Optimize and robustify asset prefetching and material loading.

- Parallelize asset prefetching (max 4 workers) with retry logic and on-screen error banner, replacing silent failures and cryptic WASM out-of-bounds crashes with explicit missing-file errors.
- Support binary Uint8Array/ArrayBuffer in C++ asset registry via typed_memory_view, preventing Embind string coercion from corrupting binary shader packages into ASCII text.
- Automatically glob .mat files in CMake instead of maintaining a manual list.
- Add missing reflection materials to prefetch arrays.
- Disable caching for index.html in web server so template/script updates apply on normal page reload without stale cache issues, the file is small so caching had a negligible upside.
- Add null resource and payload validation in ObjectManager::LoadMaterial before constructing Filament materials.

PiperOrigin-RevId: 963364509
Change-Id: I7de79df6a5cede4e54683415ee193f1c5a665286

src/experimental/studio/live.js

@@ -138,13 +138,14 @@ var Module = {
   totalDependencies: 0,
   monitorRunDependencies(left) { },
   onRuntimeInitialized: () => {
-    // Define assets to prefetch, relative to the WASM directory.
     const assetsToPrefetch = [
       "assets/fontawesome-webfont.ttf",
       "assets/ibl.ktx",
       "assets/AtkinsonHyperlegibleNext[wght].ttf",
       "assets/AtkinsonHyperlegibleMono-Regular.ttf",
       "assets/pbr.filamat",
+      "assets/pbr_reflect.filamat",
+      "assets/pbr_packed_reflect.filamat",
       "assets/pbr_transparent.filamat",
       "assets/pbr_packed.filamat",
       "assets/pbr_packed_transparent.filamat",

src/render/filament/CMakeLists.txt

@@ -92,43 +92,18 @@ add_library(mujoco::filament ALIAS ${MUJOCO_FILAMENT_TARGET_NAME})
 set(ASSETS_DIR "${CMAKE_CURRENT_SOURCE_DIR}/assets")
 set(OUTPUT_ASSETS_DIR "${CMAKE_CURRENT_BINARY_DIR}/assets")
 file(MAKE_DIRECTORY ${OUTPUT_ASSETS_DIR})
+
 file(COPY
     "${ASSETS_DIR}/ibl.ktx"
     DESTINATION ${OUTPUT_ASSETS_DIR}
 )
 
 set(MATC_EXECUTABLE matc)
-set(MATERIAL_FILES
-    pbr.mat
-    pbr_transparent.mat
-    pbr_packed.mat
-    pbr_packed_transparent.mat
-    pbr_reflect.mat
-    pbr_packed_reflect.mat
-    phong_2d_fade.mat
-    phong_2d.mat
-    phong_2d_reflect.mat
-    phong_2d_uv_fade.mat
-    phong_2d_uv.mat
-    phong_2d_uv_reflect.mat
-    phong_color_fade.mat
-    phong_color.mat
-    phong_color_reflect.mat
-    phong_cube_fade.mat
-    phong_cube.mat
-    phong_cube_reflect.mat
-    outline_composite.mat
-    outline_flatten.mat
-    outline_jumpflood.mat
-    decor.mat
-    unlit_depth.mat
-    unlit_segmentation.mat
-    unlit_ui.mat
-)
+file(GLOB MATERIAL_FILES CONFIGURE_DEPENDS "${ASSETS_DIR}/*.mat")
 
-foreach(MATERIAL_FILE ${MATERIAL_FILES})
-    get_filename_component(MATERIAL_NAME ${MATERIAL_FILE} NAME_WE)
-    set(INPUT_FILE "${ASSETS_DIR}/${MATERIAL_FILE}")
+foreach(INPUT_FILE ${MATERIAL_FILES})
+    get_filename_component(MATERIAL_NAME ${INPUT_FILE} NAME_WE)
+    get_filename_component(MATERIAL_FILE ${INPUT_FILE} NAME)
     set(OUTPUT_FILE "${OUTPUT_ASSETS_DIR}/${MATERIAL_NAME}.filamat")
 
     if(CMAKE_SYSTEM_NAME STREQUAL "Emscripten")

src/render/filament/core/object_manager.cc

@@ -42,8 +42,19 @@ static filament::Material* LoadMaterial(filament::Engine* engine,
   const std::string path = ResolveFilamentAssetPath(std::string(filename));
   mjResource* resource =
       mju_openResource("", path.c_str(), nullptr, nullptr, 0);
+  if (!resource) {
+    mju_error("Failed to open filament asset '%.*s' at '%s'",
+              static_cast<int>(filename.size()), filename.data(), path.c_str());
+    return nullptr;
+  }
   void* payload = nullptr;
   int size = mju_readResource(resource, const_cast<const void**>(&payload));
+  if (size <= 0 || !payload) {
+    mju_error("Failed to read filament asset '%.*s' (size=%d)",
+              static_cast<int>(filename.size()), filename.data(), size);
+    mju_closeResource(resource);
+    return nullptr;
+  }
   filament::Material::Builder material_builder;
   material_builder.package(payload, size);
   filament::Material* material = material_builder.build(*engine);