add fragment.crop, fragment:crop() & fix fragments rotation when width is not equal to depth & fix extra structures placements

src/logic/scripting/lua/libs/libgeneration.cpp

@@ -36,9 +36,8 @@ static int l_create_fragment(lua::State* L) {
 
 static int l_load_fragment(lua::State* L) {
     auto paths = engine->getPaths();
-    auto [prefix, filename] = EnginePaths::parsePath(lua::require_string(L, 1));
-
-    auto path = paths->resolve(prefix+":generators/"+filename+".vox");
+    auto filename = lua::require_string(L, 1);
+    auto path = paths->resolve(filename);
     if (!std::filesystem::exists(path)) {
         throw std::runtime_error("file "+path.u8string()+" does not exist");
     }

src/logic/scripting/lua/usertypes/lua_type_voxelstructure.cpp

@@ -13,6 +13,17 @@ LuaVoxelFragment::LuaVoxelFragment(std::shared_ptr<VoxelFragment> fragment)
 LuaVoxelFragment::~LuaVoxelFragment() {
 }
 
+static int l_crop(lua::State* L) {
+    if (auto fragment = touserdata<LuaVoxelFragment>(L, 1)) {
+        fragment->getFragment()->crop();
+    }
+    return 0;
+}
+
+static std::unordered_map<std::string, lua_CFunction> methods {
+    {"crop", lua::wrap<l_crop>},
+};
+
 static int l_meta_tostring(lua::State* L) {
     return pushstring(L, "VoxelFragment(0x" + util::tohex(
         reinterpret_cast<uint64_t>(topointer(L, 1)))+")");
@@ -27,12 +38,16 @@ static int l_meta_index(lua::State* L) {
         auto fieldname = tostring(L, 2);
         if (!std::strcmp(fieldname, "size")) {
             return pushivec(L, fragment->getFragment()->getSize());
+        } else {
+            auto found = methods.find(tostring(L, 2));
+            if (found != methods.end()) {
+                return pushcfunction(L, found->second);
+            }
         }
     }
     return 0;
 }
 
-
 int LuaVoxelFragment::createMetatable(lua::State* L) {
     createtable(L, 0, 2);
     pushcfunction(L, lua::wrap<l_meta_tostring>);