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nih-plug/src/context.rs
2022-07-05 23:26:23 +02:00

489 lines
21 KiB
Rust

//! Different contexts the plugin can use to make callbacks to the host in different...contexts.
use std::fmt::Display;
use crate::midi::NoteEvent;
use crate::param::internals::ParamPtr;
use crate::param::Param;
use crate::wrapper::state::PluginState;
/// Callbacks the plugin can make while it is being initialized. This is passed to the plugin during
/// [`Plugin::initialize()`][crate::plugin::Plugin::initialize()].
//
// # Safety
//
// The implementing wrapper needs to be able to handle concurrent requests, and it should perform
// the actual callback within [MainThreadQueue::do_maybe_async].
pub trait InitContext {
/// Get the current plugin API.
fn plugin_api(&self) -> PluginApi;
/// Update the current latency of the plugin. If the plugin is currently processing audio, then
/// this may cause audio playback to be restarted.
fn set_latency_samples(&self, samples: u32);
/// Set the current voice **capacity** for this plugin (so not the number of currently active
/// voices). This may only be called if
/// [`ClapPlugin::CLAP_POLY_MODULATION_CONFIG`][crate::prelude::ClapPlugin::CLAP_POLY_MODULATION_CONFIG]
/// is set. `capacity` must be between 1 and the configured maximum capacity. Changing this at
/// runtime allows the host to better optimize polyphonic modulation, or to switch to strictly
/// monophonic modulation when dropping the capacity down to 1.
fn set_current_voice_capacity(&self, capacity: u32);
}
/// Contains both context data and callbacks the plugin can use during processing. Most notably this
/// is how a plugin sends and receives note events, gets transport information, and accesses
/// sidechain inputs and auxiliary outputs. This is passed to the plugin during as part of
/// [`Plugin::process()`][crate::plugin::Plugin::process()].
//
// # Safety
//
// The implementing wrapper needs to be able to handle concurrent requests, and it should perform
// the actual callback within [MainThreadQueue::do_maybe_async].
pub trait ProcessContext {
/// Get the current plugin API.
fn plugin_api(&self) -> PluginApi;
/// Get information about the current transport position and status.
fn transport(&self) -> &Transport;
/// Returns the next note event, if there is one. Use [`NoteEvent::timing()`] to get the event's
/// timing within the buffer. Only available when
/// [`Plugin::MIDI_INPUT`][crate::prelude::Plugin::MIDI_INPUT] is set.
///
/// # Usage
///
/// You will likely want to use this with a loop, since there may be zero, one, or more events
/// for a sample:
///
/// ```ignore
/// let mut next_event = context.next_event();
/// for (sample_id, channel_samples) in buffer.iter_samples().enumerate() {
/// while let Some(event) = next_event {
/// if event.timing() != sample_id as u32 {
/// break;
/// }
///
/// match event {
/// NoteEvent::NoteOn { note, velocity, .. } => { ... },
/// NoteEvent::NoteOff { note, .. } if note == 69 => { ... },
/// NoteEvent::PolyPressure { note, pressure, .. } { ... },
/// _ => (),
/// }
///
/// next_event = context.next_event();
/// }
///
/// // Do something with `channel_samples`...
/// }
///
/// ProcessStatus::Normal
/// ```
fn next_event(&mut self) -> Option<NoteEvent>;
/// Send an event to the host. Only available when
/// [`Plugin::MIDI_OUTPUT`][crate::prelude::Plugin::MIDI_INPUT] is set. Will not do anything
/// otherwise.
fn send_event(&mut self, event: NoteEvent);
/// Update the current latency of the plugin. If the plugin is currently processing audio, then
/// this may cause audio playback to be restarted.
