[double-reverse delta inverter] make and implement crate

crates/double_reverse_delta_inverter/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "double_reverse_delta_inverter"
+version = "0.1.0"
+edition = "2018"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+baseplug = { git = "https://github.com/wrl/baseplug.git", rev = "9cec68f31cca9c0c7a1448379f75d92bbbc782a8" }
+serde = "1.0.126"

crates/double_reverse_delta_inverter/src/lib.rs

@@ -0,0 +1,61 @@
+#![allow(incomplete_features)]
+#![feature(generic_associated_types)]
+
+use baseplug::{Plugin, ProcessContext};
+use serde::{Deserialize, Serialize};
+
+baseplug::model! {
+    #[derive(Debug, Serialize, Deserialize)]
+    struct InverterModel {
+        #[model(min = 0.0, max = 1.0)]
+        #[parameter(name = "dry/wet")]
+        dry_wet: f32,
+    }
+}
+
+impl Default for InverterModel {
+    fn default() -> Self {
+        Self { dry_wet: 1.0 }
+    }
+}
+
+struct Inverter;
+
+impl Plugin for Inverter {
+    const NAME: &'static str = "double-reverse delta inverter";
+    const PRODUCT: &'static str = "double-reverse delta inverter";
+    const VENDOR: &'static str = "unnieversal";
+
+    const INPUT_CHANNELS: usize = 2;
+    const OUTPUT_CHANNELS: usize = 2;
+
+    type Model = InverterModel;
+
+    #[inline]
+    fn new(_sample_rate: f32, _model: &InverterModel) -> Self {
+        Self
+    }
+
+    #[inline]
+    fn process(&mut self, model: &InverterModelProcess, ctx: &mut ProcessContext<Self>) {
+        let input = &ctx.inputs[0].buffers;
+        let output = &mut ctx.outputs[0].buffers;
+
+        for i in 0..ctx.nframes {
+            let dw = model.dry_wet[i];
+
+            output[0][i] = inv(input[0][i]) * dw + (1.0 - dw) * input[0][i];
+            output[1][i] = inv(input[1][i]) * dw + (1.0 - dw) * input[1][i];
+        }
+    }
+}
+
+// https://www.desmos.com/calculator/dbjrrevmp0
+// this is what the function does
+// it's like a mirroring of sorts
+
+fn inv(x: f32) -> f32 {
+    (1.0 - x.abs()) * x.signum()
+}
+
+baseplug::vst2!(Inverter, b"drdi");