From a5fd304c9db6d6191a1ae2368bbe013f54c78aff Mon Sep 17 00:00:00 2001
From: skal <pascal.massimino@gmail.com>
Date: Wed, 28 Jan 2026 11:24:42 +0100
Subject: perf(synth): Optimize Hamming window generation

Moves the Hamming window initialization from synth_render to synth_init() to ensure it's generated only once, improving performance.
---
 src/audio/synth.cc | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

(limited to 'src/audio')

diff --git a/src/audio/synth.cc b/src/audio/synth.cc
index e4f6c75..b9af771 100644
--- a/src/audio/synth.cc
+++ b/src/audio/synth.cc
@@ -7,6 +7,7 @@
 #include "audio/window.h"
 #include <atomic>
 #include <math.h>
+#include <stdio.h> // For printf
 #include <string.h> // For memset
 
 struct Voice {
@@ -33,11 +34,14 @@ static struct {
 
 static Voice g_voices[MAX_VOICES];
 static volatile float g_current_output_peak = 0.0f; // Global peak for visualization
+static float g_hamming_window[WINDOW_SIZE]; // Static window for optimization
 
 void synth_init() {
   memset(&g_synth_data, 0, sizeof(g_synth_data));
   memset(g_voices, 0, sizeof(g_voices));
   g_current_output_peak = 0.0f;
+  // Initialize the Hamming window once
+  hamming_window_512(g_hamming_window);
 }
 
 void synth_shutdown() {
@@ -130,8 +134,9 @@ void synth_trigger_voice(int spectrogram_id, float volume, float pan) {
 }
 
 void synth_render(float *output_buffer, int num_frames) {
-  float window[WINDOW_SIZE];
-  hamming_window_512(window);
+  // Use the pre-calculated window
+  // float window[WINDOW_SIZE];
+  // hamming_window_512(window);
 
   // Faster decay for more responsive visuals
   g_current_output_peak *= 0.90f;
@@ -160,7 +165,7 @@ void synth_render(float *output_buffer, int num_frames) {
 
         float windowed_frame[DCT_SIZE];
         for (int j = 0; j < DCT_SIZE; ++j) {
-          windowed_frame[j] = spectral_frame[j] * window[j];
+          windowed_frame[j] = spectral_frame[j] * g_hamming_window[j]; // Use static window
         }
 
         idct_512(windowed_frame, v.time_domain_buffer);
@@ -196,4 +201,6 @@ int synth_get_active_voice_count() {
   return count;
 }
 
-float synth_get_output_peak() { return g_current_output_peak; }
\ No newline at end of file
+float synth_get_output_peak() {
+  return g_current_output_peak;
+}
\ No newline at end of file
-- 
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