synth_simple_drum.h

/* Audio Library for Teensy 3.X
 * Copyright (c) 2016, Byron Jacquot, SparkFun Electronics
 *
 * 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.
 */

#pragma once

#ifndef _SYNTH_SIMPLE_DRUM_H_
#define _SYNTH_SIMPLE_DRUM_H_
#include "AudioStream.h"
#include "utility/dspinst.h"

class AudioSynthSimpleDrum : public AudioStream
{
public:

  AudioSynthSimpleDrum() : AudioStream(1, inputQueueArray) 
  {
    length(600);
    frequency(60);
    pitchMod(0x200);
    wav_amplitude1 = 0x7fff;
    wav_amplitude2 = 0;
  }
  void noteOn();

  void frequency(float freq)
  {
    if(freq < 0.0)
      freq = 0;
    else if(freq > (AUDIO_SAMPLE_RATE_EXACT/2))
      freq = AUDIO_SAMPLE_RATE_EXACT/2;

    wav_increment = (freq * (0x7fffffffLL/AUDIO_SAMPLE_RATE_EXACT)) + 0.5;
  }

  void length(int32_t milliseconds)
  {
    if(milliseconds < 0)
      return;
    if(milliseconds > 5000)
      milliseconds = 5000;

    int32_t len_samples = milliseconds*(AUDIO_SAMPLE_RATE_EXACT/1000.0);

    env_decrement = (0x7fff0000/len_samples);
  };

  void secondMix(float level);
  void pitchMod(float depth);

  using AudioStream::release;
  virtual void update(void);

private:
  audio_block_t *inputQueueArray[1];

  // Envelope params
  int32_t env_lin_current; // present value of linear slope.
  int32_t env_decrement;   // how each sample deviates from previous.

  // Waveform params
  uint32_t wav_phasor;      
  uint32_t wav_phasor2;     
  
  int16_t wav_amplitude1;
  int16_t wav_amplitude2;
  
  uint32_t wav_increment;
  int32_t  wav_pitch_mod;
};

#endif