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, 5 insertions, 5 deletions

diff --git a/source/blender/editors/space_view3d/view3d_navigate_zoom.c b/source/blender/editors/space_view3d/view3d_navigate_zoom.c
index 8eb8fffaa31..5f6f9fde324 100644
--- a/source/blender/editors/space_view3d/view3d_navigate_zoom.c
+++ b/source/blender/editors/space_view3d/view3d_navigate_zoom.c
@@ -125,18 +125,18 @@ static void view_zoom_to_window_xy_3d(ARegion *region, float dfac, const int zoo
     float dvec[3];
     float tvec[3];
     float tpos[3];
-    float mval_f[2];
+    float xy_delta[2];
 
     float zfac;
 
     negate_v3_v3(tpos, rv3d->ofs);
 
-    mval_f[0] = (float)(((zoom_xy[0] - region->winrct.xmin) * 2) - region->winx) / 2.0f;
-    mval_f[1] = (float)(((zoom_xy[1] - region->winrct.ymin) * 2) - region->winy) / 2.0f;
+    xy_delta[0] = (float)(((zoom_xy[0] - region->winrct.xmin) * 2) - region->winx) / 2.0f;
+    xy_delta[1] = (float)(((zoom_xy[1] - region->winrct.ymin) * 2) - region->winy) / 2.0f;
 
     /* Project cursor position into 3D space */
-    zfac = ED_view3d_calc_zfac(rv3d, tpos, NULL);
-    ED_view3d_win_to_delta(region, mval_f, dvec, zfac);
+    zfac = ED_view3d_calc_zfac(rv3d, tpos);
+    ED_view3d_win_to_delta(region, xy_delta, zfac, dvec);
 
     /* Calculate view target position for dolly */
     add_v3_v3v3(tvec, tpos, dvec);