From afec66867b5b331c98a0fd1827992850cb74892f Mon Sep 17 00:00:00 2001
From: aj_genius <aj_genius>
Date: Sun, 7 Mar 2004 23:07:07 +0000
Subject: [PATCH] Rework Transpose Function to use a natural log to calculate
 proper note. This removes the For loop effectively cutting CPU usage in half.
 Currently the actual behaviour apears to be exactly like that of the old
 however it is possible that those values that go higher then the old table
 method(more then 6 octaves up for eg.) will behave slightly different. Thanks
 go to Kenny Graunke for working most of this out.

---
 .../Plugins/TransposePlugin/TransposePlugin.C | 70 ++++++++++++++-----
 .../Plugins/TransposePlugin/TransposePlugin.h | 29 ++++----
 2 files changed, 67 insertions(+), 32 deletions(-)

diff --git a/SpiralSound/Plugins/TransposePlugin/TransposePlugin.C b/SpiralSound/Plugins/TransposePlugin/TransposePlugin.C
index 9904038..5ea6680 100644
--- a/SpiralSound/Plugins/TransposePlugin/TransposePlugin.C
+++ b/SpiralSound/Plugins/TransposePlugin/TransposePlugin.C
@@ -47,7 +47,8 @@ string SpiralPlugin_GetGroupName() {
 
 TransposePlugin::TransposePlugin () :
 m_Amount(0),
-m_Out(0.0)
+m_Out(0.0),
+m_BufferInitialized(false)
 {
     m_PluginInfo.Name = "Transpose";
     m_PluginInfo.Width = 80;
@@ -72,24 +73,55 @@ SpiralGUIType *TransposePlugin::CreateGUI() {
 }
 
 void TransposePlugin::Execute () {
-     int Match [2];
-     for (int n=0; n<m_HostInfo->BUFSIZE; n++) {
-         Match[0]=0;
-         Match[1]=0;
-         for (int i=0; i<2 && InputExists(i); i++) {
-             float Freq, Dif, MinDif = 30000;
-             Freq = GetInputPitch (i, n);
-             for (int c=0; c<131; c++) {
-                 Dif = fabs (NoteTable[c] - Freq);
-                 if (Dif > MinDif) break;
-                 MinDif=Dif;
-                 Match[i]=c;
-             }
-         }
-         if (! InputExists (1)) Match[1] = m_Amount;
-         m_Out = NoteTable [(Match[0] + Match[1]) % 132];
-         SetOutputPitch (0, n, m_Out);
-     }
+	float base=110, transpose=m_Amount;
+	float alpha = 17.312340490667;
+		
+	for (int n=0; n<m_HostInfo->BUFSIZE; n++) 
+	{
+		float input0 = GetInputPitch(0, n);
+		float input1  = GetInputPitch(1, n);
+		
+		if (input0 > 0)
+		{
+			// input's half steps from base of 110 = round(alpha*logf(GetInputPitch(0, n)/110));
+			// cv's half steps from base of 110 = round(alpha*logf(GetInputPitch(1, n)/110));
+
+			if ((!m_BufferInitialized)  || (input0 != m_Buffer[0][0]) || (input1 != m_Buffer[1][0]))
+			{
+				if ((m_BufferInitialized) && (input0 == m_Buffer[0][0]))
+				{
+					base = m_Buffer[0][1];
+				}
+				else if (input0 != base)
+				{
+					base = round(alpha*logf(input0/110));
+				}
+				m_Buffer[0][0] = input0;
+				m_Buffer[0][1] = base;
+
+				if ((m_BufferInitialized) && (input1 == m_Buffer[1][0]))
+				{
+					transpose = m_Buffer[1][1];
+				}
+				else if (InputExists(1)) 
+				{
+					transpose = (input1 > 0)?round(alpha*logf(input1/110)):0;
+				}
+
+				m_Buffer[1][0] = input1;
+				m_Buffer[1][1] = transpose;
+
+				m_BufferInitialized = true;		
+			
+				m_Out = 110*exp2f((base + transpose)/12);
+			}	
+		}
+		else
+		{
+			m_Out = 8.176;	
+		}	
+		SetOutputPitch (0, n, m_Out);
+	}
 }
 
 void TransposePlugin::StreamOut (ostream &s) {
diff --git a/SpiralSound/Plugins/TransposePlugin/TransposePlugin.h b/SpiralSound/Plugins/TransposePlugin/TransposePlugin.h
index 049f417..4695cb1 100644
--- a/SpiralSound/Plugins/TransposePlugin/TransposePlugin.h
+++ b/SpiralSound/Plugins/TransposePlugin/TransposePlugin.h
@@ -23,19 +23,22 @@
 #define TransposePLUGIN
 
 class TransposePlugin : public SpiralPlugin {
-   public:
-      TransposePlugin();
-      virtual ~TransposePlugin ();
-      virtual PluginInfo& Initialise (const HostInfo *Host);
-      virtual SpiralGUIType* CreateGUI ();
-      virtual void Execute ();
-      //virtual void ExecuteCommands ();
-      virtual void StreamOut (std::ostream &s);
-      virtual void StreamIn (std::istream &s);
-      int GetAmount () { return m_Amount; }
-   private:
-      int m_Amount;
-      float m_Out;
+public:
+	TransposePlugin();
+	virtual ~TransposePlugin ();
+	virtual PluginInfo& Initialise (const HostInfo *Host);
+	virtual SpiralGUIType* CreateGUI ();
+	virtual void Execute ();
+	//virtual void ExecuteCommands ();
+	virtual void StreamOut (std::ostream &s);
+	virtual void StreamIn (std::istream &s);
+	int GetAmount () { return m_Amount; }
+private:
+	int m_Amount;
+	float m_Out;
+
+      	float m_Buffer[2][2];
+	bool m_BufferInitialized;
 };
 
 #endif