Patched to compile with latest version of xatlas and Godot 3.2

merge.cpp

@@ -805,8 +805,7 @@ void MeshMergeMaterialRepack::_generate_atlas(const int32_t p_num_meshes, Vector
 			meshDecl.indexData = indexes.ptr();
 			meshDecl.indexFormat = xatlas::IndexFormat::UInt32;
 			meshDecl.faceMaterialData = materials.ptr();
-			meshDecl.rotateCharts = false;
-			xatlas::AddMeshError::Enum error = xatlas::AddUvMesh(atlas, meshDecl);
+			xatlas::AddMeshError error = xatlas::AddUvMesh(atlas, meshDecl);
 			ERR_CONTINUE_MSG(error != xatlas::AddMeshError::Success, String("Error adding mesh ") + itos(mesh_i) + String(": ") + xatlas::StringForEnum(error));
 			mesh_count++;
 		}
@@ -817,6 +816,7 @@ void MeshMergeMaterialRepack::_generate_atlas(const int32_t p_num_meshes, Vector
 	pack_options.bruteForce = true;
 	pack_options.blockAlign = true;
 	pack_options.resolution = 2048;
+	pack_options.rotateCharts = false;
 	xatlas::PackCharts(atlas, pack_options);
 }
 
@@ -958,7 +958,7 @@ void MeshMergeMaterialRepack::map_mesh_to_index_to_material(const Vector<MeshSta
 			Array mesh = array_mesh->surface_get_arrays(j);
 			Array uvs = mesh[ArrayMesh::ARRAY_TEX_UV];
 			if (!uvs.size()) {
-				array_mesh->mesh_unwrap(Transform(), 2.0f);
+				array_mesh->lightmap_unwrap(Transform(), 2.0f);
 				break;
 			}
 		}