Refactor: Rename Object->obmat to Object->object_to_world

Motivation is to disambiguate on the naming level what the matrix
actually means. It is very easy to understand the meaning backwards,
especially since in Python the name goes the opposite way (it is
called `world_matrix` in the Python API).

It is important to disambiguate the naming without making developers
to look into the comment in the header file (which is also not super
clear either). Additionally, more clear naming facilitates the unit
verification (or, in this case, space validation) when reading an
expression.

This patch calls the matrix `object_to_world` which makes it clear
from the local code what is it exactly going on. This is only done
on DNA level, and a lot of local variables still follow the old
naming.

A DNA rename is setup in a way that there is no change on the file
level, so there should be no regressions at all.

The possibility is to add `_matrix` or `_mat` suffix to the name
to make it explicit that it is a matrix. Although, not sure if it
really helps the readability, or is it something redundant.

Differential Revision: https://developer.blender.org/D16328

7 files changed, 24 insertions, 24 deletions

diff --git a/source/blender/editors/armature/armature_add.c b/source/blender/editors/armature/armature_add.c
index 17484b2b0b7..fbdb375b8a6 100644
--- a/source/blender/editors/armature/armature_add.c
+++ b/source/blender/editors/armature/armature_add.c
@@ -181,13 +181,13 @@ static int armature_click_extrude_exec(bContext *C, wmOperator *UNUSED(op))
 
     const View3DCursor *curs = &scene->cursor;
     copy_v3_v3(newbone->tail, curs->location);
-    sub_v3_v3v3(newbone->tail, newbone->tail, obedit->obmat[3]);
+    sub_v3_v3v3(newbone->tail, newbone->tail, obedit->object_to_world[3]);
 
     if (a == 1) {
       newbone->tail[0] = -newbone->tail[0];
     }
 
-    copy_m3_m4(mat, obedit->obmat);
+    copy_m3_m4(mat, obedit->object_to_world);
     invert_m3_m3(imat, mat);
     mul_m3_v3(imat, newbone->tail);
 
@@ -1569,7 +1569,7 @@ static int armature_bone_primitive_add_exec(bContext *C, wmOperator *op)
   copy_v3_v3(curs, CTX_data_scene(C)->cursor.location);
 
   /* Get inverse point for head and orientation for tail */
-  invert_m4_m4(obedit->imat, obedit->obmat);
+  invert_m4_m4(obedit->imat, obedit->object_to_world);
   mul_m4_v3(obedit->imat, curs);
 
   if (rv3d && (U.flag & USER_ADD_VIEWALIGNED)) {
@@ -1579,7 +1579,7 @@ static int armature_bone_primitive_add_exec(bContext *C, wmOperator *op)
     unit_m3(obmat);
   }
 
-  copy_m3_m4(viewmat, obedit->obmat);
+  copy_m3_m4(viewmat, obedit->object_to_world);
   mul_m3_m3m3(totmat, obmat, viewmat);
   invert_m3_m3(imat, totmat);
 
diff --git a/source/blender/editors/armature/armature_edit.c b/source/blender/editors/armature/armature_edit.c
index 9e828ebd501..810279f1b6c 100644
--- a/source/blender/editors/armature/armature_edit.c
+++ b/source/blender/editors/armature/armature_edit.c
@@ -113,7 +113,7 @@ void ED_armature_origin_set(
   /* Find the center-point. */
   if (centermode == 2) {
     copy_v3_v3(cent, cursor);
-    invert_m4_m4(ob->imat, ob->obmat);
+    invert_m4_m4(ob->imat, ob->object_to_world);
     mul_m4_v3(ob->imat, cent);
   }
   else {
@@ -154,7 +154,7 @@ void ED_armature_origin_set(
 
   /* Adjust object location for new center-point. */
   if (centermode && (is_editmode == false)) {
-    mul_mat3_m4_v3(ob->obmat, cent); /* omit translation part */
+    mul_mat3_m4_v3(ob->object_to_world, cent); /* omit translation part */
     add_v3_v3(ob->loc, cent);
   }
 }
@@ -282,14 +282,14 @@ static int armature_calc_roll_exec(bContext *C, wmOperator *op)
       axis_flip = true;
     }
 
