Completely reset smoothing on init or restore

src/param.rs

@@ -34,9 +34,10 @@ pub trait Param {
     /// The plain parameter type.
     type Plain;
 
-    /// Update the smoother state to point to the current value. Used when initializing and
-    /// restoring a plugin so everything is in sync.
-    fn update_smoother(&mut self, sample_rate: f32);
+    /// Update the smoother state to point to the current value. Also used when initializing and
+    /// restoring a plugin so everything is in sync. In that case the smoother should completely
+    /// reset to the current value.
+    fn update_smoother(&mut self, sample_rate: f32, reset: bool);
 
     /// Set this parameter based on a string. Returns whether the updating succeeded. That can fail
     /// if the string cannot be parsed.
@@ -162,8 +163,8 @@ macro_rules! impl_plainparam {
         impl Param for $ty {
             type Plain = $plain;
 
-            fn update_smoother(&mut self, sample_rate: f32) {
-                self.smoothed.set_target(sample_rate, self.value);
+            fn update_smoother(&mut self, sample_rate: f32, reset: bool) {
+                self.smoothed.set_target(sample_rate, self.value, reset);
             }
 
             fn set_from_string(&mut self, string: &str) -> bool {
@@ -234,7 +235,7 @@ impl_plainparam!(IntParam, i32);
 impl Param for BoolParam {
     type Plain = bool;
 
-    fn update_smoother(&mut self, _sample_rate: f32) {
+    fn update_smoother(&mut self, _sample_rate: f32, _init: bool) {
         // Can't really smooth a binary parameter now can you
     }
 

src/param/internals.rs

@@ -119,18 +119,19 @@ impl ParamPtr {
         }
     }
 
-    /// Update the smoother state to point to the current value. Used when initializing and
-    /// restoring a plugin so everything is in sync.
+    /// Update the smoother state to point to the current value. Also used when initializing and
+    /// restoring a plugin so everything is in sync. In that case the smoother should completely
+    /// reset to the current value.
     ///
     /// # Safety
     ///
     /// Calling this function is only safe as long as the object this `ParamPtr` was created for is
     /// still alive.
-    pub unsafe fn update_smoother(&self, sample_rate: f32) {
+    pub unsafe fn update_smoother(&self, sample_rate: f32, reset: bool) {
         match &self {
-            ParamPtr::FloatParam(p) => (**p).update_smoother(sample_rate),
-            ParamPtr::IntParam(p) => (**p).update_smoother(sample_rate),
-            ParamPtr::BoolParam(p) => (**p).update_smoother(sample_rate),
+            ParamPtr::FloatParam(p) => (**p).update_smoother(sample_rate, reset),
+            ParamPtr::IntParam(p) => (**p).update_smoother(sample_rate, reset),
+            ParamPtr::BoolParam(p) => (**p).update_smoother(sample_rate, reset),
         }
     }
 

src/param/smoothing.rs

@@ -71,18 +71,23 @@ impl<T: Default> Smoother<T> {
 // unwrap all of those options is not going to be very fun.
 impl Smoother<f32> {
     /// Set the target value.
-    pub fn set_target(&mut self, sample_rate: f32, target: f32) {
+    pub fn set_target(&mut self, sample_rate: f32, target: f32, reset: bool) {
         self.target = target;
-        self.steps_left = match self.style {
-            SmoothingStyle::None => 1,
-            SmoothingStyle::SmoothLinear(time) => (sample_rate * time / 1000.0).round() as u32,
-        };
-        self.step_size = match self.style {
-            SmoothingStyle::None => 0.0,
-            SmoothingStyle::SmoothLinear(_) => {
-                (self.target - self.current) / self.steps_left as f32
-            }
-        };
+        if reset {
+            self.current = self.target;
+            self.steps_left = 0;
+        } else {
+            self.steps_left = match self.style {
+                SmoothingStyle::None => 1,
+                SmoothingStyle::SmoothLinear(time) => (sample_rate * time / 1000.0).round() as u32,
+            };
+            self.step_size = match self.style {
+                SmoothingStyle::None => 0.0,
+                SmoothingStyle::SmoothLinear(_) => {
+                    (self.target - self.current) / self.steps_left as f32
+                }
+            };
+        }
     }
 
     // Yes, Clippy, like I said, this was intentional
@@ -109,18 +114,23 @@ impl Smoother<f32> {
 }
 
 impl Smoother<i32> {
-    pub fn set_target(&mut self, sample_rate: f32, target: i32) {
+    pub fn set_target(&mut self, sample_rate: f32, target: i32, reset: bool) {
         self.target = target;
-        self.steps_left = match self.style {
-            SmoothingStyle::None => 1,
-            SmoothingStyle::SmoothLinear(time) => (sample_rate * time / 1000.0).round() as u32,
-        };
-        self.step_size = match self.style {
-            SmoothingStyle::None => 0.0,
-            SmoothingStyle::SmoothLinear(_) => {
-                (self.target as f32 - self.current) / self.steps_left as f32
-            }
-        };
+        if reset {
+            self.current = self.target as f32;
+            self.steps_left = 0;
+        } else {
+            self.steps_left = match self.style {
+                SmoothingStyle::None => 1,
+                SmoothingStyle::SmoothLinear(time) => (sample_rate * time / 1000.0).round() as u32,
+            };
+            self.step_size = match self.style {
+                SmoothingStyle::None => 0.0,
+                SmoothingStyle::SmoothLinear(_) => {
+                    (self.target as f32 - self.current) / self.steps_left as f32
+                }
+            };
+        }
     }
 
     #[allow(clippy::should_implement_trait)]

src/wrapper/vst3.rs

@@ -277,7 +277,7 @@ impl<P: Plugin> WrapperInner<'_, P> {
             match (param_ptr, sample_rate) {
                 (_, Some(sample_rate)) => {
                     param_ptr.set_normalized_value(normalized_value as f32);
-                    param_ptr.update_smoother(sample_rate);
+                    param_ptr.update_smoother(sample_rate, false);
                 }
                 _ => param_ptr.set_normalized_value(normalized_value as f32),
             }
@@ -536,7 +536,7 @@ impl<P: Plugin> IComponent for Wrapper<'_, P> {
 
             // Make sure everything starts out in sync
             if let Some(sample_rate) = sample_rate {
-                param_ptr.update_smoother(sample_rate);
+                param_ptr.update_smoother(sample_rate, true);
             }
         }
 
@@ -934,7 +934,7 @@ impl<P: Plugin> IAudioProcessor for Wrapper<'_, P> {
 
         // Befure initializing the plugin, make sure all smoothers are set the the default values
         for param in self.inner.param_by_hash.values() {
-            param.update_smoother(buffer_config.sample_rate);
+            param.update_smoother(buffer_config.sample_rate, true);
         }
 
         if self