release/scripts/modules/bpy_hydra.py

@@ -0,0 +1,114 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+"""
+Implementation of class `HydraRenderEngine`.
+
+Render Blender addon with Hydra render delegate should inherit `HydraRenderEngine`.
+Example:
+```
+import bpy_hydra
+
+class CustomHydraRenderEngine(HydraRenderEngine):
+    bl_idname = 'CustomHydraRenderEngine'
+    bl_label = "Hydra: Custom"
+    bl_info = "Hydra Custom render delegate"
+
+    delegate_id = 'HdCustomRendererPlugin'
+
+    @classmethod
+    def register(cls):
+        super().register()
+
+        bpy_hydra.register_plugins(["/path/to/plugin")], ["/additional/system/path")])
+
+    def get_delegate_settings(self, engine_type):
+        return {
+            'setting1': 1,
+            'setting2': "2",
+        }
+```
+"""
+
+__all__ = (
+    "HydraRenderEngine",
+    "export_mtlx",
+    "register_plugins",
+    "get_render_plugins",
+)
+
+import bpy
+import _bpy_hydra
+
+from _bpy_hydra import register_plugins, get_render_plugins
+
+
+class HydraRenderEngine(bpy.types.RenderEngine):
+    """ Render addon with Hydra render delegate should inherit this class """
+
+    bl_use_shading_nodes_custom = False
+
+    delegate_id = ''
+    engine_ptr = None
+
+    def __del__(self):
+        if not self.engine_ptr:
+            return
+
+        _bpy_hydra.engine_free(self.engine_ptr)
+
+    @classmethod
+    def register(cls):
+        _bpy_hydra.init()
+
+    @classmethod
+    def unregister(cls):
+        pass
+
+    def get_delegate_settings(self, engine_type):
+        return {}
+
+    # final render
+    def update(self, data, depsgraph):
+        pass
+
+    def render(self, depsgraph):
+        engine_type = 'PREVIEW' if self.is_preview else 'FINAL'
+
+        self.engine_ptr = _bpy_hydra.engine_create(self.as_pointer(), engine_type, self.delegate_id)
+        delegate_settings = self.get_delegate_settings(engine_type)
+
+        _bpy_hydra.engine_sync(self.engine_ptr, depsgraph.as_pointer(), bpy.context.as_pointer(), delegate_settings)
+        _bpy_hydra.engine_render(self.engine_ptr, depsgraph.as_pointer())
+
+    # viewport render
+    def view_update(self, context, depsgraph):
+        if not self.engine_ptr:
+            self.engine_ptr = _bpy_hydra.engine_create(self.as_pointer(), 'VIEWPORT', self.delegate_id)
+
+        delegate_settings = self.get_delegate_settings('VIEWPORT')
+        _bpy_hydra.engine_sync(self.engine_ptr, depsgraph.as_pointer(), context.as_pointer(), delegate_settings)
+
+    def view_draw(self, context, depsgraph):
+        if not self.engine_ptr:
+            return
+
+        _bpy_hydra.engine_view_draw(self.engine_ptr, depsgraph.as_pointer(), context.as_pointer())
+
+
+def export_mtlx(material):
+    """ Exports material to .mtlx file. It is called from Blender source code. """
+    try:
+        import materialx.utils as mx_utils
+
+        doc = mx_utils.export(material, None)
+        if not doc:
+            return ""
+
+        mtlx_file = mx_utils.get_temp_file(".mtlx", material.name)
+        mx_utils.export_to_file(doc, mtlx_file, export_deps=True, copy_deps=False)
+        return str(mtlx_file)
+
+    except ImportError:
+        print("ERROR: no MaterialX addon available")
+
+    return ""

