Add amp sim

daw-backend/Cargo.toml

@@ -39,6 +39,9 @@ serde_json = "1.0"
 # BeamDSP scripting engine
 beamdsp = { path = "../lightningbeam-ui/beamdsp" }
 
+# Neural Amp Modeler FFI
+nam-ffi = { path = "../nam-ffi" }
+
 [dev-dependencies]
 
 [profile.release]

daw-backend/src/audio/node_graph/nodes/amp_sim.rs

@@ -0,0 +1,200 @@
+use crate::audio::midi::MidiEvent;
+use crate::audio::node_graph::{AudioNode, NodeCategory, NodePort, Parameter, ParameterUnit, SignalType};
+use nam_ffi::NamModel;
+use std::path::Path;
+
+const PARAM_INPUT_GAIN: u32 = 0;
+const PARAM_OUTPUT_GAIN: u32 = 1;
+const PARAM_MIX: u32 = 2;
+
+/// Guitar amp simulator node using Neural Amp Modeler (.nam) models.
+pub struct AmpSimNode {
+    name: String,
+    input_gain: f32,
+    output_gain: f32,
+    mix: f32,
+
+    model: Option<NamModel>,
+    model_path: Option<String>,
+
+    // Mono scratch buffers for NAM processing (NAM is mono-only)
+    mono_in: Vec<f32>,
+    mono_out: Vec<f32>,
+
+    inputs: Vec<NodePort>,
+    outputs: Vec<NodePort>,
+    parameters: Vec<Parameter>,
+}
+
+impl AmpSimNode {
+    pub fn new(name: impl Into<String>) -> Self {
+        let name = name.into();
+
+        let inputs = vec![NodePort::new("Audio In", SignalType::Audio, 0)];
+        let outputs = vec![NodePort::new("Audio Out", SignalType::Audio, 0)];
+
+        let parameters = vec![
+            Parameter::new(PARAM_INPUT_GAIN, "Input Gain", 0.0, 4.0, 1.0, ParameterUnit::Generic),
+            Parameter::new(PARAM_OUTPUT_GAIN, "Output Gain", 0.0, 4.0, 1.0, ParameterUnit::Generic),
+            Parameter::new(PARAM_MIX, "Mix", 0.0, 1.0, 1.0, ParameterUnit::Generic),
+        ];
+
+        Self {
+            name,
+            input_gain: 1.0,
+            output_gain: 1.0,
+            mix: 1.0,
+            model: None,
+            model_path: None,
+            mono_in: Vec::new(),
+            mono_out: Vec::new(),
+            inputs,
+            outputs,
+            parameters,
+        }
+    }
+
+    /// Load a .nam model file. Call from the audio thread via command dispatch.
+    pub fn load_model(&mut self, path: &str) -> Result<(), String> {
+        let model_path = Path::new(path);
+        let mut model =
+            NamModel::from_file(model_path).map_err(|e| format!("{}", e))?;
+        model.set_max_buffer_size(1024);
+        self.model = Some(model);
+        self.model_path = Some(path.to_string());
+        Ok(())
+    }
+
+    /// Get the loaded model path (for preset serialization).
+    pub fn model_path(&self) -> Option<&str> {
+        self.model_path.as_deref()
+    }
+}
+
+impl AudioNode for AmpSimNode {
+    fn category(&self) -> NodeCategory {
+        NodeCategory::Effect
+    }
+
+    fn inputs(&self) -> &[NodePort] {
+        &self.inputs
+    }
+
+    fn outputs(&self) -> &[NodePort] {
+        &self.outputs
+    }
+
+    fn parameters(&self) -> &[Parameter] {
+        &self.parameters
+    }
+
+    fn set_parameter(&mut self, id: u32, value: f32) {
+        match id {
+            PARAM_INPUT_GAIN => self.input_gain = value.clamp(0.0, 4.0),
+            PARAM_OUTPUT_GAIN => self.output_gain = value.clamp(0.0, 4.0),
+            PARAM_MIX => self.mix = value.clamp(0.0, 1.0),
+            _ => {}
+        }
+    }
+
+    fn get_parameter(&self, id: u32) -> f32 {
+        match id {
+            PARAM_INPUT_GAIN => self.input_gain,
+            PARAM_OUTPUT_GAIN => self.output_gain,
+            PARAM_MIX => self.mix,
+            _ => 0.0,
+        }
+    }
+
+    fn process(
+        &mut self,
+        inputs: &[&[f32]],
+        outputs: &mut [&mut [f32]],
+        _midi_inputs: &[&[MidiEvent]],
+        _midi_outputs: &mut [&mut Vec<MidiEvent>],
+        _sample_rate: u32,
+    ) {
+        if inputs.is_empty() || outputs.is_empty() {
+            return;
+        }
+
+        let input = inputs[0];
+        let output = &mut outputs[0];
+
+        let frames = input.len() / 2;
+        let output_frames = output.len() / 2;
+        let frames_to_process = frames.min(output_frames);
+
+        if let Some(ref mut model) = self.model {
+            // Ensure scratch buffers are large enough
+            if self.mono_in.len() < frames_to_process {
+                self.mono_in.resize(frames_to_process, 0.0);
+                self.mono_out.resize(frames_to_process, 0.0);
+            }
+
+            // Deinterleave stereo to mono (average L+R) and apply input gain
+            for frame in 0..frames_to_process {
+                let left = input[frame * 2];
+                let right = input[frame * 2 + 1];
+                self.mono_in[frame] = (left + right) * 0.5 * self.input_gain;
+            }
+
+            // Process through NAM model
+            model.process(
+                &self.mono_in[..frames_to_process],
+                &mut self.mono_out[..frames_to_process],
+            );
+
+            // Apply output gain, mix wet/dry, copy mono back to stereo
+            for frame in 0..frames_to_process {
+                let dry = (input[frame * 2] + input[frame * 2 + 1]) * 0.5;
+                let wet = self.mono_out[frame] * self.output_gain;
+                let mixed = dry * (1.0 - self.mix) + wet * self.mix;
+                output[frame * 2] = mixed;
+                output[frame * 2 + 1] = mixed;
+            }
+        } else {
+            // No model loaded — pass through unchanged
+            let samples = frames_to_process * 2;
+            output[..samples].copy_from_slice(&input[..samples]);
+        }
+    }
+
+    fn reset(&mut self) {
+        // No persistent filter state to reset
+    }
+
+    fn node_type(&self) -> &str {
+        "AmpSim"
+    }
+
+    fn name(&self) -> &str {
+        &self.name
+    }
+
+    fn clone_node(&self) -> Box<dyn AudioNode> {
+        // Cannot clone the NAM model (C++ pointer), so clone without model.
+        // The model will need to be reloaded via command if needed.
+        Box::new(Self {
+            name: self.name.clone(),
+            input_gain: self.input_gain,
+            output_gain: self.output_gain,
+            mix: self.mix,
+            model: None,
+            model_path: self.model_path.clone(),
+            mono_in: Vec::new(),
+            mono_out: Vec::new(),
+            inputs: self.inputs.clone(),
+            outputs: self.outputs.clone(),
+            parameters: self.parameters.clone(),
+        })
+    }
+
+    fn as_any_mut(&mut self) -> &mut dyn std::any::Any {
+        self
+    }
+
+    fn as_any(&self) -> &dyn std::any::Any {
+        self
+    }
+}

