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

5 files changed, 26 insertions, 26 deletions

diff --git a/source/blender/draw/engines/eevee/eevee_lightprobes.c b/source/blender/draw/engines/eevee/eevee_lightprobes.c
index 942ab5502c7..eb111610706 100644
--- a/source/blender/draw/engines/eevee/eevee_lightprobes.c
+++ b/source/blender/draw/engines/eevee/eevee_lightprobes.c
@@ -403,7 +403,7 @@ static bool eevee_lightprobes_culling_test(Object *ob)
       const float max[3] = {1.0f, 1.0f, 1.0f};
       BKE_boundbox_init_from_minmax(&bbox, min, max);
 
-      copy_m4_m4(tmp, ob->obmat);
+      copy_m4_m4(tmp, ob->object_to_world);
       normalize_v3(tmp[2]);
       mul_v3_fl(tmp[2], probe->distinf);
 
@@ -445,7 +445,7 @@ void EEVEE_lightprobes_cache_add(EEVEE_ViewLayerData *sldata, EEVEE_Data *vedata
     /* Debug Display */
     DRWCallBuffer *grp = vedata->stl->g_data->planar_display_shgrp;
     if (grp && (probe->flag & LIGHTPROBE_FLAG_SHOW_DATA)) {
-      DRW_buffer_add_entry(grp, &pinfo->num_planar, ob->obmat);
+      DRW_buffer_add_entry(grp, &pinfo->num_planar, ob->object_to_world);
     }
 
     pinfo->num_planar++;
@@ -488,30 +488,30 @@ void EEVEE_lightprobes_grid_data_from_object(Object *ob, EEVEE_LightGrid *egrid,
   mul_v3_v3fl(half_cell_dim, cell_dim, 0.5f);
 
   /* Matrix converting world space to cell ranges. */
-  invert_m4_m4(egrid->mat, ob->obmat);
+  invert_m4_m4(egrid->mat, ob->object_to_world);
 
   /* First cell. */
   copy_v3_fl(egrid->corner, -1.0f);
   add_v3_v3(egrid->corner, half_cell_dim);
-  mul_m4_v3(ob->obmat, egrid->corner);
+  mul_m4_v3(ob->object_to_world, egrid->corner);
 
   /* Opposite neighbor cell. */
   copy_v3_fl3(egrid->increment_x, cell_dim[0], 0.0f, 0.0f);
   add_v3_v3(egrid->increment_x, half_cell_dim);
   add_v3_fl(egrid->increment_x, -1.0f);
-  mul_m4_v3(ob->obmat, egrid->increment_x);
+  mul_m4_v3(ob->object_to_world, egrid->increment_x);
   sub_v3_v3(egrid->increment_x, egrid->corner);
 
   copy_v3_fl3(egrid->increment_y, 0.0f, cell_dim[1], 0.0f);
   add_v3_v3(egrid->increment_y, half_cell_dim);
   add_v3_fl(egrid->increment_y, -1.0f);
-  mul_m4_v3(ob->obmat, egrid->increment_y);
+  mul_m4_v3(ob->object_to_world, egrid->increment_y);
   sub_v3_v3(egrid->increment_y, egrid->corner);
 
   copy_v3_fl3(egrid->increment_z, 0.0f, 0.0f, cell_dim[2]);
   add_v3_v3(egrid->increment_z, half_cell_dim);
   add_v3_fl(egrid->increment_z, -1.0f);
-  mul_m4_v3(ob->obmat, egrid->increment_z);
+  mul_m4_v3(ob->object_to_world, egrid->increment_z);
   sub_v3_v3(egrid->increment_z, egrid->corner);
 
   /* Visibility bias */
@@ -527,7 +527,7 @@ void EEVEE_lightprobes_cube_data_from_object(Object *ob, EEVEE_LightProbe *eprob
   LightProbe *probe = (LightProbe *)ob->data;
 
   /* Update transforms */
-  copy_v3_v3(eprobe->position, ob->obmat[3]);
+  copy_v3_v3(eprobe->position, ob->object_to_world[3]);
 