release/scripts/modules/hydra.py

@@ -1,85 +0,0 @@
-# SPDX-License-Identifier: Apache-2.0
-# Copyright 2011-2022 Blender Foundation
-
-# <pep8 compliant>
-
-import traceback
-
-import bpy
-import _hydra
-
-from _hydra import register_plugins, get_render_plugins
-
-
-class HydraRenderEngine(bpy.types.RenderEngine):
-    bl_use_preview = True
-    bl_use_shading_nodes_custom = False
-
-    delegate_id = ''
-    engine_ptr = None
-
-    def __del__(self):
-        if not self.engine_ptr:
-            return
-
-        _hydra.engine_free(self.engine_ptr)
-
-    @classmethod
-    def register(cls):
-        _hydra.init()
-
-    @classmethod
-    def unregister(cls):
-        pass
-
-    def get_delegate_settings(self, engine_type):
-        return {}
-
-    # final render
-    def update(self, data, depsgraph):
-        pass
-
-    def render(self, depsgraph):
-        engine_type = 'PREVIEW' if self.is_preview else 'FINAL'
-
-        self.engine_ptr = _hydra.engine_create(self.as_pointer(), engine_type, self.delegate_id)
-        delegate_settings = self.get_delegate_settings(engine_type)
-
-        _hydra.engine_sync(self.engine_ptr, depsgraph.as_pointer(), bpy.context.as_pointer(), delegate_settings)
-        _hydra.engine_render(self.engine_ptr, depsgraph.as_pointer())
-
-    # viewport render
-    def view_update(self, context, depsgraph):
-        if not self.engine_ptr:
-            self.engine_ptr = _hydra.engine_create(self.as_pointer(), 'VIEWPORT', self.delegate_id)
-
-        delegate_settings = self.get_delegate_settings('VIEWPORT')
-        _hydra.engine_sync(self.engine_ptr, depsgraph.as_pointer(), context.as_pointer(), delegate_settings)
-
-    def view_draw(self, context, depsgraph):
-        if not self.engine_ptr:
-            return
-
-        _hydra.engine_view_draw(self.engine_ptr, depsgraph.as_pointer(), context.as_pointer())
-
-
-def export_mtlx(material_name):
-    try:
-        import materialx.utils as mx_utils
-
-        material = bpy.data.materials[material_name]
-        doc = mx_utils.export(material, None)
-        if not doc:
-            return ""
-
-        mtlx_file = mx_utils.get_temp_file(".mtlx", material.name)
-        mx_utils.export_to_file(doc, mtlx_file, export_deps=True, copy_deps=False)
-        return str(mtlx_file)
-
-    except ImportError:
-        print("ERROR: no MaterialX addon available")
-
-    except Exception as e:
-        print("ERROR:", e, traceback.format_exc())
-
-    return ""

source/blender/python/intern/bpy_interface.c

@@ -256,8 +256,8 @@ static PyObject *CCL_initPython(void)
 #endif
 
 #ifdef WITH_HYDRA
-/* defined in USD Hydra module */
-extern PyObject *Hydra_initPython(void);
+/* defined in render_hydra module */
+extern PyObject *BPyInit_hydra(void);
 #endif
 
 static struct _inittab bpy_internal_modules[] = {
@@ -290,7 +290,7 @@ static struct _inittab bpy_internal_modules[] = {
     {"gpu", BPyInit_gpu},
     {"idprop", BPyInit_idprop},
 #ifdef WITH_HYDRA
-    {"_hydra", Hydra_initPython},
+    {"_bpy_hydra", BPyInit_hydra},
 #endif
     {NULL, NULL},
 };

source/blender/render/hydra/CMakeLists.txt

@@ -34,7 +34,9 @@ set(INC
   ../../gpu
   ../../gpu/opengl
   ../../gpu/intern
+  ../../python/intern
   ..
+  ${CMAKE_BINARY_DIR}/source/blender/makesrna/intern
 )
 
 set(INC_SYS

source/blender/render/hydra/python.cc

@@ -266,7 +266,7 @@ static PyMethodDef methods[] = {
 
 static struct PyModuleDef module = {
     PyModuleDef_HEAD_INIT,
-    "_hydra",
+    "_bpy_hydra",
     "Hydra render API",
     -1,
     methods,
@@ -282,7 +282,7 @@ static struct PyModuleDef module = {
 extern "C" {
 #endif
 
-PyObject *Hydra_initPython(void)
+PyObject *BPyInit_hydra(void)
 {
   PyObject *mod = PyModule_Create(&blender::render::hydra::module);
   return mod;

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

@@ -12,6 +12,10 @@
 #include "BKE_lib_id.h"
 #include "BKE_material.h"
 
+#include "MEM_guardedalloc.h"
+#include "RNA_blender_cpp.h"
+#include "bpy_rna.h"
+
 #include "blender_scene_delegate.h"
 #include "material.h"
 #include "mtlx_hydra_adapter.h"
@@ -74,14 +78,26 @@ void MaterialData::export_mtlx()
   gstate = PyGILState_Ensure();
 
   PyObject *module, *dict, *func, *result;
-  module = PyImport_ImportModule("hydra");
+  module = PyImport_ImportModule("bpy_hydra");
   dict = PyModule_GetDict(module);
   func = PyDict_GetItemString(dict, "export_mtlx");
-  result = PyObject_CallFunction(func, "s", name().c_str());
 
-  std::string path = PyUnicode_AsUTF8(result);
+  PointerRNA materialptr;
+  RNA_pointer_create(NULL, &RNA_Material, id, &materialptr);
+  PyObject *material = pyrna_struct_CreatePyObject(&materialptr);
 
-  Py_DECREF(result);
+  result = PyObject_CallFunction(func, "O", material);
+
+  Py_DECREF(material);
+
+  std::string path;
+  if (result) {
+    path = PyUnicode_AsUTF8(result);
+    Py_DECREF(result);
+  }
+  else {
+    PyErr_Print();
+  }
   Py_DECREF(module);
 
   PyGILState_Release(gstate);