[Bf-blender-cvs] [da4e2fe7fe8] master: OBJ: in exporter faces loop, move material index accessor outside of the loop

[Aras Pranckevicius]

Commit: da4e2fe7fe8fb006ce4574d1a642c9129eaa549a
Author: Aras Pranckevicius
Date:   Mon Jan 2 16:14:51 2023 +0200
Branches: master
https://developer.blender.org/rBda4e2fe7fe8fb006ce4574d1a642c9129eaa549a

OBJ: in exporter faces loop, move material index accessor outside of the loop

While the cost of creating AttributeAccessor and finding the "material_index"
attribute is not large, there's really no need to do that for each
polygon. Move the access outside of the per-polygon loop.

===================================================================

M	source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc

===================================================================

diff --git a/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc b/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc
index ec09a145f1b..6957e07dadd 100644
--- a/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc
+++ b/source/blender/io/wavefront_obj/exporter/obj_export_file_writer.cc
@@ -337,6 +337,9 @@ void OBJWriter::write_poly_elements(FormatHandler &fh,
   const int tot_polygons = obj_mesh_data.tot_polygons();
   const int tot_deform_groups = obj_mesh_data.tot_deform_groups();
   threading::EnumerableThreadSpecific<Vector<float>> group_weights;
+  const bke::AttributeAccessor attributes = obj_mesh_data.get_mesh()->attributes();
+  const VArray<int> material_indices = attributes.lookup_or_default<int>(
+      "material_index", ATTR_DOMAIN_FACE, 0);
 
   obj_parallel_chunked_output(fh, tot_polygons, [&](FormatHandler &buf, int idx) {
     /* Polygon order for writing into the file is not necessarily the same
@@ -372,10 +375,6 @@ void OBJWriter::write_poly_elements(FormatHandler &fh,
       }
     }
 
-    const bke::AttributeAccessor attributes = obj_mesh_data.get_mesh()->attributes();
-    const VArray<int> material_indices = attributes.lookup_or_default<int>(
-        "material_index", ATTR_DOMAIN_FACE, 0);
-
     /* Write material name and material group if different from previous. */
     if (export_params_.export_materials && obj_mesh_data.tot_materials() > 0) {
       const int16_t prev_mat = idx == 0 ? NEGATIVE_INIT : std::max(0, material_indices[prev_i]);