Defold plugin: Allow overriding z value also when exporting to .colle…

…ction

See issue #3214

NEWS.md

@@ -1,3 +1,7 @@
+### Unreleased
+
+* Defold plugin: Allow overriding z value also when exporting to .collection (#3214)
+
 ### Tiled 1.9.2 (16 September 2022)
 
 * Allow adding maps to image collection tilesets (#3447)

docs/manual/export-defold.rst

@@ -42,7 +42,15 @@ It supports:
 * Group layers (**only top-level group layers are supported, not nested ones!**)
 * Multiple Tilesets per Tilemap
 
-Upon export:
+The plugin automatically assigns a Z-index to each layer ranging between 0 and
+0.1. It supports the use of 9999 Group Layers and 9999 Tile Layers per Group
+Layer.
+
+When any additional information from the map is needed, the map can be
+exported in :ref:`Lua format <lua-export>` and loaded as Defold script.
+
+Custom Properties
+^^^^^^^^^^^^^^^^^
 
 * The ``tile_set`` property of each tilemap may need to be set up manually in
   Defold after each export. However, Tiled will attempt to find the
@@ -59,9 +67,9 @@ Upon export:
   GameObject in the Collection. This is useful when working with :doc:`Worlds
   <worlds>`.
 
-All layers of a Tilemap will have Z-index property assigned with values
-ranging between 0 and 0.1. The plugin supports the use of 9999 Group Layers
-and 9999 Tile Layers per Group Layer.
+.. raw:: html
 
-When any additional information from the map is needed, the map can be
-exported in :ref:`Lua format <lua-export>` and loaded as Defold script.
+   <div class="new">New in Tiled 1.9.3</div>
+
+* A custom float property named "z" can be added to tile layers to manually
+  specify their ``z`` value.

src/plugins/defoldcollection/defoldcollectionplugin.cpp

@@ -23,10 +23,7 @@
 
 #include "layer.h"
 #include "map.h"
-#include "mapobject.h"
-#include "objectgroup.h"
 #include "savefile.h"
-#include "tile.h"
 #include "tilelayer.h"
 #include "grouplayer.h"
 
@@ -189,10 +186,15 @@ static QString tilesetRelativePath(const QString &filePath)
 }
 
 /*
- * Returns z-Index for a layer, depending on its order in the map
+ * Returns z-Index for a layer, depending on its order in the map or a custom
+ * "z" property.
  */
 static float zIndexForLayer(const Tiled::Map &map, const Tiled::Layer &inLayer, bool isTopLayer)
 {
+    bool ok;
+    if (float z = inLayer.property(QStringLiteral("z")).toFloat(&ok); ok)
+        return z;
+
     if (isTopLayer) {
         int topLayerOrder = 0;
         for (auto layer : map.layers()) {
@@ -202,10 +204,10 @@ static float zIndexForLayer(const Tiled::Map &map, const Tiled::Layer &inLayer,
                 return qBound(0, topLayerOrder, 9999) * 0.0001f;
             topLayerOrder++;
         }
-    } else if (inLayer.parentLayer()) {
-        float zIndex = zIndexForLayer(map, *inLayer.parentLayer(), true);
+    } else if (auto parentLayer = inLayer.parentLayer()) {
+        float zIndex = zIndexForLayer(map, *parentLayer, true);
         int subLayerOrder = 0;
-        for (auto subLayer : inLayer.parentLayer()->layers()) {
+        for (auto subLayer : parentLayer->layers()) {
             if (subLayer == &inLayer) {
                 zIndex += qBound(0, subLayerOrder, 9999) * 0.00000001f;
                 return zIndex;