#include "Sphere.h"
#include "util/Solver.h"
#include <math.h>
#include <iostream>
using namespace std;

Sphere::Sphere(double radius)
{
    m_radius = radius;
    m_radius2 = radius * radius;
}

Solver::Result Sphere::intersect(const Ray & ray)
{
    Ray ray_inv = m_inverse.transform_ray(ray);

    Solver::Result res;
    QuadraticSolver solver(1.0,
                           2 * ( ray_inv.getOrigin()[0] * ray_inv.getDirection()[0]
                               + ray_inv.getOrigin()[1] * ray_inv.getDirection()[1]
                               + ray_inv.getOrigin()[2] * ray_inv.getDirection()[2] ),
                             ray_inv.getOrigin()[0] * ray_inv.getOrigin()[0]
                           + ray_inv.getOrigin()[1] * ray_inv.getOrigin()[1]
                           + ray_inv.getOrigin()[2] * ray_inv.getOrigin()[2]
                           - m_radius2);
    Solver::Result quadSolutions = solver.solve();
    for (int i = 0; i < quadSolutions.numResults; i++)
    {
        if (quadSolutions.results[i] >= 0.0)
        {
            res.results[res.numResults++] = quadSolutions.results[i];
        }
    }
    return res;
}

Vector Sphere::getNormalAt(const Vector & pt)
{
    Vector pt_inv = m_inverse.transform_point(pt);

    Vector normal = pt_inv;
    return normal.normalize();
}