Worlds are now opened by their level.dat and are centered properly.

The world spawn will be read from the level.dat and the view will be
centered to that position.

1 files changed, 41 insertions, 0 deletions

diff --git a/leveldat.go b/leveldat.go
new file mode 100644
index 0000000..51344a8
--- /dev/null
+++ b/leveldat.go
@@ -0,0 +1,41 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"github.com/kch42/gonbt/nbt"
+	"io"
+)
+
+func invalidLevelDat(err error) error {
+	return fmt.Errorf("Invalid level.dat: %s", err)
+}
+
+func getMapCenter(leveldat io.Reader) (int, int, error) {
+	lvl, _, err := nbt.ReadGzipdNamedTag(leveldat)
+	if err != nil {
+		return 0, 0, err
+	}
+
+	if lvl.Type != nbt.TAG_Compound {
+		return 0, 0, invalidLevelDat(errors.New("Root tag has wrong type"))
+	}
+	root := lvl.Payload.(nbt.TagCompound)
+
+	data, err := root.GetCompound("Data")
+	if err != nil {
+		return 0, 0, invalidLevelDat(err)
+	}
+
+	x, err := data.GetInt("SpawnX")
+	if err != nil {
+		return 0, 0, invalidLevelDat(err)
+	}
+
+	z, err := data.GetInt("SpawnZ")
+	if err != nil {
+		return 0, 0, invalidLevelDat(err)
+	}
+
+	return int(x), int(z), nil
+}