   /* Attenuation */
   eprobe->attenuation_type = probe->attenuation_type;
@@ -535,7 +535,7 @@ void EEVEE_lightprobes_cube_data_from_object(Object *ob, EEVEE_LightProbe *eprob
 
   unit_m4(eprobe->attenuationmat);
   scale_m4_fl(eprobe->attenuationmat, probe->distinf);
-  mul_m4_m4m4(eprobe->attenuationmat, ob->obmat, eprobe->attenuationmat);
+  mul_m4_m4m4(eprobe->attenuationmat, ob->object_to_world, eprobe->attenuationmat);
   invert_m4(eprobe->attenuationmat);
 
   /* Parallax */
@@ -550,7 +550,7 @@ void EEVEE_lightprobes_cube_data_from_object(Object *ob, EEVEE_LightProbe *eprob
     scale_m4_fl(eprobe->parallaxmat, probe->distinf);
   }
 
-  mul_m4_m4m4(eprobe->parallaxmat, ob->obmat, eprobe->parallaxmat);
+  mul_m4_m4m4(eprobe->parallaxmat, ob->object_to_world, eprobe->parallaxmat);
   invert_m4(eprobe->parallaxmat);
 }
 
@@ -566,8 +566,8 @@ void EEVEE_lightprobes_planar_data_from_object(Object *ob,
   vis_test->cached = false;
 
   /* Computing mtx : matrix that mirror position around object's XY plane. */
-  normalize_m4_m4(normat, ob->obmat); /* object > world */
-  invert_m4_m4(imat, normat);         /* world > object */
+  normalize_m4_m4(normat, ob->object_to_world); /* object > world */
+  invert_m4_m4(imat, normat);                   /* world > object */
   /* XY reflection plane */
   imat[0][2] = -imat[0][2];
   imat[1][2] = -imat[1][2];
@@ -576,38 +576,38 @@ void EEVEE_lightprobes_planar_data_from_object(Object *ob,
   mul_m4_m4m4(eplanar->mtx, normat, imat); /* world > object > mirrored obj > world */
 
   /* Compute clip plane equation / normal. */
-  copy_v3_v3(eplanar->plane_equation, ob->obmat[2]);
+  copy_v3_v3(eplanar->plane_equation, ob->object_to_world[2]);
   normalize_v3(eplanar->plane_equation); /* plane normal */
-  eplanar->plane_equation[3] = -dot_v3v3(eplanar->plane_equation, ob->obmat[3]);
+  eplanar->plane_equation[3] = -dot_v3v3(eplanar->plane_equation, ob->object_to_world[3]);
   eplanar->clipsta = probe->clipsta;
 
   /* Compute XY clip planes. */
-  normalize_v3_v3(eplanar->clip_vec_x, ob->obmat[0]);
-  normalize_v3_v3(eplanar->clip_vec_y, ob->obmat[1]);
+  normalize_v3_v3(eplanar->clip_vec_x, ob->object_to_world[0]);
+  normalize_v3_v3(eplanar->clip_vec_y, ob->object_to_world[1]);
 
   float vec[3] = {0.0f, 0.0f, 0.0f};
   vec[0] = 1.0f;
   vec[1] = 0.0f;
   vec[2] = 0.0f;
-  mul_m4_v3(ob->obmat, vec); /* Point on the edge */
+  mul_m4_v3(ob->object_to_world, vec); /* Point on the edge */
   eplanar->clip_edge_x_pos = dot_v3v3(eplanar->clip_vec_x, vec);
 
   vec[0] = 0.0f;
   vec[1] = 1.0f;
   vec[2] = 0.0f;
-  mul_m4_v3(ob->obmat, vec); /* Point on the edge */
+  mul_m4_v3(ob->object_to_world, vec); /* Point on the edge */
   eplanar->clip_edge_y_pos = dot_v3v3(eplanar->clip_vec_y, vec);
 
   vec[0] = -1.0f;
   vec[1] = 0.0f;
   vec[2] = 0.0f;
-  mul_m4_v3(ob->obmat, vec); /* Point on the edge */
+  mul_m4_v3(ob->object_to_world, vec); /* Point on the edge */
   eplanar->clip_edge_x_neg = dot_v3v3(eplanar->clip_vec_x, vec);
 
   vec[0] = 0.0f;
   vec[1] = -1.0f;
   vec[2] = 0.0f;
-  mul_m4_v3(ob->obmat, vec); /* Point on the edge */
+  mul_m4_v3(ob->object_to_world, vec); /* Point on the edge */
   eplanar->clip_edge_y_neg = dot_v3v3(eplanar->clip_vec_y, vec);
 
