# yabridge

[![Automated builds](https://github.com/robbert-vdh/yabridge/workflows/Automated%20builds/badge.svg?branch=master&event=push)](https://github.com/robbert-vdh/yabridge/actions?query=workflow%3A%22Automated+builds%22+branch%3Amaster)

Yet Another way to use Windows VST plugins on Linux. Yabridge seamlessly
supports running both 64-bit Windows VST2 plugins as well as 32-bit Windows VST2
plugins in a 64-bit Linux VST host, with optional support for inter-plugin
communication through [plugin groups](#plugin-groups). Its modern concurrent
architecture and focus on transparency allows yabridge to be both fast and
highly compatible, while also staying easy to debug and maintain.

## TODO

This branch is still very far removed from being in a usable state. Below is an
imcomplete list of things that still have to be done before this can be used:

- Actually start implementing VST3 support.
- Update the GitHub Actions workflows.
- Update yabridgectl to handle buth VST2 and VST3 plugins.
- Update all documentation to refer to VST2 and VST3 support separately, and
  figure out how to do this in the least confusing way possible.
- Mention that this update will break all existing symlinks and that the old
  `libyabridge.so` file should be removed when upgrading.
- Update all the AUR packages.
- Add CMake to the AUR package dependencies and to our Docker images

![yabridge screenshot](https://raw.githubusercontent.com/robbert-vdh/yabridge/master/screenshot.png)

### Table of contents

- [Tested with](#tested-with)
- [Usage](#usage)
  - [Preliminaries](#preliminaries)
  - [Automatic setup (recommended)](#automatic-setup-recommended)
  - [Manual setup](#manual-setup)
  - [DAW setup](#daw-setup)
  - [Bitbridge](#bitbridge)
  - [Wine prefixes](#wine-prefixes)
  - [Search path setup](#search-path-setup)
  - [Configuration](#configuration)
    - [Plugin groups](#plugin-groups)
    - [Compatibility options](#compatibility-options)
    - [Example](#example)
- [Troubleshooting common issues](#troubleshooting-common-issues)
- [Performance tuning](#performance-tuning)
- [Runtime dependencies and known issues](#runtime-dependencies-and-known-issues)
- [Building](#building)
  - [Building without VST3 support](#building-without-vst3-support)
  - [32-bit bitbridge](#32-bit-bitbridge)
- [Debugging](#debugging)
  - [Attaching a debugger](#attaching-a-debugger)

## Tested with

Yabridge has been tested under the following VST hosts using Wine Staging 5.9:

- Bitwig Studio 3.3
- Carla 2.2
- Ardour 6.5
- Mixbus 6.0.702
- Qtractor 0.9.18
- REAPER 6.15
- Renoise 3.2.4

Please let me know if there are any issues with other VST hosts.

## Usage

You can either download a prebuilt version of yabridge through GitHub's
[releases](https://github.com/robbert-vdh/yabridge/releases) page, or you can
compile it from source using the instructions in the [build](#Building) section
below. If you're downloading the prebuilt version you're using a distro that's
older than Ubuntu 20.04 such as Ubuntu 18.04, Debian 10, or Linux Mint 19, then
you should download the version that ends with `-ubuntu-18.04.tar.gz`.
Alternatively there are AUR packages available if you are running Arch or
Manjaro ([yabridge](https://aur.archlinux.org/packages/yabridge/),
[yabridge-bin](https://aur.archlinux.org/packages/yabridge-bin/),
[yabridge-git](https://aur.archlinux.org/packages/yabridge-git/)).

### Preliminaries

Yabridge requires a recent version of Wine Staging. Users of Debian, Ubuntu,
Linux Mint and Pop!\_OS should install Wine Staging from the [WineHQ
repositories](https://wiki.winehq.org/Download) as the versions of Wine provided
by those distro's repositories will be too old to be used with yabridge.

Most VST plugins first need to be installed in your Wine environment before
they can be converted by yabridge for use in linux. For a general overview
on how to use Wine to install Windows applications, check out Wine's
[user guide](https://wiki.winehq.org/Wine_User%27s_Guide#Using_Wine).

