ossia_value_interpolate.cpp

#include <ossia/network/value/value.hpp>
#include <ossia/editor/curve/curve_segment/easing.hpp>
#include <iostream>
#include <functional>

struct value_interpolator
{
  double progress;
  std::function<double(double start, double end, double progress)> easing;

  // the cases that make sense
  ossia::value operator()(float start, float end) const noexcept {
    return easing(start, end, progress);
  }
  ossia::value operator()(int start, int end) const noexcept {
    return easing(start, end, progress);
  }
  ossia::value operator()(int start, float end) const noexcept {
    return easing(start, end, progress);
  }
  ossia::value operator()(float start, int end) const noexcept {
    return easing(start, end, progress);
  }
  ossia::value operator()(ossia::vec2f start, ossia::vec2f end) const noexcept {
    // I guess ?
    return ossia::vec2f{
      (float)easing(start[0], end[0], progress),
      (float)easing(start[1], end[1], progress)
    };
  }

  // the ones that don't (yet), e.g. (std::string, bool), (vec2f, vec3f) & stuff...
  template<typename T1, typename T2>
  ossia::value operator()(const T1& start, const T2& end) const noexcept {
    // most likely this is between [0; 1]
    if(progress < 0.5)
      return start;
    else
      return end;
  }
};

ossia::value interpolate_a_value(ossia::value start, ossia::value end, double progress)
{
  if(!start.valid())
    return {};
  if(!end.valid())
    return {};

  auto easing_func = [] (double start, double end, double ratio) {
    // for instance with a specific easing function, maybe the user will want to choose that.
    // see <ossia/editor/curve/curve_segment/easing.hpp> for the available ones..
    return ossia::easing::ease{}(start, end, ossia::easing::quadraticInOut{}(ratio));
  };
  return ossia::apply(value_interpolator{progress, easing_func}, start, end);
}


int main()
{
  std::cerr << interpolate_a_value(ossia::value{0.}, ossia::value{10.}, 0.1) << std::endl;
  std::cerr << interpolate_a_value(ossia::value{-100.0}, ossia::value{127}, 0.9) << std::endl;
  std::cerr << interpolate_a_value(ossia::value{"foo"}, ossia::value{"bar"}, 0.1) << std::endl;
  std::cerr << interpolate_a_value(ossia::value{"foo"}, ossia::value{"bar"}, 0.9) << std::endl;
}