im searching for a way to paus a thread that for example displays some animation on a scene by switching to a different one. The background is to save cpu load of to mutch executing tasks. I also want to resume the Thread after i switch back to the scene. I know that i can do this in the method, in which i load the new scene but i cant find a way to pause and resume on that point the thread stoped. Is there an build in function in task, futuretask? My only idea was, to save the current state and by switching back i start a new task and restore the saved values/state. Are there any experts, who can give me the best practise/solution? Thanks for your help!
Sry for no code, but i think you can awnser it without any example. When not i will add some example code for sure.
Related
I'm facing an annoying issue in Blueprism a little help will be appreciated.
The error is when I run the task I have created in object studio directly in object studio it runs successfully but when I try to run the same task from process studio using action It throws an error. The application is launched but get this error. (Application is web-based.)
Internal: Failed to perform step 1 in Read Stage 'Reader1' on page 'Main' - No elements match the supplied query terms
this is Application Modeller Settings
Application Modeller
And this is how I call it in Process
Object Called in process
Action Properties
Wait Settings are following
When I try to highlight the link it does highlight it.
I think that after your Reader1 should be a decision if element was found or not and then you can proceed with log-in. But I'd check if the element you're spying is working correctly. Maybe try passing value of reader from object to process.
A process in BluePrism can have different speed of execution depending on the way you're running it.
If you're running application using "Step" function (hotkey F5), then BluePrism waits a long time between executing actions. A "Step above" (hotkey F10) is much faster, but the fastest possible speed of execution is from control room.
The delay from "Step", or "Step above" can be enough to make process work during the development. Once the process is moved to control room, then the delay is gone and sometimes the process might be running too fast. It can happen, that the BluePrism is trying to interact with the element that does not yet exist.
To make process work in control room, you need to have additional wait stages that will ensure that the process is not running ahead of the applications that are being automated. Whenever you're interacting with any element then you need to be sure that it exists.
i suspect that you're waiting for an element, but then you're trying to read a different one. It's important to wait for the exact element that you want to interact with, as elements can appear in an order, that can make your process crash.
We have a WinForms c++/cli CAD based application that uses VTK 6.1. One of the application's features is playing a script which plays back operations the user had previously done interactively. We pop a modal progress form while the script is playing and do the non-ui work of the script in a background thread. Part of the work of the background thread is creating and deleting vtkPolyDataMappers. While the background thread is going and the progress form is showing we need to update a display in the main thread by calling vtkWin32RenderWindowInteractor::Render().
We have a timer setup so Render is called every few hundred milliseconds at most in a UserControl::OnPaint event handler. This allows the view to update while the script is playing giving the user feedback.
This used to work in VTK 5. But now an infinite loop happens upon deletion of a vtkPolyDataMapper in the background thread. The infinite loop is in vtkClearOpenGLErrors:
void vtkClearOpenGLErrors()
{
while (glGetError()!=GL_NO_ERROR){;}
}
Inside the vtkpolydatamapper is a vtkOpenGLDisplayListPainter. When this gets deleted by vtkGarbageCollectorImpl::CollectInternal we get stuck in vtkClearOpenGLErrors.
Does anyone have experience with VTK and threading that could help? Do you know anything about this? It's only an apparent problem in VTK 6.1. Is it illegal to have the main UI thread calling Render on a vtkWin32RenderWindowInteractor while a background thread is doing deletes on a vtkPolyDataMapper? It isn't a timing issue. I think it might be an OpenGL context issue but not sure how to fix it. The problem does go away if we avoid calling Render on the display while the background thread is going but we'd like to give the user feedback while the script is playing.
We fixed the problem by recompiling VTK with
VTK_REPORT_OPENGL_ERRORS
turned off.
I am new to wxPython, so please be gentle. I am trying to make a game using wxPython. I need to be able to handle events (button clicks) while the game is in progress.
The process is:
Deal the cards
Wait for user input
Continue accordingly
The way I have implemented it is:
app = wx.App()
g = Game() # calls g.Play() which executes the process above
app.Mainloop()
However the application freezes. I think the problem relates to being unable to respond to events while the process is being executed. How can I get around this?
I had a look at threading, but cannot see how to make this work in my case. If I create a new thread to deal with user inputs from within Game(), that will not be able to update the values in Game().
I am sure there is a "correct" way of doing this which I don't know because I am unfamiliar with wxPython. Can anyone help?
Yo do not need a seperate function play() to run the game. Just set up the event handlers to compute the state of the game during every event which results in a move of the game.
A good option would be to define a game state as say the cards in each players hands, and the turns that have been played and the scores, all defined as an object of a state class.
Chalk out an outline of how your game's architecture first. And you might also want to take a look at some examples and documentations on wxPython if you are new to it.
wxPython (and all GUI toolkits) are event driven. What this means is that they all wait for the user to "do something", like press a button, move the mouse, press a key on the keyboard, etc. When the uses does one of these things, wxPython checks to see if any of those events are bound to an event handler. If they aren't, wx will usually ignore the events.
