rewrite chunk data decoder

bot/world/chunk.go

@@ -8,89 +8,111 @@ import (
 	pk "github.com/Tnze/go-mc/net/packet"
 )
 
-//DecodeChunkColumn decode the chunk data structure
+// DecodeChunkColumn decode the chunk data structure.
+// If decoding went error, successful decoded data will be returned.
 func DecodeChunkColumn(mask int32, data []byte) (*Chunk, error) {
 	var c Chunk
 	r := bytes.NewReader(data)
 	for sectionY := 0; sectionY < 16; sectionY++ {
-		if (mask & (1 << uint(sectionY))) == 0 { // Is the given bit set in the mask?
-			continue
+		// If the section's bit set in the mask
+		if (mask & (1 << uint(sectionY))) != 0 {
+			// read section
+			sec, err := readSection(r)
+			if err != nil {
+				return &c, fmt.Errorf("read section[%d] error: %w", sectionY, err)
 			}
-		var (
-			BlockCount   pk.Short
-			BitsPerBlock pk.Byte
-		)
-		if err := BlockCount.Decode(r); err != nil {
-			return nil, err
-		}
-		if err := BitsPerBlock.Decode(r); err != nil {
-			return nil, err
-		}
-		//读调色板
-		var palette []uint
-		if BitsPerBlock < 9 {
-			var length pk.VarInt
-			if err := length.Decode(r); err != nil {
-				return nil, fmt.Errorf("read palette (id len) fail: %v", err)
-			}
-			palette = make([]uint, length)
-
-			for id := uint(0); id < uint(length); id++ {
-				var stateID pk.VarInt
-				if err := stateID.Decode(r); err != nil {
-					return nil, fmt.Errorf("read palette (id) fail: %v", err)
-				}
-
-				palette[id] = uint(stateID)
+			c.sections[sectionY] = sec
 		}
 	}
-
-		//Section数据
-		var DataArrayLength pk.VarInt
-		if err := DataArrayLength.Decode(r); err != nil {
-			return nil, fmt.Errorf("read DataArrayLength fail: %v", err)
-		}
-
-		DataArray := make([]int64, DataArrayLength)
-		for i := 0; i < int(DataArrayLength); i++ {
-			if err := (*pk.Long)(&DataArray[i]).Decode(r); err != nil {
-				return nil, fmt.Errorf("read DataArray fail: %v", err)
-			}
-		}
-		//用数据填充区块
-		fillSection(&c.sections[sectionY], perBits(byte(BitsPerBlock)), DataArray, palette)
-	}
-
 	return &c, nil
 }
 
-func perBits(BitsPerBlock byte) uint {
+func perBits(BitsPerBlock byte) uint32 {
 	switch {
 	case BitsPerBlock <= 4:
 		return 4
 	case BitsPerBlock < 9:
-		return uint(BitsPerBlock)
+		return uint32(BitsPerBlock)
 	default:
-		return uint(data.BitsPerBlock) // DefaultBitsPerBlock
+		return uint32(data.BitsPerBlock) // DefaultBitsPerBlock
 	}
 }
 
-func fillSection(s *Section, bpb uint, DataArray []int64, palette []uint) {
-	mask := uint(1<<bpb - 1)
-	for n := 0; n < 16*16*16; n++ {
-		offset := uint(n * int(bpb))
-		data := uint(DataArray[offset/64])
-		data >>= offset % 64
-		if offset%64 > 64-bpb {
-			l := 64 - offset % 64
-			data |= uint(DataArray[offset/64+1] << l)
+func readSection(data pk.DecodeReader) (s Section, err error) {
+	var BlockCount pk.Short
+	if err := BlockCount.Decode(data); err != nil {
+		return nil, fmt.Errorf("read block count error: %w", err)
 	}
-		data &= mask
-
+	var bpb pk.UnsignedByte
+	if err := bpb.Decode(data); err != nil {
+		return nil, fmt.Errorf("read bits per block error: %w", err)
+	}
+	// If bpb values greater than or equal to 9, use directSection.
+	// Otherwise use paletteSection.
+	var palettes []uint32
 	if bpb < 9 {
-			s.blocks[n%16][n/(16*16)][n%(16*16)/16].id = palette[data]
-		} else {
-			s.blocks[n%16][n/(16*16)][n%(16*16)/16].id = data
+		// read palettes
+		var length pk.VarInt
+		if err := length.Decode(data); err != nil {
+			return nil, fmt.Errorf("read palettes length error: %w", err)
 		}
+		palettes = make([]uint32, length)
+		for i := 0; i < int(length); i++ {
+			var v pk.VarInt
+			if err := v.Decode(data); err != nil {
+				return nil, fmt.Errorf("read palettes[%d] error: %w", i, err)
+			}
+			palettes[i] = uint32(v)
+		}
+	}
+
+	// read data array
+	var dataLen pk.VarInt
+	if err := dataLen.Decode(data); err != nil {
+		return nil, fmt.Errorf("read data array length error: %w", err)
+	}
+	dataArray := make([]int64, dataLen)
+	for i := 0; i < int(dataLen); i++ {
+		var v pk.Long
+		if err := v.Decode(data); err != nil {
+			return nil, fmt.Errorf("read dataArray[%d] error: %w", i, err)
+		}
+		dataArray[i] = int64(v)
+	}
+
+	sec := directSection{bpb: perBits(byte(bpb)), data: dataArray}
+	if bpb < 9 {
+		return &paletteSection{palette: palettes, directSection: sec}, nil
+	} else {
+		return &sec, nil
 	}
 }
+
+type directSection struct {
+	bpb  uint32
+	data []int64
+}
+
+func (d *directSection) GetBlock(x, y, z int) (blockID uint32) {
+	// According to wiki.vg: Data Array is given for each block with increasing x coordinates,
+	// within rows of increasing z coordinates, within layers of increasing y coordinates.
+	// So offset equals to ( x*16^0 + z*16^1 + y*16^2 )*(bits per block).
+	offset := uint32(x+z*16+y*16*16) * d.bpb
+	block := uint32(d.data[offset/64])
+	block >>= offset % 64
+	if offset%64 > 64-d.bpb {
+		l := 64 - offset%64
+		block |= uint32(d.data[offset/64+1] << l)
+	}
+	return block & (1<<d.bpb - 1) // mask
+}
+
+type paletteSection struct {
+	palette []uint32
+	directSection
+}
+
+func (p *paletteSection) GetBlock(x, y, z int) (blockID uint32) {
+	v := p.directSection.GetBlock(x, y, z)
+	return p.palette[v]
+}

