change: Started rewriting parts of the project in Go

world/data_format.go

@@ -0,0 +1,114 @@
+package world
+
+import (
+	"fmt"
+)
+
+const (
+	// Slice size is the total number of blocks in a horizontal slice of a chunk
+	sliceSize = 16 * 16
+)
+
+type BlockPos struct {
+	X int  `json:"x"`
+	Y uint `json:"y"`
+	Z int  `json:"z"`
+}
+
+func (b BlockPos) ToChunkPos() ChunkPos {
+	return ChunkPos{
+		X: b.X / 16,
+		Z: b.Z / 16,
+	}
+}
+
+type ChunkData struct {
+	Pos      ChunkPos         `json:"pos"`
+	Sections [16]ChunkSection `json:"sections"`
+}
+
+func (cd *ChunkData) SectionFor(pos BlockPos) *ChunkSection {
+	return &cd.Sections[pos.Y%16]
+}
+
+type ChunkPos struct {
+	X int `json:"x"`
+	Z int `json:"z"`
+}
+
+func (cp *ChunkPos) ToFileName() string {
+	return fmt.Sprintf("p.%d.%d.chunk", cp.X, cp.Z)
+}
+
+type ChunkSection struct {
+	// The count of full blocks in the chunk
+	BlockCount  uint                  `json:"block_count"`
+	BlockStates [16 * 16 * 16]BlockID `json:"block_states"`
+}
+
+func rem_euclid(a, b int) int {
+	return (a%b + b) % b
+}
+
+func (cs *ChunkSection) IndexOfBlock(pos BlockPos) int {
+	baseX := rem_euclid(pos.X, 16)
+	baseY := rem_euclid(int(pos.Y), 16)
+	baseZ := rem_euclid(pos.Z, 16)
+
+	return (baseY * sliceSize) + (baseZ * 16) + baseX
+}
+
+func (cs *ChunkSection) UpdateBlockAtIndex(index int, targetState BlockID) {
+	// TODO: Keep track of the block count
+
+	cs.BlockStates[index] = targetState
+}
+
+func (cs *ChunkSection) UpdateBlock(pos BlockPos, targetState BlockID) {
+	cs.BlockStates[cs.IndexOfBlock(pos)] = targetState
+}
+
+func (cs *ChunkSection) FetchBlock(pos BlockPos) BlockID {
+	return cs.BlockStates[cs.IndexOfBlock(pos)]
+}
+
+type BlockID uint8
+
+const (
+	Empty BlockID = iota
+	Generic
+)
+
+func (b *BlockID) UnmarshalJSON(data []byte) error {
+	idName := string(data)
+
+	if len(idName) < 2 {
+		return fmt.Errorf("error decoding blockid, input was too short")
+	}
+
+	switch idName[1 : len(idName)-1] {
+	case "Empty":
+		*b = Empty
+	case "Generic":
+		*b = Generic
+	default:
+		return fmt.Errorf("unknown block id: %s", string(data))
+	}
+
+	return nil
+}
+
+func (b BlockID) MarshalJSON() ([]byte, error) {
+	var encoded []byte
+
+	switch b {
+	case Empty:
+		encoded = []byte("\"Empty\"")
+	case Generic:
+		encoded = []byte("\"Generic\"")
+	default:
+		return []byte{}, fmt.Errorf("could not turn block id %d into data", b)
+	}
+
+	return encoded, nil
+}