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Use atomics in the smoother

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This is needed so we can share the params with the editor, but it isn't
great, is there a better alternative?
This commit is contained in:
Robbert van der Helm 2022-02-06 01:33:19 +01:00
parent 47b6631283
commit bf070fce5a
1 changed files with 60 additions and 40 deletions
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96
src/param/smoothing.rs
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@ -14,6 +14,9 @@
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
use crossbeam::atomic::AtomicCell;
use std::sync::atomic::{AtomicU32, Ordering};
/// Controls if and how parameters gets smoothed.
pub enum SmoothingStyle {
/// No smoothing is applied. The parameter's `value` field contains the latest sample value
@ -31,17 +34,20 @@ pub enum SmoothingStyle {
}
/// A smoother, providing a smoothed value for each sample.
//
// TODO: We need to use atomics here so we can share the params object with the GUI. Is there a
// better alternative to allow the process function to mutate these smoothers?
pub struct Smoother<T> {
/// The kind of snoothing that needs to be applied, if any.
style: SmoothingStyle,
/// The number of steps of smoothing left to take.
steps_left: u32,
steps_left: AtomicU32,
/// The amount we should adjust the current value each sample to be able to reach the target in
/// the specified tiem frame. This is also a floating point number to keep the smoothing
/// uniform.
step_size: f32,
/// The value for the current sample. Always stored as floating point for obvious reasons.
current: f32,
current: AtomicCell<f32>,
/// The value we're smoothing towards
target: T,
}
@ -50,9 +56,9 @@ impl<T: Default> Default for Smoother<T> {
fn default() -> Self {
Self {
style: SmoothingStyle::None,
steps_left: 0,
steps_left: AtomicU32::new(0),
step_size: Default::default(),
current: 0.0,
current: AtomicCell::new(0.0),
target: Default::default(),
}
}
@ -75,7 +81,7 @@ impl<T: Default> Smoother<T> {
/// Whether calling [Self::next()] will yield a new value or an old value. Useful if you need to
/// recompute something wheenver this parameter changes.
pub fn is_smoothing(&self) -> bool {
self.steps_left > 0
self.steps_left.load(Ordering::Relaxed) > 0
}
}
@ -85,49 +91,56 @@ impl Smoother<f32> {
/// Reset the smoother the specified value.
pub fn reset(&mut self, value: f32) {
self.target = value;
self.current = value;
self.steps_left = 0;
self.current.store(value);
self.steps_left.store(0, Ordering::Relaxed);
}
/// Set the target value.
pub fn set_target(&mut self, sample_rate: f32, target: f32) {
self.target = target;
self.steps_left = match self.style {
let steps_left = match self.style {
SmoothingStyle::None => 1,
SmoothingStyle::Linear(time) | SmoothingStyle::Logarithmic(time) => {
(sample_rate * time / 1000.0).round() as u32
}
};
self.steps_left.store(steps_left, Ordering::Relaxed);
let current = self.current.load();
self.step_size = match self.style {
SmoothingStyle::None => 0.0,
SmoothingStyle::Linear(_) => (self.target - self.current) / self.steps_left as f32,
SmoothingStyle::Linear(_) => (self.target - current) / steps_left as f32,
SmoothingStyle::Logarithmic(_) => {
// We need to solve `current * (step_size ^ steps_left) = target` for
// `step_size`
nih_debug_assert_ne!(self.current, 0.0);
(self.target / self.current).powf((self.steps_left as f32).recip())
nih_debug_assert_ne!(current, 0.0);
(self.target / current).powf((steps_left as f32).recip())
}
};
}
// Yes, Clippy, like I said, this was intentional
#[allow(clippy::should_implement_trait)]
pub fn next(&mut self) -> f32 {
if self.steps_left > 1 {
pub fn next(&self) -> f32 {
if self.steps_left.load(Ordering::Relaxed) > 1 {
let current = self.current.load();
// The number of steps usually won't fit exactly, so make sure we don't do weird things
// with overshoots or undershoots
self.steps_left -= 1;
if self.steps_left == 0 {
self.current = self.target;
let old_steps_left = self.steps_left.fetch_sub(1, Ordering::Relaxed);
let new = if old_steps_left == 1 {
self.target
} else {
match &self.style {
SmoothingStyle::None => self.current = self.target,
SmoothingStyle::Linear(_) => self.current += self.step_size,
SmoothingStyle::Logarithmic(_) => self.current *= self.step_size,
};
SmoothingStyle::None => self.target,
SmoothingStyle::Linear(_) => current + self.step_size,
SmoothingStyle::Logarithmic(_) => current * self.step_size,
}
};
self.current.store(new);
self.current
new
} else {
self.target
}
@ -138,45 +151,52 @@ impl Smoother<i32> {
/// Reset the smoother the specified value.
pub fn reset(&mut self, value: i32) {
self.target = value;
self.current = value as f32;
self.steps_left = 0;
self.current.store(value as f32);
self.steps_left.store(0, Ordering::Relaxed);
}
pub fn set_target(&mut self, sample_rate: f32, target: i32) {
self.target = target;
self.steps_left = match self.style {
let steps_left = match self.style {
SmoothingStyle::None => 1,
SmoothingStyle::Linear(time) | SmoothingStyle::Logarithmic(time) => {
(sample_rate * time / 1000.0).round() as u32
}
};
self.steps_left.store(steps_left, Ordering::Relaxed);
let current = self.current.load();
self.step_size = match self.style {
SmoothingStyle::None => 0.0,
SmoothingStyle::Linear(_) => {
(self.target as f32 - self.current) / self.steps_left as f32
}
SmoothingStyle::Linear(_) => (self.target as f32 - current) / steps_left as f32,
SmoothingStyle::Logarithmic(_) => {
nih_debug_assert_ne!(self.current, 0.0);
(self.target as f32 / self.current).powf((self.steps_left as f32).recip())
nih_debug_assert_ne!(current, 0.0);
(self.target as f32 / current).powf((steps_left as f32).recip())
}
};
}
#[allow(clippy::should_implement_trait)]
pub fn next(&mut self) -> i32 {
if self.steps_left > 1 {
self.steps_left -= 1;
if self.steps_left == 0 {
self.current = self.target as f32;
if self.steps_left.load(Ordering::Relaxed) > 1 {
let current = self.current.load();
// The number of steps usually won't fit exactly, so make sure we don't do weird things
// with overshoots or undershoots
let old_steps_left = self.steps_left.fetch_sub(1, Ordering::Relaxed);
let new = if old_steps_left == 1 {
self.target as f32
} else {
match &self.style {
SmoothingStyle::None => self.current = self.target as f32,
SmoothingStyle::Linear(_) => self.current += self.step_size,
SmoothingStyle::Logarithmic(_) => self.current *= self.step_size,
};
SmoothingStyle::None => self.target as f32,
SmoothingStyle::Linear(_) => current + self.step_size,
SmoothingStyle::Logarithmic(_) => current * self.step_size,
}
};
self.current.store(new);
self.current.round() as i32
new.round() as i32
} else {
self.target
}