Merge branch 'temp-T90535-usd-alab-material-import' into temp-usd-udim-import

Removed unnecessary assert which was causing a compile
warning.  Also, removed call to std::optional::value(),
which is not supported in macOS versions prior to 10.14.1.

source/blender/editors/io/io_usd.c

@@ -73,6 +73,20 @@ const EnumPropertyItem rna_enum_usd_export_evaluation_mode_items[] = {
     {0, NULL, 0, NULL, NULL},
 };
 
+const EnumPropertyItem rna_enum_usd_mtl_name_collision_mode_items[] = {
+    {USD_MTL_NAME_COLLISION_UNIQUE_NAME,
+     "UNIQUE_NAME",
+     0,
+     "Unique Name",
+     "Create a unique name for the imported material"},
+    {USD_MTL_NAME_COLLISION_REFERENCE_EXISTING,
+     "REFERENCE_EXISTING",
+     0,
+     "Reference Existing",
+     "If a material with the same name already exists, reference that instead of importing"},
+    {0, NULL, 0, NULL, NULL},
+};
+
 /* Stored in the wmOperator's customdata field to indicate it should run as a background job.
  * This is set when the operator is invoked, and not set when it is only executed. */
 enum { AS_BACKGROUND_JOB = 1 };
@@ -318,6 +332,9 @@ static int wm_usd_import_exec(bContext *C, wmOperator *op)
 
   const float light_intensity_scale = RNA_float_get(op->ptr, "light_intensity_scale");
 
+  const eUSDMtlNameCollisionMode mtl_name_collision_mode = RNA_enum_get(op->ptr,
+                                                                        "mtl_name_collision_mode");
+
   /* TODO(makowalski): Add support for sequences. */
   const bool is_sequence = false;
   int offset = 0;
@@ -356,7 +373,8 @@ static int wm_usd_import_exec(bContext *C, wmOperator *op)
                                    .use_instancing = use_instancing,
                                    .import_usd_preview = import_usd_preview,
                                    .set_material_blend = set_material_blend,
-                                   .light_intensity_scale = light_intensity_scale};
+                                   .light_intensity_scale = light_intensity_scale,
+                                   .mtl_name_collision_mode = mtl_name_collision_mode};
 
   const bool ok = USD_import(C, filename, &params, as_background_job);
 
@@ -399,6 +417,7 @@ static void wm_usd_import_draw(bContext *UNUSED(C), wmOperator *op)
   uiItemR(col, ptr, "relative_path", 0, NULL, ICON_NONE);
   uiItemR(col, ptr, "create_collection", 0, NULL, ICON_NONE);
   uiItemR(box, ptr, "light_intensity_scale", 0, NULL, ICON_NONE);
+  uiItemR(box, ptr, "mtl_name_collision_mode", 0, NULL, ICON_NONE);
 
   box = uiLayoutBox(layout);
   col = uiLayoutColumnWithHeading(box, true, IFACE_("Experimental"));
@@ -519,6 +538,14 @@ void WM_OT_usd_import(struct wmOperatorType *ot)
                 "Scale for the intensity of imported lights",
                 0.0001f,
                 1000.0f);
+
+  RNA_def_enum(
+      ot->srna,
+      "mtl_name_collision_mode",
+      rna_enum_usd_mtl_name_collision_mode_items,
+      USD_MTL_NAME_COLLISION_UNIQUE_NAME,
+      "Material Name Collision",
+      "Behavior when the name of an imported material conflicts with an existing material");
 }
 
 #endif /* WITH_USD */

source/blender/io/usd/intern/usd_reader_material.cc

@@ -25,8 +25,11 @@
 #include "BKE_node.h"
 #include "BKE_node_tree_update.h"
 
+#include "BLI_fileops.h"
 #include "BLI_math_vector.h"
+#include "BLI_path_util.h"
 #include "BLI_string.h"
+#include "BLI_vector.hh"
 
 #include "DNA_material_types.h"
 
