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141 lines
3.7 KiB
141 lines
3.7 KiB
/* Modulated delay line
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Inspired by;
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http://musicdsp.org/showArchiveComment.php?ArchiveID=154
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But details changed for Teensy Audio.
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No feedback within the class, just done externally
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so we can add filters and stuff to the loop.
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Delay time is a signal input to the block, and functions from 0 to 0x7fff,
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scaling the delay time accordingly.
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*/
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/*
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Copyright (c) 2016, Byron Jacquot, SparkFun Electronics
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SparkFun code, firmware, and software is released under
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the MIT License(http://opensource.org/licenses/MIT).
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice, development funding notice, and this permission
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notice shall be included in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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*/
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#include "mod-delay-gain.h"
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#define INTERPOLATE (1)
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void AudioEffectModDelayGain::update(void)
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{
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audio_block_t *audioblock, *controlblockDelay, *controlblockGain;
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int16_t *data, *end, *ctrlDelay, *ctrlGain;
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int32_t extract_index;
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int32_t temp;
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#ifdef INTERPOLATE
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int32_t interp_delta;
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int32_t next;
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int16_t calc;
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#endif
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if (buffer_length == 0)
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return;
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audioblock = receiveWritable(0);
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if (!audioblock) return;
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controlblockDelay = receiveReadOnly(1);
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if (!controlblockDelay) {
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release(audioblock);
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return;
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}
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controlblockGain = receiveReadOnly(2);
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if (!controlblockGain) {
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release(audioblock);
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release(controlblockDelay);
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return;
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}
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data = audioblock->data;
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end = audioblock->data + AUDIO_BLOCK_SAMPLES;
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ctrlDelay = controlblockDelay->data;
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ctrlGain = controlblockGain->data;
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do
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{
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delayline_p[insert_index] = *data;
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insert_index++;
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if (insert_index >= buffer_length)
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{
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insert_index = 0;
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}
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#ifdef INTERPOLATE
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//
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interp_delta = (buffer_length * (*ctrlDelay));
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delay_delta = interp_delta >> 15; // MSB's for delay len
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interp_delta &= 0x7fff; //LSBs for interp distance
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#else
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delay_delta = (buffer_length * (*ctrlDelay)) >> 15;
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#endif
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extract_index = insert_index - delay_delta;
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if (extract_index < 0)
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{
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extract_index = buffer_length + extract_index;
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}
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#ifdef INTERPOLATE
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// Use the fractional part to interpolate between samples
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next = extract_index + 1;
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if (next >= buffer_length)
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{
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next = 0;
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}
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calc = delayline_p[next] - delayline_p[extract_index];
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calc = (calc * interp_delta ) >> 15;
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calc += delayline_p[extract_index];
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//*data = calc;
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temp = (int32_t)calc * (*ctrlGain);
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*data = temp >> 15;
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#else
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//data = delayline_p[extract_index];
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temp = (int32_t)delayline_p[extract_index] * (*ctrlGain);
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*data = temp >> 15;
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#endif
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data++;
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ctrlDelay++;
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ctrlGain++;
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} while (data < end);
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transmit(audioblock);
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release(audioblock);
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release(controlblockDelay);
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release(controlblockGain);
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}
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