From d90244c01ef4715b2600e28e229cab73c19b432c Mon Sep 17 00:00:00 2001
From: Philip Rosedale <philip@highfidelity.io>
Date: Tue, 25 Mar 2014 22:31:44 -0700
Subject: [PATCH] first pass, clipping audio meter

---
 interface/src/Application.cpp | 38 ++++++++++++++++++++++++++++++++++-
 interface/src/Audio.cpp       | 10 +++++++++
 interface/src/Audio.h         |  2 ++
 3 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/interface/src/Application.cpp b/interface/src/Application.cpp
index 13c05fa702..549d1f04e2 100644
--- a/interface/src/Application.cpp
+++ b/interface/src/Application.cpp
@@ -2494,7 +2494,7 @@ void Application::displayOverlay() {
                 renderCollisionOverlay(_glWidget->width(), _glWidget->height(), _audio.getCollisionSoundMagnitude());
         }
     }
-
+    
     if (Menu::getInstance()->isOptionChecked(MenuOption::Stats)) {
         _audio.renderMuteIcon(1, _glWidget->height() - 50);
         if (Menu::getInstance()->isOptionChecked(MenuOption::Oscilloscope)) {
@@ -2502,6 +2502,42 @@ void Application::displayOverlay() {
             _audioScope.render(25, oscilloscopeTop);
         }
     }
+    
+    const int AUDIO_METER_WIDTH = 300;
+    const int AUDIO_METER_INSET = 2;
+    const int AUDIO_METER_SCALE_WIDTH = AUDIO_METER_WIDTH - 2 * AUDIO_METER_INSET;
+    const int AUDIO_METER_HEIGHT = 8;
+    const int AUDIO_METER_Y = _glWidget->height() - 40;
+    const int AUDIO_METER_X = 25;
+    const float CLIPPING_INDICATOR_TIME = 1.0f;
+    float audioLevel = log10(_audio.getLastInputLoudness() + 1.0) / log10(32767.0) * (float)AUDIO_METER_SCALE_WIDTH;
+    bool isClipping = ((_audio.getTimeSinceLastClip() > 0.f) && (_audio.getTimeSinceLastClip() < CLIPPING_INDICATOR_TIME));
+
+    if (isClipping) {
+        glColor3f(1, 0, 0);
+    } else {
+        glColor3f(0, 0, 0);
+    }
+    glBegin(GL_QUADS);
+     //  Draw background Quad
+    glVertex2i(AUDIO_METER_X, AUDIO_METER_Y);
+    glVertex2i(AUDIO_METER_X + AUDIO_METER_WIDTH, AUDIO_METER_Y);
+    glVertex2i(AUDIO_METER_X + AUDIO_METER_WIDTH, AUDIO_METER_Y + AUDIO_METER_HEIGHT);
+    glVertex2i(AUDIO_METER_X, AUDIO_METER_Y + AUDIO_METER_HEIGHT);
+    
+    //   Draw Meter Quad
+    if (isClipping) {
+        glColor3f(1, 1, 1);
+    } else {
+        glColor3f(0, 1, 1);
+    }
+    // Draw Meter quad
+    glVertex2i(AUDIO_METER_X + AUDIO_METER_INSET, AUDIO_METER_Y + AUDIO_METER_INSET);
+    glVertex2i(AUDIO_METER_X + AUDIO_METER_INSET + audioLevel, AUDIO_METER_Y + AUDIO_METER_INSET);
+    glVertex2i(AUDIO_METER_X + AUDIO_METER_INSET + audioLevel, AUDIO_METER_Y + AUDIO_METER_HEIGHT - AUDIO_METER_INSET);
+    glVertex2i(AUDIO_METER_X + AUDIO_METER_INSET, AUDIO_METER_Y + AUDIO_METER_HEIGHT - AUDIO_METER_INSET);
+    
+    glEnd();
 
     if (Menu::getInstance()->isOptionChecked(MenuOption::HeadMouse)) {
         _myAvatar->renderHeadMouse();
diff --git a/interface/src/Audio.cpp b/interface/src/Audio.cpp
index 734b5345fb..92bbea3afe 100644
--- a/interface/src/Audio.cpp
+++ b/interface/src/Audio.cpp
@@ -60,6 +60,7 @@ Audio::Audio(Oscilloscope* scope, int16_t initialJitterBufferSamples, QObject* p
     _measuredJitter(0),
     _jitterBufferSamples(initialJitterBufferSamples),
     _lastInputLoudness(0),
+    _timeSinceLastClip(-1.0),
     _dcOffset(0),
     _noiseGateMeasuredFloor(0),
     _noiseGateSampleCounter(0),
@@ -469,13 +470,22 @@ void Audio::handleAudioInput() {
             const int NOISE_GATE_CLOSE_FRAME_DELAY = 5;
             const int NOISE_GATE_FRAMES_TO_AVERAGE = 5;
             const float DC_OFFSET_AVERAGING = 0.99f;
+            const float CLIPPING_THRESHOLD = 0.90f;
             
             float measuredDcOffset = 0.f;
             
+            //  Increment the time since the last clip
+            if (_timeSinceLastClip >= 0.0f) {
+                _timeSinceLastClip += (float) NETWORK_BUFFER_LENGTH_SAMPLES_PER_CHANNEL / (float) SAMPLE_RATE;
+            }
+            
             for (int i = 0; i < NETWORK_BUFFER_LENGTH_SAMPLES_PER_CHANNEL; i++) {
                 measuredDcOffset += monoAudioSamples[i];
                 monoAudioSamples[i] -= (int16_t) _dcOffset;
                 thisSample = fabsf(monoAudioSamples[i]);
+                if (thisSample > (32767.f * CLIPPING_THRESHOLD)) {
+                    _timeSinceLastClip = 0.0f;
+                }
                 loudness += thisSample;
                 //  Noise Reduction:  Count peaks above the average loudness
                 if (thisSample > (_noiseGateMeasuredFloor * NOISE_GATE_HEIGHT)) {
diff --git a/interface/src/Audio.h b/interface/src/Audio.h
index 7aa1ef5afe..2d79e82918 100644
--- a/interface/src/Audio.h
+++ b/interface/src/Audio.h
@@ -47,6 +47,7 @@ public:
     Audio(Oscilloscope* scope, int16_t initialJitterBufferSamples, QObject* parent = 0);
 
     float getLastInputLoudness() const { return glm::max(_lastInputLoudness - _noiseGateMeasuredFloor, 0.f); }
+    float getTimeSinceLastClip() const { return _timeSinceLastClip; }
     float getAudioAverageInputLoudness() const { return _lastInputLoudness; }
 
     void setNoiseGateEnabled(bool noiseGateEnabled) { _noiseGateEnabled = noiseGateEnabled; }
@@ -130,6 +131,7 @@ private:
     float _measuredJitter;
     int16_t _jitterBufferSamples;
     float _lastInputLoudness;
+    float _timeSinceLastClip;
     float _dcOffset;
     float _noiseGateMeasuredFloor;
     float* _noiseSampleFrames;