135 lines
3.3 KiB
Rust
135 lines
3.3 KiB
Rust
use crate::audio::node_graph::{AudioNode, NodeCategory, NodePort, Parameter, ParameterUnit, SignalType, cv_input_or_default};
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use crate::audio::midi::MidiEvent;
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const PARAM_GAIN: u32 = 0;
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/// Gain/volume control node
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pub struct GainNode {
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name: String,
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gain: f32,
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inputs: Vec<NodePort>,
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outputs: Vec<NodePort>,
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parameters: Vec<Parameter>,
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}
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impl GainNode {
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pub fn new(name: impl Into<String>) -> Self {
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let name = name.into();
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let inputs = vec![
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NodePort::new("Audio In", SignalType::Audio, 0),
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NodePort::new("Gain CV", SignalType::CV, 1),
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];
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let outputs = vec![
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NodePort::new("Audio Out", SignalType::Audio, 0),
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];
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let parameters = vec![
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Parameter::new(PARAM_GAIN, "Gain", 0.0, 2.0, 1.0, ParameterUnit::Generic),
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];
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Self {
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name,
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gain: 1.0,
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inputs,
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outputs,
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parameters,
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}
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}
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}
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impl AudioNode for GainNode {
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fn category(&self) -> NodeCategory {
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NodeCategory::Utility
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}
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fn inputs(&self) -> &[NodePort] {
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&self.inputs
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}
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fn outputs(&self) -> &[NodePort] {
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&self.outputs
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}
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fn parameters(&self) -> &[Parameter] {
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&self.parameters
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}
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fn set_parameter(&mut self, id: u32, value: f32) {
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match id {
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PARAM_GAIN => self.gain = value.clamp(0.0, 2.0),
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_ => {}
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}
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}
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fn get_parameter(&self, id: u32) -> f32 {
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match id {
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PARAM_GAIN => self.gain,
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_ => 0.0,
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}
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}
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fn process(
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&mut self,
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inputs: &[&[f32]],
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outputs: &mut [&mut [f32]],
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_midi_inputs: &[&[MidiEvent]],
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_midi_outputs: &mut [&mut Vec<MidiEvent>],
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_sample_rate: u32,
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) {
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if inputs.is_empty() || outputs.is_empty() {
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return;
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}
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let input = inputs[0];
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let output = &mut outputs[0];
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// Audio signals are stereo (interleaved L/R)
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// Process by frames, not samples
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let frames = input.len().min(output.len()) / 2;
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for frame in 0..frames {
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// CV input acts as a VCA (voltage-controlled amplifier)
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// CV ranges from 0.0 (silence) to 1.0 (full gain parameter value)
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// When unconnected (NaN), defaults to 1.0 (no modulation, use gain parameter as-is)
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let cv = cv_input_or_default(inputs, 1, frame, 1.0);
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let final_gain = self.gain * cv;
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// Apply gain to both channels
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output[frame * 2] = input[frame * 2] * final_gain; // Left
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output[frame * 2 + 1] = input[frame * 2 + 1] * final_gain; // Right
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}
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}
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fn reset(&mut self) {
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// No state to reset
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}
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fn node_type(&self) -> &str {
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"Gain"
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}
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fn name(&self) -> &str {
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&self.name
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}
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fn clone_node(&self) -> Box<dyn AudioNode> {
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Box::new(Self {
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name: self.name.clone(),
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gain: self.gain,
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inputs: self.inputs.clone(),
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outputs: self.outputs.clone(),
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parameters: self.parameters.clone(),
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})
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}
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fn as_any_mut(&mut self) -> &mut dyn std::any::Any {
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self
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}
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fn as_any(&self) -> &dyn std::any::Any {
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self
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}
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}
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