fn set_latency_samples(&self, samples: u32);
/// Set the current voice **capacity** for this plugin (so not the number of currently active
/// voices). This may only be called if
/// [`ClapPlugin::CLAP_POLY_MODULATION_CONFIG`][crate::prelude::ClapPlugin::CLAP_POLY_MODULATION_CONFIG]
/// is set. `capacity` must be between 1 and the configured maximum capacity. Changing this at
/// runtime allows the host to better optimize polyphonic modulation, or to switch to strictly
/// monophonic modulation when dropping the capacity down to 1.
fn set_current_voice_capacity(&self, capacity: u32);
// TODO: Add this, this works similar to [GuiContext::set_parameter] but it adds the parameter
// change to a queue (or directly to the VST3 plugin's parameter output queues) instead of
// using main thread host automation (and all the locks involved there).
// fn set_parameter<P: Param>(&self, param: &P, value: P::Plain);
}
/// Callbacks the plugin can make when the user interacts with its GUI such as updating parameter
/// values. This is passed to the plugin during [`Editor::spawn()`][crate::prelude::Editor::spawn()]. All of
/// these functions assume they're being called from the main GUI thread.
//
// # Safety
//
// The implementing wrapper can assume that everything is being called from the main thread. Since
// NIH-plug doesn't own the GUI event loop, this invariant cannot be part of the interface.
pub trait GuiContext: Send + Sync + 'static {
/// Get the current plugin API. This may be useful to display in the plugin's GUI as part of an
/// about screen.
fn plugin_api(&self) -> PluginApi;
/// Ask the host to resize the editor window to the size specified by
/// [`Editor::size()`][crate::prelude::Editor::size()]. This will return false if the host
/// somehow didn't like this and rejected the resize, in which case the window should revert to
/// its old size. You should only actually resize your embedded window once this returns `true`.
///
/// TODO: Host->Plugin resizing has not been implemented yet
fn request_resize(&self) -> bool;
/// Inform the host a parameter will be automated. Create a [`ParamSetter`] and use
/// [`ParamSetter::begin_set_parameter()`] instead for a safe, user friendly API.
///
/// # Safety
///
/// The implementing function still needs to check if `param` actually exists. This function is
/// mostly marked as unsafe for API reasons.
unsafe fn raw_begin_set_parameter(&self, param: ParamPtr);
/// Inform the host a parameter is being automated with an already normalized value. Create a
/// [`ParamSetter`] and use [`ParamSetter::set_parameter()`] instead for a safe, user friendly
/// API.
///
/// # Safety
///
/// The implementing function still needs to check if `param` actually exists. This function is
/// mostly marked as unsafe for API reasons.
unsafe fn raw_set_parameter_normalized(&self, param: ParamPtr, normalized: f32);
/// Inform the host a parameter has been automated. Create a [`ParamSetter`] and use
/// [`ParamSetter::end_set_parameter()`] instead for a safe, user friendly API.
///
/// # Safety
///
/// The implementing function still needs to check if `param` actually exists. This function is
/// mostly marked as unsafe for API reasons.
unsafe fn raw_end_set_parameter(&self, param: ParamPtr);
/// Serialize the plugin's current state to a serde-serializable object. Useful for implementing
/// preset handling within a plugin's GUI.
fn get_state(&self) -> PluginState;
/// Restore the state from a previously serialized state object. This will block the GUI thread
/// until the state has been restored and a parameter value rescan has been requested from the
/// host. If the plugin is currently processing audio, then the parameter values will be
/// restored at the end of the current processing cycle.
fn set_state(&self, state: PluginState);
}
/// Information about the plugin's transport. Depending on the plugin API and the host not all
/// fields may be available.
