[sosten] add direction

README.md

@@ -83,13 +83,14 @@ it's useful when you want to play a note super fast (over 1/64 tempo) but don't
 
 ### sosten
 
-sustains a sound by replaying a grain of sound on loop
+sustains a sound by replaying a grain of sound on loop. small but versatile
 
 parameters:
 - `enable`: will enable the sustain if it's over 0.5
 - `length`: length of the grain in samples. maximum is 48000 cause i said so
 - `manual/pitch detection`: whether to use the manually set length (if under 0.5) or use the detected pitch (over 0.5)
 - `dissipation`: amount of dissipation of the input
+- `direction`: direction in which the grain is played
 
 to use this plugin, add an automation for `enable` and set the value to `1.0` wherever you want the sustain to happen. as soon as that happens, it'll start looping the last `length` samples
 
@@ -97,13 +98,23 @@ if set to manual, it uses the provided length for the looped grain. if pitch det
 
 dissipation is a weird thingy. it smooths out the sound, and i think it's a lowpass filter? not sure. makes cool sounds though. what it does is roughly `x[n] = dissipation * x[n] + (1 - dissipation) * x[n + 1]` after each time it plays a sample, so `dissipation = 1` will leave the audio untouched, and setting it to `0.5` provides the greatest effect
 
-low lengths will almost produce a tone of frequency `1 / length`, which makes for interesting sounds
+direction is a selector, with three ranges:
+- `[0, 0.4)`: the grain will be played backwards
+- `[0.4, 0.6)`: the grain will cycle through forwards and backwards
+- `[0.6, 1.0]`: the grain will play forwards
+
+my three main uses are: 
+- sustaining a note, which you can do with `manual/pitch detection = 1`, `direction = 1`, and any amount of dissipation
+- wavetable-ish kinda thing, by setting `manual = 0` and a really low length, you can play notes of frequency `1 / length`
+- glitch repetition effect, by setting `manual = 0`, any direction (but usually forward), any dissipation, and a medium length. enable at the end of a bar or smth
+
+but you can probably use it for more stuff! idk! this are just my suggestions
 
 ### quinoa [WIP]
 
 nothing implemented yet, but it's supposed to be a granular synthesis plugin that does stuff with an audio file
 
-since this needs a ui so we can select a file to play, and i still don't know how to do that, it's kinda stuck
+since this needs a ui so we can select a file to play, and i still don't know how to do that, progress is kinda stuck
 
 ### XLowpass
 

crates/sosten/src/lib.rs

@@ -27,6 +27,9 @@ baseplug::model! {
         #[model(min = 0.0, max = 1.0)]
         #[parameter(name = "dissipation")]
         dissipation: f32,
+        #[model(min = 0.0, max = 1.0)]
+        #[parameter(name = "direction")]
+        direction: f32,
     }
 }
 
@@ -37,6 +40,7 @@ impl Default for SostenModel {
             length: 1000.0,
             manual: 0.0,
             dissipation: 1.0,
+            direction: 1.0,
         }
     }
 }
@@ -53,6 +57,9 @@ struct Sosten {
     /// Period of the processed input
     /// We keep both so we can instantly switch
     period: Option<usize>,
+
+    /// Keeps track of whether we are going forward while in cycle mode
+    forwards_in_cycle_mode: bool,
 }
 
 impl Plugin for Sosten {
@@ -76,6 +83,8 @@ impl Plugin for Sosten {
             detector_thread: pitch_detection::PitchDetectorThread::<PITCH_LEN>::new(),
             used_period: None,
             period: None,
+
+            forwards_in_cycle_mode: true,
         }
     }
 
@@ -146,9 +155,38 @@ impl Plugin for Sosten {
                 self.buffers.r[a] += (1.0 - diss) * self.buffers.r[(a + 1) % LEN];
 
                 // Loop index after we finish playing a section
-                self.buffers.idx += 1;
-                if self.buffers.idx >= len {
-                    self.buffers.idx = 0;
+                if model.direction[i] > 0.6 {
+                    // we are going forwards, so increase the idx
+                    self.buffers.idx += 1;
+                    // and loop at the end
+                    if self.buffers.idx >= len {
+                        self.buffers.idx = 0;
+                    }
+                } else if model.direction[i] > 0.4 {
+                    // we're in cycle mode
+
+                    // alternate directions at the end
+                    if self.buffers.idx == 0 {
+                        self.forwards_in_cycle_mode = true;
+                    }
+                    if self.buffers.idx >= len {
+                        self.forwards_in_cycle_mode = false;
+                    }
+
+                    // increase/decrease index
+                    if self.forwards_in_cycle_mode {
+                        self.buffers.idx += 1;
+                    } else {
+                        self.buffers.idx -= 1;
+                    }
+                } else {
+                    // we are going backwards, so loop first
+                    // this ensures we don't do 0 - 1
+                    if self.buffers.idx == 0 {
+                        self.buffers.idx = len + 1;
+                    }
+                    // then decrease index
+                    self.buffers.idx -= 1;
                 }
             } else {
                 // If it's not on a repeat section, pass all the audio fully