Cleanup: Make curve deform argument optional

The "dir" argument to `BKE_where_on_path` was only actually
used in a few places. It's easier to see where those are if there
isn't always a dummy argument.

source/blender/blenkernel/intern/anim_path.c

@@ -295,10 +295,12 @@ bool BKE_where_on_path(const Object *ob,
 
   key_curve_tangent_weights(frac, w, KEY_BSPLINE);
 
-  interp_v3_v3v3v3v3(r_dir, p0->vec, p1->vec, p2->vec, p3->vec, w);
+  if (r_dir) {
+    interp_v3_v3v3v3v3(r_dir, p0->vec, p1->vec, p2->vec, p3->vec, w);
 
-  /* Make compatible with #vec_to_quat. */
+    /* Make compatible with #vec_to_quat. */
-  negate_v3(r_dir);
+    negate_v3(r_dir);
+  }
   //}
 
   const ListBase *nurbs = BKE_curve_editNurbs_get(cu);

source/blender/blenkernel/intern/armature_update.c

@@ -405,8 +405,8 @@ static void splineik_evaluate_bone(
 
   if (pchan->bone->length < FLT_EPSILON) {
     /* Only move the bone position with zero length bones. */
-    float bone_pos[4], dir[3], rad;
+    float bone_pos[4], rad;
-    BKE_where_on_path(ik_data->tar, state->curve_position, bone_pos, dir, NULL, &rad, NULL);
+    BKE_where_on_path(ik_data->tar, state->curve_position, bone_pos, NULL, NULL, &rad, NULL);
 
     apply_curve_transform(ik_data, ob, rad, bone_pos, &rad);
 
@@ -445,13 +445,13 @@ static void splineik_evaluate_bone(
 
   /* Step 1: determine the positions for the endpoints of the bone. */
   if (point_start < 1.0f) {
-    float vec[4], dir[3], rad;
+    float vec[4], rad;
     radius = 0.0f;
 
     /* Calculate head position. */
     if (point_start == 0.0f) {
       /* Start of the path. We have no previous tail position to copy. */
-      BKE_where_on_path(ik_data->tar, point_start, vec, dir, NULL, &rad, NULL);
+      BKE_where_on_path(ik_data->tar, point_start, vec, NULL, NULL, &rad, NULL);
     }
     else {
       copy_v3_v3(vec, state->prev_tail_loc);
@@ -486,7 +486,7 @@ static void splineik_evaluate_bone(
     }
     else {
       /* Scale to fit curve end position. */
-      if (BKE_where_on_path(ik_data->tar, point_end, vec, dir, NULL, &rad, NULL)) {
+      if (BKE_where_on_path(ik_data->tar, point_end, vec, NULL, NULL, &rad, NULL)) {
         state->prev_tail_radius = rad;
         copy_v3_v3(state->prev_tail_loc, vec);
         copy_v3_v3(pose_tail, vec);

source/blender/blenkernel/intern/constraint.c

@@ -1495,7 +1495,7 @@ static void followpath_get_tarmat(struct Depsgraph *UNUSED(depsgraph),
 
   if (VALID_CONS_TARGET(ct) && (ct->tar->type == OB_CURVES_LEGACY)) {
     Curve *cu = ct->tar->data;
-    float vec[4], dir[3], radius;
+    float vec[4], radius;
     float curvetime;
 
     unit_m4(ct->matrix);
@@ -1532,7 +1532,7 @@ static void followpath_get_tarmat(struct Depsgraph *UNUSED(depsgraph),
       if (BKE_where_on_path(ct->tar,
                             curvetime,
                             vec,
-                            dir,
+                            NULL,
                             (data->followflag & FOLLOWPATH_FOLLOW) ? quat : NULL,
                             &radius,
                             NULL)) { /* quat_pt is quat or NULL. */
@@ -3886,7 +3886,7 @@ static void clampto_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *tar
 
     /* get targetmatrix */
     if (data->tar->runtime.curve_cache && data->tar->runtime.curve_cache->anim_path_accum_length) {
-      float vec[4], dir[3], totmat[4][4];
+      float vec[4], totmat[4][4];
       float curvetime;
       short clamp_axis;
 
@@ -3969,7 +3969,7 @@ static void clampto_evaluate(bConstraint *con, bConstraintOb *cob, ListBase *tar
       }
 
