func (w *world) getBlock(x, y, z int) Block {
	c := w.chunks[chunkLoc{x >> 4, z >> 4}]
	if c != nil {
		cx, cy, cz := x&15, y&15, z&15
		return c.sections[y/16].blocks[cx][cy][cz]
	}
	return Block{id: 0}
}
getBlock return the block in the position (x, y, z)
package gomcbot
type world struct {
	Entities map[int32]Entity
	chunks   map[chunkLoc]*Chunk
}
type Chunk struct {
	sections [16]Section
}
type Section struct {
	blocks [16][16][16]Block
}
type Block struct {
	id uint
}
type chunkLoc struct {
	X, Y int
}
type Entity interface {
	EntityID() int32
}
type Face byte
const (
	Bottom Face = iota
	Top
	North
	South
	West
	East
)