The GS part modify offsets, as the synthesis chains consume them. More...

#include <tabulasonora/part_modifiers.hpp>

Public Member Functions
constexpr bool	is_neutral () const noexcept
	True when nothing here would change a result.
constexpr int	attack_bias () const noexcept
	The envelope rate bias for segments 0 and 1, in rate-curve index steps.
constexpr int	decay_bias () const noexcept
	The envelope rate bias for segments 2 and 3.
constexpr int	release_bias () const noexcept
	The envelope rate bias for the release segment.
constexpr int	cutoff_offset () const noexcept
	The cutoff offset, in the 15-bit cutoff units the filter chain sums.

Public Attributes
int	vibrato_rate = neutral
	CC#76 / NRPN 01 08 / 40 1x 30 — part+0x3e4.
int	vibrato_depth = neutral
	CC#77 / NRPN 01 09 / 40 1x 31 — part+0x3e5.
int	vibrato_delay = neutral
	CC#78 / NRPN 01 0A / 40 1x 37 — part+0x3eb.
int	tvf_cutoff = neutral
	CC#74 / NRPN 01 20 / 40 1x 32 — part+0x3e6.
int	env_attack = neutral
	CC#73 / NRPN 01 63 / 40 1x 34 — part+0x3e8.
int	env_decay = neutral
	CC#75 / NRPN 01 64 / 40 1x 35 — part+0x3e9.
int	env_release = neutral
	CC#72 / NRPN 01 66 / 40 1x 36 — part+0x3ea.

Static Public Attributes
static constexpr int	neutral = 0x40
	The neutral value every one of these centres on.

Detailed Description

The GS part modify offsets, as the synthesis chains consume them.

Every one of these is a 0x40-centred byte that three writers share — the sound controllers (CC#71-78), the NRPNs (01 08-01 66) and the part SysEx (40 1x 30-37) all land on the same byte in the engine, at part+0x3e4 through part+0x3eb.

They are carried as a value rather than read off the part because the chains that consume them build voices, not parts: TvaChain and TvfChain are pure functions of a partial and a note, and the offline renderer drives them with no Part in sight. A default-constructed set is neutral and must leave every result bit-identical to having no modifiers at all, which is what makes it safe to pass one everywhere.

The engine pairs each of these with a second byte at part+0x453-0x45a, filled from the tone table only when the part is on a user bank (MSB 0x40 or 0x41) and reset to 0x40 otherwise. A standard MIDI file never programs a user tone, so that sibling is neutral throughout and the combined law reduces to the offsets here. Modelling it belongs with user tones, not here.