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, 5 insertions, 5 deletions

diff --git a/source/blender/render/intern/bake.c b/source/blender/render/intern/bake.c
index 8fd62f7ec34..9b56e18bb26 100644
--- a/source/blender/render/intern/bake.c
+++ b/source/blender/render/intern/bake.c
@@ -967,7 +967,7 @@ void RE_bake_normal_world_to_object(const BakePixel pixel_array[],
   size_t i;
   float iobmat[4][4];
 
-  invert_m4_m4(iobmat, ob->obmat);
+  invert_m4_m4(iobmat, ob->object_to_world);
 
   for (i = 0; i < pixels_num; i++) {
     size_t offset;
diff --git a/source/blender/render/intern/texture_pointdensity.c b/source/blender/render/intern/texture_pointdensity.c
index 2a2b62be1f0..b285bbd1459 100644
--- a/source/blender/render/intern/texture_pointdensity.c
+++ b/source/blender/render/intern/texture_pointdensity.c
@@ -175,7 +175,7 @@ static void pointdensity_cache_psys(
   sim.psmd = psys_get_modifier(ob, psys);
 
   /* in case ob->imat isn't up-to-date */
-  invert_m4_m4(ob->imat, ob->obmat);
+  invert_m4_m4(ob->imat, ob->object_to_world);
 
   total_particles = psys->totpart + psys->totchild;
   psys->lattice_deform_data = psys_create_lattice_deform_data(&sim);
@@ -399,12 +399,12 @@ static void pointdensity_cache_object(PointDensity *pd, Object *ob)
       case TEX_PD_OBJECTSPACE:
         break;
       case TEX_PD_OBJECTLOC:
-        mul_m4_v3(ob->obmat, co);
+        mul_m4_v3(ob->object_to_world, co);
         sub_v3_v3(co, ob->loc);
         break;
       case TEX_PD_WORLDSPACE:
       default:
-        mul_m4_v3(ob->obmat, co);
+        mul_m4_v3(ob->object_to_world, co);
         break;
     }
 
@@ -778,7 +778,7 @@ static void particle_system_minmax(Depsgraph *depsgraph,
   sim.psys = psys;
   sim.psmd = psys_get_modifier(object, psys);
 
-  invert_m4_m4(imat, object->obmat);
+  invert_m4_m4(imat, object->object_to_world);
   total_particles = psys->totpart + psys->totchild;
   psys->lattice_deform_data = psys_create_lattice_deform_data(&sim);