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#define _USE_MATH_DEFINES
#include "Sphere.h"
#include "math.h"
namespace shapes {
Sphere::Sphere(float radius, const std::shared_ptr<material::Material>& material)
: radius(radius)
, material(material)
{
}
std::shared_ptr<cam::Hit> Sphere::intersect(const cam::Ray& r)
{
util::Vec3 d = r.d;
util::Vec3 x0 = r.x0;
float a = util::dot(d, d);
float b = 2 * util::dot(x0, d);
float c = util::dot(x0, x0) - (radius * radius);
float discrim = b * b - 4 * a * c;
if (discrim >= 0) {
double t1 = (-b - sqrt(b * b - 4 * a * c)) / (2 * a);
if (r.in_range(t1)) {
util::Vec3 t1HitPoint = r(t1);
double theta = acos(t1HitPoint.y() / radius);
double phi = M_PI + atan2(t1HitPoint.x(), t1HitPoint.z());
return std::make_shared<cam::Hit>(cam::Hit(t1HitPoint, t1HitPoint, t1, material));
} else {
double t2 = (-b + sqrt(b * b - 4 * a * c)) / (2 * a);
if (r.in_range(t2)) {
util::Vec3 t2HitPoint = r(t2);
double theta = acos(t2HitPoint.y() / radius);
double phi = M_PI + atan2(t2HitPoint.x(), t2HitPoint.z());
return std::make_shared<cam::Hit>(cam::Hit(t2HitPoint, t2HitPoint, t2, material));
} else {
return nullptr;
}
}
} else {
return nullptr;
}
}
}