aabb.h

#ifndef AABB_H
#define AABB_H

#include "rtweekend.h"

class aabb {
    public:
        __device__ aabb() {}
        __device__ aabb(const point3& a, const point3& b) { minimum = a; maximum = b;}

        __device__ point3 min() const {return minimum; }
        __device__ point3 max() const {return maximum; }

		__device__ inline bool hit(const ray& r, float t_min, float t_max) const {
			for (int a = 0; a < 3; a++) {
				float invD = 1.0f / r.direction()[a];
				float t0 = (min()[a] - r.origin()[a]) * invD;
				float t1 = (max()[a] - r.origin()[a]) * invD;
				if (invD < 0.0f)
				{
					t0 += t1;
					t1 = t0 - t1;
					t0 -= t1;
				}
				t_min = t0 > t_min ? t0 : t_min;
				t_max = t1 < t_max ? t1 : t_max;
				if (t_max <= t_min)
					return false;
			}
			return true;
		}

        point3 minimum;
        point3 maximum;
};

__device__ aabb surrounding_box(aabb box0, aabb box1) {
    point3 small(fmin(box0.min().x(), box1.min().x()),
                 fmin(box0.min().y(), box1.min().y()),
                 fmin(box0.min().z(), box1.min().z()));

    point3 big(fmax(box0.max().x(), box1.max().x()),
               fmax(box0.max().y(), box1.max().y()),
               fmax(box0.max().z(), box1.max().z()));

    return aabb(small,big);
}

#endif