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_edit.c b/source/blender/editors/space_view3d/view3d_edit.c
index d6bc7ded92e..5adce170e06 100644
--- a/source/blender/editors/space_view3d/view3d_edit.c
+++ b/source/blender/editors/space_view3d/view3d_edit.c
@@ -832,13 +832,13 @@ void ED_view3d_cursor3d_position(bContext *C,
     return;
   }
 
-  ED_view3d_calc_zfac(rv3d, cursor_co, &flip);
+  ED_view3d_calc_zfac_ex(rv3d, cursor_co, &flip);
 
   /* Reset the depth based on the view offset (we _know_ the offset is in front of us). */
   if (flip) {
     negate_v3_v3(cursor_co, rv3d->ofs);
     /* re initialize, no need to check flip again */
-    ED_view3d_calc_zfac(rv3d, cursor_co, NULL /* &flip */);
+    ED_view3d_calc_zfac(rv3d, cursor_co);
   }
 
   if (use_depth) { /* maybe this should be accessed some other way */