You can learn about how to bind events properly here:
http://wiki.wxpython.org/self.Bind%20vs.%20self.button.Bind
So when you start the program, it should probably deal the cards at the start or possibly prompt the user to see if they want to start a new game or possibly continue a game. After that, the application would wait for the user to "do something". If the user executes a process that takes a long period of time (like a complex calculation, downloading a large file, etc), that process should be put into a thread. If you don't put it into a thread, then that process will block the UI's main loop and your app will freeze. See the following articles for information about wxPython and threads:
http://wiki.wxpython.org/LongRunningTasks
http://www.blog.pythonlibrary.org/2010/05/22/wxpython-and-threads/
I hope these links help you on your way.
The program I am developing uses threads to deal with long running processes. I want to be able to use Gauge Pulse to show the user that whilst a long running thread is in progress, something is actually taking place. Otherwise visually nothing will happen for quite some time when processing large files & the user might think that the program is doing nothing.
I have placed a guage within the status bar of the program. My problem is this. I am having problems when trying to call gauge pulse, no matter where I place the code it either runs to fast then halts, or runs at the correct speed for a few seconds then halts.
I've tried placing the one line of code below into the thread itself. I have also tried create another thread from within the long running process thread to call the code below. I still get the same sort of problems.
I do not think that I could use wx.CallAfter as this would defeat the point. Pulse needs to be called whilst process is running, not after the fact. Also tried usin time.sleep(2) which is also not good as it slows the process down, which is something I want to avoid. Even when using time.sleep(2) I still had the same problems.
Any help would be massively appreciated!
progress_bar.Pulse()
You will need to find someway to send update requests to the main GUI from your thread during the long running process. For example, if you were downloading a very large file using a thread, you would download it in chunks and after each chunk is complete, you would send an update to the GUI.
If you are running something that doesn't really allow chunks, such as creating a large PDF with fop, then I suppose you could use a wx.Timer() that just tells the gauge to pulse every so often. Then when the thread finishes, it would send a message to stop the timer object from updating the gauge.
The former is best for showing progress while the latter works if you just want to show the user that your app is doing something. See also
http://wiki.wxpython.org/LongRunningTasks
http://www.blog.pythonlibrary.org/2010/05/22/wxpython-and-threads/
http://www.blog.pythonlibrary.org/2013/09/04/wxpython-how-to-update-a-progress-bar-from-a-thread/
I am using LibGDX to make a game. I want to simultaneously load/unload assets on the fly as needed. However, waiting for assets to load in the main thread causes lag. In order to remedy this, I've created a background thread that monitors which assets need to be loaded (textures, sounds, etc.) and loads/unloads them appropriately.
Unfortunately, I get the following error when calling AssetManager.update() from that thread.
com.badlogic.gdx.utils.GdxRuntimeException: java.lang.RuntimeException: No OpenGL context found in the current thread.
I've tried runing the background thread in the main thread in the beginning and just dealing with the first few screens, and everything works fine. I can also change the algorithm to just load everything into memory from the start in the same thread, and that works as well. However, neither works in the background thread.
When I run this on Android with OpenGL ES 2.0 (which is flexible in odd ways) instead of on Windows, everything runs fine, and I can even get the pixel dimensions of the images - but the textures render black.
My searches have told me that this is an issue of the OpenGL context being bound to a single thread, but not much else. This explains why everything works when I shove it in the main thread, and not when I put it in a different one. How do I fix this context problem?
First things first, you should not access the OpenGL context outside of the rendering thread.
I assume you have looked at these already, but just to make sure read up on the AssetManager wiki article, which talks a bit about how to use the AssetManager for asynchronous managing of assets. In addition to the wiki article, check out the AssetManagerTest to better understand how to use it. The asset manager test is probably your best bet into loading at how to dynamically load assets.
If you are loading a ton of stuff, you may want to look into creating a loading bar to load anything large upfront. It might work to check assets and such from another thread (and set a flag to call update), but at the end of the day you will need to call update() on the rendering thread.
Keeping in mind you have to call update() it from a different thread, I don't see why you would want another thread to check conditions and set a flag. There is probably more overhead using another thread and synchronizing the update() call than to just do it all on the rendering thread. Also, the update() method only pauses for a couple milliseconds at a time as it incrementally loads files. Typically, you would simply call load() for your asset, then check isLoaded() on your asset. If it isn't loaded you would then call update() once per frame until isLoaded() returns true. Once it returns true, you can then call get() and get whatever asset you were loading. This can all be done via the main rendering thread without having the app lag while its loading.
If you really want your other thread to call update(), you need to create a Runnable object and call postRunnable() such as how they have it described in the wiki article on multi-threading with libGDX. However, this defeats the whole point of using other threads because anything you use with postRunnable runs synchronously on the rendering thread.