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

1 files changed, 17 insertions, 16 deletions

diff --git a/source/blender/editors/sculpt_paint/sculpt.c b/source/blender/editors/sculpt_paint/sculpt.c
index 34d0158f187..24c6f1b0c3d 100644
--- a/source/blender/editors/sculpt_paint/sculpt.c
+++ b/source/blender/editors/sculpt_paint/sculpt.c
@@ -2793,7 +2793,7 @@ static void calc_brush_local_mat(const Brush *brush, Object *ob, float local_mat
   float up[3];
 
   /* Ensure `ob->imat` is up to date. */
-  invert_m4_m4(ob->imat, ob->obmat);
+  invert_m4_m4(ob->imat, ob->object_to_world);
 
   /* Initialize last column of matrix. */
   mat[0][3] = 0.0f;
@@ -2833,7 +2833,7 @@ void SCULPT_tilt_apply_to_normal(float r_normal[3], StrokeCache *cache, const fl
     return;
   }
   const float rot_max = M_PI_2 * tilt_strength * SCULPT_TILT_SENSITIVITY;
-  mul_v3_mat3_m4v3(r_normal, cache->vc->obact->obmat, r_normal);
+  mul_v3_mat3_m4v3(r_normal, cache->vc->obact->object_to_world, r_normal);
   float normal_tilt_y[3];
   rotate_v3_v3v3fl(normal_tilt_y, r_normal, cache->vc->rv3d->viewinv[0], cache->y_tilt * rot_max);
   float normal_tilt_xy[3];
@@ -3284,7 +3284,7 @@ static void sculpt_topology_update(Sculpt *sd,
 
   /* Update average stroke position. */
   copy_v3_v3(location, ss->cache->true_location);
-  mul_m4_v3(ob->obmat, location);
+  mul_m4_v3(ob->object_to_world, location);
 }
 
 static void do_brush_action_task_cb(void *__restrict userdata,
@@ -3615,7 +3615,7 @@ static void do_brush_action(Sculpt *sd,
 
   /* Update average stroke position. */
   copy_v3_v3(location, ss->cache->true_location);
-  mul_m4_v3(ob->obmat, location);
+  mul_m4_v3(ob->object_to_world, location);
 
   add_v3_v3(ups->average_stroke_accum, location);
   ups->average_stroke_counter++;
@@ -4201,8 +4201,8 @@ static void sculpt_init_mirror_clipping(Object *ob, SculptSession *ss)
       /* Store matrix for mirror object clipping. */
       if (mmd->mirror_ob) {
         float imtx_mirror_ob[4][4];
-        invert_m4_m4(imtx_mirror_ob, mmd->mirror_ob->obmat);
-        mul_m4_m4m4(ss->cache->clip_mirror_mtx, imtx_mirror_ob, ob->obmat);
+        invert_m4_m4(imtx_mirror_ob, mmd->mirror_ob->object_to_world);
+        mul_m4_m4m4(ss->cache->clip_mirror_mtx, imtx_mirror_ob, ob->object_to_world);
       }
     }
   }
@@ -4354,7 +4354,7 @@ static void sculpt_update_cache_invariants(
   /* Cache projection matrix. */
   ED_view3d_ob_project_mat_get(cache->vc->rv3d, ob, cache->projection_mat);
 
-  invert_m4_m4(ob->imat, ob->obmat);
+  invert_m4_m4(ob->imat, ob->object_to_world);
   copy_m3_m4(mat, cache->vc->rv3d->viewinv);
   mul_m3_v3(mat, viewDir);
   copy_m3_m4(mat, ob->imat);
@@ -4373,7 +4373,7 @@ static void sculpt_update_cache_invariants(
     if (sd->gravity_object) {
       Object *gravity_object = sd->gravity_object;
 
-      copy_v3_v3(cache->true_gravity_direction, gravity_object->obmat[2]);
+      copy_v3_v3(cache->true_gravity_direction, gravity_object->object_to_world[2]);
     }
     else {
       cache->true_gravity_direction[0] = cache->true_gravity_direction[1] = 0.0f;
@@ -4527,27 +4527,27 @@ static void sculpt_update_brush_delta(UnifiedPaintSettings *ups, Object *ob, Bru
   }
 
