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nih-plug/src/plugin.rs
2022-08-19 14:34:21 +02:00

423 lines
21 KiB
Rust

//! Traits and structs describing plugins and editors.
use raw_window_handle::{HasRawWindowHandle, RawWindowHandle};
use std::any::Any;
use std::sync::Arc;
use crate::buffer::Buffer;
use crate::context::{GuiContext, InitContext, ProcessContext};
use crate::midi::MidiConfig;
use crate::param::internals::Params;
use crate::wrapper::clap::features::ClapFeature;
/// Basic functionality that needs to be implemented by a plugin. The wrappers will use this to
/// expose the plugin in a particular plugin format.
///
/// The main thing you need to do is define a `[Params]` struct containing all of your parameters.
/// See the trait's documentation for more information on how to do that, or check out the examples.
///
/// This is super basic, and lots of things I didn't need or want to use yet haven't been
/// implemented. Notable missing features include:
///
/// - MIDI SysEx and MIDI2 for CLAP, note expressions, polyphonic modulation and MIDI1 are already
/// supported
/// - Audio thread thread pools (with host integration in CLAP)
#[allow(unused_variables)]
pub trait Plugin: Default + Send + Sync + 'static {
const NAME: &'static str;
const VENDOR: &'static str;
const URL: &'static str;
const EMAIL: &'static str;
/// Semver compatible version string (e.g. `0.0.1`). Hosts likely won't do anything with this,
/// but just in case they do this should only contain decimals values and dots.
const VERSION: &'static str;
/// The default number of input channels. This merely serves as a default. The host will probe
/// the plugin's supported configuration using
/// [`accepts_bus_config()`][Self::accepts_bus_config()], and the selected configuration is
/// passed to [`initialize()`][Self::initialize()]. Some hosts like, like Bitwig and Ardour, use
/// the defaults instead of setting up the busses properly.
///
/// Setting this to zero causes the plugin to have no main input bus.
const DEFAULT_INPUT_CHANNELS: u32 = 2;
/// The default number of output channels. All of the same caveats mentioned for
/// `DEFAULT_INPUT_CHANNELS` apply here.
///
/// Setting this to zero causes the plugin to have no main output bus.
const DEFAULT_OUTPUT_CHANNELS: u32 = 2;
/// If set, then the plugin will have this many sidechain input busses with a default number of
/// channels. Not all hosts support more than one sidechain input bus. Negotiating the actual
/// configuration works the same was as with `DEFAULT_INPUT_CHANNELS`.
const DEFAULT_AUX_INPUTS: Option<AuxiliaryIOConfig> = None;
/// If set, then the plugin will have this many auxiliary output busses with a default number of
/// channels. Negotiating the actual configuration wroks the same was as with
/// `DEFAULT_INPUT_CHANNELS`.
const DEFAULT_AUX_OUTPUTS: Option<AuxiliaryIOConfig> = None;
/// Optional names for the main and auxiliary input and output ports. Will be generated if not
/// set. This is mostly useful to give descriptive names to the outputs for multi-output
/// plugins.
const PORT_NAMES: PortNames = PortNames {
main_input: None,
main_output: None,
aux_inputs: None,
aux_outputs: None,
};
/// Whether the plugin accepts note events, and what which events it wants to receive. If this
/// is set to [`MidiConfig::None`], then the plugin won't receive any note events.
const MIDI_INPUT: MidiConfig = MidiConfig::None;
/// Whether the plugin can output note events. If this is set to [`MidiConfig::None`], then the
/// plugin won't have a note output port. When this is set to another value, then in most hsots
/// the plugin will consume all note and MIDI CC input. If you don't want that, then you will
/// need to forward those events yourself.
const MIDI_OUTPUT: MidiConfig = MidiConfig::None;
/// If enabled, the audio processing cycle may be split up into multiple smaller chunks if
/// parameter values change occur in the middle of the buffer. Depending on the host these
/// blocks may be as small as a single sample. Bitwig Studio sends at most one parameter change
/// every 64 samples.
const SAMPLE_ACCURATE_AUTOMATION: bool = false;
/// If this is set to true, then the plugin will report itself as having a hard realtime
/// processing requirement when the host asks for it. Supported hosts will never ask the plugin
/// to do offline processing.
const HARD_REALTIME_ONLY: bool = false;
/// The plugin's parameters. The host will update the parameter values before calling
/// `process()`. These parameters are identified by strings that should never change when the
/// plugin receives an update.
fn params(&self) -> Arc<dyn Params>;
/// The plugin's editor, if it has one. The actual editor instance is created in
/// [`Editor::spawn()`]. A plugin editor likely wants to interact with the plugin's parameters
/// and other shared data, so you'll need to move [`Arc`] pointing to any data you want to
/// access into the editor. You can later modify the parameters through the
/// [`GuiContext`][crate::prelude::GuiContext] and [`ParamSetter`][crate::prelude::ParamSetter] after the editor
/// GUI has been created.
fn editor(&self) -> Option<Box<dyn Editor>> {
None
}
//
// The following functions follow the lifetime of the plugin.
