LinearFunction.hh

#ifndef GRAIL_LINEAR_FUNCTION_H
#define GRAIL_LINEAR_FUNCTION_H
 
#include "Curve.hh"
 
namespace grail
{
    namespace curves
    {
        template <typename ContextType>
        class LinearFunction final : public Curve<ContextType>
        {
        public:
            LinearFunction(std::shared_ptr<utility::Evaluator<ContextType>> childEvaluator,
                           float slope,
                           float intercept)
                : Curve<ContextType>{childEvaluator}, slope{slope}, intercept{intercept}
            {
            }
 
            LinearFunction(std::shared_ptr<utility::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 EvaluatorType GetEvaluatorType() const override final { return EvaluatorType::CURVE_LINEAR; }
 
        private:
            float slope = 0.0f;
            float intercept = 0.0f;
        };
    }
}
 
#endif // GRAIL_LINEAR_FUNCTION_H