/* ray.cc
 *   by Will Wagner <wwagner@io.com>
 *   last updated 20 Sep 1997, 17:36:35 wwagner
 *
 * This file contains the Intersection and Ray definitions for POVRay.
 *
 * Changes
 *   11 Aug 1997
 *     - Added this commment block.
 *
 *   20 Sep 1997
 *     - CONTAINING_OBJECTS_STEP was renamed to CONTAINING_OBJECTS_FACTOR.
 *
 * Things to do
 *
 */

#include <g++/algo.h>
#include "ray.h"

int Ray::ray_struct_compare(ray_struct& r, Texture *t)
{
    return (r.texture == t);
}

Ray::Ray()
    : initial(3, 0.0), direction(3, 0.0),
      containing()
{
    containing.reserve(INITIAL_CONTAINING_OBJECTS);
}

Ray::Ray(const pov_vector<DBL>& in, const pov_vector<DBL>& di)
    : initial(in), direction(di),
      containing()
{
    containing.reserve(INITIAL_CONTAINING_OBJECTS);
}

Ray::Ray(const Ray& r)
    : initial(r.initial), direction(r.direction),
      containing(),
{
    containing.reserve(r.containing.capacity());
    copy(r.containing.begin(), r.containing.end(),
	 containing.begin());
}

Ray::~Ray()
{
}

void Ray::Enter(Object *obj, Texture *tex)
{
    ray_struct rs;

    if ((containing.size() + 1) >= containing.capacity())
	/* If the containing vector is about to overflow, extend it by
	 * a factor of CONTAINING_OBJECTS_FACTOR instead of wasting
	 * lots of time doing small-increment reallocations.
	 */
	containing.reserve(containing.capacity() * CONTAINING_OBJECTS_FACTOR);

    rs.texture = tex;
    rs.object = obj;
    if ((texture->Type == PLAIN_PATTERN) && (texture->Finish != NULL))
	rs.ior = texture->Finish->Index_Of_Refraction;
    else
	rs.ior = Frame.Atmosphere_IOR;

    containing.push_back(rs);
}

void Ray::Exit(int nr)
{
    if (containing.size())
    {
	copy(containing.begin() + nr + 1, containing.end(),
	     containing.begin() + nr);
	containing.pop_back();
    }
}

int Ray::TextureInRay(Texture *tex)
{
    int found = -1;
    vector<ray_struct>::iterator i;

    i = find_if(containing.begin(), containing.end(),
		bind2nd(Ray::ray_struct_compare(), tex));
    if (i != containing.end())
	found = i - containing.begin();
    return found;
}