       /* 3. position on curve */
-      if (BKE_where_on_path(ct->tar, curvetime, vec, dir, NULL, NULL, NULL)) {
+      if (BKE_where_on_path(ct->tar, curvetime, vec, NULL, NULL, NULL, NULL)) {
         unit_m4(totmat);
         copy_v3_v3(totmat[3], vec);
 

source/blender/blenkernel/intern/object.cc

@@ -3087,12 +3087,12 @@ void BKE_object_matrix_local_get(struct Object *ob, float r_mat[4][4])
 static bool ob_parcurve(Object *ob, Object *par, float r_mat[4][4])
 {
   Curve *cu = (Curve *)par->data;
-  float vec[4], dir[3], quat[4], radius, ctime;
+  float vec[4], quat[4], radius, ctime;
 
   /* NOTE: Curve cache is supposed to be evaluated here already, however there
    * are cases where we can not guarantee that. This includes, for example,
    * dependency cycles. We can't correct anything from here, since that would
-   * cause a threading conflicts.
+   * cause threading conflicts.
    *
    * TODO(sergey): Some of the legit looking cases like T56619 need to be
    * looked into, and maybe curve cache (and other dependencies) are to be
@@ -3125,7 +3125,7 @@ static bool ob_parcurve(Object *ob, Object *par, float r_mat[4][4])
 
   /* vec: 4 items! */
   if (BKE_where_on_path(
-          par, ctime, vec, dir, (cu->flag & CU_FOLLOW) ? quat : nullptr, &radius, nullptr)) {
+          par, ctime, vec, nullptr, (cu->flag & CU_FOLLOW) ? quat : nullptr, &radius, nullptr)) {
     if (cu->flag & CU_FOLLOW) {
       quat_apply_track(quat, ob->trackflag, ob->upflag);
       normalize_qt(quat);

source/blender/blenkernel/intern/vfont.c

@@ -1372,7 +1372,7 @@ static bool vfont_to_curve(Object *ob,
 
       ct = chartransdata;
       for (i = 0; i <= slen; i++, ct++) {
-        float ctime, dtime, vec[4], tvec[4], rotvec[3];
+        float ctime, dtime, vec[4], rotvec[3];
         float si, co;
 
         /* Rotate around center character. */
@@ -1392,9 +1392,9 @@ static bool vfont_to_curve(Object *ob,
         CLAMP(ctime, 0.0f, 1.0f);
 
         /* Calculate the right loc AND the right rot separately. */
-        /* `vec`, `tvec` need 4 items. */
+        /* `vec` needs 4 items. */
-        BKE_where_on_path(cu->textoncurve, ctime, vec, tvec, NULL, NULL, NULL);
+        BKE_where_on_path(cu->textoncurve, ctime, vec, NULL, NULL, NULL, NULL);
-        BKE_where_on_path(cu->textoncurve, ctime + dtime, tvec, rotvec, NULL, NULL, NULL);
+        BKE_where_on_path(cu->textoncurve, ctime + dtime, NULL, rotvec, NULL, NULL, NULL);
 
         mul_v3_fl(vec, sizefac);
 

source/blender/draw/engines/overlay/overlay_extra.c

@@ -528,13 +528,13 @@ static void OVERLAY_forcefield(OVERLAY_ExtraCallBuffers *cb, Object *ob, ViewLay
     case PFIELD_GUIDE:
       if (cu && (cu->flag & CU_PATH) && ob->runtime.curve_cache->anim_path_accum_length) {
         instdata.size_x = instdata.size_y = instdata.size_z = pd->f_strength;
-        float pos[4], tmp[3];
+        float pos[4];
-        BKE_where_on_path(ob, 0.0f, pos, tmp, NULL, NULL, NULL);
+        BKE_where_on_path(ob, 0.0f, pos, NULL, NULL, NULL, NULL);
         copy_v3_v3(instdata.pos, ob->obmat[3]);
         translate_m4(instdata.mat, pos[0], pos[1], pos[2]);
         DRW_buffer_add_entry(cb->field_curve, color, &instdata);
 
-        BKE_where_on_path(ob, 1.0f, pos, tmp, NULL, NULL, NULL);
+        BKE_where_on_path(ob, 1.0f, pos, NULL, NULL, NULL, NULL);
         copy_v3_v3(instdata.pos, ob->obmat[3]);
         translate_m4(instdata.mat, pos[0], pos[1], pos[2]);
         DRW_buffer_add_entry(cb->field_sphere_limit, color, &instdata);