manual/Migrate2.md

Migrating v1 Plugins to v2

The API of VCV Rack v2 has been designed to be nearly backward-compatible with v1 plugins, so updating your plugin to v2 likely only involves a version update and a recompile.

Update plugin version to v2

The major version number (vMAJOR.MINOR.REVISION) of your plugin must match the major version of Rack, so change the version number in your plugin's plugin.json manifest to 2. For example, change

{
  "slug": "Fundamental",
  "version": "1.2.3",
  ...

to

{
  "slug": "Fundamental",
  "version": "2.0.0",
  ...

If you wish, you may keep the minor and revision numbers unchanged, e.g. 2.2.3.

Download the latest Rack v2 SDK. Clean and compile the plugin.

export RACK_SDK=/path/to/Rack-SDK
make clean
make dist

If your plugin compiles successfully, you are ready to test and release. Or, you may take advantage of new v2 features below.

Potential bugs

Avoid keeping Font (and Image) references across multiple frames

Rack for DAWs uses a different OpenGL context each time the plugin editor window is closed and reopened. This means that if you load a Font in a widget's constructor with font = APP->window->loadFont(...), the OpenGL font reference will be invalid if the window is reopened later.

Instead, save only the font path, and fetch the font each frame in draw(). Example:

std::shared_ptr<Font> font = APP->window->loadFont(fontPath);
if (font) {
	nvgFontFaceId(args.vg, font->handle);
	...
}

loadFont() caches the font by its path, so this operation can be efficiently called in draw() every frame.

All of the above also applies to Image and loadImage().

Optional v2 API features

SVG load function

Window::loadSvg() has been moved to Svg::load(). Search and replace:

perl -i -pe 's/APP->window->loadSvg\b/Svg::load/g' src/*

Port labels

TOOD

Light labels

TODO

TODO