98 lines
3.0 KiB
Markdown
98 lines
3.0 KiB
Markdown
# nymph
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A [Nim] library for writing audio and MIDI plugins conforming to the [LV2] standard
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## Examples
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Build the `amp.lv2` example plugin:
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nimble build_ex amp
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Check the `amp.lv2` plugin bundle with `lv2lint`:
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nimble lv2lint amp
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Run the `lv2bm` benchmark with the `amp.lv2` plugin:
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nimble lv2bm amp
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Install the `amp.lv2` example plugin:
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cp -a examples/amp.lv2 ~/.lv2
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Other example plugins can be found in the [examples](./examples) directory and
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can be built and tested with similar commands. Just change the example name to
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the basename of the plugin's LV2 bundle dir.
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Currently, there are just a few other example plugins:
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* `miditranspose`: shows how to handle receiving and sending MIDI events.
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* `multimodefilter`: shows a multimode state-variable filter implementation
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ported from C++ to Nim.
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* `tiltfilter`: shows a multimode tilt equalizer filter implementation ported
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from Rust to Nim.
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* `faustlpf`: shows how to integrate DSP C code generated from a [FAUST]
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source file in Nim (in this example the FAUST code implements a simple
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non-resonant low-pass filter from the FAUST standard library).
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## How To
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* Install this library:
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nimble install https://git.0x20.eu/chris/nymph
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* Copy `examples/amp.lv2` and `examples/amp.nim` into your project and rename
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them as you like (also rename `amp.lv2/amp.ttl`). I'll use `myplugin` as the
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base name in the examples below.
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* Edit `myplugin.lv2/manifest.ttl`:
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* Change the plugin URI.
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* Change the plugin's shared library name defined via `lv2:binary` to
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`libmyplugin.so`.
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* Change file name referenced via `rdfs:seeAlso` to `myplugin.ttl`.
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* Edit `myplugin.lv2/myplugin.ttl`:
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* Change the plugin URI.
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* Define audio, control and atom ports as needed.
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* Edit `myplugin.nim`:
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* Change the `PluginUri` constant at the top.
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* Change the `PluginPort` enum and list the ports in the order defined in
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`myplugin.ttl`.
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* Rename and update the definition of the `AmpPlugin` object type and
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define its members with the appropriate data type for the plugin port
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they will be connected to. Update the type name in the `instantiate`,
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`deactivate`, `connectPorts` and `run` procs.
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* Update and extend the `case` statement in `connectPort` to connect ports
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to your plugin object instance members.
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* Implement your DSP code in the `run` proc.
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* Compile the plugin shared library object with:
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nim c --app:lib --noMain:on --mm:arc \
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--out:myplugin.lv2/libmyplugin.so myplugin.nim
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See the definition of the `build_ex` task in the
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[nymph.nimble](./nymph.nimble#L67) file on how to create a nimble task
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to simplify compilation.
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## Dependencies
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Required:
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* [Nim] >= 2.0
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Optional:
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* [lv2bm] - For benchmarking and stress-testing plugins
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* [lv2lint] - For checking conformity of plugin bundles
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[FAUST]: https://faust.grame.fr/
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[LV2]: https://lv2plug.in/
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[lv2bm]: https://github.com/moddevices/lv2bm
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[lv2lint]: https://git.open-music-kontrollers.ch/~hp/lv2lint
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[Nim]: https://nim-lang.org/
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