From 125ef0e3e2abc949a498c1a43d2f2640f995fd59 Mon Sep 17 00:00:00 2001
From: Atlante45 <clement.brisset@gmail.com>
Date: Mon, 10 Nov 2014 15:12:40 -0800
Subject: [PATCH] make pulsate function into a cos

---
 interface/src/Audio.cpp | 33 +++++++++++++++++----------------
 interface/src/Audio.h   |  2 +-
 2 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/interface/src/Audio.cpp b/interface/src/Audio.cpp
index 7ff811b8aa..87f7163cd5 100644
--- a/interface/src/Audio.cpp
+++ b/interface/src/Audio.cpp
@@ -54,9 +54,6 @@ static const int APPROXIMATELY_30_SECONDS_OF_AUDIO_PACKETS = (int)(30.0f * 1000.
 
 // Mute icon configration
 static const int MUTE_ICON_SIZE = 24;
-static const float PULSE_MIN = 0.0f;
-static const float PULSE_MAX = 1.0f;
-static const float PULSE_STEP = 0.05f;
 
 static const int RECEIVED_AUDIO_STREAM_CAPACITY_FRAMES = 100;
 
@@ -102,7 +99,7 @@ Audio::Audio(QObject* parent) :
     _reverbOptions(&_scriptReverbOptions),
     _gverb(NULL),
     _iconColor(1.0f),
-    _iconPulseFactor(-1),
+    _iconPulseTimeReference(usecTimestampNow()),
     _processSpatialAudio(false),
     _spatialAudioStart(0),
     _spatialAudioFinish(0),
@@ -1397,33 +1394,37 @@ void Audio::renderToolBox(int x, int y, bool boxed) {
     if (!_muted) {
         glBindTexture(GL_TEXTURE_2D, _micTextureId);
         _iconColor = 1.0f;
-        _iconPulseFactor = -1;
     } else {
         glBindTexture(GL_TEXTURE_2D, _muteTextureId);
+        
         // Make muted icon pulsate
-        _iconColor += _iconPulseFactor * PULSE_STEP;
-        if (_iconColor >= PULSE_MAX) {
-            _iconColor = PULSE_MAX;
-            _iconPulseFactor = -1;
-        } else if (_iconColor <= PULSE_MIN) {
-            _iconColor = PULSE_MIN;
-            _iconPulseFactor = 1;
+        static const float PULSE_MIN = 0.4f;
+        static const float PULSE_MAX = 1.0f;
+        static const float PULSE_FREQUENCY = 1.0f; // in Hz
+        qint64 now = usecTimestampNow();
+        if (now - _iconPulseTimeReference > USECS_PER_SECOND) {
+            // Prevents t from getting too big, which would diminish glm::cos precision
+            _iconPulseTimeReference = now - ((now - _iconPulseTimeReference) % USECS_PER_SECOND);
         }
+        float t = (float)(now - _iconPulseTimeReference) / (float)USECS_PER_SECOND;
+        float pulseFactor = (glm::cos(t * PULSE_FREQUENCY * 2.0f * PI) + 1.0f) / 2.0f;
+        _iconColor = PULSE_MIN + (PULSE_MAX - PULSE_MIN) * pulseFactor;
+        
     }
 
     glColor3f(_iconColor, _iconColor, _iconColor);
     glBegin(GL_QUADS);
 
-    glTexCoord2f(1, 1);
+    glTexCoord2f(1.0f, 1.0f);
     glVertex2f(_iconBounds.left(), _iconBounds.top());
 
-    glTexCoord2f(0, 1);
+    glTexCoord2f(0.0f, 1.0f);
     glVertex2f(_iconBounds.right(), _iconBounds.top());
 
-    glTexCoord2f(0, 0);
+    glTexCoord2f(0.0f, 0.0f);
     glVertex2f(_iconBounds.right(), _iconBounds.bottom());
 
-    glTexCoord2f(1, 0);
+    glTexCoord2f(1.0f, 0.0f);
     glVertex2f(_iconBounds.left(), _iconBounds.bottom());
 
     glEnd();
diff --git a/interface/src/Audio.h b/interface/src/Audio.h
index ebdf620121..ecbef026c4 100644
--- a/interface/src/Audio.h
+++ b/interface/src/Audio.h
@@ -254,7 +254,7 @@ private:
     GLuint _boxTextureId;
     QRect _iconBounds;
     float _iconColor;
-    int _iconPulseFactor;
+    qint64 _iconPulseTimeReference;
     
     /// Audio callback in class context.
     inline void performIO(int16_t* inputLeft, int16_t* outputLeft, int16_t* outputRight);