Fix Increment Snapping Without Constraints in Non-Axis-Aligned Views

The incremental snap was always operating in the local space, which in most
cases is the VIEW type orientation.

Use only local space when the operation is affected by constraint.

Differential Revision: https://developer.blender.org/D10052

3 files changed, 20 insertions, 5 deletions

diff --git a/source/blender/editors/transform/transform_mode_translate.c b/source/blender/editors/transform/transform_mode_translate.c
index 2c73c416cf8..5640b61984a 100644
--- a/source/blender/editors/transform/transform_mode_translate.c
+++ b/source/blender/editors/transform/transform_mode_translate.c
@@ -397,9 +397,9 @@ static void applyTranslation(TransInfo *t, const int UNUSED(mval[2]))
     }
 
     float incr_dir[3];
-    mul_v3_m3v3(incr_dir, t->spacemtx_inv, global_dir);
-    if (!(activeSnap(t) && validSnap(t)) && transform_snap_increment(t, incr_dir)) {
-      mul_v3_m3v3(incr_dir, t->spacemtx, incr_dir);
+    copy_v3_v3(incr_dir, global_dir);
+    if (!(activeSnap(t) && validSnap(t)) &&
+        transform_snap_increment_ex(t, (t->con.mode & CON_APPLY) != 0, incr_dir)) {
 
       /* Test for mixed snap with grid. */
       float snap_dist_sq = FLT_MAX;
diff --git a/source/blender/editors/transform/transform_snap.c b/source/blender/editors/transform/transform_snap.c
index e461bcb88e9..fc47b053fe9 100644
--- a/source/blender/editors/transform/transform_snap.c
+++ b/source/blender/editors/transform/transform_snap.c
@@ -1523,7 +1523,7 @@ static void snap_increment_apply(TransInfo *t,
   snap_increment_apply_ex(t, max_index, increment_dist, asp, r_val, r_val);
 }
 
-bool transform_snap_increment(TransInfo *t, float *val)
+bool transform_snap_increment_ex(TransInfo *t, bool use_local_space, float *r_val)
 {
   if (!activeSnap(t)) {
     return false;
@@ -1539,12 +1539,26 @@ bool transform_snap_increment(TransInfo *t, float *val)
     return false;
   }
 
+  if (use_local_space) {
+    BLI_assert(t->idx_max == 2);
+    mul_m3_v3(t->spacemtx_inv, r_val);
+  }
+
   float increment_dist = (t->modifiers & MOD_PRECISION) ? t->snap[1] : t->snap[0];
+  snap_increment_apply(t, t->idx_max, increment_dist, r_val);
+
+  if (use_local_space) {
+    mul_m3_v3(t->spacemtx, r_val);
+  }
 
-  snap_increment_apply(t, t->idx_max, increment_dist, val);
   return true;
 }
 
+bool transform_snap_increment(TransInfo *t, float *r_val)
+{
+  return transform_snap_increment_ex(t, false, r_val);
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */
diff --git a/source/blender/editors/transform/transform_snap.h b/source/blender/editors/transform/transform_snap.h
index 5bee572c603..6ab7bbffa12 100644
--- a/source/blender/editors/transform/transform_snap.h
+++ b/source/blender/editors/transform/transform_snap.h
@@ -56,6 +56,7 @@ void snapFrameTransform(struct TransInfo *t,
 
 bool transformModeUseSnap(const TransInfo *t);
 
+bool transform_snap_increment_ex(TransInfo *t, bool use_local_space, float *r_val);
 bool transform_snap_increment(TransInfo *t, float *val);
 bool transform_snap_grid(TransInfo *t, float *val);