Compiling PD Externals - A Guide

adamtindale

Hi All,

I just got a Bela Mini and have compiled some PD externals for it and thought I would contribute a more verbose guide for others. I hope this is helpful and that people can help show me some other ways of achieving this so I can learn too.

Download PD-Extended Source Code. We will use this to transfer to the Bela and then build externals on the board. I downloaded the source from here: https://puredata.info/downloads/pd-extended
Unzip the package. This ended up in the Downloads folder for me.
Open a terminal. CD to the externals folder of PD-Extended
> cd Downloads/
> cd pd-extended/
Copy the externals folder to the Bela's pd-externals folder in the projects directory. Make sure you have it plugged in and have a working network connection first. You may have to create the pd-externals folder first by SSHing into the Bela.
> scp -r externals/ root@192.168.7.2:/root/Bela/projects/pd-externals/
SSH into the Bela.
> ssh root@192.168.7.2
Move to the externals folder.
> cd Bela/projects/pd-externals/externals
Move to the folder of your choice and run the build files. Mileage will vary. bsaylor and sigpack are easy and sound great.
> cd bsaylor
> make PD_INCLUDE=/usr/local/include/libpd/
Copy the resulting .pd_linux binaries into the pd-externals folder.
> cp *pd_linux /root/Bela/projects/pd-externals/
Load a PD project with the externals in it and enjoy.

emerson

Thanks for posting this, so helpful!

picofrom

Thank you that was really helpful. Some of the library like 'Gem' were a bit tricky to compile, the src in the folder /usr/local/include/libpd/ don't seem to be complete and I had to upload the src folder included with pd-extended into the bela

giuliomoro

That's probably still OK, compile-wise, but how are you going to use Gem if there is no video output from the board?

Remork

i thought pd-extended had long been abandoned?
not that there's no useful libs in there..

giuliomoro

Remork i thought pd-extended had long been abandoned?

that's correct. But Pd's headers (which are in the src folder that has been copied over) are backwards compatible for many many many years. Any new feature is added in a backwards-compatible way, so any external that doesn't require new features should build fine with even an old header; if it requires a new feature it won't build, so you'd know that.

Remork not that there's no useful libs in there..

Most of those should be available via deken. Btw, something I may have not mentioned is that if you find an external on deken that was built for armv7, then you can probably just install it on Bela as it is.

Flowdeeps

I hate to reanimate the dead but I'm developing on an Intel Mac and have a darwin build of a specific library (arraycopy from pd-maxlib) but for the life of me can't seem to get the build to run on the Bela. I've added the location /usr/local/include/libpd to my PATH but I'm getting an error stating that the m_pd.h can't be found.

=== EDIT ===

The magic sauce was this line cribbed from elsewhere in the forums:
make PDINCLUDEDIR=/usr/local/include/libpd/

hugo

Hi, I have been using Bela with Pd and custom externals extensively over the past years. I used to have a functional "dummy" project on the Bela for compiling my externals but after an adventurous sd card flashing I accidentally got rid of it.
I tried to set it up again using resources from this forum but this time nothing worked.
I've finally found a very straightforward way to do it and therefore took the liberty to share the process here. Please correct me if I'm wrong.

BASICS

PureData externals are additional objects which are compiled from .c or .cpp files.
They need to be compiled with the proper target architecture to work on the Bela (e.g. an external on an apple computer will end with.pd_darwin, on bela it is a .pd_linux)
to have an external working in your pd patch, it simply needs to be in the same folder as _main.pd. So once the file is compiled you can simply move it into your project, or upload it using the IDE.

STEPS

1 - Get into the Bela IDE
2 - Create a new project. You can remove all files from it. Name it what you want (pd-externals is fine)
3 - Using the IDE upload your source code file (YOUREXTERNAL.c)
4 - If you don't already use it, download pd-lib-builder (https://github.com/pure-data/pd-lib-builder)
5 - Using the IDE upload the Makefile.pdlibbuilder file in the project
6 - Get pd source code (https://github.com/pure-data/pure-data)
7 - Copy the src directory into the project (I told you it was straightforward). Several ways to do this. But scp works fine scp -r src root@192.168.7.2:/root/Bela/projects/pd-externals/.
I guess you could also just upload all the files directly in the project using the IDE if you like it messy.
8 - Create a Makefile. Minimal info is this :
lib.name = YOUREXTERNAL class.sources = YOUREXTERNAL.c include Makefile.pdlibbuilder
The Makefile.pdlibbuilder file is in the same directory so there is no need for PDLIBBUILDER_DIR

9 - From the IDE command line enter cd projects/pd-externals/ to get into the correct working directory
10 - From the IDE command line make PDINCLUDEDIR=src
that's in case you have uploaded the whole src directory, but the idea is simply to tell the compiler where "m_pd.h" is

dreamer

hugo I don't think you need all of pure-data source code to create an external. just the m_pd.h header file is enough.

I'm still interested to see if we can leverage hvcc to create externals for bela using pd source code 🙂

You can export such pd-external source using plugdata.

giuliomoro

m_pd.h is the only public header but many many externals rely on other headers as well (mainly s_stuff.h but also some of the g_* ones sometimes). That's why Pd ships with its own src folder so that externals can be built against any headers in there.

dreamer

giuliomoro thnx, I understand. This allows for deeper integration into Pd I suppose.

Now I'm wondering how we can extend the heavy external wrapper with additional features 🤔