Fix T96415: new OBJ exporter was applying scaling factor incorrectly

This is patch D14347 from Aras Pranckevicius.

Instead of scaling "the scene" (i.e. transform vertices by object matrix,
then multiply by scale factor), it was instead first applying the scale
factor in local space, and then transforming by the object matrix.

2 files changed, 12 insertions, 1 deletions

diff --git a/source/blender/io/wavefront_obj/exporter/obj_export_mesh.cc b/source/blender/io/wavefront_obj/exporter/obj_export_mesh.cc
index bd235ae07ae..5be68565054 100644
--- a/source/blender/io/wavefront_obj/exporter/obj_export_mesh.cc
+++ b/source/blender/io/wavefront_obj/exporter/obj_export_mesh.cc
@@ -246,8 +246,8 @@ float3 OBJMesh::calc_vertex_coords(const int vert_index, const float scaling_fac
 {
   float3 r_coords;
   copy_v3_v3(r_coords, export_mesh_eval_->mvert[vert_index].co);
-  mul_v3_fl(r_coords, scaling_factor);
   mul_m4_v3(world_and_axes_transform_, r_coords);
+  mul_v3_fl(r_coords, scaling_factor);
   return r_coords;
 }
 
diff --git a/source/blender/io/wavefront_obj/tests/obj_exporter_tests.cc b/source/blender/io/wavefront_obj/tests/obj_exporter_tests.cc
index 27f34ca6be9..e96a7d28561 100644
--- a/source/blender/io/wavefront_obj/tests/obj_exporter_tests.cc
+++ b/source/blender/io/wavefront_obj/tests/obj_exporter_tests.cc
@@ -475,6 +475,17 @@ TEST_F(obj_exporter_regression_test, cube_normal_edit)
                                _export.params);
 }
 
+TEST_F(obj_exporter_regression_test, cubes_positioned)
+{
+  OBJExportParamsDefault _export;
+  _export.params.export_materials = false;
+  _export.params.scaling_factor = 2.0f;
+  compare_obj_export_to_golden("io_tests/blend_geometry/cubes_positioned.blend",
+                               "io_tests/obj/cubes_positioned.obj",
+                               "",
+                               _export.params);
+}
+
 TEST_F(obj_exporter_regression_test, suzanne_all_data)
 {
   OBJExportParamsDefault _export;