From d9caf566dee3a477da19f305fa5a2ebf79f6cf56 Mon Sep 17 00:00:00 2001
From: Stephen Birarda <commit@birarda.com>
Date: Thu, 24 Jan 2013 13:08:26 -0800
Subject: [PATCH] render audio sources, vary amplitude depending on distance

---
 Source/audio.cpp | 33 ++++++++++++++++++++++++++++-----
 Source/audio.h   |  9 ++++++++-
 Source/main.cpp  |  9 ++++++++-
 3 files changed, 44 insertions(+), 7 deletions(-)

diff --git a/Source/audio.cpp b/Source/audio.cpp
index 308a59e160..a00b149284 100644
--- a/Source/audio.cpp
+++ b/Source/audio.cpp
@@ -48,9 +48,7 @@ int audioCallback (const void *inputBuffer,
     int16_t *outputLeft = ((int16_t **) outputBuffer)[0];
     int16_t *outputRight = ((int16_t **) outputBuffer)[1];
     
-    float yawRatio = data->linkedHead != NULL
-        ? data->linkedHead->getYaw() / 90.0
-        : 0;
+    float yawRatio = 0;
     
     int numSamplesDelay = abs(floor(yawRatio * PHASE_DELAY_AT_90));
     
@@ -81,6 +79,17 @@ int audioCallback (const void *inputBuffer,
     memcpy(trailingBuffer, data->delayBuffer + (PHASE_DELAY_AT_90 - numSamplesDelay), offsetBytes);
     memcpy(trailingBuffer + numSamplesDelay, samplesToQueue, BUFFER_LENGTH_BYTES - offsetBytes);
     
+    glm::vec3 headPos = data->linkedHead->getPos();
+    glm::vec3 sourcePos = data->sources[0].position;
+    
+    float distance = sqrtf(powf(-headPos[0] - sourcePos[0], 2) + powf(-headPos[2] - sourcePos[2], 2));
+    float amplitudeRatio = powf(0.5, cbrtf(distance));
+    
+    for (int i = 0; i < BUFFER_LENGTH_BYTES / sizeof(int16_t); i++) {
+        leadingBuffer[i] *= amplitudeRatio;
+        trailingBuffer[i] *= amplitudeRatio;
+    }
+    
     if (wrapAroundSamples > 0) {
         delete[] samplesToQueue;
     }
@@ -100,7 +109,8 @@ Use Audio::getError() to retrieve the error code.
  */
 bool Audio::init()
 {
-    return Audio::init(NULL);
+    Head deadHead = Head();
+    return Audio::init(&deadHead);
 }
 
 bool Audio::init(Head* mainHead)
@@ -138,6 +148,20 @@ error:
     return false;
 }
 
+void Audio::sourceSetup()
+{
+    // render gl objects on screen for our three sources
+    // assume that glMatrixPush() has been called and we are at 0,0,0
+    glColor3f(1, 0, 0);
+    
+    AudioSource source1 = AudioSource();
+    source1.position = glm::vec3(3, 0, -1);
+    data->sources[0] = source1;
+    
+    glTranslatef(source1.position[0], source1.position[1], source1.position[2]);
+    glutSolidCube(0.5);
+}
+
 void Audio::readFile()
 {
     FILE *soundFile = fopen("love.raw", "r");
@@ -150,7 +174,6 @@ void Audio::readFile()
     data->fileBuffer = new int16_t[data->fileSamples];
     std::fread(data->fileBuffer, sizeof(int16_t), data->fileSamples, soundFile);
     
-    
     std::fclose(soundFile);
 }
 
diff --git a/Source/audio.h b/Source/audio.h
index ed4052c0b5..a97e7ff970 100644
--- a/Source/audio.h
+++ b/Source/audio.h
@@ -16,12 +16,19 @@
 #define BUFFER_LENGTH_BYTES 1024
 #define PHASE_DELAY_AT_90 20
 
+struct AudioSource {
+    glm::vec3 position;
+    int16_t *audioData;
+};
+
 class Audio {
 public:
     // initializes audio I/O
     static bool init();
     static bool init(Head* mainHead);
     
+    static void sourceSetup();
+    
     // terminates audio I/O
     static bool terminate(); 
 private:
@@ -34,11 +41,11 @@ private:
         int fileSamples;
         
         // length in bytes of audio buffer
-        
         int16_t *delayBuffer;
         int16_t *fileBuffer;
         
         Head* linkedHead;
+        AudioSource sources[3];
     
         AudioData() {
             samplePointer = 0;
diff --git a/Source/main.cpp b/Source/main.cpp
index d43ff20fbf..31c954e3e3 100644
--- a/Source/main.cpp
+++ b/Source/main.cpp
@@ -103,7 +103,7 @@ ParticleSystem balls(0,
                      );
 
 
-Cloud cloud(50000,                             //  Particles
+Cloud cloud(0,                             //  Particles
             box,                                //  Bounding Box
             false                              //  Wrap
             );
@@ -600,6 +600,13 @@ void display(void)
         //  Render the world box 
         if (!display_head && stats_on) render_world_box();
     
+        // render audio sources and start them
+        if (audio_on) {
+            glPushMatrix();
+            Audio::sourceSetup();
+            glPopMatrix();
+        }
+    
         //glm::vec3 test(0.5, 0.5, 0.5); 
         //render_vector(&test);