-    copy_m3_m4(imat, ob->obmat);
+    copy_m3_m4(imat, ob->object_to_world);
     invert_m3(imat);
 
     if (type == CALC_ROLL_CURSOR) { /* Cursor */
       float cursor_local[3];
       const View3DCursor *cursor = &scene->cursor;
 
-      invert_m4_m4(ob->imat, ob->obmat);
+      invert_m4_m4(ob->imat, ob->object_to_world);
       copy_v3_v3(cursor_local, cursor->location);
       mul_m4_v3(ob->imat, cursor_local);
 
@@ -730,7 +730,7 @@ static int armature_fill_bones_exec(bContext *C, wmOperator *op)
     ebp = points.first;
 
     /* Get points - cursor (tail) */
-    invert_m4_m4(obedit->imat, obedit->obmat);
+    invert_m4_m4(obedit->imat, obedit->object_to_world);
     mul_v3_m4v3(curs, obedit->imat, scene->cursor.location);
 
     /* Create a bone */
@@ -767,7 +767,7 @@ static int armature_fill_bones_exec(bContext *C, wmOperator *op)
         float dist_sq_a, dist_sq_b;
 
         /* get cursor location */
-        invert_m4_m4(obedit->imat, obedit->obmat);
+        invert_m4_m4(obedit->imat, obedit->object_to_world);
         mul_v3_m4v3(curs, obedit->imat, scene->cursor.location);
 
         /* get distances */
diff --git a/source/blender/editors/armature/armature_relations.c b/source/blender/editors/armature/armature_relations.c
index 9f1883ccac0..fccf2964868 100644
--- a/source/blender/editors/armature/armature_relations.c
+++ b/source/blender/editors/armature/armature_relations.c
@@ -289,7 +289,7 @@ int ED_armature_join_objects_exec(bContext *C, wmOperator *op)
 
   /* Inverse transform for all selected armatures in this object,
    * See #object_join_exec for detailed comment on why the safe version is used. */
-  invert_m4_m4_safe_ortho(oimat, ob_active->obmat);
+  invert_m4_m4_safe_ortho(oimat, ob_active->object_to_world);
 
   /* Get edit-bones of active armature to add edit-bones to */
   ED_armature_to_edit(arm);
@@ -321,7 +321,7 @@ int ED_armature_join_objects_exec(bContext *C, wmOperator *op)
       // BASACT->flag &= ~OB_MODE_POSE;
 
       /* Find the difference matrix */
-      mul_m4_m4m4(mat, oimat, ob_iter->obmat);
+      mul_m4_m4m4(mat, oimat, ob_iter->object_to_world);
 
       /* Copy bones and posechannels from the object to the edit armature */
       for (pchan = opose->chanbase.first; pchan; pchan = pchann) {
diff --git a/source/blender/editors/armature/armature_select.c b/source/blender/editors/armature/armature_select.c
index 6b8f790d30f..3ee0510ca7f 100644
--- a/source/blender/editors/armature/armature_select.c
+++ b/source/blender/editors/armature/armature_select.c
@@ -1601,8 +1601,8 @@ static const EnumPropertyItem prop_similar_types[] = {
 static float bone_length_squared_worldspace_get(Object *ob, EditBone *ebone)
 {
   float v1[3], v2[3];
-  mul_v3_mat3_m4v3(v1, ob->obmat, ebone->head);
-  mul_v3_mat3_m4v3(v2, ob->obmat, ebone->tail);
+  mul_v3_mat3_m4v3(v1, ob->object_to_world, ebone->head);
+  mul_v3_mat3_m4v3(v2, ob->object_to_world, ebone->tail);
   return len_squared_v3v3(v1, v2);
 }
 
@@ -1650,8 +1650,8 @@ static void bone_direction_worldspace_get(Object *ob, EditBone *ebone, float *r_
   copy_v3_v3(v1, ebone->head);
   copy_v3_v3(v2, ebone->tail);
 
