Struct ctru::services::ndsp::Channel

pub struct Channel<'ndsp> { /* private fields */ }

NDSP Channel representation.

There are 24 individual channels in total and each can play a different audio Wave simultaneuosly.

Default

NDSP initialises all channels with default values on initialization, but the developer is supposed to change these values to correctly work with the service.

In particular:

• Default audio format is set to AudioFormat::PCM16Mono.
• Default sample rate is set to 1 Hz.
• Default interpolation type is set to InterpolationType::Polyphase.
• Default mix is set to AudioMix::default()

The handle to a channel can be retrieved with Ndsp::channel()

Implementations

impl Channel<'_>

pub fn reset(&mut self)

Reset the channel (clear the queue and reset parameters).

Example

use ctru::services::ndsp::Ndsp;
let ndsp = Ndsp::new()?;
let mut channel_0 = ndsp.channel(0)?;

channel_0.reset();

pub fn init_parameters(&mut self)

Initialize the channel’s parameters with default values.

Example

use ctru::services::ndsp::Ndsp;
let ndsp = Ndsp::new()?;
let mut channel_0 = ndsp.channel(0)?;

channel_0.init_parameters();

pub fn is_playing(&self) -> bool

Returns whether the channel is playing any audio.

Example

use ctru::services::ndsp::Ndsp;
let ndsp = Ndsp::new()?;
let mut channel_0 = ndsp.channel(0)?;

// The channel is not playing any audio.
assert!(!channel_0.is_playing());

pub fn is_paused(&self) -> bool

Returns whether the channel’s playback is currently paused.

Example

use ctru::services::ndsp::Ndsp;
let ndsp = Ndsp::new()?;
let mut channel_0 = ndsp.channel(0)?;

// The channel is not paused.
assert!(!channel_0.is_paused());

pub fn id(&self) -> u8

Returns the channel’s index.

Example

use ctru::services::ndsp::Ndsp;
let ndsp = Ndsp::new()?;
let mut channel_0 = ndsp.channel(0)?;

// The channel's index is 0.
assert_eq!(channel_0.id(), 0);

pub fn sample_position(&self) -> usize

Returns the index of the currently played sample.

Because of how fast this value changes, it should only be used as a rough estimate of the current progress.

pub fn wave_sequence_id(&self) -> u16

Returns the channel’s current wave sequence’s id.

pub fn set_paused(&mut self, state: bool)

Pause or un-pause the channel’s playback.

Example

use ctru::services::ndsp::Ndsp;
let ndsp = Ndsp::new()?;
let mut channel_0 = ndsp.channel(0)?;

channel_0.set_paused(true);

// The channel is paused.
assert!(channel_0.is_paused());

pub fn set_format(&mut self, format: AudioFormat)

Set the channel’s output format.

Change this setting based on the used wave’s format.

Example

use ctru::services::ndsp::{AudioFormat, Ndsp};
let ndsp = Ndsp::new()?;
let mut channel_0 = ndsp.channel(0)?;

// Use the PCM16 interleaved dual-channel audio format.
channel_0.set_format(AudioFormat::PCM16Stereo);

pub fn set_interpolation(&mut self, interp_type: InterpolationType)

Set the channel’s interpolation mode.

Example

use ctru::services::ndsp::{InterpolationType, Ndsp};
let ndsp = Ndsp::new()?;
let mut channel_0 = ndsp.channel(0)?;

// Use linear interpolation within frames.
channel_0.set_interpolation(InterpolationType::Linear);

pub fn set_mix(&mut self, mix: &AudioMix)

Set the channel’s volume mix.

Look at AudioMix for more information on the volume mix.

Example

use ctru::services::ndsp::{AudioMix, Ndsp};
let ndsp = Ndsp::new()?;
let mut channel_0 = ndsp.channel(0)?;

// Front-left and front-right channel maxed.
channel_0.set_mix(&AudioMix::default());

pub fn set_sample_rate(&mut self, rate: f32)

Set the channel’s rate of sampling in hertz.

Example

use ctru::services::ndsp::Ndsp;
let ndsp = Ndsp::new()?;
let mut channel_0 = ndsp.channel(0)?;

// Standard CD sample rate. (44100 Hz)
channel_0.set_sample_rate(44100.);

pub fn clear_queue(&mut self)

Clear the wave buffer queue and stop playback.

Example

use ctru::services::ndsp::Ndsp;
let ndsp = Ndsp::new()?;
let mut channel_0 = ndsp.channel(0)?;

// Clear the audio queue and stop playback.
channel_0.clear_queue();

pub fn queue_wave<Buffer: LinearAllocation + AsRef<[u8]>>( &mut self, wave: &mut Wave<Buffer> ) -> Result<(), Error>

Add a wave buffer to the channel’s queue. If there are no other buffers in queue, playback for this buffer will start.

Warning

libctru expects the user to manually keep the info data (in this case Wave) alive during playback. To ensure safety, checks within Wave will clear the whole channel queue if any queued Wave is dropped prematurely.

Example

use ctru::services::ndsp::wave::Wave;
use ctru::services::ndsp::{AudioFormat, Ndsp};
let ndsp = Ndsp::new()?;
let mut channel_0 = ndsp.channel(0)?;


// Provide your own audio data.
let mut wave = Wave::new(audio_data, AudioFormat::PCM16Stereo, false);

// Clear the audio queue and stop playback.
channel_0.queue_wave(&mut wave);

impl Channel<'_>

Functions to handle audio filtering.

Refer to libctru for more info.

pub fn iir_mono_set_enabled(&mut self, enable: bool)

Enables/disables monopole filters.

pub fn iir_mono_set_params_high_pass_filter(&mut self, cut_off_freq: f32)

Set the monopole to be a high pass filter.

Notes

This is a lower quality filter than the Biquad alternative.

pub fn iir_mono_set_params_low_pass_filter(&mut self, cut_off_freq: f32)

Set the monopole to be a low pass filter.

Notes

This is a lower quality filter than the Biquad alternative.

pub fn iir_biquad_set_enabled(&mut self, enable: bool)

Enables/disables biquad filters.

pub fn iir_biquad_set_params_high_pass_filter( &mut self, cut_off_freq: f32, quality: f32 )

Set the biquad to be a high pass filter.

pub fn iir_biquad_set_params_low_pass_filter( &mut self, cut_off_freq: f32, quality: f32 )

Set the biquad to be a low pass filter.

pub fn iir_biquad_set_params_notch_filter( &mut self, notch_freq: f32, quality: f32 )

Set the biquad to be a notch filter.

pub fn iir_biquad_set_params_band_pass_filter( &mut self, mid_freq: f32, quality: f32 )

Set the biquad to be a band pass filter.

pub fn iir_biquad_set_params_peaking_equalizer( &mut self, central_freq: f32, quality: f32, gain: f32 )

Set the biquad to be a peaking equalizer.