scripts/modules/bpy_hydra.py

@@ -100,19 +100,18 @@ class HydraRenderEngine(bpy.types.RenderEngine):
         _bpy_hydra.engine_view_draw(self.engine_ptr, depsgraph.as_pointer(), context.as_pointer())
 
 
-def export_mtlx(material, mtlx_file):
+def export_mtlx(material):
     """ Exports material to .mtlx file. It is called from Blender source code. """
     try:
         import materialx.utils as mx_utils
     except ImportError:
         print("ERROR: no MaterialX addon available")
-        return False
+        return ""
 
-    raise TypeError("asasfas")
-    
     doc = mx_utils.export(material, None)
     if not doc:
-        return False
+        return ""
 
+    mtlx_file = mx_utils.get_temp_file(".mtlx", f"mat_{material.as_pointer():016x}")
     mx_utils.export_to_file(doc, mtlx_file, export_deps=True, copy_deps=False)
-    return True
+    return str(mtlx_file)

source/blender/render/hydra/scene_delegate/material.cc

@@ -17,7 +17,6 @@
 #include "blender_scene_delegate.h"
 #include "material.h"
 #include "mtlx_hydra_adapter.h"
-#include "../utils.h"
 
 namespace blender::render::hydra {
 
@@ -66,24 +65,19 @@ void MaterialData::init()
   RNA_pointer_create(NULL, &RNA_Material, id_, &materialptr);
   PyObject *material = pyrna_struct_CreatePyObject(&materialptr);
 
-  char file_name[32];
-  snprintf(file_name, 32, "mat_%016llx.mtlx", (uintptr_t)id_);
-  std::string file_path = temp_file_path(file_name);
-  result = PyObject_CallFunction(func, "Os", material, file_path.c_str());
+  result = PyObject_CallFunction(func, "O", material);
 
   Py_DECREF(material);
 
- if (!PyErr_Occurred()) {
-    if (!PyObject_IsTrue(result)) {
-      file_path = "";
-    }
+  std::string path;
+
+  if (!PyErr_Occurred()) {
+    path = PyUnicode_AsUTF8(result);
     Py_DECREF(result);
   }
   else {
-    file_path = "";
-
     /* Clearing and logging exception data */
-    PyObject *type, *value, *traceback, *pstr;
+    PyObject *type, *value, *traceback;
     PyErr_Fetch(&type, &value, &traceback);
     PyErr_NormalizeException(&type, &value, &traceback);
     std::string err_str = ((PyTypeObject *)type)->tp_name;
@@ -97,13 +91,14 @@ void MaterialData::init()
     Py_XDECREF(value);
     Py_DECREF(type);
 
-    CLOG_ERROR(LOG_BSD, "Export error for %s (%s): %s", p_id_.GetText(), id_->name, err_str.c_str());
+    CLOG_ERROR(
+        LOG_BSD, "Export error for %s (%s): %s", p_id_.GetText(), id_->name, err_str.c_str());
   }
   Py_DECREF(module);
 
   PyGILState_Release(gstate);
 
-  mtlx_path_ = pxr::SdfAssetPath(file_path, file_path);
+  mtlx_path_ = pxr::SdfAssetPath(path, path);
   ID_LOG(2, "mtlx=%s", mtlx_path_.GetResolvedPath().c_str());
 }
 

source/blender/render/hydra/utils.cc

@@ -99,11 +99,4 @@ std::string cache_image(Main *bmain,
   return tempfile;
 }
 
-std::string temp_file_path(std::string const &file_name)
-{
-  char tempfile[FILE_MAX];
-  BLI_path_join(tempfile, sizeof(tempfile), BKE_tempdir_session(), "render_hydra", file_name.c_str());
-  return tempfile;
-}
-
 }  // namespace blender::render::hydra

source/blender/render/hydra/utils.h

@@ -21,6 +21,5 @@ std::string cache_image(Main *bmain,
                         ImageUser *iuser,
                         ImageSaveOptions *opts,
                         ReportList *reports);
-std::string temp_file_path(std::string const &file_name);
 
 }  // namespace blender::render::hydra