View source for Building a plugin for MOD Duo and MOD Duo X

== Introduction ==

This is a quick start guide to get an LV2 plugin running in a MOD Duo device.
Let's cut the chatter and get started.

== LV2 Basics ==

This information is well described elsewhere. The SDK assumes that you have a working lv2 plugin for desktop linux. If you haven't gotten that far, you should start with these links:

* [[Creating_Audio_Plugins|Creating Audio Plugins]]
* [http://lv2plug.in/book/ LV2 Book]
* [http://harryhaaren.blogspot.com/2012/06/writing-lv2-plugins-lv2-overview.html Writing Lv2 plugins : An Lv2 Overview]

== Prepare build tools ==

'''This section needs to be updated with DuoX information'''

In order to run a plugin in the MOD Duo we must compile it for its specific architecture.

The Duo uses an ARMv7 processor running a very basic and stripped-down version of Linux.

Several audio-related libraries are included (fftw, libsndfile, libresample, etc) as well as generic libraries (boost, eigen, qt5core, etc).

We currently provide a custom build system that gives developers a similar system to what's available inside the Duo.

Do not use a regular Linux system, it might lead to issues due to mismatching library versions.

If you're running Linux just clone [https://github.com/moddevices/mod-plugin-builder MOD Plugin Builder] and follow the [https://github.com/moddevices/mod-plugin-builder/blob/master/README.md instructions].

In summary:

<source lang="console">
$ git clone git://github.com/moddevices/mod-plugin-builder
$ cd mod-plugin-builder
$ ./bootstrap.sh
</source>

This process should take at least 1 hour, probably more depending on your CPU.
When it finishes you'll be able to build plugins for Duo.

=== Using docker ===

Alternatively, if you're familiar with [https://www.docker.com/ docker] or are not running Linux, you can also use our [https://hub.docker.com/r/moddevices/mod-plugin-builder/ mod-plugin-builder image] which includes an already built system.

See [[How_To_Use_Docker_Toolbox_With_MPB| this HowTo]] for more information about docker and mod-plugin-builder.

== Build using buildroot '.mk' files ==

In order to publish your plugin in Mod Labs cloud, you need to use [https://buildroot.org/ buildroot]. See [[Using_buildroot|this guide]] on how to use buildroot to build plugins.

== Local development ==

For local development of plugins using buildroot can be bothersome and confusing.

You can use the cross-compiler and toolchain directly instead of going through buildroot methods.

Note that this expects that your source code build system is cross-compile friendly (ie, no hardcoded compiler and paths and uses pkg-config to find extra libraries).

Also this only works on a real Linux system, without using docker.

The setup is as simple as: (adjust as needed)

<source lang="console">
$ . ~/mod-plugin-builder/local.env
$ make
</source>

The local.env file will setup your Linux compiler environment variables (such as CC, CXX, CFLAGS, etc) to use mod-plugin-builder files.

If everything goes well, the resulting binaries will be ARMv7, MOD Duo compatible.

=== Quick example plugin ===

A quick example plugin is available inside mod-plugin-builder in make -C plugins/package/eg-amp-lv2/source/, which works with this cross-compilation setup.

See https://github.com/moddevices/mod-plugin-builder/tree/master/plugins/package/eg-amp-lv2-labs/source

Building this example plugin is as simple as:

<source lang="console">
$ . ~/mod-plugin-builder/local.env
$ make -C ~/mod-plugin-builder/plugins/package/eg-amp-lv2/source
</source>

That's it! After this the eg-amp.lv2 bundle is ready to be deployed into a MOD unit.