### Automatic setup (recommended)

The easiest way to get up and running is through
[yabridgectl](https://github.com/robbert-vdh/yabridge/tree/master/tools/yabridgectl).
You can download yabridgectl from GitHub's [releases
page](https://github.com/robbert-vdh/yabridge/releases). There are also AUR
packages available if you're running Arch or Manjaro
([yabridgectl](https://aur.archlinux.org/packages/yabridgectl/),
[yabridgectl-git](https://aur.archlinux.org/packages/yabridgectl-git/), and it's
also included in
[yabridge-bin](https://aur.archlinux.org/packages/yabridge-bin/)). More
comprehensive documentation on yabridgectl can be found in its
[readme](https://github.com/robbert-vdh/yabridge/tree/master/tools/yabridgectl),
or by running `yabridgectl --help`.

First, yabridgectl needs to know where it can find yabridge's files. If you have
downloaded the prebuilt binaries, then you can simply extract the archive to
`~/.local/share` and both yabridge and yabridgectl will pick up the files in
`~/.local/share/yabridge` automatically. You also won't have to do any
additional work if you're using one of the AUR packages. If you have compiled
yabridge from source or if you installed the files to some other location, then
you can use `yabridgectl set --path=<path>` to tell yabridgectl where it can
find the files.

Next, you'll want to tell yabridgectl where it can find your plugins. For this
you can use yabridgectl's `add`, `rm` and `list` commands. For instance, to add
the most common VST2 plugin directory, use `yabridgectl add "$HOME/.wine/drive_c/Program Files/Steinberg/VstPlugins"`. You can use
`yabridgectl status` to get an overview of the current settings and the
installation status of all of your plugins.

Finally, you can run `yabridgectl sync` to finish setting up yabridge for all of
your plugins. Simply tell your VST host to search for plugins in the directories
you've just added using `yabridgectl add` and you'll be good to go. _Don't
forget to rerun `yabridgectl sync` whenever you update yabridge if you are using
the default copy-based installation method._

### Manual setup

Setting up yabridge through yabridgectl is the recommended installation method
as it makes updating easier and yabridgectl will check for some common mistakes
during the installation process. To set up yabridge without using yabridgectl,
first download and extract yabridge's files like in the section above. The rest
of this section assumes that you have extracted the files to `~/.local/share`
(such that `~/.local/share/yabridge/libyabridge-vst2.so` exists), and that you
want to set up yabridge for the VST2 plugin called
`~/.wine/drive_c/Program Files/Steinberg/VstPlugins/plugin.dll`.

Depending on whether you want to use copy or symlink-based installation method,
you can then set up yabridge for that plugin by creating a copy or symlink of
`libyabridge-vst2.so` next to `plugin.dll` called `plugin.so`. For the example,
you can use either:

```shell
# For the copy-based installation method
cp ~/.local/share/yabridge/libyabridge-vst2.so "$HOME/.wine/drive_c/Program Files/Steinberg/VstPlugins/plugin.so"
# For the symlink-based installation method
ln -sf ~/.local/share/yabridge/libyabridge-vst2.so "$HOME/.wine/drive_c/Program Files/Steinberg/VstPlugins/plugin.so"
```

The symlink-based installation method will not work with any host that does not
individually sandbox its plugins. If you are using the copy-based installation
method, then don't forget to overwrite all copies of `libyabridge-vst2.so` you
created this way whenever you update yabridge.

### DAW setup

Finally, open your DAW's VST location configuration and tell it to look for
plugins under `~/.wine/drive_c/Program Files/Steinberg/VstPlugins`, or whichever
directories you've added in yabridgectl. That way it will automatically pick up
all of your Windows VST2 plugins.

### Bitbridge

If you have downloaded the prebuilt version of yabridge or if have followed the
instructions from the [bitbridge](#32-bit-bitbridge) section below, then
yabridge is also able to load 32-bit VST plugins. The installation procedure for
32-bit plugins is exactly the same as for 64-bit plugins. Yabridge will
automatically detect whether a plugin is 32-bit or 64-bit on startup and it will
handle it accordingly.

### Wine prefixes

It is also possible to use yabridge with multiple Wine prefixes. Yabridge will
automatically detect and use the Wine prefix the plugin's `.dll` file is located
in. Alternatively you can set the `WINEPREFIX` environment variable to override
the Wine prefix for all instances of yabridge.

