1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/sphere.cc	Sun Nov 09 13:03:36 2014 +0200
     1.3 @@ -0,0 +1,52 @@
     1.4 +#include <stdio.h>
     1.5 +#include "sphere.h"
     1.6 +
     1.7 +Sphere::Sphere()
     1.8 +{
     1.9 +	radius = 1.0;
    1.10 +}
    1.11 +
    1.12 +Sphere::Sphere(const Vector3 &pos, float rad)
    1.13 +{
    1.14 +	radius = rad;
    1.15 +	this->pos = pos;
    1.16 +}
    1.17 +
    1.18 +bool Sphere::intersect(const Ray &inray, HitPoint *pt) const
    1.19 +{
    1.20 +	Ray ray = inray.transformed(inv_xform);
    1.21 +
    1.22 +	float a = dot_product(ray.dir, ray.dir);
    1.23 +	float b = 2.0 * ray.dir.x * (ray.origin.x - pos.x) +
    1.24 +		2.0 * ray.dir.y * (ray.origin.y - pos.y) +
    1.25 +		2.0 * ray.dir.z * (ray.origin.z - pos.z);
    1.26 +	float c = dot_product(ray.origin, ray.origin) + dot_product(pos, pos) -
    1.27 +		2.0 * dot_product(ray.origin, pos) - radius * radius;
    1.28 +
    1.29 +	float discr = b * b - 4.0 * a * c;
    1.30 +	if(discr < 1e-4)
    1.31 +		return false;
    1.32 +
    1.33 +	float sqrt_discr = sqrt(discr);
    1.34 +	float t0 = (-b + sqrt_discr) / (2.0 * a);
    1.35 +	float t1 = (-b - sqrt_discr) / (2.0 * a);
    1.36 +
    1.37 +	if(t0 < 1e-4)
    1.38 +		t0 = t1;
    1.39 +	if(t1 < 1e-4)
    1.40 +		t1 = t0;
    1.41 +
    1.42 +	float t = t0 < t1 ? t0 : t1;
    1.43 +	if(t < 1e-4)
    1.44 +		return false;
    1.45 +
    1.46 +	// fill the HitPoint structure
    1.47 +	pt->obj = this;
    1.48 +	pt->dist = t;
    1.49 +	pt->pos = ray.origin + ray.dir * t;
    1.50 +	pt->normal = (pt->pos - pos) / radius;
    1.51 +
    1.52 +	pt->pos.transform(xform);
    1.53 +	pt->normal.transform(dir_xform);
    1.54 +	return true;
    1.55 +}