99 lines
2.8 KiB
C++
Executable file
99 lines
2.8 KiB
C++
Executable file
/* Audio Library for Teensy 3.X
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* Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com
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*
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* Development of this audio library was funded by PJRC.COM, LLC by sales of
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* Teensy and Audio Adaptor boards. Please support PJRC's efforts to develop
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* open source software by purchasing Teensy or other PJRC products.
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*
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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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*
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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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*
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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 <Arduino.h>
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#include "effect_fade.h"
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#include "utility/dspinst.h"
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extern "C" {
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extern const int16_t fader_table[257];
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};
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void AudioEffectFade::update(void)
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{
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audio_block_t *block;
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uint32_t i, pos, inc, index, scale;
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int32_t val1, val2, val, sample;
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uint8_t dir;
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pos = position;
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if (pos == 0) {
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// output is silent
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block = receiveReadOnly();
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if (block) release(block);
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return;
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} else if (pos == 0xFFFFFFFF) {
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// output is 100%
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block = receiveReadOnly();
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if (!block) return;
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transmit(block);
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release(block);
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return;
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}
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block = receiveWritable();
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if (!block) return;
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inc = rate;
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dir = direction;
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for (i=0; i < AUDIO_BLOCK_SAMPLES; i++) {
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index = pos >> 24;
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val1 = fader_table[index];
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val2 = fader_table[index+1];
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scale = (pos >> 8) & 0xFFFF;
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val2 *= scale;
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val1 *= 0x10000 - scale;
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val = (val1 + val2) >> 16;
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sample = block->data[i];
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sample = (sample * val) >> 15;
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block->data[i] = sample;
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if (dir > 0) {
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// output is increasing
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if (inc < 0xFFFFFFFF - pos) pos += inc;
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else pos = 0xFFFFFFFF;
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} else {
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// output is decreasing
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if (inc < pos) pos -= inc;
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else pos = 0;
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}
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}
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position = pos;
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transmit(block);
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release(block);
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}
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void AudioEffectFade::fadeBegin(uint32_t newrate, uint8_t dir)
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{
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__disable_irq();
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uint32_t pos = position;
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if (pos == 0) position = 1;
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else if (pos == 0xFFFFFFFF) position = 0xFFFFFFFE;
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rate = newrate;
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direction = dir;
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__enable_irq();
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}
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