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

@@ -36,6 +36,7 @@
 #include "intern/usd_exporter_context.h"
 #include "intern/usd_writer_material.h"
 #ifdef WITH_MATERIALX
+#  include "shader/materialx/node_parser.h"
 #  include "shader/materialx/material.h"
 #endif
 namespace blender::io::hydra {
@@ -79,7 +80,7 @@ void MaterialData::init()
 #ifdef WITH_MATERIALX
   if (scene_delegate_->use_materialx) {
     MaterialX::DocumentPtr doc = blender::nodes::materialx::export_to_materialx(
-        scene_delegate_->depsgraph, (Material *)id);
+        scene_delegate_->depsgraph, (Material *)id, cache_or_get_image_file);
     pxr::UsdMtlxRead(doc, stage);
 
     /* Logging stage: creating lambda stage_str() to not call stage->ExportToString()

source/blender/nodes/shader/CMakeLists.txt

@@ -22,13 +22,6 @@ set(INC
   ${CMAKE_BINARY_DIR}/source/blender/makesrna
 )
 
-if(WITH_HYDRA)
-  list(APPEND INC
-    ../../io/usd
-  )
-  add_definitions(-DWITH_HYDRA)
-endif()
-
 set(INC_SYS
 )
 

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

@@ -32,8 +32,14 @@ NodeItem GroupNodeParser::compute()
 #endif
 
   NodeItem out =
-      GroupOutputNodeParser(
+      GroupOutputNodeParser(graph,
-          graph, depsgraph_, material_, node_out, socket_out_, NodeItem::Type::Any, this)
+                                       depsgraph_,
+                                       material_,
+                                       node_out,
+                                       socket_out_,
+                                       NodeItem::Type::Any,
+                                       this,
+                                       export_image_fn_)
           .compute_full();
 
 #ifdef USE_MATERIALX_NODEGRAPH

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

@@ -54,7 +54,9 @@ class DefaultMaterialNodeParser : public NodeParser {
   }
 };
 
-MaterialX::DocumentPtr export_to_materialx(Depsgraph *depsgraph, Material *material)
+MaterialX::DocumentPtr export_to_materialx(Depsgraph *depsgraph,
+                                           Material *material,
+                                           ExportImageFunction export_image_fn)
 {
   CLOG_INFO(LOG_MATERIALX_SHADER, 0, "Material: %s", material->id.name);
 
@@ -63,19 +65,36 @@ MaterialX::DocumentPtr export_to_materialx(Depsgraph *depsgraph, Material *mater
     material->nodetree->ensure_topology_cache();
     bNode *output_node = ntreeShaderOutputNode(material->nodetree, SHD_OUTPUT_ALL);
     if (output_node) {
-      NodeParserData data = {
+      NodeParserData data = {doc.get(),
-          doc.get(), depsgraph, material, NodeItem::Type::Material, nullptr, NodeItem(doc.get())};
+                             depsgraph,
+                             material,
+                             NodeItem::Type::Material,
+                             nullptr,
+                             NodeItem(doc.get()),
+                             export_image_fn};
       output_node->typeinfo->materialx_fn(&data, output_node, nullptr);
     }
     else {
-      DefaultMaterialNodeParser(
+      DefaultMaterialNodeParser(doc.get(),
-          doc.get(), depsgraph, material, nullptr, nullptr, NodeItem::Type::Material, nullptr)
+                                depsgraph,
+                                material,
+                                nullptr,
+                                nullptr,
+                                NodeItem::Type::Material,
+                                nullptr,
+                                export_image_fn)
           .compute_error();
     }
   }
   else {
-    DefaultMaterialNodeParser(
+    DefaultMaterialNodeParser(doc.get(),
-        doc.get(), depsgraph, material, nullptr, nullptr, NodeItem::Type::Material, nullptr)
+                              depsgraph,
+                              material,
+                              nullptr,
+                              nullptr,
+                              NodeItem::Type::Material,
+                              nullptr,
+                              export_image_fn)
         .compute();
   }
 

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

@@ -9,8 +9,12 @@
 struct Depsgraph;
 struct Material;
 
+class ExportImageFunction;
+
 namespace blender::nodes::materialx {
 
-MaterialX::DocumentPtr export_to_materialx(Depsgraph *depsgraph, Material *material);
+MaterialX::DocumentPtr export_to_materialx(Depsgraph *depsgraph,
+                                           Material *material,
+                                           ExportImageFunction export_image_fn);
 
 }  // namespace blender::nodes::materialx

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

@@ -20,14 +20,16 @@ NodeParser::NodeParser(MaterialX::GraphElement *graph,
                        const bNode *node,
                        const bNodeSocket *socket_out,
                        NodeItem::Type to_type,
-                       GroupNodeParser *group_parser)
+                       GroupNodeParser *group_parser,
+                       ExportImageFunction export_image_fn)
     : graph_(graph),
       depsgraph_(depsgraph),
       material_(material),
       node_(node),
       socket_out_(socket_out),
       to_type_(to_type),
-      group_parser_(group_parser)
+      group_parser_(group_parser),
+      export_image_fn_(export_image_fn)
 {
 }
 
@@ -212,13 +214,25 @@ NodeItem NodeParser::get_input_link(const bNodeSocket &socket, NodeItem::Type to
   }
 
   if (from_node->is_group()) {
-    return GroupNodeParser(
+    return GroupNodeParser(graph_,
-               graph_, depsgraph_, material_, from_node, link->fromsock, to_type, group_parser_)
+                           depsgraph_,
+                           material_,
+                           from_node,
+                           link->fromsock,
+                           to_type,
+                           group_parser_,
+                           export_image_fn_)
         .compute_full();
   }
   if (from_node->is_group_input()) {
-    return GroupInputNodeParser(
+    return GroupInputNodeParser(graph_,
-               graph_, depsgraph_, material_, from_node, link->fromsock, to_type, group_parser_)
+                                depsgraph_,
+                                material_,
+                                from_node,
+                                link->fromsock,
+                                to_type,
+                                group_parser_,
+                                export_image_fn_)
         .compute_full();
   }
 
