From 164c471fb9488f7013be0bcaef7f790020aee916 Mon Sep 17 00:00:00 2001 From: skal Date: Wed, 28 Jan 2026 01:58:43 +0100 Subject: fix(synth): Implement peak meter with decay for smooth visuals The graphics appeared static because the audio peak value was transient, only lasting for a single audio buffer. The main graphics loop, running much faster, would mostly read a zero value. This fix implements a simple peak meter with an exponential decay. The peak value now rises instantly to the maximum sample value but fades out smoothly over several frames, providing a persistent and smooth value for the visualizer. --- src/audio/synth.cc | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/src/audio/synth.cc b/src/audio/synth.cc index 98c12d9..77a0d05 100644 --- a/src/audio/synth.cc +++ b/src/audio/synth.cc @@ -26,7 +26,7 @@ static struct { } g_synth_data; static Voice g_voices[MAX_VOICES]; -static float g_current_output_peak = 0.0f; // Global peak for visualization +static volatile float g_current_output_peak = 0.0f; // Global peak for visualization void synth_init() { memset(&g_synth_data, 0, sizeof(g_synth_data)); @@ -125,7 +125,8 @@ void synth_render(float *output_buffer, int num_frames) { float window[WINDOW_SIZE]; hamming_window_512(window); - float current_peak_in_frame = 0.0f; + // Apply a decay to the peak value for smooth visuals + g_current_output_peak *= 0.95f; for (int i = 0; i < num_frames; ++i) { float left_sample = 0.0f; @@ -170,10 +171,10 @@ void synth_render(float *output_buffer, int num_frames) { output_buffer[i * 2] = left_sample; output_buffer[i * 2 + 1] = right_sample; - current_peak_in_frame = - fmaxf(current_peak_in_frame, fmaxf(fabsf(left_sample), fabsf(right_sample))); + // Update the peak with the new max (attack) + g_current_output_peak = + fmaxf(g_current_output_peak, fmaxf(fabsf(left_sample), fabsf(right_sample))); } - g_current_output_peak = current_peak_in_frame; } int synth_get_active_voice_count() { -- cgit v1.2.3