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Lua Player Plus: Debugging Lua Scripts Quickly

Open discussions on programming specifically for the PS Vita.
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beelzebielsk
Posts: 2
Joined: Wed Jan 03, 2018 6:20 pm

Lua Player Plus: Debugging Lua Scripts Quickly

Post by beelzebielsk » Wed Jan 03, 2018 6:59 pm

I've just found LPP and I'm trying to make a few games with it.
However, debugging is prohibitively slow, as I'm making a lot of
mistakes.
  • There's no stack trace when I hit an error. I know where the error
    actually happened, but I have no idea how I got to the error.
  • Each time I have to change something, it seems that I have to
    rebuild the whole vpk and re-install it.
So, the questions I have are:
  • Is there already some way to test these lua scripts on my computer
    before sending it to the PSVITA?
    • If there's no current way to do this, do I essentially have to
      rebuild the Lua Player Plus modules, like `Control` and
      `Graphics` for use on my computer?
  • Are stack traces supposed to be present and I'm just missing
    something? Or would I have to write up my own stack trace
    functionality?
  • Is there some way to quickly update game files on the PSVITA? For
    instance, when I navigate to my homebrew's directory on the PSVITA
    (inside of ux0:/app), I can see that the lua script itself is
    inside of the directory. Can I just swap out this script instead
    of reinstalling the whole application?
    • Further, could I do this while the application itself is
      running? Specifically, if the application has hit an error,
      and I now have the option of restarting and/or starting an FTP
      server. If my application hits an error, then I start an FTP
      server through the application, then replace my lua script, and
      then restart the application, should I expect to just see the
      new code running? Or is this something dangerous to do, and
      ought to be avoided?
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beelzebielsk
Posts: 2
Joined: Wed Jan 03, 2018 6:20 pm

Re: Lua Player Plus: Debugging Lua Scripts Quickly

Post by beelzebielsk » Wed Jan 03, 2018 8:25 pm

I found a little bit of extra informaton after digging around. I think that directly swapping the lua scripts would be safe.

The location of the actual installed application is in

Code: Select all

ux0:/app
. I figure that there might be some files that I can ignore, like the files for the background of the application, or for the application's bubble.

If there's some dangerous/undesirable behavior that could be caused by swapping the scripts directly, it would have to be reflected somehow in the application code itself. Basically, there would have to be a change that happens to the application code when doing a proper install that doesn't happen when swapping scripts directly; otherwise, the exact same sequence of actions would happen, since the VITA is a deterministic machine.

So, if the only change between version to version of my application is the lua scripts, then I can probably assume that directly swapping out the lua scripts is reasonably safe. I dunno about swapping them during runtime after hitting an error, but swapping just a script instead of sending a whole package and reinstalling would be much faster.
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Rinnegatamante
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Re: Lua Player Plus: Debugging Lua Scripts Quickly

Post by Rinnegatamante » Fri Jan 05, 2018 11:13 pm

beelzebielsk wrote:
Wed Jan 03, 2018 6:59 pm
I've just found LPP and I'm trying to make a few games with it.
However, debugging is prohibitively slow, as I'm making a lot of
mistakes.
  • There's no stack trace when I hit an error. I know where the error
    actually happened, but I have no idea how I got to the error.
  • Each time I have to change something, it seems that I have to
    rebuild the whole vpk and re-install it.
So, the questions I have are:
  • Is there already some way to test these lua scripts on my computer
    before sending it to the PSVITA?
    • If there's no current way to do this, do I essentially have to
      rebuild the Lua Player Plus modules, like `Control` and
      `Graphics` for use on my computer?
  • Are stack traces supposed to be present and I'm just missing
    something? Or would I have to write up my own stack trace
    functionality?
  • Is there some way to quickly update game files on the PSVITA? For
    instance, when I navigate to my homebrew's directory on the PSVITA
    (inside of ux0:/app), I can see that the lua script itself is
    inside of the directory. Can I just swap out this script instead
    of reinstalling the whole application?
    • Further, could I do this while the application itself is
      running? Specifically, if the application has hit an error,
      and I now have the option of restarting and/or starting an FTP
      server. If my application hits an error, then I start an FTP
      server through the application, then replace my lua script, and
      then restart the application, should I expect to just see the
      new code running? Or is this something dangerous to do, and
      ought to be avoided?
- As you said, you can directly fix your lua script in ux0:app/TITLEID. Fixing in runtime too should be relatively safe but depending on when the crash happened, it could cause strange behaviours. (For example if the code crashed during sound reproduction).

- Lua scripts can't be tested on PC atm but RPCS3 is adding Vita support. Homebrews should be loadable in few weeks i think.

- As for debugging on PC, i wrote long time ago a minimalist lpp-3ds debugger for PC that far from being complete. That's essentially the way to go to have lpp-vita code running on PC without a Vita emulator.
https://github.com/Rinnegatamante/lppd-3ds
If you want, visit my website: http://rinnegatamante.it :D

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