is showing desktop

In a Windows desktop application written in C# and running on Windows 8 how can I detect if Windows 8 is in desktop mode (i.e. showing the Desktop rather than the modern UI)?
Although it's in C++, the Start Screen Visibility Sample should be a good starting point for you. It uses COM objects to get the state of all monitors on the system that are either displaying Windows Store Apps or the Start Screen, and illustrates how to receive notifications when the state of a monitor changes or when the visibility of the Start screen changes.

Is there an analogue of Windows Phone 'User Idle Detection' in Windows 8?

I've used the following code on Windows Phone 7 and 8 to disable user idle detection when my App is displaying data to the user and they are unlikely to interact with the screen e.g. A recipe App where the screen needs to stay on:
http://msdn.microsoft.com/en-us/library/microsoft.phone.shell.phoneapplicationservice.useridledetectionmode(v=vs.92).aspx
Does anyone know if there is an analogue of this available for Windows 8 applications? My tablet app has the same requirement to disable the screen turning off. I haven't managed to find anything :-(
Many thanks,
Jon
You should use the DisplayRequest class, specifically DisplayRequest.RequestActive for this purpose. You must also remember to call DisplayRequest.RequestRelease once you are done to allow the display to sleep, for example, if you are not viewing a recipe, or you are in a menu screen, etc.

How do I go about writing a windows driver for a bluetooth device?

I am looking for some advice/input on writing a device driver. I have never written one for windows before, let alone for bluetooth.
Can you recommend a book or website or something to get me started? I have the windows driver kit, and the examples therein but with out some place to start I am dead in the water.
The specifics: My friend gave me his mac Magic Mouse. I have a windows 7 machine. With the mouse set up as just a generic HID device it works ok as a two button mouse with no scroll, the motion is smooth and the acceleration what you expect in a windows mouse.
The mouse actually has a fairly good lpi resolution, making it pretty sensitive. There are mac drivers available, extracted from bootcamp. They kind of work. The cursor will randomly freeze or stop responding to the mouse's movement, which is buffered, and then leap once whatever has caused the stall stops. As an added touch the mac drivers make the cursor move like it would on a mac, with that logarithmic acceleration, that will completely throw off any windows user. With the driers you get vertical and horizontal scroll, but that's it. There is no multi touch functionality, and you can't change any of the behaviors, like acceleration. There isn't multiclutch for windows, or other 3rd party software for a multi touch mouse.
So I figured I would endeavor to make my own drivers and multi touch functionality in windows for this thing. I know mac will never support it properly under windows and windows won't write there own drivers until there is a reason.
Also if any one knows of any one else trying to do the same or similar things, point me to them.

My Windows Phone 7 animations look clunky on the emulator - should I be worried?

I'm doing a phone app with some animations and they look really clunky on the emulator. I don't have a phone yet so this is the only way I can test my app.
Sometimes the animations start late (up to a second after user input) and the they are almost always very jagged. Far from the smooth fades and transitions that I've seen on the interwebs. I'm not using anything hairy - just basic rotations and opacity fades on one or two elements.
Does anyone else see this in the emulator? If not, i guess I have a bug somewhere. If so, is there a work around? Should I bump the priority of the xde.exe in process explorer? Other?
Thanks!
This may be a consequence of gpu detection no working on your system.
You can verify this by checking if you can see the frame rate counters.
Jeff Wilcox – Frame rate counters in Windows Phone
Note the emulator system requirements here also.
Setup and System Requirements for Windows Phone Emulator

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