@@ -35,6 +38,7 @@
 #include <pxr/usd/usdShade/shader.h>
 
 #include <iostream>
+#include <optional>
 #include <vector>
 
 namespace usdtokens {
@@ -110,6 +114,65 @@ static void link_nodes(
   nodeAddLink(ntree, source, source_socket, dest, dest_socket);
 }
 
+/* Returns a layer handle retrieved from the given attribute's property specs.
+ * Note that the returned handle may be invalid if no layer could be found. */
+static pxr::SdfLayerHandle get_layer_handle(const pxr::UsdAttribute &attribute)
+{
+  for (auto PropertySpec : attribute.GetPropertyStack(pxr::UsdTimeCode::EarliestTime())) {
+    if (PropertySpec->HasDefaultValue() ||
+        PropertySpec->GetLayer()->GetNumTimeSamplesForPath(PropertySpec->GetPath()) > 0) {
+      return PropertySpec->GetLayer();
+    }
+  }
+
+  return pxr::SdfLayerHandle();
+}
+
+static bool is_udim_path(const std::string &path)
+{
+  return path.find("<UDIM>") != std::string::npos;
+}
+
+/* For the given UDIM path (assumed to contain the UDIM token), returns an array
+ * containing valid tile indices.
+ * Returns std::nullopt if no tiles were found. */
+static std::optional<blender::Vector<int>> get_udim_tiles(const std::string &file_path)
+{
+  char base_udim_path[FILE_MAX];
+  BLI_strncpy(base_udim_path, file_path.c_str(), sizeof(base_udim_path));
+
+  blender::Vector<int> udim_tiles;
+
+  /* Extract the tile numbers from all files on disk. */
+  ListBase tiles = {nullptr, nullptr};
+  int tile_start, tile_range;
+  bool result = BKE_image_get_tile_info(base_udim_path, &tiles, &tile_start, &tile_range);
+  if (result) {
+    LISTBASE_FOREACH (LinkData *, tile, &tiles) {
+      int tile_number = POINTER_AS_INT(tile->data);
+      udim_tiles.append(tile_number);
+    }
+  }
+
+  BLI_freelistN(&tiles);
+
+  if (udim_tiles.is_empty()) {
+    return std::nullopt;
+  }
+
+  return udim_tiles;
+}
+
+/* Add tiles with the given indices to the given image. */
+static void add_udim_tiles(Image *image, const blender::Vector<int> &indices)
+{
+  image->source = IMA_SRC_TILED;
+
+  for (int tile_number : indices) {
+    BKE_image_add_tile(image, tile_number, nullptr);
+  }
+}
+
 /* Returns true if the given shader may have opacity < 1.0, based
  * on heuristics. */
 static bool needs_blend(const pxr::UsdShadeShader &usd_shader)
@@ -616,6 +679,26 @@ void USDMaterialReader::load_tex_image(const pxr::UsdShadeShader &usd_shader,
 
   const pxr::SdfAssetPath &asset_path = file_val.Get<pxr::SdfAssetPath>();
   std::string file_path = asset_path.GetResolvedPath();
+  if (file_path.empty()) {
+    /* No resolved path, so use the asset path (usually
+     * necessary for UDIM paths). */
+    file_path = asset_path.GetAssetPath();
+
+    /* Texture paths are frequently relative to the USD, so get
+     * the absolute path. */
+    if (pxr::SdfLayerHandle layer_handle = get_layer_handle(file_input.GetAttr())) {
+      file_path = layer_handle->ComputeAbsolutePath(file_path);
+    }
+  }
+
+  /* If this is a UDIM texture, this will store the
+   * UDIM tile indices. */
+  std::optional<blender::Vector<int>> udim_tiles;
+
+  if (is_udim_path(file_path)) {
+    udim_tiles = get_udim_tiles(file_path);
+  }
+
   if (file_path.empty()) {
     std::cerr << "WARNING: Couldn't resolve image asset '" << asset_path
               << "' for Texture Image node." << std::endl;
@@ -630,6 +713,12 @@ void USDMaterialReader::load_tex_image(const pxr::UsdShadeShader &usd_shader,
     return;
   }
 