@@ -230,7 +244,8 @@ NodeItem NodeParser::get_input_link(const bNodeSocket &socket, NodeItem::Type to
     return empty();
   }
 
-  NodeParserData data = {graph_, depsgraph_, material_, to_type, group_parser_, empty()};
+  NodeParserData data = {
+      graph_, depsgraph_, material_, to_type, group_parser_, empty(), export_image_fn_};
   from_node->typeinfo->materialx_fn(&data, const_cast<bNode *>(from_node), link->fromsock);
   return data.result;
 }

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

@@ -18,6 +18,8 @@ extern struct CLG_LogRef *LOG_MATERIALX_SHADER;
 
 class GroupNodeParser;
 
+using ExportImageFunction = std::function<std::string(Main *,Scene *, Image *, ImageUser *)>;
+
 /**
  * This is base abstraction class for parsing Blender nodes into MaterialX nodes.
  * NodeParser::compute() should be overrided in child classes.
@@ -31,6 +33,7 @@ class NodeParser {
   const bNodeSocket *socket_out_;
   NodeItem::Type to_type_;
   GroupNodeParser *group_parser_;
+  ExportImageFunction export_image_fn_;
 
  public:
   NodeParser(MaterialX::GraphElement *graph,
@@ -39,7 +42,8 @@ class NodeParser {
              const bNode *node,
              const bNodeSocket *socket_out,
              NodeItem::Type to_type,
-             GroupNodeParser *group_parser);
+             GroupNodeParser *group_parser,
+             ExportImageFunction export_image_fn);
   virtual ~NodeParser() = default;
 
   virtual NodeItem compute() = 0;
@@ -99,6 +103,7 @@ struct NodeParserData {
   NodeItem::Type to_type;
   GroupNodeParser *group_parser;
   NodeItem result;
+  ExportImageFunction export_image_fn;
 };
 
 #define NODE_SHADER_MATERIALX_BEGIN \
@@ -119,7 +124,14 @@ struct NodeParserData {
   { \
     materialx::NodeParserData *d = reinterpret_cast<materialx::NodeParserData *>(data); \
     d->result = MaterialXNodeParser( \
-                    d->graph, d->depsgraph, d->material, node, out, d->to_type, d->group_parser) \
+                    d->graph, \
+                                    d->depsgraph, \
+                                    d->material, \
+                                    node, \
+                                    out, \
+                                    d->to_type, \
+                                    d->group_parser, \
+                                    d->export_image_fn) \
                     .compute_full(); \
   }
 

source/blender/nodes/shader/nodes/node_shader_tex_environment.cc

@@ -11,8 +11,6 @@
 
 #include "IMB_colormanagement.h"
 
-#include "hydra/image.h"
-
 #include "DEG_depsgraph_query.h"
 
 namespace blender::nodes::node_shader_tex_environment_cc {
@@ -142,13 +140,13 @@ NODE_SHADER_MATERIALX_BEGIN
   }
 
   NodeTexEnvironment *tex_env = static_cast<NodeTexEnvironment *>(node_->storage);
-  Scene *scene = DEG_get_input_scene(depsgraph_);
-  Main *bmain = DEG_get_bmain(depsgraph_);
 
-  /* TODO: What if Blender built without Hydra? Also io::hydra::cache_or_get_image_file contains
+  std::string image_path = image->id.name;
-   * pretty general code, so could be moved from bf_usd project. */
+  if (export_image_fn_) {
-  std::string image_path = io::hydra::cache_or_get_image_file(
+    Scene *scene = DEG_get_input_scene(depsgraph_);
-      bmain, scene, image, &tex_env->iuser);
+    Main *bmain = DEG_get_bmain(depsgraph_);
+    image_path = export_image_fn_(bmain, scene, image, &tex_env->iuser);
+  }
 
   NodeItem vector = get_input_link("Vector", NodeItem::Type::Vector2);
   if (!vector) {

source/blender/nodes/shader/nodes/node_shader_tex_image.cc

@@ -11,8 +11,6 @@
 
 #include "IMB_colormanagement.h"
 
-#include "hydra/image.h"
-
 #include "DEG_depsgraph_query.h"
 
 namespace blender::nodes::node_shader_tex_image_cc {
@@ -191,13 +189,13 @@ NODE_SHADER_MATERIALX_BEGIN
     Image *image = (Image *)node_->id;
     if (image) {
       NodeTexImage *tex_image = static_cast<NodeTexImage *>(node_->storage);
-      Scene *scene = DEG_get_input_scene(depsgraph_);
-      Main *bmain = DEG_get_bmain(depsgraph_);
 
-      /* TODO: What if Blender built without Hydra? Also io::hydra::cache_or_get_image_file
+      std::string image_path = image->id.name;
-       * contains pretty general code, so could be moved from bf_usd project. */
+      if (export_image_fn_) {
-      std::string image_path = io::hydra::cache_or_get_image_file(
+        Scene *scene = DEG_get_input_scene(depsgraph_);
-          bmain, scene, image, &tex_image->iuser);
+        Main *bmain = DEG_get_bmain(depsgraph_);
+        image_path = export_image_fn_(bmain, scene, image, &tex_image->iuser);
+      }
 
       NodeItem vector = get_input_link("Vector", NodeItem::Type::Vector2);
       if (!vector) {