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

2 files changed, 10 insertions, 10 deletions

diff --git a/source/blender/ikplugin/intern/iksolver_plugin.c b/source/blender/ikplugin/intern/iksolver_plugin.c
index 6d99fde9df6..c467e48d21e 100644
--- a/source/blender/ikplugin/intern/iksolver_plugin.c
+++ b/source/blender/ikplugin/intern/iksolver_plugin.c
@@ -406,7 +406,7 @@ static void execute_posetree(struct Depsgraph *depsgraph,
   }
   copy_v3_v3(rootmat[3], pchan->pose_head);
 
-  mul_m4_m4m4(imat, ob->obmat, rootmat);
+  mul_m4_m4m4(imat, ob->object_to_world, rootmat);
   invert_m4_m4(goalinv, imat);
 
   for (target = tree->targets.first; target; target = target->next) {
@@ -465,7 +465,7 @@ static void execute_posetree(struct Depsgraph *depsgraph,
       /* end effector in world space */
       copy_m4_m4(end_pose, pchan->pose_mat);
       copy_v3_v3(end_pose[3], pchan->pose_tail);
-      mul_m4_series(world_pose, goalinv, ob->obmat, end_pose);
+      mul_m4_series(world_pose, goalinv, ob->object_to_world, end_pose);
 
       /* blend position */
       goalpos[0] = fac * goalpos[0] + mfac * world_pose[3][0];
diff --git a/source/blender/ikplugin/intern/itasc_plugin.cpp b/source/blender/ikplugin/intern/itasc_plugin.cpp
index 9317f14b7f1..2878bbb6da7 100644
--- a/source/blender/ikplugin/intern/itasc_plugin.cpp
+++ b/source/blender/ikplugin/intern/itasc_plugin.cpp
@@ -586,10 +586,10 @@ static bool target_callback(const iTaSC::Timestamp &timestamp,
       float chanmat[4][4];
       copy_m4_m4(chanmat, pchan->pose_mat);
       copy_v3_v3(chanmat[3], pchan->pose_tail);
-      mul_m4_series(restmat, target->owner->obmat, chanmat, target->eeRest);
+      mul_m4_series(restmat, target->owner->object_to_world, chanmat, target->eeRest);
     }
     else {
-      mul_m4_m4m4(restmat, target->owner->obmat, target->eeRest);
+      mul_m4_m4m4(restmat, target->owner->object_to_world, target->eeRest);
     }
     /* blend the target */
     blend_m4_m4m4(tarmat, restmat, tarmat, constraint->enforce);
@@ -620,10 +620,10 @@ static bool base_callback(const iTaSC::Timestamp &timestamp,
     ikscene->baseFrame.setValue(&chanmat[0][0]);
     /* iTaSC armature is scaled to object scale, scale the base frame too */
     ikscene->baseFrame.p *= ikscene->blScale;
-    mul_m4_m4m4(rootmat, ikscene->blArmature->obmat, chanmat);
+    mul_m4_m4m4(rootmat, ikscene->blArmature->object_to_world, chanmat);
   }
   else {
-    copy_m4_m4(rootmat, ikscene->blArmature->obmat);
+    copy_m4_m4(rootmat, ikscene->blArmature->object_to_world);
     ikscene->baseFrame = iTaSC::F_identity;
   }
   next.setValue(&rootmat[0][0]);
@@ -1065,7 +1065,7 @@ static void convert_pose(IK_Scene *ikscene)
   int a, joint;
 
   /* assume uniform scaling and take Y scale as general scale for the armature */
-  scale = len_v3(ikscene->blArmature->obmat[1]);
+  scale = len_v3(ikscene->blArmature->object_to_world[1]);
   rot = ikscene->jointArray(0);
   for (joint = a = 0, ikchan = ikscene->channels;
        a < ikscene->numchan && joint < ikscene->numjoint;
@@ -1105,7 +1105,7 @@ static void BKE_pose_rest(IK_Scene *ikscene)
   int a, joint;
 
   /* assume uniform scaling and take Y scale as general scale for the armature */
-  scale = len_v3(ikscene->blArmature->obmat[1]);
+  scale = len_v3(ikscene->blArmature->object_to_world[1]);
   /* rest pose is 0 */
   SetToZero(ikscene->jointArray);
   /* except for transY joints */
@@ -1183,7 +1183,7 @@ static IK_Scene *convert_tree(
   }
   ikscene->blArmature = ob;
   /* assume uniform scaling and take Y scale as general scale for the armature */
-  ikscene->blScale = len_v3(ob->obmat[1]);
+  ikscene->blScale = len_v3(ob->object_to_world[1]);
   ikscene->blInvScale = (ikscene->blScale < KDL::epsilon) ? 0.0f : 1.0f / ikscene->blScale;
 
   std::string joint;
@@ -1667,7 +1667,7 @@ static void create_scene(struct Depsgraph *depsgraph, Scene *scene, Object *ob,
 static int init_scene(Object *ob)
 {
   /* check also if scaling has changed */
-  float scale = len_v3(ob->obmat[1]);
+  float scale = len_v3(ob->object_to_world[1]);
   IK_Scene *scene;
 
   if (ob->pose->ikdata) {