85 void box_intersect(box *bx, ray *ry) {  in box_intersect()  argument
93         if ((ry->o.x < bx->min.x) || (ry->o.x > bx->max.x))  in box_intersect()
97         tx1 = (bx->min.x - ry->o.x) / ry->d.x;  in box_intersect()
98         tx2 = (bx->max.x - ry->o.x) / ry->d.x;  in box_intersect()
115         if ((ry->o.y < bx->min.y) || (ry->o.y > bx->max.y))  in box_intersect()
119         ty1 = (bx->min.y - ry->o.y) / ry->d.y;  in box_intersect()
120         ty2 = (bx->max.y - ry->o.y) / ry->d.y;  in box_intersect()
137         if ((ry->o.z < bx->min.z) || (ry->o.z > bx->max.z))  in box_intersect()
141         tz1 = (bx->min.z - ry->o.z) / ry->d.z;  in box_intersect()
142         tz2 = (bx->max.z - ry->o.z) / ry->d.z;  in box_intersect()
158     add_intersection(tnear, (object *)bx, ry);  in box_intersect()
159     add_intersection(tfar, (object *)bx, ry);  in box_intersect()
162 void box_normal(box *bx, vector *pnt, ray *incident, vector *N) {  in box_normal()  argument
166     c.x = (bx->max.x + bx->min.x) / 2.0;  in box_normal()
167     c.y = (bx->max.y + bx->min.y) / 2.0;  in box_normal()
168     c.z = (bx->max.z + bx->min.z) / 2.0;  in box_normal()