Getting the rom name and emulator

daveyman123

How would i go about getting the rom/emulator name of the current game within a python script? The idea being to send the information to a display hat on the pi.

Thanks,
Dm123

BuZz

@daveyman123 https://retropie.org.uk/docs/Runcommand/#runcommand-onstart-and-runcommand-onend-scripts

daveyman123

@buzz said in Getting the rom name and emulator:

@daveyman123 https://retropie.org.uk/docs/Runcommand/#runcommand-onstart-and-runcommand-onend-scripts

"Useful data are passed as arguments to these scripts:

$1 - the system (eg: atari2600, nes, snes, megadrive, fba, etc).
$2 - the emulator (eg: lr-stella, lr-fceumm, lr-picodrive, pifba, etc).
$3 - the full path to the rom file.
$4 - the full command line used to launch the emulator."

would i use subprocess.call within python to call these commands?

BuZz

@daveyman123 No - you could call your python script from the bash script passing the arguments in, then when launching a game the code will be called and you can send the game name to your display etc.

daveyman123

thank you for the replies. very much appreciated :)

daveyman123

@buzz said in Getting the rom name and emulator:

@daveyman123 No - you could call your python script from the bash script passing the arguments in, then when launching a game the code will be called and you can send the game name to your display etc.

OK so i create the bash script and make it executable. inside the script i have given the command "python /path/to/myscript.py"

I can run the bash script from terminal and it works!

However,
when i launch a game the script doesnt run

again i have put the the python script in the "runcommand-onstart.sh" script and not made the script executable or added anything other than what i mentioned before

thanks,
DM123

BuZz

@daveyman123 Where did you put the file ? What version of RetroPie are you running ? Please post the script (use a code block - http://commonmark.org/help/)

daveyman123

@buzz said in Getting the rom name and emulator:

@daveyman123 Where did you put the file ? What version of RetroPie are you running ? Please post the script (use a code block - http://commonmark.org/help/)

@buzz said in Getting the rom name and emulator:

@daveyman123 Where did you put the file ? What version of RetroPie are you running ? Please post the script (use a code block - http://commonmark.org/help/)

damnit all i forgot was to put sudo! :/ its working now!

i guess the next question i would ask would be: how do i retrieve the information

in the document you provided it says "$1" will get me the emulator. but i am unsure how to use this with python

thanks so much for your continued help!
DM123

BuZz

@daveyman123

python /path/to/myscript.py "$@"

will pass all the script arguments to your python script.

or use

python /path/to/myscript.py" "$1"

to pass a single parameter for example

cyperghost

@buzz Just a coding question.
If I use "$@" is there need to use loops to get all arguments or will all arguments pathed?
I used always "$1"... parameters and definated emulator=$1.

Can I resolve the $@ command and say emlulator=$1 romname=$2

What's is the better method to handle those calls?

cyperghost

@daveyman123
You can look to this >> lfl-launcher.source and see lines 33-37

These arguements were created by the bash-file >> create favourties.sh

So the bash file (Create Favourites.sh) gives arguments to binary (lfl-launcher) the first command "/home/pi/RetroPie/roms/My Favourites" was given manually.

BTW: There is no need to use this binary @pjft did a great job introducing favorites in our Emulations Station :D

daveyman123

@cyperghost

very informative Cyperghost. Thank You. so basically retropie is written in bash or am i way off?

BuZz

@daveyman123 RetroPie-Setup (the installer script etc) is written in bash and so is the launch script. Components are written in various other languages (C/C++/Python).

BuZz

@cyperghost I don't understand your question.

cyperghost

@buzz I call a python programm with $@ within runcommand. What will be the result and how does the python script "knows" how many arguments are given.

So if
$1 - the system (eg: atari2600, nes, snes, megadrive, fba, etc).
$2 - the emulator (eg: lr-stella, lr-fceumm, lr-picodrive, pifba, etc).
$3 - the full path to the rom file.
$4 - the full command line used to launch the emulator

can I just use romfile=$3 variable within python and I get my romfile even by using $@?

BuZz

@cyperghost "$@" is all the parameters. eg it expands to

"$1" "$2" "$3" (for any parameters that exist) so it will pass all the parameters on to the python script

https://stackoverflow.com/questions/4824590/propagate-all-arguments-in-a-bash-shell-script#4824637

daveyman123

@BuZz
@cyperghost
either of you know why i would have to powercycle my entire raspberry pi to get the "Pimoroni Unicorn Hat" to work more than once i.e. it screws up and lighting is random after one scroll through?

BuZz

@daveyman123 no idea.

meleu

@cyperghost said in Getting the rom name and emulator:

@buzz I call a python programm with $@ within runcommand. What will be the result and how does the python script "knows" how many arguments are given.

So if
$1 - the system (eg: atari2600, nes, snes, megadrive, fba, etc).
$2 - the emulator (eg: lr-stella, lr-fceumm, lr-picodrive, pifba, etc).
$3 - the full path to the rom file.
$4 - the full command line used to launch the emulator

can I just use romfile=$3 variable within python and I get my romfile even by using $@?

I'm not comfortable with python at all, I only learned it to tweak the joy2key tool and never used it again. But I think the answer for your question can be found here: https://docs.python.org/2/library/sys.html#sys.argv

Maybe this example can answer too:

[PROMPT] $ cat args.py 
#!/usr/bin/python

import sys

print '\nnumber of arguments:'
print len(sys.argv)

print '\nhere are the given arguments:'
for arg in sys.argv:
    print arg

print '\nhere is the third argument:'
print sys.argv[3]


[PROMPT] $ ./args.py one two three

number of arguments:
4

here is the given arguments:
./args.py
one
two
three

here is the third argument:
three

[PROMPT] $ ./args.py catch errors

number of arguments:
3

here is the given arguments:
./args.py
catch
errors

here is the third argument:
Traceback (most recent call last):
  File "./args.py", line 13, in <module>
    print sys.argv[3]
IndexError: list index out of range

cyperghost

@meleu That's it
Thank you