   /* Facing factors */
diff --git a/source/blender/draw/engines/eevee/eevee_lights.c b/source/blender/draw/engines/eevee/eevee_lights.c
index 312305a31f7..f8250f9520d 100644
--- a/source/blender/draw/engines/eevee/eevee_lights.c
+++ b/source/blender/draw/engines/eevee/eevee_lights.c
@@ -132,7 +132,7 @@ static void eevee_light_setup(Object *ob, EEVEE_Light *evli)
   const float light_threshold = draw_ctx->scene->eevee.light_threshold;
 
   /* Position */
-  copy_v3_v3(evli->position, ob->obmat[3]);
+  copy_v3_v3(evli->position, ob->object_to_world[3]);
 
   /* Color */
   copy_v3_v3(evli->color, &la->r);
@@ -153,7 +153,7 @@ static void eevee_light_setup(Object *ob, EEVEE_Light *evli)
   evli->invsqrdist_volume = 1.0f / max_ff(1e-4f, square_f(att_radius_volume));
 
   /* Vectors */
-  normalize_m4_m4_ex(mat, ob->obmat, scale);
+  normalize_m4_m4_ex(mat, ob->object_to_world, scale);
   copy_v3_v3(evli->forwardvec, mat[2]);
   normalize_v3(evli->forwardvec);
   negate_v3(evli->forwardvec);
diff --git a/source/blender/draw/engines/eevee/eevee_motion_blur.c b/source/blender/draw/engines/eevee/eevee_motion_blur.c
index a3ca19c88e1..9f7fb1c154c 100644
--- a/source/blender/draw/engines/eevee/eevee_motion_blur.c
+++ b/source/blender/draw/engines/eevee/eevee_motion_blur.c
@@ -292,7 +292,7 @@ void EEVEE_motion_blur_curves_cache_populate(EEVEE_ViewLayerData *UNUSED(sldata)
 
   int mb_step = effects->motion_blur_step;
   /* Store transform. */
-  copy_m4_m4(mb_data->obmat[mb_step], ob->obmat);
+  copy_m4_m4(mb_data->obmat[mb_step], ob->object_to_world);
 
   EEVEE_HairMotionData *mb_curves = EEVEE_motion_blur_curves_data_get(mb_data);
 
@@ -362,7 +362,7 @@ void EEVEE_motion_blur_cache_populate(EEVEE_ViewLayerData *UNUSED(sldata),
   if (mb_data) {
     int mb_step = effects->motion_blur_step;
     /* Store transform. */
-    copy_m4_m4(mb_data->obmat[mb_step], ob->obmat);
+    copy_m4_m4(mb_data->obmat[mb_step], ob->object_to_world);
 
     EEVEE_GeometryMotionData *mb_geom = EEVEE_motion_blur_geometry_data_get(mb_data);
 
diff --git a/source/blender/draw/engines/eevee/eevee_shadows.c b/source/blender/draw/engines/eevee/eevee_shadows.c
index 9e571b1d15b..1cf3c7c6da1 100644
--- a/source/blender/draw/engines/eevee/eevee_shadows.c
+++ b/source/blender/draw/engines/eevee/eevee_shadows.c
@@ -153,7 +153,7 @@ void EEVEE_shadows_caster_register(EEVEE_ViewLayerData *sldata, Object *ob)
   for (int i = 0; i < 8; i++) {
     float vec[3];
     copy_v3_v3(vec, bb->vec[i]);
-    mul_m4_v3(ob->obmat, vec);
+    mul_m4_v3(ob->object_to_world, vec);
     minmax_v3v3_v3(min, max, vec);
   }
 
diff --git a/source/blender/draw/engines/eevee/eevee_volumes.c b/source/blender/draw/engines/eevee/eevee_volumes.c
index 05b2bafdb3a..872696a8b7c 100644
--- a/source/blender/draw/engines/eevee/eevee_volumes.c
+++ b/source/blender/draw/engines/eevee/eevee_volumes.c
@@ -299,7 +299,7 @@ void EEVEE_volumes_cache_object_add(EEVEE_ViewLayerData *sldata,
   }
 
   float size[3];
-  mat4_to_size(size, ob->obmat);
+  mat4_to_size(size, ob->object_to_world);
   /* Check if any of the axes have 0 length. (see T69070) */
   const float epsilon = 1e-8f;
   if ((size[0] < epsilon) || (size[1] < epsilon) || (size[2] < epsilon)) {