LinearFunction.hh

// Copyright QED Software 2023.
 
#ifndef GRAIL_LINEAR_FUNCTION_H
#define GRAIL_LINEAR_FUNCTION_H
 
#include "Curve.hh"
 
namespace grail
{
namespace evaluator
{
 template <typename ContextType>
 class LinearFunction final : public Curve<ContextType>
 {
 public:
 LinearFunction(std::shared_ptr<Evaluator<ContextType>> childEvaluator,
 float slope,
 float intercept)
 : Curve<ContextType>{childEvaluator}, slope{slope}, intercept{intercept}
 {
 }
 
 LinearFunction(std::shared_ptr<Evaluator<ContextType>> childEvaluator,
 std::pair<float, float> firstPoint,
 std::pair<float, float> secondPoint)
 : Curve<ContextType>{childEvaluator}
 {
 assert(firstPoint.first != secondPoint.first);
 if(firstPoint.second == secondPoint.second)
 {
 slope = 0.0f;
 intercept = firstPoint.second;
 }
 else
 {
 if(firstPoint.first > secondPoint.first)
 {
 float x = firstPoint.first;
 float y = firstPoint.second;
 firstPoint.first = secondPoint.first;
 firstPoint.second = secondPoint.second;
 secondPoint.first = x;
 secondPoint.second = y;
 }
 slope = (secondPoint.second - firstPoint.second) / (secondPoint.first - firstPoint.first);
 intercept = firstPoint.second - (slope * firstPoint.first);
 }
 }
 
 virtual float Sample(float argument) const override final
 {
 return slope * argument + intercept;
 }
 
 float GetSlope() const { return slope; }
 float GetIntercept() const { return intercept; }
 
 virtual data::EvaluatorType GetEvaluatorType() const override final { return data::EvaluatorType::CURVE_LINEAR; }
 
 private:
 float slope = 0.0f;
 float intercept = 0.0f;
 };
}
}
 
#endif // GRAIL_LINEAR_FUNCTION_H