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FP-Audio-lib/filter_moog.cpp

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/* Audio Library for Teensy 3.X
* Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com
*
* Development of this audio library was funded by PJRC.COM, LLC by sales of
* Teensy and Audio Adaptor boards. Please support PJRC's efforts to develop
* open source software by purchasing Teensy or other PJRC products.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice, development funding notice, and this permission
* notice shall be included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "filter_moog.h"
#if defined(KINETISK)
void AudioFilterMoog::update_fixed(const int16_t *in,int16_t *lp)
{
const float MAX_INT = 32678.0;
for (int i = 0; i < AUDIO_BLOCK_SAMPLES; i++) {
float cs = (float)in[i];
cs=cs/MAX_INT;
cs = tanhf(cs * driv);
y_a = y_a + g * (tanhf(cs - q * ((y_d_1 + y_d)/2) - tanhf(y_a)));
y_b = y_b + g * (tanhf(y_a) - tanhf(y_b));
y_c = y_c + g * (tanhf(y_b) - tanhf(y_c));
y_d_1 = y_d;
y_d = y_d + g * (tanhf(y_c) - tanhf(y_d));
cs=y_d*MAX_INT;
lp[i] = (int16_t)cs;
}
}
void AudioFilterMoog::update_variable(const int16_t *in,const int16_t *ctl, int16_t *lp)
{
const float MAX_INT = 32678.0;
int over=1;
float cs = (float)ctl[0];
cs=cs/MAX_INT;
float nf=basef*(exp2f(cs*oct));
// Serial.println(nf);
frequency(nf,false);
update_fixed(in,lp) ;
}
void AudioFilterMoog::update(void)
{
audio_block_t *input_block=NULL, *control_block=NULL;
audio_block_t *lowpass_block=NULL;
input_block = receiveReadOnly(0);
control_block = receiveReadOnly(1);
if (!input_block) {
if (control_block) release(control_block);
return;
}
lowpass_block = allocate();
if (!lowpass_block) {
release(input_block);
if (control_block) release(control_block);
return;
}
if (control_block) {
update_variable(input_block->data, control_block->data, lowpass_block->data);
release(control_block);
} else {
update_fixed(input_block->data, lowpass_block->data);
}
release(input_block);
transmit(lowpass_block, 0);
release(lowpass_block);
return;
}
#elif defined(KINETISL)
void AudioFilterMoog::update(void)
{
audio_block_t *block;
block = receiveReadOnly(0);
if (block) release(block);
block = receiveReadOnly(1);
if (block) release(block);
}
#endif