From 5205bdb94eb970adb629f0e1b1b7d3fd994837a4 Mon Sep 17 00:00:00 2001
From: James Harlow <jharlow@twitter.com>
Date: Thu, 1 Aug 2013 18:50:36 +0100
Subject: [PATCH] Have arary elements sit on the pentatonic scale

---
 src/SortSound.cpp | 19 ++++++++++++++++++-
 src/WMain.cpp     |  8 ++++----
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/src/SortSound.cpp b/src/SortSound.cpp
index 672abb783..60e3ef106 100644
--- a/src/SortSound.cpp
+++ b/src/SortSound.cpp
@@ -218,7 +218,24 @@ void SoundAccess(size_t i)
 /// function mapping array index (normalized to [0,1]) to frequency
 static double arrayindex_to_frequency(double aindex)
 {
-    return 120 + 1200 * (aindex*aindex);
+    double low_c = 65.406;
+    double low_d = 73.416;
+    double low_e = 82.407;
+    double low_g = 97.999;
+    double low_a = 110;
+
+    int index = aindex * 40;
+    float tone;
+    switch (index % 5) {
+        case 0: tone = low_c; break;
+        case 1: tone = low_d; break;
+        case 2: tone = low_e; break;
+        case 3: tone = low_g; break;
+        case 4: tone = low_a; break;
+    }
+    return tone * ((index / 5) + 1);
+
+    // return 120 + 1200 * (aindex*aindex);
 }
 
 /// reset internal sound data (called from main thread)
diff --git a/src/WMain.cpp b/src/WMain.cpp
index 961c182b3..d86ea705c 100644
--- a/src/WMain.cpp
+++ b/src/WMain.cpp
@@ -37,7 +37,7 @@ WMain::WMain(wxWindow* parent)
     infoTextctrl->Hide();
 
     // program icon
-    {    
+    {
         #include "sos.xpm"
 	SetIcon( wxIcon(sos) );
     }
@@ -57,8 +57,8 @@ WMain::WMain(wxWindow* parent)
     sortview->FillInputlist(inputTypeChoice);
     sortview->FillData(0, 100);
     inputTypeChoice->SetSelection(0);
-    arraySizeSlider->SetValue(100);
-    SetArraySize(100);
+    arraySizeSlider->SetValue(40);
+    SetArraySize(40);
 
     // insert quicksort pivot rules into wxChoice
     for (const wxChar** pt = g_quicksort_pivot_text; *pt; ++pt)
@@ -79,7 +79,7 @@ WMain::WMain(wxWindow* parent)
     // Set the audio format
     sdlaudiospec.freq = 44100;
     sdlaudiospec.format = AUDIO_S16SYS;
-    sdlaudiospec.channels = 1;    	/* 1 = mono, 2 = stereo */
+    sdlaudiospec.channels = 2;    	/* 1 = mono, 2 = stereo */
     sdlaudiospec.samples = 4096;  	/* Good low-latency value for callback */
     sdlaudiospec.callback = SoundCallback;
     sdlaudiospec.userdata = sortview;