func NewStoneFieldGenerator(db *engine.EntityDB, fill float64) *StoneFieldGenerator { grass := db.New() db.Set(grass, "art", base.NewArt('.', 0, 1, 0, 0, 0, 0)) stone := db.New() db.Set(stone, "art", base.NewArt('#', .7, .7, .7, 0, 0, 0)) return &StoneFieldGenerator{stone: stone, grass: grass, fill: fill} }