Struct RenderContext 

pub struct RenderContext {
    pub sample_pos: u64,
    pub samples_since_last: u32,
    pub sample_rate: f32,
    pub transport: TransportState,
    pub speed_ratio: f64,
}

Unified render context — passed by & reference through the entire signal graph during one processing block.

Built by the I/O backend once per block on the stack. Contains sample-clock metadata, host transport state, and hardware clock correction factor.

Field summary

Field	Source	Used by
sample_pos	I/O backend sample counter	Time-aware generators, sequencers
samples_since_last	Block size	Delta-time computation
sample_rate	I/O backend config	Frequency calculations, filters
transport	JACK/PipeWire transport or MIDI clock	BPM-synced LFOs, sequencers, automations
speed_ratio	SPA clock / DLL filter	Sample-rate conversion (resampling compensation)

Fields

sample_pos: u64

Absolute sample position since graph start.

samples_since_last: u32

Number of samples processed in this block.

sample_rate: f32

Current sample rate in Hz.

transport: TransportState

Host transport state (BPM, playing flag, musical position).

speed_ratio: f64

Hardware clock correction factor.

1.0 = nominal. > 1.0 = sound card is slow (resample up). < 1.0 = sound card is fast (resample down). Set by PipeWire’s spa_io_clock.rate_match or a JACK DLL filter.

Implementations

impl RenderContext

pub fn new(sample_pos: u64, samples_since_last: u32, sample_rate: f32) -> Self

Create a minimal render context from basic clock parameters.

Transport defaults to 120 BPM, playing, 4/4.

pub fn with_tempo( sample_pos: u64, samples_since_last: u32, sample_rate: f32, bpm: f32, ) -> Self

Create a render context with an explicit BPM.

pub fn delta_seconds(&self) -> f64

Time delta of this block in seconds.

pub fn absolute_seconds(&self) -> f64

Absolute time in seconds since graph start.

pub fn bpm(&self) -> f32

Current BPM as f32 for backward compatibility.

pub fn beat_position(&self) -> Option<f64>

Musical beat position (requires valid BPM).

Returns None if BPM is zero.

pub fn musical_position(&self) -> Option<(u32, u8, u8)>

Musical position as (bar, beat_in_bar, sixteenth) triple.

Uses time_sig_num and time_sig_den from the transport state.

pub fn is_new_bar(&self) -> bool

Whether this block starts a new bar.

pub fn is_new_beat(&self) -> bool

Whether this block starts a new beat.

Trait Implementations

impl Clone for RenderContext

fn clone(&self) -> RenderContext

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for RenderContext

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for RenderContext

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.