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firewheel_nodes/
stereo_to_mono.rs

1use firewheel_core::node::NodeError;
2use firewheel_core::{
3    channel_config::{ChannelConfig, ChannelCount},
4    node::{
5        AudioNode, AudioNodeInfo, AudioNodeProcessor, ConstructProcessorContext, EmptyConfig,
6        ProcBuffers, ProcExtra, ProcInfo, ProcessStatus,
7    },
8};
9
10/// A node that converts a stereo signal into a mono signal
11#[derive(Default, Debug, Clone, Copy, PartialEq, Eq)]
12#[cfg_attr(feature = "bevy", derive(bevy_ecs::prelude::Component))]
13#[cfg_attr(feature = "bevy_reflect", derive(bevy_reflect::Reflect))]
14#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
15pub struct StereoToMonoNode;
16
17impl AudioNode for StereoToMonoNode {
18    type Configuration = EmptyConfig;
19
20    fn info(&self, _config: &Self::Configuration) -> Result<AudioNodeInfo, NodeError> {
21        Ok(AudioNodeInfo::new()
22            .debug_name("stereo_to_mono")
23            .channel_config(ChannelConfig {
24                num_inputs: ChannelCount::STEREO,
25                num_outputs: ChannelCount::MONO,
26            }))
27    }
28
29    fn construct_processor(
30        &self,
31        _config: &Self::Configuration,
32        _cx: ConstructProcessorContext,
33    ) -> Result<impl AudioNodeProcessor, NodeError> {
34        Ok(StereoToMonoProcessor)
35    }
36}
37
38struct StereoToMonoProcessor;
39
40impl AudioNodeProcessor for StereoToMonoProcessor {
41    fn process(
42        &mut self,
43        info: &ProcInfo,
44        buffers: ProcBuffers,
45        _extra: &mut ProcExtra,
46    ) -> ProcessStatus {
47        if info.in_silence_mask.all_channels_silent(2) {
48            return ProcessStatus::ClearAllOutputs;
49        }
50
51        for (out_s, (&in1, &in2)) in buffers.outputs[0]
52            .iter_mut()
53            .zip(buffers.inputs[0].iter().zip(buffers.inputs[1].iter()))
54        {
55            *out_s = (in1 + in2) * 0.5;
56        }
57
58        ProcessStatus::OutputsModified
59    }
60}