text: // Copyright 2016 Olivier Gillet.
  //
  // Author: Olivier Gillet (ol.gillet@gmail.com)
  //
  // 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.
  // 
  // See http://creativecommons.org/licenses/MIT/ for more information.
  //
  // -----------------------------------------------------------------------------
  //
  // 808 and synthetic bass drum generators.
  
  #include "plaits/dsp/engine/bass_drum_engine.h"
  
  #include <algorithm>
  
  namespace plaits {
  
  using namespace std;
  using namespace stmlib;
  
  void BassDrumEngine::Init(BufferAllocator* allocator) {
    analog_bass_drum_.Init();
    synthetic_bass_drum_.Init();
    overdrive_.Init();
  }
  
  void BassDrumEngine::Reset() {
    
  }
  
  void BassDrumEngine::Render(
      const EngineParameters& parameters,
      float* out,
      float* aux,
      size_t size,
      bool* already_enveloped) {
    const float f0 = NoteToFrequency(parameters.note);
    
    const float attack_fm_amount = min(parameters.harmonics * 4.0f, 1.0f);
    const float self_fm_amount = max(min(parameters.harmonics * 4.0f - 1.0f, 1.0f), 0.0f);
    const float drive = max(parameters.harmonics * 2.0f - 1.0f, 0.0f) * \
        max(1.0f - 16.0f * f0, 0.0f);
    
    const bool sustain = parameters.trigger & TRIGGER_UNPATCHED;
    
    analog_bass_drum_.Render(
        sustain,
        parameters.trigger & TRIGGER_RISING_EDGE,
        parameters.accent,
        f0,
        parameters.timbre,
        parameters.morph,
        attack_fm_amount,
        self_fm_amount,
        out,
        size);
  
    overdrive_.Process(
        0.5f + 0.5f * drive,
        out,
        size);
  
    synthetic_bass_drum_.Render(
        sustain,
        parameters.trigger & TRIGGER_RISING_EDGE,
        parameters.accent,
        f0,
        parameters.timbre,
        parameters.morph,
        sustain
            ? parameters.harmonics
            : 0.4f - 0.25f * parameters.morph * parameters.morph,
        min(parameters.harmonics * 2.0f, 1.0f),
        max(parameters.harmonics * 2.0f - 1.0f, 0.0f),
        aux,
        size);
  }
  
  }  // namespace plaits
  