serumalt/Source/synth/AGENTS.md

synth module

Related source files

This directory contains guidance. All files listed below remain in the parent Source/ directory.

• Wavetable.h, Wavetable.cpp
• Oscillator.h, Oscillator.cpp
• SubOscillator.h, SubOscillator.cpp
• NoiseOscillator.h, NoiseOscillator.cpp
• Envelope.h, Envelope.cpp
• LFO.h, LFO.cpp
• Filter.h, Filter.cpp
• FilterBank.h, FilterBank.cpp
• SynthVoice.h, SynthVoice.cpp

Rules

• Use noexcept on every per-sample DSP path and cheap getter.
• Use std::array for fixed-size state and std::vector<float> for delay lines and table buffers.
• Size every buffer and delay line in prepare(), never in process or render.
• Clamp filter and envelope state so extreme settings cannot produce NaN or inf.
• Use juce::MathConstants<T>::pi and twoPi instead of raw pi literals.
• Use (size_t) casts when indexing containers with int loop variables.
• Pass global per-block state into voices as a const RenderContext&.
• Never allocate memory in the audio path.
• Keep oscillator phase when changing held-note parameters. LFO phase offsets are separate from the running phase.

IF-THEN

• Wavetables are prebuilt during Engine construction. Audio and GUI code read them without triggering generation.
• IF a parameter is read every block THEN snapshot it into a struct (OscParams, RenderContext) instead of reading the APVTS per sample.

Examples

// BAD: lazy table build reached from the render path allocates on the audio thread
const Wavetable& wt = library.getTable (wave);

// GOOD: build once in the Engine constructor, then only read const references
library.prebuild();                 // in the Engine constructor
const Wavetable& wt = library.getTable (wave);   // lookup, no allocation

// BAD: raw pi literal duplicated across files
const double step = 6.28318530717958647692 * freq / sr;

// GOOD: single source
const double step = juce::MathConstants<double>::twoPi * freq / sr;

This file overrides /AGENTS.md where they conflict.