SpeedFrequencyLookup.h

#ifndef SpeedFrequencyLookup_h__
#define SpeedFrequencyLookup_h__
 
#include <algorithm>
#include <cstddef>
#include <vector>
 
namespace Ship
{
 
struct AxisBracket
{
   std::size_t lo;         
   double      fraction;   
};
 
inline AxisBracket FindAxisBracket(const std::vector<double>& axis, double value)
{
   const auto upper = std::upper_bound(axis.begin(), axis.end(), value);   // first node above the value
   std::size_t hi = static_cast<std::size_t>(upper - axis.begin());
   hi = std::clamp<std::size_t>(hi, 1, axis.size() - 1);
   const std::size_t lo = hi - 1;
   return {lo, (value - axis[lo]) / (axis[hi] - axis[lo])};
}
 
template<class T>
T BlendSpeedFrequency(const T& q00, const T& q01, const T& q10, const T& q11, double speedFraction, double frequencyFraction)
{
   return q00 * ((1.0 - speedFraction) * (1.0 - frequencyFraction)) + q01 * ((1.0 - speedFraction) * frequencyFraction) +
          q10 * (speedFraction * (1.0 - frequencyFraction)) + q11 * (speedFraction * frequencyFraction);
}
 
}   // namespace Ship
 
#endif   // SpeedFrequencyLookup_h__