SpectrumEffect

Source: SpectrumEffect.h

SpectrumEffect

class SpectrumEffect

src/light/effects/SpectrumEffect.h:25

Inherits: EffectBase

Audio effect: a spectrum analyzer with asymmetric ballistics and falling peak dots.

Two behaviors are what make a meter read as an instrument rather than a bar chart. A bar rises fast enough to catch a transient and falls slowly enough to be readable. A dot then marks the highest recent level and drifts down, showing what has passed.

Prior art: the standard VU and PPM meter ballistics, and WLED's GEQ for the band mapping.

Public Attributes

uint8_t attack = 200 : How fast a bar rises toward a new level, where 255 is instant.

uint8_t release = 30 : How fast it falls back, which is deliberately slower.

uint8_t peakDecay = 2 : How fast the peak dot drifts down.

bool showPeaks = true : Draw the held peak above each bar.

bool colorByColumn = false : Color each bar by its column rather than by height.

Public Methods

virtual inline const char * tags() const override : Catalog tags: a showcase, and audio-reactive.

virtual inline Dim dimensions() const override : Writes the z=0 slice, which extrude fills through a volume.

virtual inline void defineControls() override : Publish the ballistics, the peak's decay and the coloring.

virtual inline void prepare() override : Size one follower and one peak per column.

virtual inline void tick() override : Follow each band with its own ballistics, then draw its bar and peak.

More info

The ballistics live in the toolbox

smoothFollow and peakHold are shared, so any effect wanting a meter gets the same feel. GEQEffect hand-rolls its own peak tracker into a buffer sized to the column count instead. [draw::bar] draws the columns too, so this effect owns no drawing loop. What remains is the band-to-column mapping and the choice of colors, which is its own.