// CSE 143 
// Homework 5 
// http://www.cs.washington.edu/education/courses/143/00su/homework/ 
// 30 Jul 2000, Ken Yasuhara

// class Projectile 
//
// MovingObject whose motion is affected by gravity (constant 
// downward acceleration)


#ifndef _PROJECTILE_H_
#define _PROJECTILE_H_

#include "movingobject.h"


// in y direction only (obviously); in pixels per frame update^2
const double ACCEL_GRAVITY = -0.5;


class Projectile : public MovingObject {
public:
  Projectile(const double newX, const double newY, 
             const double newVx, const double newVy) 
    : MovingObject(newX, newY, newVx, newVy) {}

  virtual void getNextPosition(double &nextX, double &nextY);

  virtual void paint(GP142Display &display) const = 0;

protected:
  // effectively disallow public use of default constructor
  Projectile() {}
};


#endif // _PROJECTILE_H_