Make Entities layer optional.

It can also be disabled using "visible" flag in tiled.

Closes issue #19

2 files changed, 11 insertions, 3 deletions

diff --git a/docs/tools.md b/docs/tools.md
index 67b797a..caf67c4 100644
--- a/docs/tools.md
+++ b/docs/tools.md
@@ -88,7 +88,7 @@ This is a map importer to use with [tiled](https://www.mapeditor.org/) JSON form
 
 The map importer supports:
 
-- **entities**: an object layer describing game entities such as enemies.
+- **entities**: an optional object layer describing game entities such as enemies. If the "visible" property on this layer is set to "false", the layer will be ignored even if present.
 - **map**: a tile layer describing the map itself.
 
 #### Map requirements
diff --git a/tools/map.py b/tools/map.py
index 60ef887..476c1cd 100755
--- a/tools/map.py
+++ b/tools/map.py
@@ -220,8 +220,16 @@ def main():
         # ents size placeholder 0
         out[i] = [size & 0xFF, size >> 8, 0] + out[i]
 
-    entities_layer = find_name(data["layers"], "Entities")
-    if len(entities_layer):
+    try:
+        entities_layer = find_name(data["layers"], "Entities")
+    except ValueError:
+        entities_layer = []
+        if not args.quiet:
+            print(
+                "%s: warning: 'Entities' layer not found" % path.basename(sys.argv[0]),
+                file=sys.stderr,
+            )
+    if len(entities_layer) and entities_layer["visible"]:
         map_ents = defaultdict(list)
         map_ents_w = defaultdict(int)
         map_ents_bytes = defaultdict(int)