#[derive(Debug)]
pub struct Transport {
/// Whether the transport is currently running.
pub playing: bool,
/// Whether recording is enabled in the project.
pub recording: bool,
/// Whether the pre-roll is currently active, if the plugin API reports this information.
pub preroll_active: Option<bool>,
/// The sample rate in Hertz. Also passed in
/// [`Plugin::initialize()`][crate::prelude::Plugin::initialize()], so if you need this then you
/// can also store that value.
pub sample_rate: f32,
/// The proejct's tempo in beats per minute.
pub tempo: Option<f64>,
/// The time signature's numerator.
pub time_sig_numerator: Option<i32>,
/// The time signature's denominator.
pub time_sig_denominator: Option<i32>,
// XXX: VST3 also has a continuous time in samples that ignores loops, but we can't reconstruct
// something similar in CLAP so it may be best to just ignore that so you can't rely on it
/// The position in the song in samples. Can be used to calculate the time in seconds if needed.
pub(crate) pos_samples: Option<i64>,
/// The position in the song in quarter notes. Can be used to calculate the time in samples if
/// needed.
pub(crate) pos_seconds: Option<f64>,
/// The position in the song in quarter notes. Can be calculated from the time in seconds and
/// the tempo if needed.
pub(crate) pos_beats: Option<f64>,
/// The last bar's start position in beats. Can be calculated from the beat position and time
/// signature if needed.
pub(crate) bar_start_pos_beats: Option<f64>,
/// The number of the bar at `bar_start_pos_beats`. This starts at 0 for the very first bar at
/// the start of the song. Can be calculated from the beat position and time signature if
/// needed.
pub(crate) bar_number: Option<i32>,
/// The loop range in samples, if the loop is active and this information is available. None of
/// the plugin API docs mention whether this is exclusive or inclusive, but just assume that the
/// end is exclusive. Can be calulcated from the other loop range information if needed.
pub(crate) loop_range_samples: Option<(i64, i64)>,
/// The loop range in seconds, if the loop is active and this information is available. None of
/// the plugin API docs mention whether this is exclusive or inclusive, but just assume that the
/// end is exclusive. Can be calulcated from the other loop range information if needed.
pub(crate) loop_range_seconds: Option<(f64, f64)>,
/// The loop range in quarter notes, if the loop is active and this information is available.
/// None of the plugin API docs mention whether this is exclusive or inclusive, but just assume
/// that the end is exclusive. Can be calulcated from the other loop range information if
/// needed.
pub(crate) loop_range_beats: Option<(f64, f64)>,
}
/// A convenience helper for setting parameter values. Any changes made here will be broadcasted to
/// the host and reflected in the plugin's [`Params`][crate::param::internals::Params] object. These
/// functions should only be called from the main thread.
pub struct ParamSetter<'a> {
pub raw_context: &'a dyn GuiContext,
}
/// The currently active plugin API. This may be useful to display in an about screen in the
/// plugin's GUI for debugging purposes.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum PluginApi {
Clap,
Standalone,
Vst3,
}
impl Display for PluginApi {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
match self {
PluginApi::Clap => write!(f, "CLAP"),
PluginApi::Standalone => write!(f, "standalone"),
PluginApi::Vst3 => write!(f, "VST3"),
}
}
}
// TODO: These conversions have not really been tested yet, there might be an error in there somewhere
impl Transport {
/// Initialize the transport struct without any information.
pub(crate) fn new(sample_rate: f32) -> Self {
Self {
playing: false,
recording: false,
preroll_active: None,
sample_rate,
tempo: None,
time_sig_numerator: None,
time_sig_denominator: None,
pos_samples: None,
pos_seconds: None,
pos_beats: None,
bar_start_pos_beats: None,
bar_number: None,
loop_range_samples: None,
loop_range_seconds: None,
loop_range_beats: None,
}
}
/// The position in the song in samples. Will be calculated from other information if needed.
pub fn pos_samples(&self) -> Option<i64> {
match (
self.pos_samples,
self.pos_seconds,
self.pos_beats,
self.tempo,
) {
(Some(pos_samples), _, _, _) => Some(pos_samples),
(_, Some(pos_seconds), _, _) => {
Some((pos_seconds * self.sample_rate as f64).round() as i64)
}
(_, _, Some(pos_beats), Some(tempo)) => {
Some((pos_beats / tempo * 60.0 * self.sample_rate as f64).round() as i64)
}
(_, _, _, _) => None,
}
}
/// The position in the song in quarter notes. Will be calculated from other information if
/// needed.
