jcoady
commented
3 years ago Attached is an example of running a loop in a function in a jupyter notebook cell. You will need use asyncio and make sure your loop has a rate() statement which contains the code to send messages from python to the javascript front-end. In the attached notebook file the loop code is in an asynchronous function called periodic which has async/await keywords and it updates the scene continuously from the function. Try running the example in the attached notebook to see how it can be done.
import asyncio async def periodic(): while True: await asyncio.sleep(0) rate(100) if running: currentobject.rotate(angle=1e-4*sl.value, axis=vec(0,1,0))
loop = asyncio.get_event_loop() task = loop.create_task(periodic())
Note that in a Jupyter Notebook a notebook cell needs to run to completion before another notebook cell can be executed. So normally if you have a loop that runs forever like in a vpython simulation then the cell will never finish executing and you won't be able to run other cells in the notebook. But if you put your vpython loop in an asyncio coroutine like in the above example then the loop will run asynchronously and the cell will complete execution so that you can execute other cells in the notebook while the vpython simulation is running.
John
From: "thomas-bc" @.> To: "vpython" @.> Cc: "Subscribed" @.***> Sent: Saturday, April 3, 2021 5:22:38 AM Subject: [BruceSherwood/vpython-jupyter] Scene update within functions (#147)
Dear all,
I am walking my first steps with this library, I can already say I am impressed, and yet I find it hard to understand how to run it efficiently (for instance in a notebook). I noticed I can run code from the examples in a jupyter notebook, but only if I execute the main loop directly in a cell. As soon as I try to encapsulate the loop logic in a function (or a method, which is what I am really interested in), the scene is not updated until the end of the loop.
Is there anything I can include to run the main update loop from a function? Thanks!
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BruceSherwood
sntgluca
Dear all,
I am walking my first steps with this library, I can already say I am impressed, and yet I find it hard to understand how to run it efficiently (for instance in a notebook). I noticed I can run code from the examples in a jupyter notebook, but only if I execute the main loop directly in a cell. As soon as I try to encapsulate the loop logic in a function (or a method, which is what I am really interested in), the scene is not updated until the end of the loop.
Is there anything I can include to run the main update loop from a function? Thanks!