Struct Channel 

pub struct Channel {

    pub sample_index: u8,
    pub sample_pos: f32,
    pub period: u16,
    pub volume: u8,
    pub active: bool,
    pub finetune: i8,
    pub effect: u8,
    pub effect_param: u8,
    pub arp_base_period: u16,
    pub mem_porta_up: u8,
    pub mem_porta_down: u8,
    pub tone_porta_target: u16,
    pub tone_porta_speed: u8,
    pub mem_vibrato: u8,
    pub vib_pos: i8,
    pub vib_wave: Waveform,
    pub mem_tremolo: u8,
    pub trem_pos: i8,
    pub trem_wave: Waveform,
    pub mem_sample_offset: u8,
    pub mem_volslide: u8,
    pub retrig_ticks: u8,
    pub cut_tick: u8,
    pub delay: Option<DelayedTrigger>,
    pub glissando: bool,
    pub pending_sample: u8,
    pub pending_led: Option<bool>,
    pub pan: u8,
    pub last_mixed_sample: f32,
    pub ramp_prev_sample: f32,
    pub ramp_remaining_frames: u32,
}

Per-channel playback state.

Fields

sample_index: u8

1-based sample index (0 = no sample ever triggered).

sample_pos: f32

Fractional read position into the sample’s pcm buffer.

period: u16

Current period (0 = silent / not playing).

volume: u8

Current volume 0..=64.

active: bool

Whether this channel is currently sounding.

finetune: i8

Current finetune for the most recently loaded sample.

effect: u8

Current effect command (0..=0xF).

effect_param: u8

arp_base_period: u16

Arpeggio base period — the un-modulated period for this row.

mem_porta_up: u8

Last portamento-up param (1xx), used when param == 0.

mem_porta_down: u8

Last portamento-down param (2xx), used when param == 0.

tone_porta_target: u16

Tone portamento target period (set by a note on a 3xy / 5xy row).

tone_porta_speed: u8

Tone portamento speed (3xy / 5xy param; 0 reuses the last value).

mem_vibrato: u8

Last vibrato params — nibble format rate<<4 | depth.

vib_pos: i8

Vibrato LFO position, signed -32..=31.

vib_wave: Waveform

Vibrato waveform control.

mem_tremolo: u8

Last tremolo params — nibble format rate<<4 | depth.

trem_pos: i8

Tremolo LFO position, signed -32..=31.

trem_wave: Waveform

Tremolo waveform control.

mem_sample_offset: u8

Last 9xx sample-offset param.

mem_volslide: u8

Last volume-slide param (A/5/6).

retrig_ticks: u8

E9x retrigger period (ticks between retriggers).

cut_tick: u8

ECx note-cut tick (0 = no cut pending).

delay: Option<DelayedTrigger>

EDx note-delay state — Some(delay_tick) while pending, filled in on row entry.

glissando: bool

Glissando flag (E3x): if set, tone portamento snaps to nearest semitone each tick rather than sliding smoothly.

pending_sample: u8

Sample number written on a row that did not also trigger a note — the swap is deferred until the next note-on per Protracker quirk (see enter_row for the citation). 0 means no pending swap.

pending_led: Option<bool>

Pending LED-filter state from an E0x on this channel’s row. Some(true) = filter ON (E00, LED on). Some(false) = filter OFF (E01, LED off). None = no E0 this row. Resolved at the end of enter_row after all four channels’ tick-0 effects are processed: like Fxx, a later channel’s E0 wins on the same row.

pan: u8

Per-channel pan position, 0..=255. 0 = hard LEFT, 255 = hard RIGHT, 128 = centre. This is the FT-extension panning state set by 8xx (full 8-bit pan, Protracker-effects- MODFIL12.txt lines 1201-1207: “Command 8: Set FINE Panning … xxxxyyyy = panning position. (0=Most left, 255=most right.)”) and by E8x (rough nibble pan, Protracker-effects- MODFIL12.txt lines 1503-1505: “Command $E8: Set (Rough) Panning … yyyy = panning value. $0 = most left, $F = most right.”) — the E8 nibble is replicated across both halves of the byte so E80 → 0x00, E8F → 0xFF, E87 → 0x77, matching the “rough” 16-step interpretation also documented in multimedia-cx-protracker.html (“$0 is hard left, $F is hard right”). Initial values follow the Amiga LRRL hard-pan convention (channels 0 & 3 → 0, 1 & 2 → 255, pattern repeats every 4) so a MOD with no panning commands renders identically to the pre-r75 build.

last_mixed_sample: f32

Last post-volume sample emitted by this channel’s mixer. Used as the starting point for the crossfade ramp on the next re-trigger (see ramp_prev_sample). Updated by mix_one every output frame.

ramp_prev_sample: f32

Volume that the previous note was being mixed at the moment this channel was re-triggered. Captured by enter_row on every fresh note-on (and on retrigger paths like E9x and the EDx delayed trigger) so the mixer can crossfade from this old value to the new note’s first sample over a short ramp, instead of stepping discontinuously and producing the audible pop that a hard re-trigger leaves behind.

Without the ramp, every note-on creates a discontinuity in the mixed bus equal to (last sample of the old note) → (first sample of the new note), which is typically a step of a few hundred i16 LSBs and accumulates into the per-trigger HF drift observed on real-world MODs (halluc.mod, rhmst.mod).

ramp_remaining_frames: u32

Number of output frames remaining in the per-trigger crossfade ramp. The ramp linearly interpolates from ramp_prev_sample to the new note’s mixed sample. Set to PlayerState::RAMP_FRAMES on every fresh trigger; counted down by mix_one once per output frame.

Trait Implementations

impl Clone for Channel

fn clone(&self) -> Channel

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Channel

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

Formats the value using the given formatter.

impl Default for Channel

fn default() -> Channel

Returns the “default value” for a type.