new audio gain/mute object

libraries/audio/src/AudioGain.h

@@ -0,0 +1,75 @@
+//
+//  AudioGain.h
+//  hifi
+//
+//  Created by Craig Hansen-Sturm on 9/1/14.
+//  Copyright 2014 High Fidelity, Inc.
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+
+#ifndef hifi_AudioGain_h
+#define hifi_AudioGain_h
+
+class AudioGain
+{
+    float32_t _gain;
+    bool _mute;
+    
+public:
+    AudioGain() {
+        initialize();
+    }
+    
+    ~AudioGain() {
+        finalize();
+    }
+    
+    void initialize() {
+        setParameters(1.0f,0.0f);
+    }
+    
+    void finalize() {
+    }
+    
+    void reset() {
+        initialize();
+    }
+    
+    void setParameters(const float gain, const float mute) {
+        _gain = std::min(std::max(gain, 0.0f), 1.0f);
+        _mute = mute != 0.0f;
+        
+    }
+    
+    void getParameters(float& gain, float& mute) {
+        gain = _gain;
+        mute = _mute ? 1.0f : 0.0f;
+    }
+    
+    void render(AudioBufferFloat32& frameBuffer) {
+        if (_mute) {
+            frameBuffer.zeroFrames();
+            return;
+        } 
+        
+        float32_t** samples = frameBuffer.getFrameData();
+        for (uint16_t j = 0; j < frameBuffer.getChannelCount(); ++j) {
+            for (uint16_t i = 0; i < frameBuffer.getFrameCount(); i += 8) {
+                samples[j][i + 0] *= _gain;
+                samples[j][i + 1] *= _gain;
+                samples[j][i + 2] *= _gain;
+                samples[j][i + 3] *= _gain;
+                samples[j][i + 4] *= _gain;
+                samples[j][i + 5] *= _gain;
+                samples[j][i + 6] *= _gain;
+                samples[j][i + 7] *= _gain;
+            }
+        }
+    }
+};
+
+#endif // AudioGain_h
+
+