### Search path setup

This section is only relevant if you're using the _copy-based_ installation
method and your yabridge files are located somewhere other than in
`~/.local/share/yabridge`. If you're using one of the AUR packages then you can
also skip this section.

Yabridge needs to know where it can find `yabridge-host.exe`. By default
yabridge will search your through search path as well as in
`~/.local/share/yabridge` if that exists. When loading yabridge from a
non-standard location, such as when building from source, you may have to modify
your _login shell_'s `PATH` environment variable so that yabridge is able to
find its files. Yabridgectl will automatically check whether this is set up
correctly when you run `yabridgectl sync`, and it will show a warning if it
detects any issues. _If you do not see such a warning after running `yabridgectl sync`, then you can skip this section._

To set this, you'll want to add yabridge's installation directory to your login
shell's `PATH` environment variable. If you're unsure what your login shell is,
then you can open a terminal and run `echo $SHELL` to find out. For the below
examples I'll assume you're using the default installation location at
`~/.local/share/yabridge`.

- If you are using the default **Bash** shell, then you will want to add the
  following line to `~/.bash_profile` (or `~/.profile` if it does not exist):

  ```shell
  export PATH="$HOME/.local/share/yabridge:$PATH"
  ```

- If you are using **Zsh**, then you can add the following line to `~/.zprofile`
  (`~/.zshenv` should also work, but some distros such as Arch Linux overwrite
  `PATH` after this file has been read):

  ```shell
  export PATH="$HOME/.local/share/yabridge:$PATH"
  ```

- If you are using **fish**, then you can add the following line to either
  `~/.config/fish/config.fish` or some file in `~/.config/fish/conf.d/`:

  ```shell
  set -gp fish_user_paths ~/.local/share/yabridge
  ```

Rerun `yabridgectl sync` to make sure that the setup has been successful. If the
environment variable has been set up correctly, you should not be seeing any
warnings. _Make sure to log out and log back in again to ensure that all
applications pick up the new changes._

### Configuration

Yabridge can be configured on a per plugin basis to host multiple plugins within
a single process using [plugin groups](#plugin-groups), and there are also a
variety of [compatibility options](#compatibility-options) available to improve
compatibility with certain hosts and plugins.

Configuring yabridge is done through a `yabridge.toml` file located in either
the same directory as the plugin's `.so` file you're trying to configure, or in
any of its parent directories. This file contains case sensitive
[glob](https://www.man7.org/linux/man-pages/man7/glob.7.html) patterns that
match paths to yabridge `.so` files relative to the `yabridge.toml` file. These
patterns can also match an entire directory to apply settings to all plugins
within that directory. To avoid confusion, only the first `yabridge.toml` file
found and only the first matching glob pattern within that file will be
considered. See below for an [example](#example) of a `yabridge.toml` file.

#### Plugin groups

| Option  | Values            | Description                                                            |
| ------- | ----------------- | ---------------------------------------------------------------------- |
| `group` | `{"<string>",""}` | Defaults to `""`, meaning that the plugin will be hosted individually. |

Some plugins have the ability to communicate with other instances of that same
plugin or even with other plugins made by the same manufacturer. This is often
used in mixing plugins to allow different tracks to reference each other without
having to route audio between them. Examples of plugins that do this are
FabFilter Pro-Q 3, MMultiAnalyzer and the iZotope mixing plugins. In order for
this to work, all instances of a particular plugin will have to be hosted in the
same process.

Yabridge has the concept of _plugin groups_, which are user defined groups of
plugins that will all be hosted inside of a single process. Plugins groups can
be configured for a plugin by setting the `group` option of that plugin to some
name. All plugins with the same group name will be hosted within a single
process. Of course, plugin groups with the same name but in different Wine
prefixes and with different architectures will be run independently of each
other. See below for an [example](#example) of how these groups can be set up.

