1 files changed, 31 insertions, 0 deletions
diff --git a/src/main.cc b/src/main.cc
index 9f61f07..3d05822 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -101,6 +101,37 @@ int main(int argc, char** argv) {
   int beat_count = 0;
 
   auto update_game_logic = [&](double t) {
+    // Variable tempo test: Accelerate and decelerate based on physical time
+    // Phase 1 (0-10s): Steady at 1.0x
+    // Phase 2 (10-15s): Accelerate from 1.0x to 2.0x
+    // Phase 3 (15-20s): Reset to 1.0x (with denser patterns in track)
+    // Phase 4 (20-25s): Decelerate from 1.0x to 0.5x
+    // Phase 5 (25s+): Reset to 1.0x (back to normal)
+    const float prev_tempo = g_tempo_scale;
+    if (t < 10.0) {
+      g_tempo_scale = 1.0f;  // Phase 1: Steady
+    } else if (t < 15.0) {
+      // Phase 2: Linear acceleration
+      const float progress = (float)(t - 10.0) / 5.0f;
+      g_tempo_scale = 1.0f + progress * 1.0f;  // 1.0 → 2.0
+    } else if (t < 20.0) {
+      g_tempo_scale = 1.0f;  // Phase 3: Reset to normal
+    } else if (t < 25.0) {
+      // Phase 4: Linear deceleration
+      const float progress = (float)(t - 20.0) / 5.0f;
+      g_tempo_scale = 1.0f - progress * 0.5f;  // 1.0 → 0.5
+    } else {
+      g_tempo_scale = 1.0f;  // Phase 5: Reset to normal
+    }
+
+#if !defined(STRIP_ALL)
+    // Debug output when tempo changes significantly
+    if (fabsf(g_tempo_scale - prev_tempo) > 0.05f) {
+      printf("[Tempo] t=%.2fs, tempo=%.3fx, music_time=%.3fs\n", (float)t,
+             g_tempo_scale, g_music_time);
+    }
+#endif
+
     // Calculate delta time and advance music time at scaled rate
     const float dt = (float)(t - g_last_physical_time);
     g_last_physical_time = t;