Support for loading compress NVDBs

tsd/CMakeLists.txt

@@ -62,6 +62,8 @@ option(TSD_USE_MPI "Enable MPI support" OFF)
 option(TSD_USE_NETWORKING "Enable networking support via boost.asio" OFF)
 option(TSD_NANOVDB_SKIP_INVALID_VOLUMES
   "Skip NanoVDB volumes with zero active voxels" OFF)
+option(TSD_NANOVDB_USE_ZIP
+  "Enable zlib so NanoVDB importer can read ZIP-compressed .nvdb files" ON)
 option(TSD_USE_LUA "Enable Lua scripting support" ON)
 
 if (APPLE)

tsd/external/CMakeLists.txt

@@ -12,6 +12,7 @@ add_subdirectory(tsd_tinyexr)
 add_subdirectory(tsd_tinygltf)
 add_subdirectory(tsd_tinyobjloader)
 add_subdirectory(tsd_tinyply)
+add_subdirectory(tsd_zlib EXCLUDE_FROM_ALL)
 
 add_subdirectory(
   ${CMAKE_CURRENT_LIST_DIR}/../../devices/rtx/external

tsd/external/tsd_nanovdb/CMakeLists.txt

@@ -9,3 +9,12 @@ if (TSD_USE_TBB)
   project_link_libraries(INTERFACE TBB::tbb)
   project_compile_definitions(INTERFACE NANOVDB_USE_TBB)
 endif()
+
+if (TSD_NANOVDB_USE_ZIP)
+  # zlib decompresses ZIP-encoded .nvdb files at read time. ANARI always
+  # receives the decompressed in-memory grid buffer — the codec only
+  # affects on-disk storage. The tsd FindZLIB.cmake module supplies a
+  # fetched static fallback when no system zlib is available.
+  project_link_libraries(INTERFACE tsd_ext_zlib)
+  project_compile_definitions(INTERFACE NANOVDB_USE_ZIP)
+endif()

tsd/external/tsd_zlib/CMakeLists.txt

@@ -0,0 +1,58 @@
+## Copyright 2026 NVIDIA Corporation
+## SPDX-License-Identifier: Apache-2.0
+
+# zlib - compression/decompression library
+# Static fallback build when no system zlib is available.
+
+project(tsd_ext_zlib LANGUAGES C)
+
+find_package(ZLIB QUIET)
+if(ZLIB_FOUND)
+  project_add_library(INTERFACE)
+  project_link_libraries(INTERFACE ZLIB::ZLIB)
+  return()
+endif()
+
+message(STATUS
+  "ZLIB not found via find_package — fetching upstream zlib 1.3.1.")
+anari_sdk_fetch_project(
+  NAME ${PROJECT_NAME}
+  URL https://github.com/madler/zlib/releases/download/v1.3.1/zlib-1.3.1.tar.gz
+  MD5 9855b6d802d7fe5b7bd5b196a2271655
+)
+
+# Minimal static build — only the bits the compress/uncompress path needs.
+# gzip stream I/O (gz*.c) is intentionally excluded.
+project_add_library(STATIC
+  ${tsd_ext_zlib_LOCATION}/adler32.c
+  ${tsd_ext_zlib_LOCATION}/crc32.c
+  ${tsd_ext_zlib_LOCATION}/deflate.c
+  ${tsd_ext_zlib_LOCATION}/infback.c
+  ${tsd_ext_zlib_LOCATION}/inffast.c
+  ${tsd_ext_zlib_LOCATION}/inflate.c
+  ${tsd_ext_zlib_LOCATION}/inftrees.c
+  ${tsd_ext_zlib_LOCATION}/trees.c
+  ${tsd_ext_zlib_LOCATION}/zutil.c
+  ${tsd_ext_zlib_LOCATION}/compress.c
+  ${tsd_ext_zlib_LOCATION}/uncompr.c
+)
+
+project_include_directories(
+  PUBLIC
+    $<BUILD_INTERFACE:${tsd_ext_zlib_LOCATION}>
+)
+
+set_target_properties(${PROJECT_NAME} PROPERTIES POSITION_INDEPENDENT_CODE ON)
+
+# Suppress warnings from zlib code
+if(CMAKE_C_COMPILER_ID MATCHES "GNU|Clang")
+  project_compile_options(PRIVATE -w)
+elseif(MSVC)
+  # zlib uses a handful of CRT functions MSVC flags as "unsafe".
+  project_compile_options(PRIVATE /W0)
+  project_compile_definitions(PRIVATE
+    _CRT_SECURE_NO_DEPRECATE
+    _CRT_NONSTDC_NO_DEPRECATE
+  )
+endif()
+

tsd/src/tsd/io/importers/import_NVDB.cpp

@@ -15,6 +15,7 @@
 
 #include <filesystem>
 #include <limits>
+#include <string_view>
 
 namespace tsd::io {
 
@@ -186,7 +187,17 @@ SpatialFieldRef import_NVDB(Scene &scene, const char *filepath)
 
     logStatus("[import_NVDB] ...done!");
   } catch (const std::exception &e) {
+    using namespace std::string_view_literals;
+    const std::string_view msg(e.what());
     logStatus("[import_NVDB] failed: %s", e.what());
+    if (msg.find("compression codec was disabled"sv) != std::string_view::npos) {
+      logStatus(
+          "[import_NVDB] '%s' is stored with a compressed codec but TSD was "
+          "built without it. Reconfigure with -DTSD_NANOVDB_USE_ZIP=ON (and "
+          "ensure zlib is available) to decompress at read time. ANARI is "
+          "always handed the uncompressed in-memory grid buffer.",
+          filepath);
+    }
     scene.removeObject(field.data());
     return {};
   }