add variants (WIP)

src/graphics/render/ModelsGenerator.hpp

@@ -8,6 +8,7 @@ struct ItemDef;
 class Assets;
 class Content;
 class Block;
+struct Variant;
 
 class ModelsGenerator {
 public:
@@ -28,4 +29,8 @@ public:
     static model::Model loadCustomBlockModel(
         const dv::value& primitives, const Assets& assets, bool lighting
     );
+
+    static void prepareModel(
+        Assets& assets, const Block& def, Variant& variant, uint8_t variantId
+    );
 };