source/blender/io/usd/intern/usd_capi_import.cc

@@ -397,11 +397,6 @@ void USD_ensure_plugin_path_registered()
   blender::io::usd::ensure_usd_plugin_path_registered();
 }
 
-void USD_setup_usd_mtlx_environment()
-{
-  blender::io::usd::setup_usd_mtlx_environment();
-}
-
 bool USD_import(struct bContext *C,
                 const char *filepath,
                 const USDImportParams *params,

source/blender/io/usd/intern/usd_common.cc

@@ -5,11 +5,6 @@
 
 #include <pxr/base/plug/registry.h>
 
-#include "BKE_appdir.h"
-#include "BLI_string.h"
-#include "BLI_fileops.h"
-#include "BLI_path_util.h"
-
 namespace blender::io::usd {
 
 void ensure_usd_plugin_path_registered()
@@ -35,43 +30,4 @@ void ensure_usd_plugin_path_registered()
 #endif
 }
 
-void setup_usd_mtlx_environment()
-{
-  /* PXR_MTLX_STDLIB_SEARCH_PATHS - path to the MaterialX standard library
-   * USD's MaterialX code expects to be set. */
-
-  static bool mtlx_env_set = false;
-  if (mtlx_env_set) {
-    return;
-  }
-  mtlx_env_set = true;
-
-  char stdlib_path[FILE_MAX] = "";
-  size_t stdlib_path_len = BLI_path_join(
-      stdlib_path, sizeof(stdlib_path), BKE_appdir_program_dir(), "materialx", "libraries");
-  if (stdlib_path_len == 0 || !BLI_exists(stdlib_path)) {
-    return;
-  }
-
-#ifdef _WIN32
-#  define PATH_SEP ";"
-#else
-#  define PATH_SEP ":"
-#endif
-
-  const char *env_var_name = "PXR_MTLX_STDLIB_SEARCH_PATHS";
-  const char *env_var = BLI_getenv(env_var_name);
-  if (!env_var) {
-    BLI_setenv(env_var_name, stdlib_path);
-  }
-  else {
-    size_t env_var_len = strlen(env_var);
-    size_t combined_len = stdlib_path_len + 1 + env_var_len + 1;
-    char *combined = (char *)malloc(sizeof(char) * combined_len);
-    BLI_snprintf(combined, combined_len, "%s" PATH_SEP "%s", stdlib_path, env_var);
-    BLI_setenv(env_var_name, combined);
-    free(combined);
-  }
-}
-
 }  // namespace blender::io::usd

source/blender/io/usd/intern/usd_common.h

@@ -5,6 +5,5 @@
 namespace blender::io::usd {
 
 void ensure_usd_plugin_path_registered();
-void setup_usd_mtlx_environment();
 
 }  // namespace blender::io::usd

source/blender/io/usd/usd.h

@@ -138,7 +138,6 @@ struct CacheReader *CacheReader_open_usd_object(struct CacheArchiveHandle *handl
 void USD_CacheReader_incref(struct CacheReader *reader);
 void USD_CacheReader_free(struct CacheReader *reader);
 void USD_ensure_plugin_path_registered(void);
-void USD_setup_usd_mtlx_environment(void);
 #ifdef __cplusplus
 }
 #endif

source/blender/render/hydra/python.cc

@@ -13,6 +13,9 @@
 
 #include "glog/logging.h"
 #include "BKE_appdir.h"
+#include "BLI_string.h"
+#include "BLI_fileops.h"
+#include "BLI_path_util.h"
 
 #include "finalEngine.h"
 #include "viewportEngine.h"
@@ -21,12 +24,51 @@ using namespace std;
 
 namespace blender::render::hydra {
 
+void setup_usd_mtlx_environment()
+{
+  /* PXR_MTLX_STDLIB_SEARCH_PATHS - path to the MaterialX standard library
+   * USD's MaterialX code expects to be set. */
+
+  static bool mtlx_env_set = false;
+  if (mtlx_env_set) {
+    return;
+  }
+  mtlx_env_set = true;
+
+  char stdlib_path[FILE_MAX] = "";
+  size_t stdlib_path_len = BLI_path_join(
+      stdlib_path, sizeof(stdlib_path), BKE_appdir_program_dir(), "materialx", "libraries");
+  if (stdlib_path_len == 0 || !BLI_exists(stdlib_path)) {
+    return;
+  }
+
+#ifdef _WIN32
+#  define PATH_SEP ";"
+#else
+#  define PATH_SEP ":"
+#endif
+
+  const char *env_var_name = "PXR_MTLX_STDLIB_SEARCH_PATHS";
+  const char *env_var = BLI_getenv(env_var_name);
+  if (!env_var) {
+    BLI_setenv(env_var_name, stdlib_path);
+  }
+  else {
+    size_t env_var_len = strlen(env_var);
+    std::string combined(stdlib_path_len + 1 + env_var_len, '\0');
+    BLI_snprintf(combined.data(), combined.capacity(), "%s" PATH_SEP "%s", stdlib_path, env_var);
+    BLI_setenv(env_var_name, combined.c_str());
+  }
+}
+
 static PyObject *init_func(PyObject * /*self*/, PyObject *args)
 {
   LOG(INFO) << "init_func";
 
   pxr::PlugRegistry::GetInstance().RegisterPlugins(string(BKE_appdir_program_dir()) + "/blender.shared/usd");
 
+  setup_usd_mtlx_environment();
+
   Py_RETURN_NONE;
 }
 

source/creator/CMakeLists.txt

@@ -1513,10 +1513,6 @@ if(WITH_USD)
   absolute_include_dirs(../blender/io/usd)
 endif()
 
-if(WITH_MATERIALX)
-  add_definitions(-DWITH_MATERIALX)
-endif()
-
 # Always install USD shared library and datafiles regardless if Blender
 # itself uses them, the bundled Python module still needs it.
 if((DEFINED LIBDIR) AND TARGETDIR_LIB)

source/creator/creator.c

@@ -477,9 +477,6 @@ int main(int argc,
 
 #ifdef WITH_USD
   USD_ensure_plugin_path_registered();
-#  ifdef WITH_MATERIALX
-  USD_setup_usd_mtlx_environment();
-#  endif
 #endif
 
 #ifndef WITH_PYTHON_MODULE