Monorepo for Aesthetic.Computer
aesthetic.computer
fix: sample playback — restore pointer swap, don't kill voices on load
The previous fix (kill all voices + memcpy under lock) prevented
crashes but also prevented playback — every loadData call killed
active voices and held the lock too long for the audio callback.
Restore the back-buffer swap approach: write to sample_buf_back
without lock, then swap pointers under a brief lock. The audio
callback's trylock skips at most one 5ms period during the swap.
No voices are killed, playback continues uninterrupted.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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+9
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fedac/native/src/audio.c
+9
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fedac/native/src/audio.c
···
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}
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void audio_sample_load_data(ACAudio *audio, const float *data, int len, unsigned int rate) {
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-
if (!audio || !data || len <= 0 || !audio->sample_buf) return;
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if (!audio || !data || len <= 0 || !audio->sample_buf_back) return;
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if (len > audio->sample_max_len) len = audio->sample_max_len;
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// Kill all active sample voices first — prevents reading during write
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+
// Write to back buffer (only JS thread writes here — safe without lock)
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memcpy(audio->sample_buf_back, data, len * sizeof(float));
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if (len < audio->sample_max_len)
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memset(audio->sample_buf_back + len, 0, (audio->sample_max_len - len) * sizeof(float));
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// Swap pointers under lock — audio callback checks sample_loading flag
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pthread_mutex_lock(&audio->lock);
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for (int i = 0; i < AUDIO_MAX_SAMPLE_VOICES; i++)
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audio->sample_voices[i].active = 0;
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audio->sample_len = 0; // prevent audio callback from reading
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__sync_synchronize();
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// Now safe to write — no readers
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memcpy(audio->sample_buf, data, len * sizeof(float));
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if (len < audio->sample_max_len)
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memset(audio->sample_buf + len, 0, (audio->sample_max_len - len) * sizeof(float));
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float *tmp = audio->sample_buf;
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audio->sample_buf = audio->sample_buf_back;
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audio->sample_buf_back = tmp;
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audio->sample_len = len;
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if (rate > 0) audio->sample_rate = rate;
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__sync_synchronize();