From 241f31dbb905e9da2550ebf47ebc31fc7feb113e Mon Sep 17 00:00:00 2001
From: aj_genius <aj_genius>
Date: Sun, 7 Mar 2004 22:58:29 +0000
Subject: [PATCH] Add Denormal CPU Spike Workaround via a minimal value
 threshhold, this adds a minimal sound to the filters if it falls below the
 range the spike usually happens(for me). This prevents huge CPU overhead when
 using multiple Formants and Filter Plugins on slow lines.

---
 .../Plugins/FilterPlugin/FilterPlugin.C       | 116 ++++++++++--------
 .../FormantFilterPlugin/FormantFilterPlugin.C |  36 +++++-
 2 files changed, 95 insertions(+), 57 deletions(-)

diff --git a/SpiralSound/Plugins/FilterPlugin/FilterPlugin.C b/SpiralSound/Plugins/FilterPlugin/FilterPlugin.C
index ad1835b..df360ea 100644
--- a/SpiralSound/Plugins/FilterPlugin/FilterPlugin.C
+++ b/SpiralSound/Plugins/FilterPlugin/FilterPlugin.C
@@ -113,58 +113,70 @@ SpiralGUIType *FilterPlugin::CreateGUI()
 void FilterPlugin::Execute()
 {
 	float Cutoff;
-    float Resonance;
+	float Resonance;
+	float out, in;
 
-    if (fc<0) return;
+	if (fc<0) return;
    
-    for (int n=0; n<m_HostInfo->BUFSIZE; n++)
+	for (int n=0; n<m_HostInfo->BUFSIZE; n++)
 	{
-  	 	coef = iir.coef + 1;     /* Skip k, or gain */ 
-   	 	k=0.25;
+
+		//reset memory if disconnected, and skip out (prevents CPU spike)
+		if (! InputExists(0)) 
+		{	
+			out = 0;	 
+		}
+		else
+		{
+			in = GetInput(0,n);
+			
+			// work around denormal calculation CPU spikes where in --> 0
+			if ((in >= 0) && (in < 0.000000001))
+				in += 0.000000001;
+			else
+				if ((in <= 0) && (in > -0.000000001))
+					in -= 0.000000001;
+
+			coef = iir.coef + 1;     /* Skip k, or gain */ 
+			k=0.25;
 	
-	 	Cutoff = fc + (GetInput(1,n) * 1000);
-	 	Resonance = Q + GetInput(2,n);  
+			Cutoff = fc + (GetInput(1,n) * 1000);
+			Resonance = Q + GetInput(2,n);  
 	 	
-	 	Cutoff/=2;
+			Cutoff/=2;
 	 
-	 	if (Resonance>MAX_RES) Resonance=MAX_RES; 
-	 	if (Cutoff>MAX_CUTOFF) Cutoff=MAX_CUTOFF; 
-	 	if (Resonance<MIN_RES) Resonance=MIN_RES; 
-	 	if (Cutoff<MIN_CUTOFF) Cutoff=MIN_CUTOFF; 
+			if (Resonance>MAX_RES) Resonance=MAX_RES; 
+			if (Cutoff>MAX_CUTOFF) Cutoff=MAX_CUTOFF; 
+			if (Resonance<MIN_RES) Resonance=MIN_RES; 
+			if (Cutoff<MIN_CUTOFF) Cutoff=MIN_CUTOFF; 
 	 
-	 	if (n%FILTERGRAN==0)
-	 	{
-	 		for (nInd = 0; nInd < iir.length; nInd++) 
-    		{
-			    a2 = ProtoCoef[nInd].a2; 
+			if (n%FILTERGRAN==0)
+			{
+				for (nInd = 0; nInd < iir.length; nInd++) 
+				{
+					a2 = ProtoCoef[nInd].a2; 
 		
-	            a0 = ProtoCoef[nInd].a0; 
-	            a1 = ProtoCoef[nInd].a1; 
+					a0 = ProtoCoef[nInd].a0; 
+					a1 = ProtoCoef[nInd].a1; 
 	          
-	            b0 = ProtoCoef[nInd].b0; 
-	            b1 = ProtoCoef[nInd].b1 / Resonance;      
-	            b2 = ProtoCoef[nInd].b2; 	
-	            szxform(&a0, &a1, &a2, &b0, &b1, &b2, Cutoff*(Cutoff/1000.0f), fs, &k, coef); 
-   		        coef += 4;                       
+					b0 = ProtoCoef[nInd].b0; 
+					b1 = ProtoCoef[nInd].b1 / Resonance;      
+					b2 = ProtoCoef[nInd].b2; 	
+					szxform(&a0, &a1, &a2, &b0, &b1, &b2, Cutoff*(Cutoff/1000.0f), fs, &k, coef); 
+					coef += 4;                       
 
