#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <malloc.h>

#ifdef WIN32
#include <fstream.h>
#else
#include <fstream.h>
#include <stream.h>
#endif

class Point {
  public:
  double x,y,z;
};

class Ray {
  public:
  Point p,v;
};

class Cylinder {
  public:
  Point centre;
  double radius,height;
};

class Camera {
  public:
  double nearZ;
  double leftX,rightX;
  double bottomY,topY;
  int width,height;
};

class Pixel {
  public:
  int x,y;
};

Ray   *make_ray(Camera& cam, Pixel& pix);
Point *ray_cylinder_intersect(Ray *ray, Cylinder &cyl);

Ray     *ray;
Cylinder cyl;
Camera   cam;
Pixel    *pixels;
int nPixels;

void readData(char *camFile, char *cylFile, char *pixFile) {
  ifstream inCam;
  ifstream inCyl;
  ifstream inPix;

  inCam.open(camFile);
  inCam >> cam.nearZ >> cam.leftX >> cam.rightX >> cam.bottomY >> cam.topY
	>> cam.width >> cam.height;
  inCam.close();

  inCyl.open(cylFile);
  inCyl >> cyl.centre.x >> cyl.centre.y >> cyl.centre.z
	>> cyl.radius >> cyl.height;
  inCyl.close();

  inPix.open(pixFile);
  inPix >> nPixels;
  pixels = new Pixel[nPixels];
  for (int i=0; i<nPixels && !inPix.eof(); i++) {
    inPix >> pixels[i].x >> pixels[i].y;
  }
  inPix.close();
}

int main (int argc, char *argv[]) {
  Point *hitpoint;

  if (argc != 4) {
    cerr << "Usage:" << endl
	 << "intersect [camera-file] [cylinder-file] [pixel-file]" << endl;
	exit(1);
  }

  readData(argv[1], argv[2], argv[3]);

  for (int i=0; i<nPixels; i++) {
    ray = make_ray(cam,pixels[i]);

    hitpoint = ray_cylinder_intersect(ray,cyl);
    if (hitpoint == NULL)
      cout << "no hit" << endl;
    else
      printf("hit at (%8.3lf %8.3lf %8.3lf)\n",
	     hitpoint->x,hitpoint->y,hitpoint->z);
	}

	return 0;
}

/**************************************************************
 * The code that you must change starts HERE.
 */

Ray *make_ray(Camera& cam, Pixel& pix) {
  Ray *ray = new Ray;

 /*
  * These are arbitrary values.
  *  You'll have to set all of them correctly yourself.
  */

  ray->p.x = 0.0;
  ray->p.y = 0.0;
  ray->p.z = 0.0;

  ray->v.x = 0.0;
  ray->v.y = 0.0;
  ray->v.z = 1.0;

  return ray;
}

/*
 * This is also incorrect.  You have to change it to return
 * NULL if there is no intersection, and to return a new hit point if
 * there IS an intersection.
 */
Point *ray_cylinder_intersect(Ray *ray, Cylinder& cyl) {
  return NULL;
}