Dooho Yi
91f92c0e6c
migration from 'smp_v1p0' dev. for 'sampler' -> skip irrelavant note msg. and keep playing
79 lines
2.5 KiB
C++
79 lines
2.5 KiB
C++
/*
|
|
* Waveshaper for Teensy 3.X audio
|
|
*
|
|
* Copyright (c) 2017 Damien Clarke, http://damienclarke.me
|
|
*
|
|
* 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 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 <Arduino.h>
|
|
#include "effect_waveshaper.h"
|
|
|
|
AudioEffectWaveshaper::~AudioEffectWaveshaper()
|
|
{
|
|
if(this->waveshape) {
|
|
delete [] this->waveshape;
|
|
}
|
|
}
|
|
|
|
void AudioEffectWaveshaper::shape(float* waveshape, int length)
|
|
{
|
|
// length must be bigger than 1 and equal to a power of two + 1
|
|
// anything else means we don't continue
|
|
if(!waveshape || length < 2 || length > 32769 || ((length - 1) & (length - 2))) return;
|
|
|
|
if(this->waveshape) {
|
|
delete [] this->waveshape;
|
|
}
|
|
this->waveshape = new int16_t[length];
|
|
for(int i = 0; i < length; i++) {
|
|
this->waveshape[i] = 32767 * waveshape[i];
|
|
}
|
|
|
|
// set lerpshift to the number of bits to shift while interpolating
|
|
// to cover the entire waveshape over a uint16_t input range
|
|
int index = length - 1;
|
|
lerpshift = 16;
|
|
while (index >>= 1) --lerpshift;
|
|
}
|
|
|
|
void AudioEffectWaveshaper::update(void)
|
|
{
|
|
if(!waveshape) return;
|
|
|
|
audio_block_t *block;
|
|
block = receiveWritable();
|
|
if (!block) return;
|
|
|
|
uint16_t x, xa;
|
|
int16_t i, ya, yb;
|
|
for (i = 0; i < AUDIO_BLOCK_SAMPLES; i++) {
|
|
// bring int16_t data into uint16_t range
|
|
x = block->data[i] + 32768;
|
|
// lerp waveshape (from http://coranac.com/tonc/text/fixed.htm)
|
|
xa = x >> lerpshift;
|
|
ya = waveshape[xa];
|
|
yb = waveshape[xa + 1];
|
|
block->data[i] = ya + ((yb - ya) * (x - (xa << lerpshift)) >> lerpshift);
|
|
}
|
|
|
|
transmit(block);
|
|
release(block);
|
|
}
|