Separate BiQuad, OnePole filters as their own classes in BasicFilters.h

Might do the same for other filter types, but these two are kind of "basic building blocks" for many effects so it makes most sense for them

include/BasicFilters.h

@@ -47,8 +47,85 @@
 
 //#include <iostream>
 //#include <cstdlib>
+template<ch_cnt_t CHANNELS> class BasicFilters;
+template<ch_cnt_t CHANNELS>
+class BiQuad
+{
+	MM_OPERATORS
+public:
+	BiQuad() 
+	{
+		clearHistory();
+	}
+	virtual ~BiQuad() {}
+	
+	inline void setCoeffs( float a1, float a2, float b0, float b1, float b2 )
+	{
+		m_a1 = a1;
+		m_a2 = a2;
+		m_b0 = b0;
+		m_b1 = b1;
+		m_b2 = b2;
+	}
+	inline void clearHistory()
+	{
+		for( int i = 0; i < CHANNELS; ++i )
+		{
+			m_z1[i] = 0.0f;
+			m_z2[i] = 0.0f;
+		}
+	}
+	inline float update( float in, ch_cnt_t ch )
+	{
+		// biquad filter in transposed form
+		const float out = m_z1[ch] + m_b0 * in;
+		m_z1[ch] = m_b1 * in + m_z2[ch] - m_a1 * out;
+		m_z2[ch] = m_b2 * in - m_a2 * out;
+		return out;
+	}
+private:
+	float m_a1, m_a2, m_b0, m_b1, m_b2;
+	float m_z1 [CHANNELS], m_z2 [CHANNELS];
+	
+	friend class BasicFilters<CHANNELS>;
+};
+typedef BiQuad<2> StereoBiQuad;
 
-template<ch_cnt_t CHANNELS/* = DEFAULT_CHANNELS*/>
+template<ch_cnt_t CHANNELS>
+class OnePole
+{
+	MM_OPERATORS
+public:
+	OnePole()
+	{
+		m_a0 = 1.0; 
+		m_b1 = 0.0;
+		for( int i = 0; i < CHANNELS; ++i )
+		{
+			m_z1[i] = 0.0;
+		}
+	}
+	virtual ~OnePole() {}
+	
+	inline void setCoeffs( float a0, float b1 )
+	{
+		m_a0 = a0;
+		m_b1 = b1;
+	}
+	
+	inline float update( float s, ch_cnt_t ch )
+	{
+		if( s < 1.0e-10f && m_z1[ch] < 1.0e-10f ) return 0.0f;
+		return m_z1[ch] = s * m_a0 + m_z1[ch] * m_b1;
+	}
+	
+private:
+	float m_a0, m_b1; 
+	float m_z1 [CHANNELS];
+};
+typedef OnePole<2> StereoOnePole;
+
+template<ch_cnt_t CHANNELS>
 class BasicFilters
 {
 	MM_OPERATORS
@@ -130,12 +207,12 @@ public:
 
 	inline void clearHistory()
 	{
+		// reset in/out history for biquads
+		m_biQuad.clearHistory();
+
 		// reset in/out history
 		for( ch_cnt_t _chnl = 0; _chnl < CHANNELS; ++_chnl )
 		{
-			// reset in/out history for simple filters
-			m_z1[_chnl] = m_z2[_chnl] = 0.0f;
-
 			// reset in/out history for moog-filter
 			m_y1[_chnl] = m_y2[_chnl] = m_y3[_chnl] = m_y4[_chnl] =
 					m_oldx[_chnl] = m_oldy1[_chnl] =
@@ -534,10 +611,7 @@ public:
 			}
 
 			default:
-				// biquad filter in transposed form
-				out = m_z1[_chnl] + m_b0a0 * _in0;
-				m_z1[_chnl] = m_b1a0 * _in0 + m_z2[_chnl] - m_a1a0 * out;
-				m_z2[_chnl] = m_b2a0 * _in0 - m_a2a0 * out;
+				out = m_biQuad.update( _in0, _chnl );
 				break;
 		}
 