pub fn pos_seconds(&self) -> Option<f64> {
match (
self.pos_samples,
self.pos_seconds,
self.pos_beats,
self.tempo,
) {
(_, Some(pos_seconds), _, _) => Some(pos_seconds),
(Some(pos_samples), _, _, _) => Some(pos_samples as f64 / self.sample_rate as f64),
(_, _, Some(pos_beats), Some(tempo)) => Some(pos_beats / tempo * 60.0),
(_, _, _, _) => None,
}
}
/// The position in the song in quarter notes. Will be calculated from other information if
/// needed.
pub fn pos_beats(&self) -> Option<f64> {
match (
self.pos_samples,
self.pos_seconds,
self.pos_beats,
self.tempo,
) {
(_, _, Some(pos_beats), _) => Some(pos_beats),
(_, Some(pos_seconds), _, Some(tempo)) => Some(pos_seconds / 60.0 * tempo),
(Some(pos_samples), _, _, Some(tempo)) => {
Some(pos_samples as f64 / self.sample_rate as f64 / 60.0 * tempo)
}
(_, _, _, _) => None,
}
}
/// The last bar's start position in beats. Will be calculated from other information if needed.
pub fn bar_start_pos_beats(&self) -> Option<f64> {
if self.bar_start_pos_beats.is_some() {
return self.bar_start_pos_beats;
}
match (
self.time_sig_numerator,
self.time_sig_denominator,
self.pos_beats(),
) {
(Some(time_sig_numerator), Some(time_sig_denominator), Some(pos_beats)) => {
let quarter_note_bar_length =
time_sig_numerator as f64 / time_sig_denominator as f64 * 4.0;
Some(pos_beats.div_euclid(quarter_note_bar_length))
}
(_, _, _) => None,
}
}
/// The number of the bar at `bar_start_pos_beats`. This starts at 0 for the very first bar at
/// the start of the song. Will be calculated from other information if needed.
pub fn bar_number(&self) -> Option<i32> {
if self.bar_number.is_some() {
return self.bar_number;
}
match (
self.time_sig_numerator,
self.time_sig_denominator,
self.pos_beats(),
) {
(Some(time_sig_numerator), Some(time_sig_denominator), Some(pos_beats)) => {
let quarter_note_bar_length =
time_sig_numerator as f64 / time_sig_denominator as f64 * 4.0;
Some((pos_beats / quarter_note_bar_length).floor() as i32)
}
(_, _, _) => None,
}
}
/// The loop range in samples, if the loop is active and this information is available. None of
/// the plugin API docs mention whether this is exclusive or inclusive, but just assume that the
/// end is exclusive. Will be calculated from other information if needed.
pub fn loop_range_samples(&self) -> Option<(i64, i64)> {
match (
self.loop_range_samples,
self.loop_range_seconds,
self.loop_range_beats,
self.tempo,
) {
(Some(loop_range_samples), _, _, _) => Some(loop_range_samples),
(_, Some((start_seconds, end_seconds)), _, _) => Some((
((start_seconds * self.sample_rate as f64).round() as i64),
((end_seconds * self.sample_rate as f64).round() as i64),
)),
(_, _, Some((start_beats, end_beats)), Some(tempo)) => Some((
(start_beats / tempo * 60.0 * self.sample_rate as f64).round() as i64,
(end_beats / tempo * 60.0 * self.sample_rate as f64).round() as i64,
)),
(_, _, _, _) => None,
}
}
/// The loop range in seconds, if the loop is active and this information is available. None of
/// the plugin API docs mention whether this is exclusive or inclusive, but just assume that the
/// end is exclusive. Will be calculated from other information if needed.