-  mul_m4_v3(ob->obmat, v1);
-  mul_m4_v3(ob->obmat, v2);
+  mul_m4_v3(ob->object_to_world, v1);
+  mul_m4_v3(ob->object_to_world, v2);
 
   sub_v3_v3v3(r_dir, v1, v2);
   normalize_v3(r_dir);
diff --git a/source/blender/editors/armature/armature_skinning.c b/source/blender/editors/armature/armature_skinning.c
index 6155aac621d..3c9c8cf05b3 100644
--- a/source/blender/editors/armature/armature_skinning.c
+++ b/source/blender/editors/armature/armature_skinning.c
@@ -365,8 +365,8 @@ static void add_verts_to_dgroups(ReportList *reports,
       copy_v3_v3(tip[j], bone->arm_tail);
     }
 
-    mul_m4_v3(par->obmat, root[j]);
-    mul_m4_v3(par->obmat, tip[j]);
+    mul_m4_v3(par->object_to_world, root[j]);
+    mul_m4_v3(par->object_to_world, tip[j]);
 
     /* set selected */
     if (wpmode) {
@@ -414,7 +414,7 @@ static void add_verts_to_dgroups(ReportList *reports,
     if (!vertsfilled) {
       copy_v3_v3(verts[i], mesh_verts[i].co);
     }
-    mul_m4_v3(ob->obmat, verts[i]);
+    mul_m4_v3(ob->object_to_world, verts[i]);
   }
 
   /* compute the weights based on gathered vertices and bones */
@@ -438,7 +438,7 @@ static void add_verts_to_dgroups(ReportList *reports,
                             root,
                             tip,
                             selected,
-                            mat4_to_scale(par->obmat));
+                            mat4_to_scale(par->object_to_world));
   }
 
   /* only generated in some cases but can call anyway */
diff --git a/source/blender/editors/armature/meshlaplacian.c b/source/blender/editors/armature/meshlaplacian.c
index 567977e51c4..dfb9e8a79fa 100644
--- a/source/blender/editors/armature/meshlaplacian.c
+++ b/source/blender/editors/armature/meshlaplacian.c
@@ -1788,11 +1788,11 @@ void ED_mesh_deform_bind_callback(Object *object,
   mmd_orig->bindcagecos = (float *)mdb.cagecos;
   mmd_orig->verts_num = mdb.verts_num;
   mmd_orig->cage_verts_num = mdb.cage_verts_num;
-  copy_m4_m4(mmd_orig->bindmat, mmd_orig->object->obmat);
+  copy_m4_m4(mmd_orig->bindmat, mmd_orig->object->object_to_world);
 
   /* transform bindcagecos to world space */
   for (a = 0; a < mdb.cage_verts_num; a++) {
-    mul_m4_v3(mmd_orig->object->obmat, mmd_orig->bindcagecos + a * 3);
+    mul_m4_v3(mmd_orig->object->object_to_world, mmd_orig->bindcagecos + a * 3);
   }
 
   /* free */
diff --git a/source/blender/editors/armature/pose_transform.c b/source/blender/editors/armature/pose_transform.c
index f92b72bbb66..51071815823 100644
--- a/source/blender/editors/armature/pose_transform.c
+++ b/source/blender/editors/armature/pose_transform.c
@@ -77,10 +77,10 @@ static void applyarmature_fix_boneparents(const bContext *C, Scene *scene, Objec
       /* apply current transform from parent (not yet destroyed),
        * then calculate new parent inverse matrix
        */
-      BKE_object_apply_mat4(ob, ob->obmat, false, false);
+      BKE_object_apply_mat4(ob, ob->object_to_world, false, false);
 
       BKE_object_workob_calc_parent(depsgraph, scene, ob, &workob);
-      invert_m4_m4(ob->parentinv, workob.obmat);
+      invert_m4_m4(ob->parentinv, workob.object_to_world);
     }
   }
 }