2026-03-24 13:40:24 +00:00

232 lines
8.1 KiB
Rust

use std::sync::Arc;
use prometeu_abi::model::Sample;
use prometeu_hardware_contract::AudioBridge;
/// Maximum number of simultaneous audio voices supported by the hardware.
pub const MAX_CHANNELS: usize = 16;
/// Standard sample rate for the final audio output.
pub const OUTPUT_SAMPLE_RATE: u32 = 48000;
/// Looping mode for samples (re-exported from the hardware contract).
pub use prometeu_hardware_contract::LoopMode;
use crate::memory_banks::SoundBankPoolAccess;
/// State of a single playback voice (channel).
///
/// The Core maintains this state to provide information to the App (e.g., is_playing),
/// but the actual real-time mixing is performed by the Host using commands.
pub struct Channel {
/// The actual sample data being played.
pub sample: Option<Arc<Sample>>,
/// Whether this channel is currently active.
pub active: bool,
/// Current playback position within the sample (fractional for pitch shifting).
pub pos: f64,
/// Playback speed multiplier (1.0 = original speed).
pub pitch: f64,
/// Voice volume (0-255).
pub volume: u8,
/// Stereo panning (0=Full Left, 127=Center, 255=Full Right).
pub pan: u8,
/// Loop configuration for this voice.
pub loop_mode: LoopMode,
/// Playback priority (used for voice stealing policies).
pub priority: u8,
}
impl Default for Channel {
fn default() -> Self {
Self {
sample: None,
active: false,
pos: 0.0,
pitch: 1.0,
volume: 255,
pan: 127,
loop_mode: LoopMode::Off,
priority: 0,
}
}
}
/// Commands sent from the Core to the Host audio backend.
///
/// Because the Core logic runs at 60Hz and Audio is generated at 48kHz,
/// we use an asynchronous command queue to synchronize them.
pub enum AudioCommand {
/// Start playing a sample on a specific voice.
Play {
sample: Arc<Sample>,
voice_id: usize,
volume: u8,
pan: u8,
pitch: f64,
priority: u8,
loop_mode: LoopMode,
},
/// Immediately stop playback on a voice.
Stop {
voice_id: usize,
},
/// Update volume of an ongoing playback.
SetVolume {
voice_id: usize,
volume: u8,
},
/// Update panning of an ongoing playback.
SetPan {
voice_id: usize,
pan: u8,
},
/// Update pitch of an ongoing playback.
SetPitch {
voice_id: usize,
pitch: f64,
},
/// Pause all audio processing.
MasterPause,
/// Resume audio processing.
MasterResume,
}
/// PROMETEU Audio Subsystem.
///
/// Models a multi-channel PCM sampler (SPU).
/// The audio system in Prometeu is **command-based**. This means the Core
/// doesn't generate raw audio samples; instead, it sends high-level commands
/// (like `Play`, `Stop`, `SetVolume`) to a queue. The physical host backend
/// (e.g., CPAL on desktop) then consumes these commands and performs the
/// actual mixing at the native hardware sample rate.
///
/// ### Key Features:
/// - **16 Simultaneous Voices**: Independent volume, pan, and pitch.
/// - **Sample-based Synthesis**: Plays PCM data stored in SoundBanks.
/// - **Stereo Output**: 48kHz output target.
pub struct Audio {
/// Local state of the hardware voices. This state is used for logic
/// (e.g., checking if a sound is still playing) and is synchronized with the Host.
pub voices: [Channel; MAX_CHANNELS],
/// Queue of pending commands to be processed by the Host mixer.
/// This queue is typically flushed and sent to the Host once per frame.
pub commands: Vec<AudioCommand>,
/// Interface to access sound memory banks (ARAM).
