add hand skeleton

src/content/Content.cpp

@@ -63,6 +63,14 @@ const rigging::SkeletonConfig* Content::getSkeleton(const std::string& id
     return found->second.get();
 }
 
+const rigging::SkeletonConfig& Content::requireSkeleton(const std::string& id) const {
+    auto skeleton = getSkeleton(id);
+    if (skeleton == nullptr) {
+        throw std::runtime_error("skeleton '" + id + "' not loaded");
+    }
+    return *skeleton;
+}
+
 const BlockMaterial* Content::findBlockMaterial(const std::string& id) const {
     auto found = blockMaterials.find(id);
     if (found == blockMaterials.end()) {

src/content/Content.hpp

@@ -212,6 +212,7 @@ public:
     }
 
     const rigging::SkeletonConfig* getSkeleton(const std::string& id) const;
+    const rigging::SkeletonConfig& requireSkeleton(const std::string& id) const;
     const BlockMaterial* findBlockMaterial(const std::string& id) const;
     const ContentPackRuntime* getPackRuntime(const std::string& id) const;
     ContentPackRuntime* getPackRuntime(const std::string& id);