Add BlockRegion helper class

world/block_region.gd

@@ -0,0 +1,45 @@
+class_name BlockRegion
+extends RefCounted
+
+static var LOCAL_CHUNK := BlockRegion.new(Vector2i.ZERO, Vector2i.ONE * (Chunk.SIZE - 1))
+
+var min: Vector2i
+var max: Vector2i
+
+func _init(a: Vector2i, b: Vector2i) -> void:
+	min = a.min(b)
+	max = a.max(b)
+
+func size() -> Vector2i:
+	return max - min + Vector2i.ONE
+
+func contains(pos: Vector2i) -> bool:
+	return (pos.x >= min.x) && (pos.x <= max.x) and (pos.y >= min.y) && (pos.y <= max.y)
+
+
+func offset(value: Vector2i) -> BlockRegion:
+	return BlockRegion.new(min + value, max + value)
+
+func extend(amount: int) -> BlockRegion:
+	var v := Vector2i.ONE * amount
+	return BlockRegion.new(min - v, max + v)
+
+
+func array_index(pos: Vector2i) -> int:
+	assert(contains(pos))
+	var size  := size()
+	var index := (pos.x - min.x) + (pos.y - min.y) * size.x
+	return clampi(index, 0, size.x * size.y)
+
+
+# Custom iterators in GDScript are WEIRD.
+func _iter_init(state: Array) -> bool:
+	state[0] = min
+	return true
+func _iter_next(state: Array) -> bool:
+	var cur: Vector2i = state[0]
+	if   cur.x < max.x: state[0].x += 1; return true
+	elif cur.y < max.y: state[0] = Vector2i(min.x, cur.y + 1); return true
+	else: return false
+func _iter_get(state: Variant) -> Vector2i:
+	return state

world/block_region.gd.uid

@@ -0,0 +1 @@
+uid://w5fuyrkwf40c

world/chunk.gd

@@ -76,7 +76,4 @@ static func pos_to_center(chunk_pos: Vector2i) -> Vector2:
 
 ## Creates an integer index from a chunk-local block position that can be used to index into an array.
 static func array_index(local_pos: Vector2i) -> int:
-	assert((local_pos.x >= 0) and (local_pos.x < Chunk.SIZE))
+	return BlockRegion.LOCAL_CHUNK.array_index(local_pos)
-	assert((local_pos.y >= 0) and (local_pos.y < Chunk.SIZE))
-	# Using `posmod` ensures `local_pos` is valid, and this returns a valid index.
-	return posmod(local_pos.x, Chunk.SIZE) + posmod(local_pos.y, Chunk.SIZE) * Chunk.SIZE

world/generation/generator_simple.gd

@@ -31,9 +31,7 @@ func generate(world: World, chunk: Chunk) -> void:
 
 	var matter: Matter.Layer = chunk.get_or_create_layer(Matter)
 	var shapes: Shape.Layer  = chunk.get_or_create_layer(Shape)
-	for x in Chunk.SIZE:
+	for local_pos in BlockRegion.LOCAL_CHUNK:
-		for y in Chunk.SIZE:
-			var local_pos := Vector2i(x, y)
 		var shape: Shape
 		match _values(local_pos):
 			[  true,  true,  true,  true ]: shape = Shape.FULL

world/layers/matter.gd

@@ -41,13 +41,14 @@ class Layer extends MeshInstance2D:
 	@rpc("reliable")
 	func set_id_at(pos: Vector2i, id: int) -> void:
 		var index := Chunk.array_index(pos)
-		if data[index] != id:
+		if data[index] == id: return
+
 		# TODO: Keep track of how many non-air blocks are present, to allow for cleaning empty chunks.
 		data[index] = id
 		chunk.dirty = true
 
-			# Send change to every player tracking this chunk.
 		if multiplayer.is_server():
+			# Send change to every player tracking this chunk.
 			for player in chunk.get_players_tracking():
 				if player.network.is_local: continue # skip server player
 				set_id_at.rpc_id(player.network.peer_id, pos, id)
@@ -66,9 +67,7 @@ class Layer extends MeshInstance2D:
 
 		var shapes: Shape.Layer = chunk.get_layer_or_null(Shape)
 		if shapes: # Should exist, but let's sanity check.
-			for x in Chunk.SIZE:
+			for pos in BlockRegion.LOCAL_CHUNK:
-				for y in Chunk.SIZE:
-					var pos    := Vector2i(x, y)
 				var offset := (Vector2.ONE / 2) + Vector2(pos)
 
 				# TODO: Support different matter.

world/layers/shape.gd

@@ -130,13 +130,14 @@ class Layer extends StaticBody2D:
 	@rpc("reliable")
 	func set_id_at(pos: Vector2i, id: int) -> void:
 		var index := Chunk.array_index(pos)
-		if data[index] != id:
+		if data[index] == id: return
+
 		# TODO: Keep track of how many non-air blocks are present, to allow for cleaning empty chunks.
 		data[index] = id
 		chunk.dirty = true
 
-			# Send change to every player tracking this chunk.
 		if multiplayer.is_server():
+			# Send change to every player tracking this chunk.
 			for player in chunk.get_players_tracking():
 				if player.network.is_local: continue # skip server player
 				set_id_at.rpc_id(player.network.peer_id, pos, id)
@@ -155,9 +156,7 @@ class Layer extends StaticBody2D:
 			if child is CollisionShape2D:
 				child.queue_free()
 
-		for x in Chunk.SIZE:
+		for pos in BlockRegion.LOCAL_CHUNK:
-			for y in Chunk.SIZE:
-				var pos   := Vector2i(x, y)
 			var shape := get_at(pos)
 			if shape.shape == null: continue