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.

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; 
 } 

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);	 
 	}