spring.h

#ifndef SPRING_H
#define SPRING_H

#include <physics_entity.h>
#include <memory>
#include <atomic>
struct Spring
{
    private:
        static std::atomic<GLint> next_id;

    public :
        GLint id; // unique id for this spring
        GLfloat k; // stiffness coefficent
        GLfloat l0; // rest length
        std::shared_ptr<PhysicsEntity> entity1_ptr;
        std::shared_ptr<PhysicsEntity> entity2_ptr;

    Spring();
    
    Spring(GLfloat k, GLfloat l0, std::shared_ptr<PhysicsEntity> entity1_ptr, std::shared_ptr<PhysicsEntity> entity2_ptr);
};
#endif