sine.hpp

#pragma once
#include <ossia/dataflow/graph_node.hpp>
#include <ossia/dataflow/port.hpp>
#include <ossia/detail/math.hpp>
 
#include <boost/predef.h>
 
namespace ossia::nodes
{
struct sine final : public ossia::nonowning_graph_node
{
  ossia::value_inlet freq_in;
  ossia::audio_outlet audio_out;
 
  double m_cos = 1.;
  double m_sin = 0.;
 
public:
  double freq = 440.;
  double amplitude = 0.8;
  sine()
  {
    m_inlets.push_back(&freq_in);
    m_outlets.push_back(&audio_out);
  }
  void run(const ossia::token_request& t, ossia::exec_state_facade st) noexcept override
  {
    auto& vals = freq_in.target<ossia::value_port>()->get_data();
    if(!vals.empty())
    {
      freq = ossia::clamp(ossia::convert<float>(vals.back().value), 0.f, 20000.f);
    }
 
    ossia::audio_port& audio = *audio_out;
    const auto [tick_start, N] = st.timings(t);
 
    if(N > 0)
    {
      audio.set_channels(1);
      auto& c = audio.channel(0);
      c.resize(tick_start + N);
 
      // Uses the method in
      // https://github.com/mbrucher/AudioTK/blob/master/ATK/Tools/SinusGeneratorFilter.cpp
      const auto fs = st.sampleRate();
      auto frequ_cos = std::cos(ossia::two_pi * freq / fs);
      auto frequ_sin = std::sin(ossia::two_pi * freq / fs);
      for(int64_t i = tick_start; i < tick_start + N; i++)
      {
        auto new_cos = m_cos * frequ_cos - m_sin * frequ_sin;
        auto new_sin = m_cos * frequ_sin + m_sin * frequ_cos;
        auto norm = (new_cos * new_cos + new_sin * new_sin);
 
        m_cos = new_cos / norm;
        m_sin = new_sin / norm;
 
        c[i] = amplitude * m_sin;
      }
    }
  }
};
}