source/blender/io/usd/CMakeLists.txt

@@ -205,6 +205,11 @@ if(WITH_OPENVDB)
   )
 endif()
 
+if(WITH_MATERIALX)
+  list(APPEND LIB MaterialXCore)
+  list(APPEND LIB MaterialXFormat)
+endif()
+
 blender_add_lib(bf_usd "${SRC}" "${INC}" "${INC_SYS}" "${LIB}")
 
 # RNA_prototypes.h

source/blender/io/usd/hydra/material.cc

@@ -12,6 +12,9 @@
 #include <pxr/imaging/hd/tokens.h>
 #include <pxr/usdImaging/usdImaging/materialParamUtils.h>
 
+#include <pxr/usd/usdMtlx/reader.h>
+#include <pxr/usd/usdMtlx/utils.h>
+
 #include "MEM_guardedalloc.h"
 
 #include "BKE_lib_id.h"
@@ -30,6 +33,7 @@
 
 #include "intern/usd_exporter_context.h"
 #include "intern/usd_writer_material.h"
+#include "shader/materialx/material.h"
 
 namespace blender::io::hydra {
 
@@ -68,25 +72,33 @@ void MaterialData::init()
                                          image_cache_file_path()};
 
   /* Create USD material. */
-  pxr::UsdShadeMaterial usd_material = usd::create_usd_material(
+  //pxr::UsdShadeMaterial usd_material = usd::create_usd_material(export_context, material_path, (Material *)id, "st");
-      export_context, material_path, (Material *)id, "st");
 
   /* Convert USD material to Hydra material network map, adapted for render delegate. */
-  const pxr::HdRenderDelegate *render_delegate =
+  const pxr::HdRenderDelegate *render_delegate = scene_delegate_->GetRenderIndex().GetRenderDelegate();
-      scene_delegate_->GetRenderIndex().GetRenderDelegate();
   const pxr::TfTokenVector contextVector = render_delegate->GetMaterialRenderContexts();
   pxr::TfTokenVector shaderSourceTypes = render_delegate->GetShaderSourceTypes();
 
   pxr::HdMaterialNetworkMap network_map;
 
-  if (pxr::UsdShadeShader surface = usd_material.ComputeSurfaceSource(contextVector)) {
+  MaterialX::DocumentPtr doc = blender::nodes::materialx::export_to_materialx((Material *)id);
-    pxr::UsdImagingBuildHdMaterialNetworkFromTerminal(surface.GetPrim(),
+  pxr::UsdMtlxRead(doc, stage);
+
+  if (pxr::UsdPrim materials = stage->GetPrimAtPath(pxr::SdfPath("/MaterialX/Materials"))) {
+    if (pxr::UsdPrimSiblingRange children = materials.GetChildren()) {
+      if (auto usd_material = pxr::UsdShadeMaterial(*children.begin())) {
+        if (pxr::UsdShadeShader mtlx_surface = usd_material.ComputeSurfaceSource(contextVector))
+        {
+          UsdImagingBuildHdMaterialNetworkFromTerminal(mtlx_surface.GetPrim(),
                                                        pxr::HdMaterialTerminalTokens->surface,
                                                        shaderSourceTypes,
                                                        contextVector,
                                                        &network_map,
                                                        time);
         }
+      }
+    }
+  }
 
   material_network_map_ = pxr::VtValue(network_map);
 }

source/blender/nodes/shader/materialx/material.cc

@@ -5,6 +5,7 @@
 #include "material.h"
 
 #include <MaterialXCore/Node.h>
+#include <MaterialXFormat/XmlIo.h>
 
 namespace blender::nodes::materialx {
 
@@ -17,20 +18,28 @@ static void create_standard_surface(MaterialX::DocumentPtr doc, Material *materi
 
   standard_surface->addInput("base", "float")->setValue(1.0);
   standard_surface->addInput("base_color", "color3")
-      ->setValue(MaterialX::Color3(material->r, material->g, material->a));
+      ->setValue(MaterialX::Color3(material->r, material->g, material->b));
 
   surfacematerial->addInput(standard_surface->getType(), standard_surface->getType())
                  ->setNodeName(standard_surface->getName());
 }
 
+static void export_nodegraph(MaterialX::DocumentPtr doc, Material *material)
+{
+  ;
+}
+
 MaterialX::DocumentPtr export_to_materialx(Material* material) {
   MaterialX::DocumentPtr doc = MaterialX::createDocument();
   if (material->use_nodes) {
-    ;
+    export_nodegraph(doc, material);
   }
   else {
     create_standard_surface(doc, material);
   }
+  MaterialX::writeToXmlFile(
+      doc,
+      MaterialX::FilePath("c:/Users/Vasyl_Pidhirskyi/Work/AMD/blender-git/tmp/material.mtlx"));
   return doc;
 }
 

source/blender/nodes/shader/materialx/material.h

@@ -11,6 +11,8 @@
 namespace blender::nodes::materialx {
 
 MaterialX::DocumentPtr export_to_materialx(Material *material);
+static void create_standard_surface(MaterialX::DocumentPtr doc, Material *material);
+static void export_nodegraph(MaterialX::DocumentPtr doc, Material *material);
 
 }  // namespace blender::materialx