io: remove unnecessary transposes when using mat3_from_axis_conversion

Some I/O code paths (Collada, OBJ) were using mat3_from_axis_conversion
followed by transpose_m3, instead of swapping the axis arguments
which achieves exactly the same result.

Reviewed By: Aras Pranckevicius
Differential Revision: https://developer.blender.org/D15158

4 files changed, 4 insertions, 14 deletions

diff --git a/source/blender/io/collada/BCMath.cpp b/source/blender/io/collada/BCMath.cpp
index fc97110611a..d48e46ca115 100644
--- a/source/blender/io/collada/BCMath.cpp
+++ b/source/blender/io/collada/BCMath.cpp
@@ -49,11 +49,7 @@ BCMatrix::BCMatrix(BC_global_forward_axis global_forward_axis, BC_global_up_axis
   float mrot[3][3];
   float mat[4][4];
   mat3_from_axis_conversion(
-      BC_DEFAULT_FORWARD, BC_DEFAULT_UP, global_forward_axis, global_up_axis, mrot);
-
-  /* TODO: Verify that `mat3_from_axis_conversion()` returns a transposed matrix */
-  transpose_m3(mrot);
-
+      global_forward_axis, global_up_axis, BC_DEFAULT_FORWARD, BC_DEFAULT_UP, mrot);
   copy_m4_m3(mat, mrot);
   set_transform(mat);
 }
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 8556d7c275c..e2ecda32717 100644
--- a/source/blender/io/wavefront_obj/exporter/obj_export_mesh.cc
+++ b/source/blender/io/wavefront_obj/exporter/obj_export_mesh.cc
@@ -122,9 +122,7 @@ void OBJMesh::set_world_axes_transform(const eIOAxis forward, const eIOAxis up)
   float axes_transform[3][3];
   unit_m3(axes_transform);
   /* +Y-forward and +Z-up are the default Blender axis settings. */
-  mat3_from_axis_conversion(IO_AXIS_Y, IO_AXIS_Z, forward, up, axes_transform);
-  /* mat3_from_axis_conversion returns a transposed matrix! */
-  transpose_m3(axes_transform);
+  mat3_from_axis_conversion(forward, up, IO_AXIS_Y, IO_AXIS_Z, axes_transform);
   mul_m4_m3m4(world_and_axes_transform_, axes_transform, export_object_eval_.obmat);
   /* mul_m4_m3m4 does not transform last row of obmat, i.e. location data. */
   mul_v3_m3v3(world_and_axes_transform_[3], axes_transform, export_object_eval_.obmat[3]);
diff --git a/source/blender/io/wavefront_obj/exporter/obj_export_nurbs.cc b/source/blender/io/wavefront_obj/exporter/obj_export_nurbs.cc
index c0c29fcfdf8..172a59e5341 100644
--- a/source/blender/io/wavefront_obj/exporter/obj_export_nurbs.cc
+++ b/source/blender/io/wavefront_obj/exporter/obj_export_nurbs.cc
@@ -30,9 +30,7 @@ void OBJCurve::set_world_axes_transform(const eIOAxis forward, const eIOAxis up)
   float axes_transform[3][3];
   unit_m3(axes_transform);
   /* +Y-forward and +Z-up are the Blender's default axis settings. */
-  mat3_from_axis_conversion(IO_AXIS_Y, IO_AXIS_Z, forward, up, axes_transform);
-  /* mat3_from_axis_conversion returns a transposed matrix! */
-  transpose_m3(axes_transform);
+  mat3_from_axis_conversion(forward, up, IO_AXIS_Y, IO_AXIS_Z, axes_transform);
   mul_m4_m3m4(world_axes_transform_, axes_transform, export_object_eval_->obmat);
   /* #mul_m4_m3m4 does not transform last row of #Object.obmat, i.e. location data. */
   mul_v3_m3v3(world_axes_transform_[3], axes_transform, export_object_eval_->obmat[3]);
diff --git a/source/blender/io/wavefront_obj/importer/importer_mesh_utils.cc b/source/blender/io/wavefront_obj/importer/importer_mesh_utils.cc
index 3c0ef646e13..f33753d720d 100644
--- a/source/blender/io/wavefront_obj/importer/importer_mesh_utils.cc
+++ b/source/blender/io/wavefront_obj/importer/importer_mesh_utils.cc
@@ -100,9 +100,7 @@ void transform_object(Object *object, const OBJImportParams &import_params)
   unit_m4(obmat);
   /* +Y-forward and +Z-up are the default Blender axis settings. */
   mat3_from_axis_conversion(
-      import_params.forward_axis, import_params.up_axis, IO_AXIS_Y, IO_AXIS_Z, axes_transform);
-  /* mat3_from_axis_conversion returns a transposed matrix! */
-  transpose_m3(axes_transform);
+      IO_AXIS_Y, IO_AXIS_Z, import_params.forward_axis, import_params.up_axis, axes_transform);
   copy_m4_m3(obmat, axes_transform);
 
   BKE_object_apply_mat4(object, obmat, true, false);