+  if (udim_tiles) {
+    /* Not calling udim_tiles.value(), which is not
+     * supported in macOS versions prior to 10.14.1. */
+    add_udim_tiles(image, *udim_tiles);
+  }
+
   tex_image->id = &image->id;
 
   /* Set texture color space.

source/blender/io/usd/intern/usd_reader_mesh.cc

@@ -76,45 +76,90 @@ static void build_mat_map(const Main *bmain, std::map<std::string, Material *> *
   }
 }
 
+static pxr::UsdShadeMaterial compute_bound_material(const pxr::UsdPrim &prim)
+{
+  pxr::UsdShadeMaterialBindingAPI api = pxr::UsdShadeMaterialBindingAPI(prim);
+  pxr::UsdShadeMaterial mtl = api.ComputeBoundMaterial();
+
+  if (!mtl) {
+    /* Check for a preview material as fallback. */
+    mtl = api.ComputeBoundMaterial(pxr::UsdShadeTokens->preview);
+  }
+
+  return mtl;
+}
+
+/* Returns an existing Blender material that corresponds to the USD
+ * material with with the given path.  Returns null if no such material
+ * exists. */
+static 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_UNIQUE_NAME) {
+    /* 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;
+      }
+      else {
+        std::cout
+            << "WARNING: Couldn't find previously assigned Blender material for USD material "
+            << usd_mat_path << std::endl;
+      }
+    }
+  }
+  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;
+}
+
 static void assign_materials(Main *bmain,
                              Object *ob,
                              const std::map<pxr::SdfPath, int> &mat_index_map,
                              const USDImportParams &params,
-                             pxr::UsdStageRefPtr stage)
+                             pxr::UsdStageRefPtr stage,
+                             std::map<std::string, std::string> &usd_path_to_mat_name)
 {
   if (!(stage && bmain && ob)) {
     return;
   }
 
-  bool can_assign = true;
   std::map<pxr::SdfPath, int>::const_iterator it = mat_index_map.begin();
 
-  int matcount = 0;
-  for (; it != mat_index_map.end(); ++it, matcount++) {
+  for (; it != mat_index_map.end(); ++it) {
     if (!BKE_object_material_slot_add(bmain, ob)) {
-      can_assign = false;
-      break;
+      std::cout << "WARNING: couldn't create slot for material " << it->first << " on object "
+                << ob->id.name << std::endl;
+      return;
     }
   }
 
-  if (!can_assign) {
-    return;
-  }
-
-  /* TODO(kevin): use global map? */
+  /* TODO(makowalski): use global map? */
   std::map<std::string, Material *> mat_map;
   build_mat_map(bmain, &mat_map);
 
   blender::io::usd::USDMaterialReader mat_reader(params, bmain);
 
   for (it = mat_index_map.begin(); it != mat_index_map.end(); ++it) {
-    std::string mat_name = it->first.GetName();
 
-    std::map<std::string, Material *>::iterator mat_iter = mat_map.find(mat_name);
-
-    Material *assigned_mat = nullptr;
-
-    if (mat_iter == mat_map.end()) {
+    Material *assigned_mat = find_existing_material(
+        it->first, params, mat_map, usd_path_to_mat_name);
+    if (!assigned_mat) {
       /* Blender material doesn't exist, so create it now. */
 
       /* Look up the USD material. */
@@ -136,11 +181,14 @@ static void assign_materials(Main *bmain,
         continue;
       }
 
