// Check if coordinate on (or beyond) map is accessible to movement.
char passable = 0;
if (0 <= x && x < world->map->width && 0 <= y && y < world->map->height)
// Check if coordinate on (or beyond) map is accessible to movement.
char passable = 0;
if (0 <= x && x < world->map->width && 0 <= y && y < world->map->height)