Migrating 0.6 plugins to Rack v1

This document is a draft. It is not recommended to migrate plugins at this time. If you begin now, you will likely need to follow this guide again when the Rack v1 API is stable.


Install new build dependencies.


brew install python jq


pacman -S python mingw-w64-x86_64-jq


On Ubuntu 16.04:

sudo apt install jq

On Arch Linux:

pacman -S python jq

The easy way: using the rack0.hpp compatibility header

Change #include "rack.hpp" to #include "rack0.hpp"

Create a plugin.json manifest file for your plugin using the helper.py script included in the Rack SDK.

python <Rack SDK>/helper.py createmanifest

Add a module entry to plugin.json for each module in your plugin. When prompted, don’t overwrite the module .cpp file.

python <Rack SDK>/helper.py createmodule <module slug>

Remove SLUG and VERSION from the Makefile, and remove p->slug = ... and p->version = ... from your plugin’s main .cpp file, since they are now defined in plugin.json.

For each module, change the Model::create call

Model *modelMyModule = Model::create<MyModule, MyModuleWidget>("Template", "MyModule", "My Module", OSCILLATOR_TAG);


Model *modelMyModule = Model::create<MyModule, MyModuleWidget>("MyModule");

since the plugin name, module name, and module tags are now defined in plugin.json.

For the following replacements, make sure you have perl installed (perl -v), and paste these lines into your terminal in the root of your plugin directory to automatically make replacements. It might even be a good idea to review the changes and git commit between each step.

Rename the plugin variable to avoid a name collision with the plugin:: namespace.

perl -pi -e 's/\bplugin\b/pluginInstance/g' src/*

Rename X::create() functions to createX().

perl -pi -e 's/Model::create/createModel/g' src/*
perl -pi -e 's/ParamWidget::create/createParam/g' src/*
perl -pi -e 's/ModuleLightWidget::create/createLight/g' src/*
perl -pi -e 's/Port::create/createPort/g' src/*
perl -pi -e 's/Port::OUTPUT/PortWidget::OUTPUT/g' src/*
perl -pi -e 's/Port::INPUT/PortWidget::INPUT/g' src/*
perl -pi -e 's/Widget::create/createWidget/g' src/*
perl -pi -e 's/MenuLabel::create/createMenuLabel/g' src/*
perl -pi -e 's/MenuItem::create/createMenuItem/g' src/*

Rename to/fromJson() methods to dataTo/FromJson().

perl -pi -e 's/toJson/dataToJson/g' src/*
perl -pi -e 's/fromJson/dataFromJson/g' src/*

If your plugin uses any of Rack’s dsp/*.hpp headers, remove the #include "dsp/..." lines since they are now automatically included by rack.hpp.

Now compile your plugin. Hundreds of deprecation warnings should appear, but it might succeed. If so, your plugin can now be distributed as a Rack v1 plugin. If not, read the compile errors, and don’t hesitate to ask questions in the Development category of the VCV Community or Rack GitHub issue tracker. If your plugin is open-source, you may even ask the VCV Repair Team to create a pull request in your repository.

The right way: using the Rack v1 API

First complete the above section using the compatibility header as a first step.

Once it is able to compile, change #include "rack0.hpp" back to #include "rack.hpp".

Add new arguments to the step() (now called process()) and draw() methods.

perl -pi -e 's/void (\w+::)?step\(\)/void $1process(const ProcessArgs &args)/g' src/*
perl -pi -e 's/void draw\(NVGcontext \*vg\)/void draw(const DrawArgs &args)/g' src/*
perl -pi -e 's/\bvg\b/args.vg/g' src/*
perl -pi -e 's/engineGetSampleRate\(\)/args.sampleRate/g' src/*
perl -pi -e 's/engineGetSampleTime\(\)/args.sampleTime/g' src/*

Use the APP macro for accessing global state.

perl -pi -e 's/Font::load/APP->window->loadFont/g' src/*
perl -pi -e 's/Image::load/APP->window->loadImage/g' src/*
perl -pi -e 's/SVG::load/APP->window->loadSvg/g' src/*

Use createInput/Output() functions instead of createPort().

perl -pi -e 's/, PortWidget::INPUT//g' src/*
perl -pi -e 's/addInput\(createPort/addInput(createInput/g' src/*
perl -pi -e 's/, PortWidget::OUTPUT//g' src/*
perl -pi -e 's/addOutput\(createPort/addOutput(createOutput/g' src/*

Add namespaces to global functions.

perl -pi -e 's/\bassetPlugin\b/asset::plugin/g' src/*
perl -pi -e 's/\brandomUniform\b/random::uniform/g' src/*
perl -pi -e 's/\brandomNormal\b/random::normal/g' src/*
perl -pi -e 's/\brandomu32\b/random::u32/g' src/*

Change .value to getters and setters, and change .active to isConnected().

perl -pi -e 's/(params\[.*?\])\.value/$1.getValue()/g' src/*
perl -pi -e 's/(inputs\[.*?\])\.value/$1.getVoltage()/g' src/*
perl -pi -e 's/(outputs\[.*?\])\.value = (.*?);/$1.setVoltage($2);/g' src/*
perl -pi -e 's/(inputs\[.*?\])\.active/$1.isConnected()/g' src/*
perl -pi -e 's/(outputs\[.*?\])\.active/$1.isConnected()/g' src/*

Add the dsp:: namespace to dsp classes. TODO

Add config() to the Module constructor, and add setModule to the ModuleWidget constructor.

perl -pi -e 's/: Module\(NUM_PARAMS, NUM_INPUTS, NUM_OUTPUTS, NUM_LIGHTS\) \{/{\n\t\tconfig(NUM_PARAMS, NUM_INPUTS, NUM_OUTPUTS, NUM_LIGHTS);/g' src/*
perl -pi -e 's/: ModuleWidget\(module\) \{/{\n\t\tsetModule(module);/g' src/*

Now make sure your plugin compiles.

Adding new Rack v1 features

You are now ready to add optional Rack v1 features to your plugin.

Parameters now have optional labels. Add configParam() to the Module constructor.

configParam(X_PARAM, 0.0, 1.0, 0.0, "Label");