nilsandClaude Opus 5.5
9d84dc6d15
MusicPulse reads 40-120 Hz and lights only on jumps of the bass, so held notes and bass lines stay dark. Settings gets "Pumpkin light follows the music" (Halloween only, off by default); off, the audio analyser never starts. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01LhzAVaUyqcw5PkGjz4mWW6
52 lines
2.4 KiB
Java
52 lines
2.4 KiB
Java
package com.evsuite.abrp;
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/**
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* How strongly the Halloween pumpkin's light answers the music at this moment, from 0 to 1, out of
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* the kick drum's band the audio analyser reports. What counts is the hit, not the loudness: only
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* a jump of the bass since the last reading lights it, measured against the biggest jumps of the
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* last seconds, so quiet and loud songs both flash, and a held bass note or a steady hum does not.
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* Jumps that are small against the bass's own level (a swelling note, noise) are ignored. It
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* flares at once and dies down within a beat, as a flame does. No reading or silence falls back to
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* 0, so without music the light stays as it is. Android-free and unit-tested.
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*/
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final class MusicPulse {
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/** Below this the bass counts as silence. */
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static final float SILENT = 0.005f;
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/** The kick drum's band, in Hz, that {@link MusicTap} reads. */
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static final float FROM_HZ = 40f, TO_HZ = 120f;
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private static final float FALL_S = 0.2f, AVERAGE_S = 2f, PEAK_S = 4f;
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/** A jump below this share of the recent biggest one lights nothing. */
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private static final float THRESHOLD = 0.2f;
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/** A jump has to be at least this share of the bass's average level to count at all. */
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private static final float LEVEL_SHARE = 0.5f;
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private float last, average, peakJump, pulse;
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/** One reading, {@code seconds} after the last; null when it failed. Returns the new pulse. */
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float update(Float bass, float seconds) {
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float target = 0f;
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if (bass == null || bass.isNaN() || bass < SILENT) {
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last = 0f;
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average = 0f;
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peakJump = 0f;
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} else {
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float jump = Math.max(0f, bass - last);
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last = bass;
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average = average == 0f ? bass : average + (bass - average) * share(seconds, AVERAGE_S);
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peakJump = Math.max(jump, peakJump - peakJump * share(seconds, PEAK_S));
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float reference = Math.max(peakJump, average * LEVEL_SHARE);
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if (reference > 0f) {
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target = Math.max(0f, Math.min(1f, (jump / reference - THRESHOLD) / (1f - THRESHOLD)));
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}
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}
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pulse = target > pulse ? target : pulse + (target - pulse) * share(seconds, FALL_S);
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if (pulse < 0.005f) pulse = 0f;
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return pulse;
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}
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private static float share(float seconds, float timeConstant) {
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return Math.min(1f, Math.max(0f, seconds) / timeConstant);
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}
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}
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