//
/// Whether the plugin supports a bus config. This only acts as a check, and the plugin
/// shouldn't do anything beyond returning true or false.
fn accepts_bus_config(&self, config: &BusConfig) -> bool {
config.num_input_channels == Self::DEFAULT_INPUT_CHANNELS
&& config.num_output_channels == Self::DEFAULT_OUTPUT_CHANNELS
}
/// Initialize the plugin for the given bus and buffer configurations. These configurations will
/// not change until this function is called again, so feel free to copy these objects to your
/// plugin's object. If the plugin is being restored from an old state, then that state will
/// have already been restored at this point. If based on those parameters (or for any reason
/// whatsoever) the plugin needs to introduce latency, then you can do so here using the process
/// context. Depending on how the host restores plugin state, this function may also be called
/// twice in rapid succession. If the plugin fails to inialize for whatever reason, then this
/// should return `false`.
///
/// Before this point, the plugin should not have done any expensive initialization. Please
/// don't be that plugin that takes twenty seconds to scan.
///
/// After this function [`reset()`][Self::reset()] will always be called. If you need to clear
/// state, such as filters or envelopes, then you should do so in that function inistead.
fn initialize(
&mut self,
bus_config: &BusConfig,
buffer_config: &BufferConfig,
context: &mut impl InitContext,
) -> bool {
true
}
/// Clear internal state such as filters and envelopes. This is always called after
/// [`initialize()`][Self::initialize()], and it may also be called at any other time from the
/// audio thread. You should thus not do any allocations in this function.
fn reset(&mut self) {}
/// Process audio. The host's input buffers have already been copied to the output buffers if
/// they are not processing audio in place (most hosts do however). All channels are also
/// guarenteed to contain the same number of samples. Lastly, denormals have already been taken
/// case of by NIH-plug, and you can optionally enable the `assert_process_allocs` feature to
/// abort the program when any allocation accurs in the process function while running in debug
/// mode.
///
/// The framework provides convenient iterators on the [`Buffer`] object to process audio either
/// either per-sample per-channel, or per-block per-channel per-sample. The first approach is
/// preferred for plugins that don't require block-based processing because of their use of
/// per-sample SIMD or excessive branching. The parameter smoothers can also work in both modes:
/// use [`Smoother::next()`][crate::prelude::Smoother::next()] for per-sample processing, and
/// [`Smoother::next_block()`][crate::prelude::Smoother::next_block()] for block-based
/// processing.
///
/// The `context` object contains context information as well as callbacks for working with note
/// events. The [`AuxiliaryBuffers`] contain the plugin's sidechain input buffers and
/// auxiliary output buffers if it has any.
///
/// TODO: Provide a way to access auxiliary input channels if the IO configuration is
/// assymetric
fn process(
&mut self,
buffer: &mut Buffer,
aux: &mut AuxiliaryBuffers,
context: &mut impl ProcessContext,
) -> ProcessStatus;
/// Called when the plugin is deactivated. The host will call
/// [`initialize()`][Self::initialize()] again before the plugin resumes processing audio. These
/// two functions will not be called when the host only temporarily stops processing audio. You
/// can clean up or deallocate resources here. In most cases you can safely ignore this.
///
/// There is no one-to-one relationship between calls to `initialize()` and `deactivate()`.
/// `initialize()` may be called more than once before `deactivate()` is called, for instance
/// when restoring state while the plugin is still activate.
fn deactivate(&mut self) {}
}
/// Provides auxiliary metadata needed for a CLAP plugin.
pub trait ClapPlugin: Plugin {
/// A unique ID that identifies this particular plugin. This is usually in reverse domain name
/// notation, e.g. `com.manufacturer.plugin-name`.
const CLAP_ID: &'static str;
/// An optional short description for the plugin.
const CLAP_DESCRIPTION: Option<&'static str>;
/// The URL to the plugin's manual, if available.
const CLAP_MANUAL_URL: Option<&'static str>;
/// The URL to the plugin's support page, if available.
const CLAP_SUPPORT_URL: Option<&'static str>;
/// Keywords describing the plugin. The host may use this to classify the plugin in its plugin
/// browser.
const CLAP_FEATURES: &'static [ClapFeature];
/// If set, this informs the host about the plugin's capabilities for polyphonic modulation.
const CLAP_POLY_MODULATION_CONFIG: Option<PolyModulationConfig> = None;
}
/// Provides auxiliary metadata needed for a VST3 plugin.
pub trait Vst3Plugin: Plugin {
/// The unique class ID that identifies this particular plugin. You can use the
/// `*b"fooofooofooofooo"` syntax for this.