#### Compatibility options

| Option                | Values         | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                |
| --------------------- | -------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `cache_time_info`     | `{true,false}` | Compatibility option for plugins that call `audioMasterGetTime()` multiple times during a single processing cycle. With this option subsequent calls during a single audio processing cycle will reuse the value returned by the first call to this function. This is a bug in the plugin, and this option serves as a temporary workaround until the plugin fixes the issue.                                                                              |
| `editor_double_embed` | `{true,false}` | Compatibility option for plugins that rely on the absolute screen coordinates of the window they're embedded in. Since the Wine window gets embedded inside of a window provided by your DAW, these coordinates won't match up and the plugin would end up drawing in the wrong location without this option. Currently the only known plugins that require this option are _PSPaudioware_ plugins with expandable GUIs, such as E27. Defaults to `false`. |

These options are workarounds for issues mentioned in the [known
issues](#runtime-dependencies-and-known-issues) section. Depending on the hosts
and plugins you use you might want to enable some of them.

#### Example

All of the paths used here are relative to the `yabridge.toml` file.

```toml
# ~/.wine/drive_c/Program Files/Steinberg/VstPlugins/yabridge.toml

# This would cause all plugins to be hosted within a single process. Doing so
# greatly reduces the loading time of individual plugins, with the caveat being
# that plugins are no longer sandboxed from eachother.
#
# ["*"]
# group = "all"

["FabFilter Pro-Q 3.so"]
group = "fabfilter"

["MeldaProduction/Tools/MMultiAnalyzer.so"]
group = "melda"

# Matches an entire directory and all files inside it, make sure to not include
# a trailing slash
["ToneBoosters"]
group = "toneboosters"

["PSPaudioware"]
editor_double_embed = true

["SWAM Cello 64bit.so"]
cache_time_info = true

# Simple glob patterns can be used to avoid unneeded repetition
["iZotope*/Neutron *"]
group = "izotope"

# Since this file has already been matched by the above glob pattern, this won't
# do anything
["iZotope7/Neutron 2 Mix Tap.so"]
group = "This will be ignored!"

# Of course, you can also add multiple plugins to the same group by hand
["iZotope7/Insight 2.so"]
group = "izotope"
```

## Troubleshooting common issues

- If you have the `WINEPREFIX` environment variable set and you _don't_ want all
  of your plugins to use that specific Wine prefix then you should unset it to
  allow yabridge to automatically detect Wine prefixes for you.

- If you're using the copy-based installation method and plugins are getting
  skipped or blacklisted immediately when your VST host is scanning them, then
  this is likely caused by `yabridge-host.exe` not being found in your search
  path. See the [search path setup](#search-path-setup) section for instructions
  on how to fix this.

- If you're using the symlink installation method and you're seeing multiple
  duplicate instances of the same plugin, or after opening a single plugin every
  subsequent plugin opens as another instance of that first plugin, then your
  VST host is not sandboxing individual plugins. If you're using Bitwig Studio,
  the make sure the '_Per plugin-in_'` or '_Individually_' plugin hosting mode
  is enabled and all of the checkboxes in the list of sandboxing exceptions are
  left unchecked.

- If you're not using yabridgectl and a plugin is not getting picked up at all,
  then you can verify that the symlink or copy is correct by running:

  ```shell
  readelf -s ~/.wine/drive_c/path/to/plugin.so | grep yabridge
  ```

  The output should contain several lines related to yabridge.

- If you're seeing errors related to Wine either when running `yabridgectl sync`
  or when trying to load a plugin, then it can be that your installed version of
  Wine is much older than the version that yabridge has been compiled for.
  Yabridgectl will automatically check for this when you run `yabridgectl sync`
  after updating Wine or yabridge. You can also manually verify that Wine is
  working correctly by running one of the VST host applications. Assuming that
  yabridge is installed under `~/.local/share/yabridge`, then running
  `~/.local/share/yabridge/yabridge-host.exe` directly (so _not_
  `wine ~/.local/share/yabridge/yabridge-host.exe`, that won't work) in a
  terminal should print a few messages related to Wine's startup process
  followed by the following line:

  ```
  Usage: yabridge-host.exe <vst_plugin_dll> <endpoint_base_directory>
  ```

  If you're seeing a `002b:err:module:__wine_process_init` error instead, then
  your version of Wine is too old for this version of yabridge and you'll have
  to upgrade your Wine version. Instructions for how to do this on Ubuntu can be
  found on the [WineHQ website](https://wiki.winehq.org/Ubuntu).