   /* Compute 3d coordinate at same z from original location + mval. */
-  mul_v3_m4v3(loc, ob->obmat, cache->orig_grab_location);
+  mul_v3_m4v3(loc, ob->object_to_world, cache->orig_grab_location);
   ED_view3d_win_to_3d(cache->vc->v3d, cache->vc->region, loc, mval, grab_location);
 
   /* Compute delta to move verts by. */
   if (!SCULPT_stroke_is_first_brush_step_of_symmetry_pass(ss->cache)) {
     if (sculpt_needs_delta_from_anchored_origin(brush)) {
       sub_v3_v3v3(delta, grab_location, cache->old_grab_location);
-      invert_m4_m4(imat, ob->obmat);
+      invert_m4_m4(imat, ob->object_to_world);
       mul_mat3_m4_v3(imat, delta);
       add_v3_v3(cache->grab_delta, delta);
     }
     else if (sculpt_needs_delta_for_tip_orientation(brush)) {
       if (brush->flag & BRUSH_ANCHORED) {
         float orig[3];
-        mul_v3_m4v3(orig, ob->obmat, cache->orig_grab_location);
+        mul_v3_m4v3(orig, ob->object_to_world, cache->orig_grab_location);
         sub_v3_v3v3(cache->grab_delta, grab_location, orig);
       }
       else {
         sub_v3_v3v3(cache->grab_delta, grab_location, cache->old_grab_location);
       }
-      invert_m4_m4(imat, ob->obmat);
+      invert_m4_m4(imat, ob->object_to_world);
       mul_mat3_m4_v3(imat, cache->grab_delta);
     }
     else {
@@ -4592,7 +4592,7 @@ static void sculpt_update_brush_delta(UnifiedPaintSettings *ups, Object *ob, Bru
   /* Handle 'rake' */
   cache->is_rake_rotation_valid = false;
 
-  invert_m4_m4(imat, ob->obmat);
+  invert_m4_m4(imat, ob->object_to_world);
   mul_mat3_m4_v3(imat, grab_location);
 
   if (SCULPT_stroke_is_first_brush_step_of_symmetry_pass(ss->cache)) {
@@ -4913,7 +4913,7 @@ float SCULPT_raycast_init(ViewContext *vc,
   ED_view3d_win_to_segment_clipped(
       vc->depsgraph, vc->region, vc->v3d, mval, ray_start, ray_end, true);
 
-  invert_m4_m4(obimat, ob->obmat);
+  invert_m4_m4(obimat, ob->object_to_world);
   mul_m4_v3(obimat, ray_start);
   mul_m4_v3(obimat, ray_end);
 
@@ -5021,7 +5021,7 @@ bool SCULPT_cursor_geometry_info_update(bContext *C,
   float radius;
 
   /* Update cursor data in SculptSession. */
-  invert_m4_m4(ob->imat, ob->obmat);
+  invert_m4_m4(ob->imat, ob->object_to_world);
   copy_m3_m4(mat, vc.rv3d->viewinv);
   mul_m3_v3(mat, viewDir);
   copy_m3_m4(mat, ob->imat);
@@ -5512,7 +5512,8 @@ static void sculpt_stroke_update_step(bContext *C,
   sculpt_restore_mesh(sd, ob);
 
   if (sd->flags & (SCULPT_DYNTOPO_DETAIL_CONSTANT | SCULPT_DYNTOPO_DETAIL_MANUAL)) {
-    float object_space_constant_detail = 1.0f / (sd->constant_detail * mat4_to_scale(ob->obmat));
+    float object_space_constant_detail = 1.0f / (sd->constant_detail *
+                                                 mat4_to_scale(ob->object_to_world));
     BKE_pbvh_bmesh_detail_size_set(ss->pbvh, object_space_constant_detail);
   }
   else if (sd->flags & SCULPT_DYNTOPO_DETAIL_BRUSH) {