///
/// This will be shuffled into a different byte order on Windows for project-compatibility.
const VST3_CLASS_ID: [u8; 16];
/// One or more categories, separated by pipe characters (`|`), up to 127 characters. Anything
/// logner than that will be truncated. See the VST3 SDK for examples of common categories:
/// <https://github.com/steinbergmedia/vst3_pluginterfaces/blob/2ad397ade5b51007860bedb3b01b8afd2c5f6fba/vst/ivstaudioprocessor.h#L49-L90>
//
// TODO: Create a category enum similar to ClapFeature
const VST3_CATEGORIES: &'static str;
/// [`VST3_CLASS_ID`][Self::VST3_CLASS_ID`] in the correct order for the current platform so
/// projects and presets can be shared between platforms. This should not be overridden.
const PLATFORM_VST3_CLASS_ID: [u8; 16] = swap_vst3_uid_byte_order(Self::VST3_CLASS_ID);
}
#[cfg(not(target_os = "windows"))]
const fn swap_vst3_uid_byte_order(uid: [u8; 16]) -> [u8; 16] {
uid
}
#[cfg(target_os = "windows")]
const fn swap_vst3_uid_byte_order(mut uid: [u8; 16]) -> [u8; 16] {
// No mutable references in const functions, so we can't use `uid.swap()`
let original_uid = uid;
uid[0] = original_uid[3];
uid[1] = original_uid[2];
uid[2] = original_uid[1];
uid[3] = original_uid[0];
uid[4] = original_uid[5];
uid[5] = original_uid[4];
uid[6] = original_uid[7];
uid[7] = original_uid[6];
uid
}
/// An editor for a [`Plugin`].
pub trait Editor: Send + Sync {
/// Create an instance of the plugin's editor and embed it in the parent window. As explained in
/// [`Plugin::editor()`], you can then read the parameter values directly from your [`Params`]
/// object, and modifying the values can be done using the functions on the
/// [`ParamSetter`][crate::prelude::ParamSetter]. When you change a parameter value that way it will be
/// broadcasted to the host and also updated in your [`Params`] struct.
///
/// This function should return a handle to the editor, which will be dropped when the editor
/// gets closed. Implement the [`Drop`] trait on the returned handle if you need to explicitly
/// handle the editor's closing behavior.
///
/// If [`set_scale_factor()`][Self::set_scale_factor()] has been called, then any created
/// windows should have their sizes multiplied by that factor.
///
/// The wrapper guarantees that a previous handle has been dropped before this function is
/// called again.
//
// TODO: Think of how this would work with the event loop. On Linux the wrapper must provide a
// timer using VST3's `IRunLoop` interface, but on Window and macOS the window would
// normally register its own timer. Right now we just ignore this because it would
// otherwise be basically impossible to have this still be GUI-framework agnostic. Any
// callback that deos involve actual GUI operations will still be spooled to the IRunLoop
// instance.
// TODO: This function should return an `Option` instead. Right now window opening failures are
// always fatal. This would need to be fixed in basevie first.
fn spawn(
&self,
parent: ParentWindowHandle,
context: Arc<dyn GuiContext>,
) -> Box<dyn Any + Send + Sync>;
/// Returns the (currnent) size of the editor in pixels as a `(width, height)` pair. This size
/// must be reported in _logical pixels_, i.e. the size before being multiplied by the DPI
/// scaling factor to get the actual physical screen pixels.
fn size(&self) -> (u32, u32);
/// Set the DPI scaling factor, if supported. The plugin APIs don't make any guarantees on when
/// this is called, but for now just assume it will be the first function that gets called
/// before creating the editor. If this is set, then any windows created by this editor should
/// have their sizes multiplied by this scaling factor on Windows and Linux.
///
/// Right now this is never called on macOS since DPI scaling is built into the operating system
/// there.
fn set_scale_factor(&self, factor: f32) -> bool;
/// A callback that will be called wheneer the parameter values changed while the editor is
/// open. You don't need to do anything with this, but this can be used to force a redraw when
/// the host sends a new value for a parameter or when a parameter change sent to the host gets
/// processed.
///
/// This function will be called from the **audio thread**. It must thus be lock-free and may
/// not allocate.
fn param_values_changed(&self);
// TODO: Reconsider adding a tick function here for the Linux `IRunLoop`. To keep this platform
// and API agnostic, add a way to ask the GuiContext if the wrapper already provides a
// tick function. If it does not, then the Editor implementation must handle this by
// itself. This would also need an associated `PREFERRED_FRAME_RATE` constant.
