svf.cc
// Copyright 2013 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.
//
// -----------------------------------------------------------------------------
//
// SVF used for modeling the bridged T-networks.

#include "streams/svf.h"

#include "stmlib/utils/dsp.h"

#include "streams/resources.h"

namespace streams {

using namespace stmlib;

void Svf::Init() {
  lp_ = 0;
  bp_ = 0;
  frequency_ = 33 << 7;
  resonance_ = 16384;
  dirty_ = true;
}

void Svf::Process(int32_t in) {
  if (dirty_) {
    f_ = Interpolate824(lut_svf_cutoff, frequency_ << 17);
    damp_ = Interpolate824(lut_svf_damp, resonance_ << 17);
    dirty_ = false;
  }
  int32_t f = f_;
  int32_t damp = damp_;
  int32_t notch = in - (bp_ * damp >> 15);
  lp_ += f * bp_ >> 15;
  CLIP(lp_)
  hp_ = notch - lp_;
  bp_ += f * hp_ >> 15;
  CLIP(bp_)
  CLIP(hp_)
}


}  // namespace streams