From a8f7ff7d8a24d0734c37aae943862aa75ca55644 Mon Sep 17 00:00:00 2001
From: Ken Cooke <ken@highfidelity.io>
Date: Wed, 26 Sep 2018 18:18:20 -0700
Subject: [PATCH] Add HRTF reset()

---
 libraries/audio/src/AudioHRTF.h | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/libraries/audio/src/AudioHRTF.h b/libraries/audio/src/AudioHRTF.h
index 8993842d6e..c50b4dfc0b 100644
--- a/libraries/audio/src/AudioHRTF.h
+++ b/libraries/audio/src/AudioHRTF.h
@@ -13,6 +13,7 @@
 #define hifi_AudioHRTF_h
 
 #include <stdint.h>
+#include <string.h>
 
 static const int HRTF_AZIMUTHS = 72;    // 360 / 5-degree steps
 static const int HRTF_TAPS = 64;        // minimum-phase FIR coefficients
@@ -56,6 +57,27 @@ public:
     void setGainAdjustment(float gain) { _gainAdjust = HRTF_GAIN * gain; };
     float getGainAdjustment() { return _gainAdjust; }
 
+    // clear internal state, but retain settings
+    void reset() {
+        // FIR history
+        memset(_firState, 0, sizeof(_firState));
+
+        // integer delay history
+        memset(_delayState, 0, sizeof(_delayState));
+
+        // biquad history
+        memset(_bqState, 0, sizeof(_bqState));
+
+        // parameter history
+        _azimuthState = 0.0f;
+        _distanceState = 0.0f;
+        _gainState = 0.0f;
+
+        // _gainAdjust is retained
+
+        _silentState = false;
+    }
+
 private:
     AudioHRTF(const AudioHRTF&) = delete;
     AudioHRTF& operator=(const AudioHRTF&) = delete;