98 lines
4.2 KiB
Rust
98 lines
4.2 KiB
Rust
// nih-plug: plugins, but rewritten in Rust
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// Copyright (C) 2022 Robbert van der Helm
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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use std::pin::Pin;
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use crate::params::Params;
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/// Basic functionality that needs to be implemented by a plugin. The wrappers will use this to
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/// expose the plugin in a particular plugin format.
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///
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/// This is super basic, and lots of things I didn't need or want to use yet haven't been
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/// implemented. Notable missing features include:
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///
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/// - MIDI
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/// - Sidechain inputs
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/// - Multiple output busses
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/// - Storing custom state, only the parameters are saved right now
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/// - Sample accurate automation (this would be great, but sadly few hosts even support it so until
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/// they do we'll ignore that it's a thing)
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/// - Parameter update callbacks
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/// - Parameter hierarchies/groups
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/// - Outputting parameter changes from the plugin
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/// - GUIs
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/// - Suspension and tail processing. This will be handled soon in a similar way to how CLAP
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/// handnles it.
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pub trait Plugin: Default + Sync {
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/// The default number of inputs. Some hosts like, like Bitwig and Ardour, use the defaults
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/// instead of setting up the busses properly.
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const DEFAULT_NUM_INPUTS: u32;
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/// The default number of inputs. Some hosts like, like Bitwig and Ardour, use the defaults
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/// instead of setting up the busses properly.
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const DEFAULT_NUM_OUTPUTS: u32;
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/// The plugin's parameters. The host will update the parameter values before calling
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/// `process()`. These parameters are identified by strings that should never change when the
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/// plugin receives an update.
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///
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/// TODO: Rethink the API a bit more. Also Requiring the pin on self makes more sense, but it's
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/// not strictly necessary. We'll have to change this once the API is usable to see what's
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/// ergonmic.
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fn params(&self) -> Pin<&dyn Params>;
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//
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// The following functions follow the lifetime of the plugin.
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//
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/// Whether the plugin supports a bus config. This only acts as a check, and the plugin
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/// shouldn't do anything beyond returning true or false.
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fn accepts_bus_config(&self, config: &BusConfig) -> bool;
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/// Initialize the plugin for the given bus and buffer configurations.
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///
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/// Before this point, the plugin should not have done any expensive initialization. Pleaes
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/// don't be that plugin that takes twenty seconds to scan.
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fn initialize(&mut self, bus_config: &BusConfig, buffer_config: &BufferConfig) -> bool;
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/// Process audio. To not have to worry about aliasing, the host's input buffer have already
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/// been copied to the output buffers if they are not handling buffers in place (most hosts do
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/// however).
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///
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/// TODO: &mut [&mut [f32]] may not be the correct type here
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/// TODO: Provide a way to access auxiliary input channels if the IO configuration is
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/// assymetric
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/// TODO: Add a process result to handle tails
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/// TODO: Handle FTZ stuff on the wrapper side and mention that this has been handled
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fn process(&mut self, samples: &mut [&mut [f32]]);
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}
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/// We only support a single main input and output bus at the moment.
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pub struct BusConfig {
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/// The number of input channels for the plugin.
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pub num_input_channels: u32,
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/// The number of output channels for the plugin.
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pub num_output_channels: u32,
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}
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/// Configuration for (the host's) audio buffers.
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pub struct BufferConfig {
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/// The current sample rate.
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pub sample_rate: f32,
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/// The maximum buffer size the host will use. The plugin should be able to accept variable
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/// sized buffers up to this size.
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pub max_buffer_size: u32,
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}
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