-	        	iir.coef[0] = k; 
+					iir.coef[0] = k; 
 				
-				m_LastQ=Q;
-				m_LastFC=fc;			
-			}
-		 }		  
+					m_LastQ=Q;
+					m_LastFC=fc;			
+				}
+			}		  
 		 		 
-		 float in = GetInput(0,n);
-		 //if (in!=0)
-		 //{
-		 	SetOutput(0,n,iir_filter(in/0.5f,&iir));	 
-		 //}
-		 //else
-		 //{
-		 //	m_Output[0]->Set(n,0);
-		 //}
-	}
-		
+		 	out = iir_filter(in/0.5f,&iir);
+		}	 
+
+	 	SetOutput(0,n,out);
+	}		
 }
 	
 void FilterPlugin::StreamOut(ostream &s)
@@ -182,16 +194,16 @@ void FilterPlugin::StreamIn(istream &s)
 void FilterPlugin::SetupCoeffs()
 {
 	ProtoCoef[0].a0 = 1.0; 
-    ProtoCoef[0].a1 = 0; 
-    ProtoCoef[0].a2 = 0; 
-    ProtoCoef[0].b0 = 1.0; 
-    ProtoCoef[0].b1 = 0.765367; 
-    ProtoCoef[0].b2 = 1.0; 
-
-    ProtoCoef[1].a0 = 1.0; 
-    ProtoCoef[1].a1 = 0; 
-    ProtoCoef[1].a2 = 0; 
-    ProtoCoef[1].b0 = 1.0; 
-    ProtoCoef[1].b1 = 1.847759; 
-    ProtoCoef[1].b2 = 1.0; 
+	ProtoCoef[0].a1 = 0; 
+	ProtoCoef[0].a2 = 0; 
+	ProtoCoef[0].b0 = 1.0; 
+	ProtoCoef[0].b1 = 0.765367; 
+	ProtoCoef[0].b2 = 1.0; 
+
+	ProtoCoef[1].a0 = 1.0; 
+	ProtoCoef[1].a1 = 0; 
+	ProtoCoef[1].a2 = 0; 
+	ProtoCoef[1].b0 = 1.0; 
+	ProtoCoef[1].b1 = 1.847759; 
+	ProtoCoef[1].b2 = 1.0; 
 } 
diff --git a/SpiralSound/Plugins/FormantFilterPlugin/FormantFilterPlugin.C b/SpiralSound/Plugins/FormantFilterPlugin/FormantFilterPlugin.C
index eee48d3..4492052 100644
--- a/SpiralSound/Plugins/FormantFilterPlugin/FormantFilterPlugin.C
+++ b/SpiralSound/Plugins/FormantFilterPlugin/FormantFilterPlugin.C
@@ -140,6 +140,13 @@ void FormantFilterPlugin::Execute()
 		{
 			in = GetInput(0,n);
 			
+			// work around denormal calculation CPU spikes where in --> 0
+			if ((in >= 0) && (in < 0.000000001))
+				in += 0.000000001;
+			else
+				if ((in <= 0) && (in > -0.000000001))
+					in -= 0.000000001;
+  
 			for (int v=0; v<5; v++)
 			{
 				res= (float) (coeff[v][0]*(in*0.1f) +
@@ -174,11 +181,30 @@ void FormantFilterPlugin::Execute()
 			}
 		
 			// mix between vowel sounds
-			if (m_Vowel<1) out=Linear(0,1,m_Vowel,o[1],o[0]); 
-			else if (m_Vowel>1 && m_Vowel<2) out=Linear(0,1,m_Vowel-1.0f,o[2],o[1]);
-			else if (m_Vowel>2 && m_Vowel<3) out=Linear(0,1,m_Vowel-2.0f,o[3],o[2]);
-			else if (m_Vowel>3 && m_Vowel<4) out=Linear(0,1,m_Vowel-3.0f,o[4],o[3]);
-			else if (m_Vowel==4) out=o[4];
+			if (m_Vowel<1) 
+			{
+				out=Linear(0,1,m_Vowel,o[1],o[0]); 
+			}	
+			else 
+				if (m_Vowel>1 && m_Vowel<2) 
+				{
+					out=Linear(0,1,m_Vowel-1.0f,o[2],o[1]);
+				}	
+			else 
+				if (m_Vowel>2 && m_Vowel<3) 
+				{
+					out=Linear(0,1,m_Vowel-2.0f,o[3],o[2]);
+				}	
+			else 
+				if (m_Vowel>3 && m_Vowel<4) 
+				{
+					out=Linear(0,1,m_Vowel-3.0f,o[4],o[3]);
+				}	
+			else 
+				if (m_Vowel==4) 
+				{
+					out=o[4];
+				}	
 		}		
 		SetOutput(0,n,out);	 
 	}