USD import unbound materials.

This addresses issue T97195.

Added a new Unbound Materials USD import option,
to import materials not assigned to any geometry.

1 files changed, 48 insertions, 0 deletions

diff --git a/source/blender/io/usd/intern/usd_reader_material.cc b/source/blender/io/usd/intern/usd_reader_material.cc
index d1af4553083..6416f6861d4 100644
--- a/source/blender/io/usd/intern/usd_reader_material.cc
+++ b/source/blender/io/usd/intern/usd_reader_material.cc
@@ -757,4 +757,52 @@ void USDMaterialReader::convert_usd_primvar_reader_float2(
   link_nodes(ntree, uv_map, "UV", dest_node, dest_socket_name);
 }
 
+
+void build_material_map(const Main *bmain, std::map<std::string, Material *> *r_mat_map)
+{
+  if (r_mat_map == nullptr) {
+    return;
+  }
+
+  Material *material = static_cast<Material *>(bmain->materials.first);
+
+  for (; material; material = static_cast<Material *>(material->id.next)) {
+    (*r_mat_map)[pxr::TfMakeValidIdentifier(material->id.name + 2)] = material;
+  }
+}
+
+Material *find_existing_material(
+    const pxr::SdfPath &usd_mat_path,
+    const USDImportParams &params,
+    const std::map<std::string, Material *> &mat_map,
+    const std::map<std::string, std::string> &usd_path_to_mat_name)
+{
+  if (params.mtl_name_collision_mode == USD_MTL_NAME_COLLISION_MAKE_UNIQUE) {
+    /* Check if we've already created the Blender material with a modified name. */
+    std::map<std::string, std::string>::const_iterator path_to_name_iter =
+        usd_path_to_mat_name.find(usd_mat_path.GetAsString());
+
+    if (path_to_name_iter != usd_path_to_mat_name.end()) {
+      std::string mat_name = path_to_name_iter->second;
+      std::map<std::string, Material *>::const_iterator mat_iter = mat_map.find(mat_name);
+      if (mat_iter != mat_map.end()) {
+        return mat_iter->second;
+      }
+      /* We can't find the Blender material which was previously created for this USD
+       * material, which should never happen. */
+      BLI_assert_unreachable();
+    }
+  }
+  else {
+    std::string mat_name = usd_mat_path.GetName();
+    std::map<std::string, Material *>::const_iterator mat_iter = mat_map.find(mat_name);
+
+    if (mat_iter != mat_map.end()) {
+      return mat_iter->second;
+    }
+  }
+
+  return nullptr;
+}
+
 }  // namespace blender::io::usd