world/world.go: Fixed spawn points in other dimensions, closes #1102. (#1143)

Author: FDUTCH

server/world/tick.go

@@ -40,7 +40,7 @@ func (t ticker) tick(tx *Tx) {
 	w := tx.World()
 
 	w.set.Lock()
-	if s := w.set.Spawn; s[1] > tx.Range()[1] {
+	if s := w.set.Spawn; s[1] > tx.Range()[1] && w.Dimension() == Overworld {
 		// Vanilla will set the spawn position's Y value to max to indicate that
 		// the player should spawn at the highest position in the world.
 		w.set.Spawn[1] = w.highestObstructingBlock(s[0], s[2]) + 1

server/world/world.go

@@ -779,6 +779,13 @@ func (w *World) Spawn() cube.Pos {
 	if w == nil {
 		return cube.Pos{}
 	}
+
+	if w.Dimension() == End {
+		return cube.Pos{100, 50}
+	} else if w.Dimension() == Nether {
+		return cube.Pos{}
+	}
+
 	w.set.Lock()
 	defer w.set.Unlock()
 	return w.set.Spawn
@@ -790,6 +797,12 @@ func (w *World) SetSpawn(pos cube.Pos) {
 	if w == nil {
 		return
 	}
+
+	// nether has no spawn point and end spawn point is always 100 50 0.
+	if w.Dimension() == Nether || w.Dimension() == End {
+		return
+	}
+
 	w.set.Lock()
 	w.set.Spawn = pos
 	w.set.Unlock()