bot/world/motion.go

@@ -1,78 +0,0 @@
-package world
-
-// import (
-// 	"math"
-// 	"time"
-// )
-
-// // SetPosition method move your character around.
-// // Server will ignore this if changes too much.
-// func (g *Client) SetPosition(x, y, z float64, onGround bool) {
-// 	g.motion <- func() {
-// 		g.player.X, g.player.Y, g.player.Z = x, y, z
-// 		g.player.OnGround = onGround
-// 		sendPlayerPositionPacket(g) //向服务器更新位置
-// 	}
-// }
-
-// // LookAt method turn player's hand and make it look at a point.
-// func (g *Client) LookAt(x, y, z float64) {
-// 	x0, y0, z0 := g.player.X, g.player.Y, g.player.Z
-// 	x, y, z = x-x0, y-y0, z-z0
-
-// 	r := math.Sqrt(x*x + y*y + z*z)
-// 	yaw := -math.Atan2(x, z) / math.Pi * 180
-// 	for yaw < 0 {
-// 		yaw = 360 + yaw
-// 	}
-// 	pitch := -math.Asin(y/r) / math.Pi * 180
-
-// 	g.LookYawPitch(float32(yaw), float32(pitch))
-// }
-
-// // LookYawPitch set player's hand to the direct by yaw and pitch.
-// // yaw can be [0, 360) and pitch can be (-180, 180).
-// // if |pitch|>90 the player's hand will be very strange.
-// func (g *Client) LookYawPitch(yaw, pitch float32) {
-// 	g.motion <- func() {
-// 		g.player.Yaw, g.player.Pitch = yaw, pitch
-// 		sendPlayerLookPacket(g) //向服务器更新朝向
-// 	}
-// }
-
-// // SwingHand sent when the player's arm swings.
-// // if hand is true, swing the main hand
-// func (g *Client) SwingHand(hand bool) {
-// 	if hand {
-// 		sendAnimationPacket(g, 0)
-// 	} else {
-// 		sendAnimationPacket(g, 1)
-// 	}
-// }
-
-// // Dig a block in the position and wait for it's breaked
-// func (g *Client) Dig(x, y, z int) error {
-// 	b := g.GetBlock(x, y, z).id
-// 	sendPlayerDiggingPacket(g, 0, x, y, z, Top) //start
-// 	sendPlayerDiggingPacket(g, 2, x, y, z, Top) //end
-
-// 	for {
-// 		time.Sleep(time.Millisecond * 50)
-// 		if g.GetBlock(x, y, z).id != b {
-// 			break
-// 		}
-// 		g.SwingHand(true)
-// 	}
-
-// 	return nil
-// }
-
-// // UseItem use the item in hand.
-// // if hand is true, swing the main hand
-// func (g *Client) UseItem(hand bool) {
-// 	if hand {
-// 		sendUseItemPacket(g, 0)
-// 	} else {
-// 		sendUseItemPacket(g, 1)
-// 	}
-// }

bot/world/world.go

@@ -10,19 +10,14 @@ type World struct {
 	Chunks   map[ChunkLoc]*Chunk
 }
 
-//Chunk store a 256*16*16 clolumn blocks
+//Chunk store a 256*16*16 column blocks
 type Chunk struct {
 	sections [16]Section
 }
 
 //Section store a 16*16*16 cube blocks
-type Section struct {
-	blocks [16][16][16]Block
-}
-
-//Block is the base of world
-type Block struct {
-	id uint
+type Section interface {
+	GetBlock(x, y, z int) (blockID uint32)
 }
 
 type ChunkLoc struct {

bot/world/world_test.go

@@ -1,9 +0,0 @@
-package world
-
-// import "testing"
-
-// func TestBlockString(t *testing.T) {
-// 	for i := uint(0); i < 8598+1; i++ {
-// 		t.Log(Block{id: i})
-// 	}
-// }