Cleanup: ED_view3d_win_to_delta & ED_view3d_calc_zfac usage

- Rename ED_view3d_win_to_delta `mval` argument to `xy_delta` as it
  as it was misleading since this is an screen-space offset not a region
  relative cursor position (typical use of the name `mval`).
  Also rename the variable passed to this function which also used the
  term `mval` in many places.
- Re-order the output argument of ED_view3d_win_to_delta last.
  use an r_ prefix for return arguments.
- Document how the `zfac` argument is intended to be used.
- Split ED_view3d_calc_zfac into two functions as the `r_flip` argument
  was only used in some special cases.

1 files changed, 2 insertions, 2 deletions

diff --git a/source/blender/editors/space_view3d/view3d_navigate.c b/source/blender/editors/space_view3d/view3d_navigate.c
index 21e0459f346..d1e7f6ffb12 100644
--- a/source/blender/editors/space_view3d/view3d_navigate.c
+++ b/source/blender/editors/space_view3d/view3d_navigate.c
@@ -396,7 +396,7 @@ ViewOpsData *viewops_data_create(bContext *C, const wmEvent *event, enum eViewOp
   {
     float tvec[3];
     negate_v3_v3(tvec, rv3d->ofs);
-    vod->init.zfac = ED_view3d_calc_zfac(rv3d, tvec, NULL);
+    vod->init.zfac = ED_view3d_calc_zfac(rv3d, tvec);
   }
 
   vod->reverse = 1.0f;
@@ -559,7 +559,7 @@ void viewmove_apply(ViewOpsData *vod, int x, int y)
   else {
     float dvec[3];
 
-    ED_view3d_win_to_delta(vod->region, event_ofs, dvec, vod->init.zfac);
+    ED_view3d_win_to_delta(vod->region, event_ofs, vod->init.zfac, dvec);
 
     sub_v3_v3(vod->rv3d->ofs, dvec);