- Timeout errors during plugin scanning are caused by the Wine process not being
  able to start. There should be plugin output messages in your DAW or terminal
  that with more information on what went wrong.

- Sometimes left over Wine processes can cause problems. Run `wineserver -k` to
  terminate Wine related in the current or default Wine prefix.

- If you're using a _lot_ of plugins and you're unable to load any new plugins,
  then you may be running into Xorg's client limit. The exact number of plugins
  it takes for this to happen will depend on your system and the other
  applications running in the background. An easy way to check if this is the
  case would be to try and run `wine cmd.exe` from a terminal. If this prints a
  message about the maximum number of clients being reached (or if you are not
  able to open the terminal at all), then you might want to consider using
  [plugin groups](#plugin-groups) to run multiple instances of your most
  frequently used plugins within a single process.

## Performance tuning

Running Windows VST plugins under Wine should have minimal performance impact,
but you may still notice an increase in audio spikes and overall processing
latency. Luckily there are a few things you can do to get rid of most or all of
these negative side effects:

- First of all, you'll want to make sure that you can run programs with realtime
  priorities. Note that on Arch and Manjaro this does not necessarily require a
  realtime kernel as they include the `PREMPT` patch set in their regular
  kernels. You can verify that this is workign correctly by running
  `chrt -f 10 whoami`, which should print your username.

- The other even more important thing you can do is to use a build of Wine with
  Proton's fsync patches. This can improve performance significantly, especially
  when using a lot of plugins at the same time. If you're running Arch or
  Manjaro, then you can use the
  [wine-nspa](https://github.com/nine7nine/pkgbuilds_nspa/tree/master/wine-nspa)
  PKGBUILD for an audio production optimized version of Wine Staging 5.9, or
  [wine-tkg](https://github.com/Frogging-Family/wine-tkg-git) for a more up to
  date version with a different patch set. Aside from a patched copy of Wine
  you'll also need a supported kernel for this to work. Manjaro's kernel
  supports fsync out of the box, and on Arch you can use the `linux-zen` kernel.
  Finally you'll have to set the `WINEFSYNC` environment variable to `1` to
  enable fsync. See the [search path setup](#search-path-setup) section for more
  information on where to do this. You can use the following command to check if
  this is set correctly:

  ```shell
  env -i HOME="$HOME" $SHELL -l -c 'echo $WINEFSYNC'
  ```

  If this prints `1` then everything is set up correctly. Running `wineboot`
  from a terminal should now also print `fsync: up and running.`. You'll have to
  log out and back in again for this to take effect on applications launched
  from the GUI.

  If anyone knows a good way to install an fsync patched version of Wine on
  other distros, then please let me know!

- [Plugin groups](#plugin-groups) can also greatly improve performance when
  using many instances of the same plugin. Some plugins, like the BBC Spitfire
  plugins, can share a lot of resources between different instances of the
  plugin. Hosting all instances of the same plugin in a single process can in
  those cases greatly reduce overall CPU usage and get rid of latency spikes.

## Runtime dependencies and known issues

Any VST2 plugin should function out of the box, although some plugins will need
some additional dependencies for their GUIs to work correctly. Notable examples
include:

