473     gridindex curvox, step, out;  in grid_intersect()  local
495         out.x = 0; /* never goes out of bounds on this axis */  in grid_intersect()
500         step.x = out.x = -1;  in grid_intersect()
506         out.x = g->xsize;  in grid_intersect()
514         out.y = 0; /* never goes out of bounds on this axis */  in grid_intersect()
519         step.y = out.y = -1;  in grid_intersect()
525         out.y = g->ysize;  in grid_intersect()
533         out.z = 0; /* never goes out of bounds on this axis */  in grid_intersect()
538         step.z = out.z = -1;  in grid_intersect()
544         out.z = g->zsize;  in grid_intersect()
570             if (ry->maxdist < tmax.x || curvox.x == out.x)  in grid_intersect()
589             if (ry->maxdist < tmax.z || curvox.z == out.z)  in grid_intersect()
608             if (ry->maxdist < tmax.y || curvox.y == out.y)  in grid_intersect()