ENGINE=gigaverb · src/engine/gigaverb/ · built via the gen~ / gen-dsp method

The stock Max/MSP gen~ reverb example (Tom Erbe's gigaverb), exported to C++ and run as an engine through gen-dsp - the first engine built this way, and the worked example for the method. The mechanism (genlib isolation, the arena-bound allocator, the generic GenEngine<W> wrapper, the codegen) is documented in engine-types/gen.md; this page is the gigaverb specifics.

Implementation, the file map, and dev notes live in docs/dev/gigaverb-impl.md.

Control map

_Generated from docs/diagrams/controls/gigaverb.json via make diagrams._

set_param arrives normalized 0..1 and is linear-mapped into each gen~ param's declared [min,max] (from manifest.json). The map uses only ParamIds the platform delivers to a single-deck engine via set_param() - the six plain panel knobs, plus two modifier layers for the two extra params:

This map is declared in src/engine/gigaverb/gigaverb.json - the knobs block (control name -> gen~ param name), the gen~ analogue of a Faust engine's manifest. The generator resolves it (control -> ParamId, param name -> index, validated against the export) and emits the index_of() switch in gigaverb_engine.h; edit the manifest, not the generated .h, then re-run the generator. ParamId::ModSpeed is intentionally absent - the MODFREQ knob routes to set_mod_speed(), which a gen engine does not receive (see the method doc for the full reachability rules and the knob grammar in README.md).

Build / flash / regenerate

make -j8 ENGINE=gigaverb           # build; the link prints SRAM_EXEC usage
make ENGINE=gigaverb program-dfu   # flash (device in DFU mode first)
make engine-gigaverb               # one-shot: clean + build + flash
make gen-engine MANIFEST=src/engine/gigaverb/gigaverb.json            # regenerate (gen-dsp + glue) from the manifest
make gen-engine MANIFEST=src/engine/gigaverb/gigaverb.json NOGEN=1 FORCE=1   # glue only (no gen-dsp), after editing the knob map