ts::EngineNoise Class Reference

The engine's shared pseudo-random generator. More...

#include <tabulasonora/engine_noise.hpp>

Public Member Functions
std::uint16_t	next () noexcept
	Draws the next 16-bit value.
int	next_pan () noexcept
	Draws a random pan position, 0 to 127, on the same scale as CC#10.
void	reset () noexcept
	Returns the generator to the engine's reset state.

Detailed Description

The engine's shared pseudo-random generator.

The original keeps two 16-bit registers, seeded at engine reset to 0xEFA6 and 0x9C23. The first is a right-shifting Fibonacci LFSR whose new bit 15 is bit 5 XOR bit 15; the second shifts left and inserts bit 9 when bit 2 is clear, or the complement of bit 13 when bit 2 is set. A draw steps both and returns their XOR.

The sequence is therefore deterministic from engine reset; what polyphony changes is only the order in which voices consume draws. The generator is shared by the random LFO waveforms, the pitch start jitter, and the random detune redraw — so anything that consumes a draw it should not shifts every later one.

Member Function Documentation

next()

std::uint16_t ts::EngineNoise::next ( )

inlinenodiscardnoexcept

Draws the next 16-bit value.

next_pan()

int ts::EngineNoise::next_pan ( )

inlinenodiscardnoexcept

Draws a random pan position, 0 to 127, on the same scale as CC#10.

The engine takes the top seven bits of a draw. This is what GS random pan resolves to — a part whose CC#10 is zero, or a drum key whose pan NRPN is zero, is repositioned per note.

reset()

void ts::EngineNoise::reset ( )

inlinenoexcept

Returns the generator to the engine's reset state.

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The documentation for this class was generated from the following file:

• include/tabulasonora/engine_noise.hpp