+      std::string mat_name = pxr::TfMakeValidIdentifier(assigned_mat->id.name + 2);
       mat_map[mat_name] = assigned_mat;
-    }
-    else {
-      /* We found an existing Blender material. */
-      assigned_mat = mat_iter->second;
+
+      if (params.mtl_name_collision_mode == USD_MTL_NAME_COLLISION_UNIQUE_NAME) {
+        /* Record the name of the Blender material we created for the USD material
+         * with the given path. */
+        usd_path_to_mat_name[it->first.GetAsString()] = mat_name;
+      }
     }
 
     if (assigned_mat) {
@@ -148,7 +196,7 @@ static void assign_materials(Main *bmain,
     }
     else {
       /* This shouldn't happen. */
-      std::cout << "WARNING: Couldn't assign material " << mat_name << std::endl;
+      std::cout << "WARNING: Couldn't assign material " << it->first << std::endl;
     }
   }
 }
@@ -695,11 +743,8 @@ void USDMeshReader::assign_facesets_to_mpoly(double motionSampleTime,
   int current_mat = 0;
   if (!subsets.empty()) {
     for (const pxr::UsdGeomSubset &subset : subsets) {
-      pxr::UsdShadeMaterialBindingAPI subset_api = pxr::UsdShadeMaterialBindingAPI(
-          subset.GetPrim());
-
-      pxr::UsdShadeMaterial subset_mtl = subset_api.ComputeBoundMaterial();
 
+      pxr::UsdShadeMaterial subset_mtl = utils::compute_bound_material(subset.GetPrim());
       if (!subset_mtl) {
         continue;
       }
@@ -728,10 +773,9 @@ void USDMeshReader::assign_facesets_to_mpoly(double motionSampleTime,
   }
 
   if (r_mat_map->empty()) {
-    pxr::UsdShadeMaterialBindingAPI api = pxr::UsdShadeMaterialBindingAPI(prim_);
-
-    if (pxr::UsdShadeMaterial mtl = api.ComputeBoundMaterial()) {
 
+    pxr::UsdShadeMaterial mtl = utils::compute_bound_material(prim_);
+    if (mtl) {
       pxr::SdfPath mtl_path = mtl.GetPath();
 
       if (!mtl_path.IsEmpty()) {
@@ -749,7 +793,12 @@ void USDMeshReader::readFaceSetsSample(Main *bmain, Mesh *mesh, const double mot
 
   std::map<pxr::SdfPath, int> mat_map;
   assign_facesets_to_mpoly(motionSampleTime, mesh->mpoly, mesh->totpoly, &mat_map);
-  utils::assign_materials(bmain, object_, mat_map, this->import_params_, this->prim_.GetStage());
+  utils::assign_materials(bmain,
+                          object_,
+                          mat_map,
+                          this->import_params_,
+                          this->prim_.GetStage(),
+                          this->settings_->usd_path_to_mat_name);
 }
 
 Mesh *USDMeshReader::read_mesh(Mesh *existing_mesh,

source/blender/io/usd/intern/usd_reader_prim.h

@@ -24,6 +24,9 @@
 
 #include <pxr/usd/usd/prim.h>
 
+#include <map>
+#include <string>
+
 struct Main;
 struct Object;
 
@@ -50,6 +53,10 @@ struct ImportSettings {
 
   CacheFile *cache_file;
 
+  /* Map a USD matrial prim path to a Blender material name.
+   * This map is updated by readers during stage traversal. */
+  mutable std::map<std::string, std::string> usd_path_to_mat_name;
+
   ImportSettings()
       : do_convert_mat(false),
         from_up(0),

source/blender/io/usd/usd.h

@@ -31,6 +31,13 @@ struct CacheReader;
 struct Object;
 struct bContext;
 
+/* Behavior when the name of an imported material
+ * conflicts with an existing material. */
+typedef enum eUSDMtlNameCollisionMode {
+  USD_MTL_NAME_COLLISION_UNIQUE_NAME = 0,
+  USD_MTL_NAME_COLLISION_REFERENCE_EXISTING = 1,
+} eUSDMtlNameCollisionMode;
+
 struct USDExportParams {
   bool export_animation;
   bool export_hair;
@@ -69,6 +76,7 @@ struct USDImportParams {
   bool import_usd_preview;
   bool set_material_blend;
   float light_intensity_scale;
+  eUSDMtlNameCollisionMode mtl_name_collision_mode;
 };
 
 /* The USD_export takes a as_background_job parameter, and returns a boolean.