PulpEffect #

Category: validation Type: Effect Path: examples/pulp-effect/

Summary #

A biquad filter effect with frequency, resonance, filter type (lowpass/highpass/bandpass), dry/wet mix, and bypass parameters. Validates diverse parameter types and more complex DSP than PulpGain across the three plugin formats.

What It Demonstrates #

Multiple parameter types: continuous (frequency, resonance, mix), stepped enum (filter type), boolean (bypass)
Wide-range frequency parameter (20 Hz to 20 kHz)
Biquad filter DSP with coefficient computation for lowpass, highpass, and bandpass modes
Dry/wet mix blending
Per-channel filter state management (supports up to 8 channels)
The release() lifecycle method for clearing DSP state
Parameter diversity validation across VST3, AU, and CLAP adapters

Supported Formats #

Format	Supported
VST3	Yes
AU v2	Yes
CLAP	Yes
Standalone	No

Supported Platforms #

Platform	Supported
macOS	Yes
Windows	Build stubs present, not yet validated
Linux	Build stubs present, not yet validated

Key Files #

File	Purpose
`pulp_effect.hpp`	Processor with biquad filter, coefficient computation, and mix parameter
`vst3_entry.cpp`	VST3 format entry point
`au_v2_entry.cpp`	Audio Unit v2 entry point
`clap_entry.cpp`	CLAP format entry point
`test_pulp_effect.cpp`	Unit tests for filter processing and state serialization
`Info.plist.au`	AU bundle metadata
`CMakeLists.txt`	Build configuration using `pulp_add_plugin()`

Parameters #

ID	Name	Unit	Range	Default
1	Frequency	Hz	20 to 20000	1000
2	Resonance	(Q)	0.1 to 10	0.707
3	Type	(stepped)	0 to 2	0 (lowpass)
4	Mix	%	0 to 100	100
5	Bypass	(toggle)	0 to 1	0

Known Limitations #

Filter coefficients are recalculated per block rather than per sample. Fast frequency sweeps may produce audible artifacts.
No standalone target is configured for this example.

PulpGain -- simpler effect with fewer parameters
PulpCompressor -- another effect example with sidechain and multi-bus support