- **Serum** requires you to disable `d2d1.dll` in `winecfg` and to install
  `gdiplus` through `winetricks`.
- **Native Instruments** plugins work, but Native Access is unable to finish
  installing the plugins. To work around this you can open the .iso file
  downloaded to your downloads directory and run the installer directly. When
  activating the plugins you may have to cancel the self-updating in NI Service
  Center. You may also have to manually terminate the ISO driver installation
  process when installing Native Access for the first time to allow the
  installation to proceed.
- **MeldaProduction** plugins have minor rendering issues when GPU acceleration
  is enabled. This can be fixed by disabling GPU acceleration in the plugin
  settings. I'm not sure whether this is an issue with Wine or the plugins
  themselves. Notable issues here are missing redraws and incorrect positioning
  when the window gets dragged offscreen on the top and left dies of the screen.
- If **Scaler 2**'s interface lags, blacks out, or otherwise renders poorly,
  then you can try enabling [software
  rendering](https://forum.scalerplugin.com/t/scaler-2-black-empty-window/3540/8)
  to fix these issues.
- Plugins by **KiloHearts** have file descriptor leaks when _esync_ is enabled,
  causing Wine and yabridge to eventually stop working after the system hits the
  open file limit. To fix this, either unset `WINEESYNC` while using yabridge or
  switch to using [_fsync_](#performance-tuning).
- **PSPaudioware** plugins with expandable GUIs, such as E27, may have their GUI
  appear in the wrong location after the GUI has been expanded. You can enable
  an alternative [editor hosting mode](#compatibility-options) to fix this.
- **SWAM Cello** has a bug where it asks the host for the current buffer's time
  and tempo information for every sample it processes instead of doing it only
  once per buffer, resulting in very bad performance. You can enable the time
  info cache [compatibility option](#compatibility-options) to work around this
  until this is fixed on the plugin's side.
- Plugins like **FabFilter Pro-Q 3** that can share data between different
  instances of the same plugin plugins have to be hosted within a single process
  for that functionality to work. See the [plugin groups](#plugin-groups)
  section for instructions on how to set this up.
- **Drag-and-drop** from applications running under Wine to X11 does not yet
  work, so you won't be able to drag samples and MIDI files from a plugin to the
  host. At least, not directly. Because Windows applications have to create
  actual files on the disk for drag-and-drop to work, you can keep a file
  explorer open and manually drag the generated files into your DAW as a
  workaround. To find out where in `~/.wine` the plugin is creating its files,
  you can use the following command to monitor the Wine prefix for any newly
  created files:

  ```shell
  inotifywait -mre CLOSE_WRITE --format '%w%f' ~/.wine/drive_c
  ```

Aside from that, these are some known caveats:

- Most recent **iZotope** plugins don't have a functional GUI in a typical out
  of the box Wine setup because of missing dependencies. Please let me know if
  you know which dependencies are needed for these plugins to render correctly.
- MIDI key labels (commonly used for drum machines and multisamplers) will not
  be updated after the host first asks for them since VST 2.4 has no way to let
  the host know that those labels have been updated. Deactivating and
  reactivating the plugin will cause these labels to be updated again for the
  current patch.

There are also some VST2.X extension features that have not been implemented yet
because I haven't seen them used. Let me know if you need any of these features
for a certain plugin or VST host:

- SysEx messages. In addition to MIDI, VST 2.4 also supports SysEx. I don't know
  of any hosts or plugins that use this, but please let me know if this is
  needed for something.
- Vendor specific extension (for instance, for
  [REAPER](https://www.reaper.fm/sdk/vst/vst_ext.php), though most of these
  extension functions will work out of the box without any modifications).

## Building

To compile yabridge, you'll need [Meson](https://mesonbuild.com/index.html) and
the following dependencies:

- GCC 10+[\*](#building-ubuntu-18.04)
- A Wine installation with `winegcc` and the development headers. The latest
  commits contain a workaround for a winelib [compilation
  issue](https://bugs.winehq.org/show_bug.cgi?id=49138) with Wine 5.7+.
- CMake for VST3 support[\*](#building-without-vst3-support)
- Boost version 1.66 or higher[\*](#building-ubuntu-18.04)
- libxcb

The following dependencies are included in the repository as a Meson wrap:

- [bitsery](https://github.com/fraillt/bitsery)
- [function2](https://github.com/Naios/function2)
- [tomlplusplus](https://github.com/marzer/tomlplusplus)
- The [VST3 SDK](https://github.com/robbert-vdh/vst3sdk)

The project can then be compiled as follows:

```shell
meson setup --buildtype=release --cross-file cross-wine.conf build
ninja -C build
```

After you've finished building you can follow the instructions under the
[usage](#usage) section on how to set up yabridge.

