feat: core

.gitignore

@@ -0,0 +1,21 @@
+# Created by https://www.toptal.com/developers/gitignore/api/rust
+# Edit at https://www.toptal.com/developers/gitignore?templates=rust
+
+### Rust ###
+# Generated by Cargo
+# will have compiled files and executables
+debug/
+target/
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
+Cargo.lock
+
+# These are backup files generated by rustfmt
+**/*.rs.bk
+
+# MSVC Windows builds of rustc generate these, which store debugging information
+*.pdb
+
+# End of https://www.toptal.com/developers/gitignore/api/rust
+

Cargo.toml

@@ -0,0 +1,3 @@
+[workspace]
+resolver = "3"
+members = ["crates/core"]

crates/core/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "soft-mixer-core"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+crossbeam = { version = "0.8.4", features = ["crossbeam-channel"] }
+parking_lot = "0.12.4"
+rayon = "1.11.0"
+thiserror = "2.0.16"

crates/core/src/buffer.rs

@@ -0,0 +1,11 @@
+use crate::constant::SAMPLE;
+
+pub struct AudioBuffer<const N: usize>(pub [SAMPLE; N]);
+
+impl<const N: usize> AudioBuffer<N> {
+    pub fn add_mut(&mut self, other: &Self) {
+        for i in 0..N {
+            self.0[i] = self.0[i].saturating_add(other.0[i]);
+        }
+    }
+}

crates/core/src/constant.rs

@@ -0,0 +1 @@
+pub type SAMPLE = i16;

crates/core/src/lib.rs

@@ -0,0 +1,4 @@
+mod buffer;
+mod constant;
+pub mod stream;
+pub mod transformer;

crates/core/src/stream.rs

@@ -0,0 +1,13 @@
+use crate::{buffer::AudioBuffer, constant::SAMPLE};
+
+pub trait AudioStream<const N: usize>: Send {
+    fn update(&self, upstream: &mut AudioBuffer<N>);
+}
+
+pub trait AudioSource<const N: usize>: Send {
+    fn update(&self) -> AudioBuffer<N>;
+}
+
+pub trait BinaryStream<const N: usize>: Send {
+    fn next(&self) -> [u8; N];
+}

crates/core/src/transformer.rs

@@ -0,0 +1 @@
+pub mod mixer;

crates/core/src/transformer/mixer.rs

@@ -0,0 +1,31 @@
+use crate::{buffer::AudioBuffer, stream::AudioStream};
+use rayon::prelude::ParallelIterator;
+
+pub struct Mixed<S, const N: usize>
+where
+    S: AudioStream<N>,
+{
+    upstreams: Vec<S>,
+}
+
+impl<S, const N: usize> AudioStream<N> for Mixed<S, N>
+where
+    S: AudioStream<N>,
+{
+    fn update(&self, out: &mut AudioBuffer<N>) {
+        let bufs: Vec<AudioBuffer<N>> = self
+            .upstreams
+            .iter() // TODO = DO IT PARALLEL. It's the main purpose of the project. Why
+            // do you even do it in single thread if you develop the engine?
+            .map(|upstream| {
+                let mut out = AudioBuffer([0; N]);
+                upstream.update(&mut out);
+                out
+            })
+            .collect();
+
+        for buf in bufs {
+            out.add_mut(&buf);
+        }
+    }
+}