daw-backend/src/audio/node_graph/preset.rs

@@ -127,6 +127,10 @@ pub struct SerializedNode {
     /// For Script nodes: BeamDSP source code
     #[serde(skip_serializing_if = "Option::is_none")]
     pub script_source: Option<String>,
+
+    /// For AmpSim nodes: path to the .nam model file
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub nam_model_path: Option<String>,
 }
 
 /// Serialized group definition (frontend-only visual grouping, stored opaquely by backend)
@@ -222,6 +226,7 @@ impl SerializedNode {
             template_graph: None,
             sample_data: None,
             script_source: None,
+            nam_model_path: None,
         }
     }
 

daw-backend/src/command/types.rs

@@ -186,6 +186,9 @@ pub enum Command {
     /// Load audio sample data into a Script node's sample slot (track_id, node_id, slot_index, audio_data, sample_rate, name)
     GraphSetScriptSample(TrackId, u32, usize, Vec<f32>, u32, String),
 
+    /// Load a NAM model into an AmpSim node (track_id, node_id, model_path)
+    AmpSimLoadModel(TrackId, u32, String),
+
     /// Load a sample into a SimpleSampler node (track_id, node_id, file_path)
     SamplerLoadSample(TrackId, u32, String),
     /// Load a sample from the audio pool into a SimpleSampler node (track_id, node_id, pool_index)

lightningbeam-ui/Cargo.lock

@@ -1142,6 +1142,15 @@ dependencies = [
  "error-code",
 ]
 
+[[package]]
+name = "cmake"
+version = "0.1.54"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e7caa3f9de89ddbe2c607f4101924c5abec803763ae9534e4f4d7d8f84aa81f0"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "codespan-reporting"
 version = "0.12.0"
@@ -1678,6 +1687,7 @@ dependencies = [
  "memmap2",
  "midir",
  "midly",
+ "nam-ffi",
  "pathdiff",
  "petgraph 0.6.5",
  "rand 0.8.5",
@@ -3823,6 +3833,13 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "nam-ffi"
+version = "0.1.0"
+dependencies = [
+ "cmake",
+]
+
 [[package]]
 name = "ndk"
 version = "0.9.0"

lightningbeam-ui/Cargo.toml

@@ -50,6 +50,9 @@ notify-rust = "4.11"
 [profile.dev.package.daw-backend]
 opt-level = 2
 
+[profile.dev.package.nam-ffi]
+opt-level = 2
+
 [profile.dev.package.beamdsp]
 opt-level = 2