<sup id="building-ubuntu-18.04">
  *The versions of GCC and Boost that ship with Ubuntu 18.04 by default are too
  old to compile yabridge. If you do wish to build yabridge from scratch rather
  than using the <a
  href="https://github.com/robbert-vdh/yabridge/actions?query=workflow%3A%22Automated+builds%22+branch%3Amaster">prebuilt
  binaries</a>, then you should take a look at the <a
  href="https://github.com/robbert-vdh/docker-yabridge/blob/master/bionic/Dockerfile">docker
  image</a> used when building yabridge on Ubuntu 18.04 for on overview of what
  would need to be installed to compile on Ubuntu 18.04.
</sup>

### Building without VST3 support

As mentioned above, building the VST3 SDK requires CMake. We might be able to
easily replace the default build definitions for the SDK with a simple
`meson.build` file in the future, but for now if you wish to build yabridge
without VST3 support then you can disable it as follows:

```shell
# Disable VST3 support, removing the dependency on CMake
meson configure build -Dwith-vst3=false
```

### 32-bit bitbridge

It is also possible to compile a host application for yabridge that's compatible
with 32-bit plugins such as old SynthEdit plugins. This will allow yabridge to
act as a bitbirdge, allowing you to run old 32-bit only Windows VST2 plugins in
a modern 64-bit Linux VST host. For this you'll need to have installed the 32
bit versions of the Boost and XCB libraries. This can then be set up as follows:

```shell
# Enable the bitbridge on an existing build
meson configure build -Dwith-bitbridge=true
# Or configure a new build from scratch
meson setup --buildtype=release --cross-file cross-wine.conf -Dwith-bitbridge=true build

ninja -C build
```

This will produce four files called `yabridge-host-32.exe`,
`yabridge-host-32.exe.so`, `yabridge-group-32.exe` and
`yabridge-group-32.exe.so`. Yabridge will detect whether the plugin you're
trying to load is 32-bit or 64-bit, and will run either the regular version or
the `*-32.exe` variant accordingly.

## Debugging

Wine's error messages and warning are usually very helpful whenever a plugin
doesn't work right away. However, with some VST hosts it can be hard read a
plugin's output. To make it easier to debug malfunctioning plugins, yabridge
offers these two environment variables to control yabridge's logging facilities:

- `YABRIDGE_DEBUG_FILE=<path>` allows you to write yabridge's debug messages as
  well as all output produced by the plugin and by Wine itself to a file. For
  instance, you could launch your DAW with
  `env YABRIDGE_DEBUG_FILE=/tmp/yabridge.log <daw>`, and then use
  `tail -F /tmp/yabridge.log` to keep track of the output. If this option is not
  present then yabridge will write all of its debug output to STDERR instead.
- `YABRIDGE_DEBUG_LEVEL={0,1,2}` allows you to set the verbosity of the debug
  information. Each level increases the amount of debug information printed:

  - A value of `0` (the default) means that yabridge will only log the output
    from the Wine process the Wine process and some basic information about the
    environment, the configuration and the plugin being loaded.
  - A value of `1` will log detailed information about most events and function
    calls sent between the VST host and the plugin. This filters out some noisy
    events such as `effEditIdle()` and `audioMasterGetTime()` since those are
    sent multiple times per second by for every plugin.
  - A value of `2` will cause all of the events to be logged without any
    filtering. This is very verbose but it can be crucial for debugging
    plugin-specific problems.

  More detailed information about these debug levels can be found in
  `src/common/logging.h`.

Wine's own [logging facilities](https://wiki.winehq.org/Debug_Channels) can also
be very helpful when diagnosing problems. In particular the `+message`,
`+module` and `+relay` channels are very useful to trace the execution path
within loaded VST plugin itself.

### Attaching a debugger

When needed, I found the easiest way to debug the plugin to be to load it in an
instance of Carla with gdb attached:

```shell
env YABRIDGE_DEBUG_FILE=/tmp/yabridge.log YABRIDGE_DEBUG_LEVEL=2 carla --gdb
```

Doing the same thing for the Wine VST host can be a bit tricky. You'll need to
launch winedbg in a seperate detached terminal emulator so it doesn't terminate
together with the plugin, and winedbg can be a bit picky about the arguments it
accepts. I've already set this up behind a feature flag for use in KDE Plasma.
Other desktop environments and window managers will require some slight
modifications in `src/plugin/host-process.cpp`. To enable this, simply run:

```shell
meson configure build --buildtype=debug -Dwith-winedbg=true
```
