Method dayCycle

source/game/StarSky.cpp:355–382

}

float Sky::dayCycle() const {
  // Always middle of the night in orbit or warp space.
  if (type() == SkyType::Orbital || type() == SkyType::Warp)
    return 3.0f;

  // This will misbehave badly if dayTransitionTime is greater than dayLength /
  // 2

  float transitionTime = m_settings.queryFloat("dayTransitionTime") / 2;
  float dayLength = Sky::dayLength();
  float timeOfDay = Sky::timeOfDay();

  // timeOfDay() is defined such that 0.0 is mid-dawn.  For convenience, shift
  // the time of day forwards such that 0.0 is the beginning of the morning.
  float shiftedTime = pfmod(timeOfDay + transitionTime / 2, dayLength);

  // There are 5 times here, beginning of the morning, end of the morning,
  // beginning of the evening, end of the evening, and then the beginning of
  // the morning again (wrapping around).
  Array<float, 5> transitionPositions = {
      0.0f, transitionTime, dayLength / 2, dayLength / 2 + transitionTime, dayLength};
  // The values here are mid-night, mid-day, mid-day, mid-night, mid-night.
  Array<float, 5> transitionValues = {-1.0f, 1.0f, 1.0f, 3.0f, 3.0f};

  return pfmod(parametricInterpolate2(
                   transitionPositions, transitionValues, shiftedTime, SinWeightOperator<float>(), BoundMode::Clamp),
      4.0f);
}

float Sky::skyAlpha() const {
  if (m_skyType != SkyType::Atmospheric) {