pub fn loop_range_seconds(&self) -> Option<(f64, f64)> {
match (
self.loop_range_samples,
self.loop_range_seconds,
self.loop_range_beats,
self.tempo,
) {
(_, Some(loop_range_seconds), _, _) => Some(loop_range_seconds),
(Some((start_samples, end_samples)), _, _, _) => Some((
start_samples as f64 / self.sample_rate as f64,
end_samples as f64 / self.sample_rate as f64,
)),
(_, _, Some((start_beats, end_beats)), Some(tempo)) => {
Some((start_beats / tempo * 60.0, end_beats / tempo * 60.0))
}
(_, _, _, _) => None,
}
}
/// The loop range in quarter notes, if the loop is active and this information is available.
/// None of the plugin API docs mention whether this is exclusive or inclusive, but just assume
/// that the end is exclusive. Will be calculated from other information if needed.
pub fn loop_range_beats(&self) -> Option<(f64, f64)> {
match (
self.loop_range_samples,
self.loop_range_seconds,
self.loop_range_beats,
self.tempo,
) {
(_, _, Some(loop_range_beats), _) => Some(loop_range_beats),
(_, Some((start_seconds, end_seconds)), _, Some(tempo)) => {
Some((start_seconds / 60.0 * tempo, end_seconds / 60.0 * tempo))
}
(Some((start_samples, end_samples)), _, _, Some(tempo)) => Some((
start_samples as f64 / self.sample_rate as f64 / 60.0 * tempo,
end_samples as f64 / self.sample_rate as f64 / 60.0 * tempo,
)),
(_, _, _, _) => None,
}
}
}
impl<'a> ParamSetter<'a> {
pub fn new(context: &'a dyn GuiContext) -> Self {
Self {
raw_context: context,
}
}
/// Inform the host that you will start automating a parmater. This needs to be called before
/// calling [`set_parameter()`][Self::set_parameter()] for the specified parameter.
pub fn begin_set_parameter<P: Param>(&self, param: &P) {
unsafe { self.raw_context.raw_begin_set_parameter(param.as_ptr()) };
}
/// Set a parameter to the specified parameter value. You will need to call
/// [`begin_set_parameter()`][Self::begin_set_parameter()] before and
/// [`end_set_parameter()`][Self::end_set_parameter()] after calling this so the host can
/// properly record automation for the parameter. This can be called multiple times in a row
/// before calling [`end_set_parameter()`][Self::end_set_parameter()], for instance when moving
/// a slider around.
///
/// This function assumes you're already calling this from a GUI thread. Calling any of these
/// functions from any other thread may result in unexpected behavior.
pub fn set_parameter<P: Param>(&self, param: &P, value: P::Plain) {
let ptr = param.as_ptr();
let normalized = param.preview_normalized(value);
unsafe {
self.raw_context
.raw_set_parameter_normalized(ptr, normalized)
};
}
/// Set a parameter to an already normalized value. Works exactly the same as
/// [`set_parameter()`][Self::set_parameter()] and needs to follow the same rules, but this may
/// be useful when implementing a GUI.
///
/// This does not perform any snapping. Consider converting the normalized value to a plain
/// value and setting that with [`set_parameter()`][Self::set_parameter()] instead so the
/// normalized value known to the host matches `param.normalized_value()`.
pub fn set_parameter_normalized<P: Param>(&self, param: &P, normalized: f32) {
let ptr = param.as_ptr();
unsafe {
self.raw_context
.raw_set_parameter_normalized(ptr, normalized)
};
}
/// Inform the host that you are done automating a parameter. This needs to be called after one
/// or more [`set_parameter()`][Self::set_parameter()] calls for a parameter so the host knows
/// the automation gesture has finished.
pub fn end_set_parameter<P: Param>(&self, param: &P) {
unsafe { self.raw_context.raw_end_set_parameter(param.as_ptr()) };
}
}