pub sound_banks: Arc<dyn SoundBankPoolAccess>,
}
impl AudioBridge for Audio {
fn play(&mut self, bank_id: u8, sample_id: u16, voice_id: usize, volume: u8, pan: u8, pitch: f64, priority: u8, loop_mode: prometeu_hardware_contract::LoopMode) {
let lm = match loop_mode { prometeu_hardware_contract::LoopMode::Off => LoopMode::Off, prometeu_hardware_contract::LoopMode::On => LoopMode::On };
self.play(bank_id, sample_id, voice_id, volume, pan, pitch, priority, lm)
}
fn play_sample(&mut self, sample: Arc<Sample>, voice_id: usize, volume: u8, pan: u8, pitch: f64, priority: u8, loop_mode: prometeu_hardware_contract::LoopMode) {
let lm = match loop_mode { prometeu_hardware_contract::LoopMode::Off => LoopMode::Off, prometeu_hardware_contract::LoopMode::On => LoopMode::On };
self.play_sample(sample, voice_id, volume, pan, pitch, priority, lm)
}
fn stop(&mut self, voice_id: usize) { self.stop(voice_id) }
fn set_volume(&mut self, voice_id: usize, volume: u8) { self.set_volume(voice_id, volume) }
fn set_pan(&mut self, voice_id: usize, pan: u8) { self.set_pan(voice_id, pan) }
fn set_pitch(&mut self, voice_id: usize, pitch: f64) { self.set_pitch(voice_id, pitch) }
fn is_playing(&self, voice_id: usize) -> bool { self.is_playing(voice_id) }
fn clear_commands(&mut self) { self.clear_commands() }
}
impl Audio {
/// Initializes the audio system with empty voices and sound bank access.
pub fn new(sound_banks: Arc<dyn SoundBankPoolAccess>) -> Self {
Self {
voices: std::array::from_fn(|_| Channel::default()),
commands: Vec::new(),
sound_banks,
}
}
pub fn play(&mut self, bank_id: u8, sample_id: u16, voice_id: usize, volume: u8, pan: u8, pitch: f64, priority: u8, loop_mode: LoopMode) {
if voice_id >= MAX_CHANNELS {
return;
}
// Resolve the sample from the hardware pools
let sample = self.sound_banks.sound_bank_slot(bank_id as usize)
.and_then(|bank| bank.samples.get(sample_id as usize).map(Arc::clone));
if let Some(s) = sample {
println!("[Audio] Resolved sample from bank {} sample {}. Playing on voice {}.", bank_id, sample_id, voice_id);
self.play_sample(s, voice_id, volume, pan, pitch, priority, loop_mode);
} else {
eprintln!("[Audio] Failed to resolve sample from bank {} sample {}.", bank_id, sample_id);
}
}
pub fn play_sample(&mut self, sample: Arc<Sample>, voice_id: usize, volume: u8, pan: u8, pitch: f64, priority: u8, loop_mode: LoopMode) {
if voice_id >= MAX_CHANNELS {
return;
}
// Update local state
self.voices[voice_id] = Channel {
sample: Some(Arc::clone(&sample)),
active: true,
pos: 0.0,
pitch,
volume,
pan,
loop_mode,
priority,
};
// Push command to the host
self.commands.push(AudioCommand::Play {
sample,
voice_id,
volume,
pan,
pitch,
priority,
loop_mode,
});
}
pub fn stop(&mut self, voice_id: usize) {
if voice_id < MAX_CHANNELS {
self.voices[voice_id].active = false;
self.voices[voice_id].sample = None;
self.commands.push(AudioCommand::Stop { voice_id });
}
}
pub fn set_volume(&mut self, voice_id: usize, volume: u8) {
if voice_id < MAX_CHANNELS {
self.voices[voice_id].volume = volume;
self.commands.push(AudioCommand::SetVolume { voice_id, volume });
}
}
pub fn set_pan(&mut self, voice_id: usize, pan: u8) {
if voice_id < MAX_CHANNELS {
self.voices[voice_id].pan = pan;
self.commands.push(AudioCommand::SetPan { voice_id, pan });
}
}
pub fn set_pitch(&mut self, voice_id: usize, pitch: f64) {
if voice_id < MAX_CHANNELS {
self.voices[voice_id].pitch = pitch;
self.commands.push(AudioCommand::SetPitch { voice_id, pitch });
}
}
pub fn is_playing(&self, voice_id: usize) -> bool {
if voice_id < MAX_CHANNELS {
self.voices[voice_id].active
} else {
false
}
}
/// Clears the command queue. The Host should consume this every frame.
pub fn clear_commands(&mut self) {
self.commands.clear();
}
}