// TODO: Host->Plugin resizing
}
/// A raw window handle for platform and GUI framework agnostic editors.
pub struct ParentWindowHandle {
pub handle: RawWindowHandle,
}
unsafe impl HasRawWindowHandle for ParentWindowHandle {
fn raw_window_handle(&self) -> RawWindowHandle {
self.handle
}
}
/// The plugin's IO configuration.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct BusConfig {
/// The number of input channels for the plugin.
pub num_input_channels: u32,
/// The number of output channels for the plugin.
pub num_output_channels: u32,
/// Any additional sidechain inputs.
pub aux_input_busses: AuxiliaryIOConfig,
/// Any additional outputs.
pub aux_output_busses: AuxiliaryIOConfig,
}
/// Configuration for auxiliary inputs or outputs on [`BusCofnig`].
#[derive(Debug, Default, Clone, Copy, PartialEq, Eq)]
pub struct AuxiliaryIOConfig {
/// The number of auxiliary input or output busses.
pub num_busses: u32,
/// The number of channels in each bus.
pub num_channels: u32,
}
/// Contains names for the main input and output ports as well as for all of the auxiliary input and
/// output ports. Setting these is optional, but it makes working with multi-output plugins much
/// more convenient.
#[derive(Debug, Default, Clone, PartialEq, Eq)]
pub struct PortNames {
/// The name for the main input port. Will be generated if not set.
pub main_input: Option<&'static str>,
/// The name for the main output port. Will be generated if not set.
pub main_output: Option<&'static str>,
/// Names for auxiliary (sidechain) input ports. Will be generated if not set or if this slice
/// does not contain enough names.
pub aux_inputs: Option<&'static [&'static str]>,
/// Names for auxiliary output ports. Will be generated if not set or if this slice does not
/// contain enough names.
pub aux_outputs: Option<&'static [&'static str]>,
}
/// Configuration for (the host's) audio buffers.
#[derive(Debug, Clone, Copy, PartialEq)]
pub struct BufferConfig {
/// The current sample rate.
pub sample_rate: f32,
/// The minimum buffer size the host will use. This may not be set.
pub min_buffer_size: Option<u32>,
/// The maximum buffer size the host will use. The plugin should be able to accept variable
/// sized buffers up to this size, or between the minimum and the maximum buffer size if both
/// are set.
pub max_buffer_size: u32,
/// The current processing mode. The host will reinitialize the plugin any time this changes.
pub process_mode: ProcessMode,
}
/// Contains auxiliary (sidechain) input and output buffers for a process call.
pub struct AuxiliaryBuffers<'a> {
/// All auxiliary (sidechain) inputs defined for this plugin. The data in these buffers can
/// safely be overwritten. Auxiliary inputs can be defined by setting
/// [`Plugin::DEFAULT_AUX_INPUTS`][`crate::prelude::Plugin::DEFAULT_AUX_INPUTS`].
pub inputs: &'a mut [Buffer<'a>],
/// Get all auxiliary outputs defined for this plugin. Auxiliary outputs can be defined by
/// setting [`Plugin::DEFAULT_AUX_OUTPUTS`][`crate::prelude::Plugin::DEFAULT_AUX_OUTPUTS`].
pub outputs: &'a mut [Buffer<'a>],
}
/// Indicates the current situation after the plugin has processed audio.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum ProcessStatus {
/// Something went wrong while processing audio.
Error(&'static str),
/// The plugin has finished processing audio. When the input is silent, the most may suspend the
/// plugin to save resources as it sees fit.
Normal,
/// The plugin has a (reverb) tail with a specific length in samples.
Tail(u32),
/// This plugin will continue to produce sound regardless of whether or not the input is silent,
/// and should thus not be deactivated by the host. This is essentially the same as having an
/// infite tail.
KeepAlive,
}
/// The plugin's current processing mode. Can be queried through [`ProcessContext::process_mode()`].
/// The host will reinitialize the plugin whenever this changes.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum ProcessMode {
/// The plugin is processing audio in real time at a fixed rate.
Realtime,
/// The plugin is processing audio at a real time-like pace, but at irregular intervals. The
/// host may do this to process audio ahead of time to loosen realtime constraints and to reduce
/// the chance of xruns happening. This is only used by VST3.
Buffered,
/// The plugin is rendering audio offline, potentially faster than realtime ('freewheeling').
/// The host will continuously call the process function back to back until all audio has been
/// processed.
Offline,
}
/// Configuration for the plugin's polyphonic modulation options, if it supports .
pub struct PolyModulationConfig {
/// The maximum number of voices this plugin will ever use. Call the context's
/// `set_current_voice_capacity()` method during initialization or audio processing to set the
/// polyphony limit.
pub max_voice_capacity: u32,
/// If set to `true`, then the host may send note events for the same channel and key, but using
/// different voice IDs. Bitwig Studio, for instance, can use this to do voice stacking. After
/// enabling this, you should always prioritize using voice IDs to map note events to voices.
pub supports_overlapping_voices: bool,
}