@@ -665,59 +739,61 @@ public:
 
 		const float a0 = 1.0f / ( 1.0f + alpha );
 
-		m_a1a0 = -2.0f * tcos * a0;
-		m_a2a0 = ( 1.0f - alpha ) * a0;
+		const float a1 = -2.0f * tcos * a0;
+		const float a2 = ( 1.0f - alpha ) * a0;
 
 		switch( m_type )
 		{
 			case LowPass:
-				m_b1a0 = ( 1.0f - tcos ) * a0;
-				m_b0a0 = m_b1a0 * 0.5f;
-				m_b2a0 = m_b0a0;//((1.0f-tcos)/2.0f)*a0;
+			{
+				const float b1 = ( 1.0f - tcos ) * a0;
+				const float b0 = b1 * 0.5f;
+				m_biQuad.setCoeffs( a1, a2, b0, b1, b0 );
 				break;
+			}
 			case HiPass:
-				m_b1a0 = ( -1.0f - tcos ) * a0;
-				m_b0a0 = m_b1a0 * -0.5f;
-				m_b2a0 = m_b0a0;//((1.0f+tcos)/2.0f)*a0;
+			{
+				const float b1 = ( -1.0f - tcos ) * a0;
+				const float b0 = b1 * -0.5f;
+				m_biQuad.setCoeffs( a1, a2, b0, b1, b0 );
 				break;
+			}
 			case BandPass_CSG:
-				m_b1a0 = 0.0f;
-				m_b0a0 = tsin * a0;
-				m_b2a0 = -m_b0a0;
+			{
+				const float b0 = tsin * a0;
+				m_biQuad.setCoeffs( a1, a2, b0, 0.0f, -b0 );
 				break;
+			}
 			case BandPass_CZPG:
-				m_b1a0 = 0.0f;
-				m_b0a0 = alpha * a0;
-				m_b2a0 = -m_b0a0;
+			{
+				const float b0 = alpha * a0;
+				m_biQuad.setCoeffs( a1, a2, b0, 0.0f, -b0 );
 				break;
+			}
 			case Notch:
-				m_b1a0 = m_a1a0;
-				m_b0a0 = a0;
-				m_b2a0 = a0;
+			{
+				m_biQuad.setCoeffs( a1, a2, a0, a1, a0 );
 				break;
+			}
 			case AllPass:
-				m_b1a0 = m_a1a0;
-				m_b0a0 = m_a2a0;
-				m_b2a0 = 1.0f;//(1.0f+alpha)*a0;
+			{
+				m_biQuad.setCoeffs( a1, a2, a2, a1, 1.0f );
 				break;
+			}
 			default:
 				break;
 		}
 
 		if( m_doubleFilter )
 		{
-			m_subFilter->m_b0a0 = m_b0a0;
-			m_subFilter->m_b1a0 = m_b1a0;
-			m_subFilter->m_b2a0 = m_b2a0;
-			m_subFilter->m_a1a0 = m_a1a0;
-			m_subFilter->m_a2a0 = m_a2a0;
+			m_subFilter->m_biQuad.setCoeffs( m_biQuad.m_a1, m_biQuad.m_a2, m_biQuad.m_b0, m_biQuad.m_b1, m_biQuad.m_b2 );
 		}
 	}
 
 
 private:
-	// filter coeffs
-	float m_b0a0, m_b1a0, m_b2a0, m_a1a0, m_a2a0;
+	// biquad filter
+	BiQuad<CHANNELS> m_biQuad;
 
 	// coeffs for moog-filter
 	float m_r, m_p, m_k;
@@ -733,9 +809,6 @@ private:
 
 	typedef sample_t frame[CHANNELS];
 
-	// in/out history
-	frame m_z1, m_z2;
-
 	// in/out history for moog-filter
 	frame m_y1, m_y2, m_y3, m_y4, m_oldx, m_oldy1, m_oldy2, m_oldy3;
 	// additional one for Tripole filter