add support for Layer's OverrideTilesetUid

Author: progrematic

include/LDtkLoader/Layer.hpp

@@ -57,6 +57,7 @@ namespace ldtk {
         void updateTileVerticesCol(const Tile& tile) const;
 
         const LayerDef* m_definition = nullptr;
+        const Tileset* m_override_tileset = nullptr;
 
         bool m_visible;
         mutable IntPoint m_total_offset;

src/Layer.cpp

@@ -15,6 +15,10 @@ m_total_offset(j["__pxTotalOffsetX"].get<int>(), j["__pxTotalOffsetY"].get<int>(
 m_opacity(j["__opacity"].get<float>()),
 m_grid_size({j["__cWid"].get<int>(), j["__cHei"].get<int>()})
 {
+    if ( !j["overrideTilesetUid"].is_null() ) {
+        m_override_tileset = &w->getTileset(j["overrideTilesetUid"].get<int>());
+    }
+
     std::string key = "gridTiles";
     int coordId_index = 0;
     if (getType() == LayerType::IntGrid || getType() == LayerType::AutoLayer) {
@@ -112,11 +116,11 @@ void Layer::setOpacity(float opacity) const {
 }
 
 auto Layer::hasTileset() const -> bool {
-    return m_definition->m_tileset != nullptr;
+    return m_override_tileset != nullptr || m_definition->m_tileset != nullptr;
 }
 
 auto Layer::getTileset() const -> const Tileset& {
-    return *m_definition->m_tileset;
+    return m_override_tileset == nullptr ? *m_definition->m_tileset : *m_override_tileset;
 }
 
 auto Layer::allTiles() const -> const std::vector<Tile>& {