Diff: filter.h

Revision:

0:5a419ba2726d

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/filter.h	Tue Oct 28 12:19:22 2014 +0000
@@ -0,0 +1,89 @@
+/*
+Copyright 2013 Paul Soulsby www.soulsbysynths.com
+    This file is part of Atmegatron.
+
+    Atmegatron is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Atmegatron is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Atmegatron.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+//***15 Biquad filter algorithms***
+
+#ifndef __FILTER_H__
+#define __FILTER_H__
+
+
+//the filter types
+#define FILT_OFF 0
+#define FILT_LPF 1
+#define FILT_HPF 2
+#define FILT_BPF 3
+#define FILT_NOTCH 4
+#define FILT_PEAK10 5
+#define FILT_PEAK30 6
+#define FILT_PEAK100 7
+#define FILT_LS10 8
+#define FILT_LS30 9
+#define FILT_HS10 10
+#define FILT_HS30 11
+#define FILT_BUTLPF 12
+#define FILT_BUTHPF 13
+#define FILT_BESLPF 14
+#define FILT_BESHPF 15
+
+//These constants are used to define the MAXIMUM amount the env and lfo can effect the filter cutoff.
+//The default max (for both env and lfo) is: 
+//********multiplier = 4***********
+#define FILT_MAX 1.386294361119891f  //ln(multiplier)
+#define FILT_MULT 64                 //multipler used for calculating lookup table  (256 / multiplier)  
+#define FILT_BS 6UL                  //bitshift amount when multiplying fc by filt lfo amt.  log2(FILT_MULT)
+
+#define SQRT2 1.414213562373095f    //squareroot 2 - useful!
+#define PI  3.141592653589793f
+
+#define MINQ 0.5f                  //minimum value of Q (default = 0.5)
+#define MULTQ 0.076470588235294f   //multiplier to convert from filt_q(0-255) to real Q (0.5-20) = (20 - 0.5)/255;
+
+#define abs(a)  (a)>=0? (a) : -(a)
+
+
+void Filt_Let_Fc(byte newfc);
+byte Filt_Get_Fc(void);
+void Filt_Let_Q(byte newq);
+byte Filt_Get_Q(void);
+void Filt_Let_Type(byte newtype);
+byte Filt_Get_Type(void);
+void Filt_Let_GainAdj(boolean newadj);
+boolean Filt_Get_GainAdj(void);
+void Filt_CalcVals(void);
+void LPValCalculator(void);
+void HPValCalculator(void);
+void BPSkirtValCalculator(void);
+void NotchValCalculator(void);
+void PeakingEQValCalculator(void);
+void LowShelfValCalculator(void);
+void HighShelfValCalculator(void);
+void ButterworthLPCalculator(void);
+void ButterworthHPCalculator(void);
+void BesselLPCalculator(void);
+void BesselHPCalculator(void);
+void Filt_Process(void);
+float Biquad_process(float bi0);
+void Filt_Let_LFOAmt(byte newamt);
+byte Filt_Get_LFOAmt(void);
+byte Filt_Get_LFOGain(void);
+void Filt_Let_FenvAmt(byte newamt);
+byte Filt_Get_FenvAmt(void);
+byte Filt_Get_FenvGain(void);
+
+
+#endif // __FILTER_H__