NLA: Shift-Tab toggles tweakmode AND makes that track solo

To help make it more convenient to edit stashed actions, Shift-Tab
(i.e. holding down the Shift key, which "tabbing" into tweakmode as
usual to edit the action referenced by the active NLA strip) now flags
the NLA Track that the strip occupies as being "solo" too.

This allows you to use the NLA to select a stashed action, then Shift-Tab
to start editing it without any other actions in the NLA stack interfering.
Like the "Next/Previous Layer" tools in the Action Editor, this is designed
to help with checking on stashed actions.

2 files changed, 36 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_nla.h b/source/blender/blenkernel/BKE_nla.h
index c3fc29e811f..3bf8bba47f5 100644
--- a/source/blender/blenkernel/BKE_nla.h
+++ b/source/blender/blenkernel/BKE_nla.h
@@ -76,6 +76,8 @@ void BKE_nlameta_flush_transforms(struct NlaStrip *mstrip);
 struct NlaTrack *BKE_nlatrack_find_active(ListBase *tracks);
 void BKE_nlatrack_set_active(ListBase *tracks, struct NlaTrack *nlt);
 
+struct NlaTrack *BKE_nlatrack_find_tweaked(struct AnimData *adt);
+
 void BKE_nlatrack_solo_toggle(struct AnimData *adt, struct NlaTrack *nlt);
 
 bool BKE_nlatrack_has_space(struct NlaTrack *nlt, float start, float end);
diff --git a/source/blender/blenkernel/intern/nla.c b/source/blender/blenkernel/intern/nla.c
index c87f378d5ae..eaa4460ce70 100644
--- a/source/blender/blenkernel/intern/nla.c
+++ b/source/blender/blenkernel/intern/nla.c
@@ -926,6 +926,40 @@ NlaTrack *BKE_nlatrack_find_active(ListBase *tracks)
 	return NULL;
 }
 
+/* Get the NLA Track that the active action/action strip comes from,
+ * since this info is not stored in AnimData. It also isn't as simple
+ * as just using the active track, since multiple tracks may have been
+ * entered at the same time.
+ */
+// TODO: Store this info in AnimData... Old files would still need to use this function for version patching though
+NlaTrack *BKE_nlatrack_find_tweaked(AnimData *adt)
+{
+	NlaTrack *nlt;
+	
+	/* sanity check */
+	if (adt == NULL)
+		return NULL;
+	
+	/* Since the track itself gets disabled, we want the first disabled... */
+	for (nlt = adt->nla_tracks.first; nlt; nlt = nlt->next) {
+		if (nlt->flag & (NLATRACK_ACTIVE | NLATRACK_DISABLED)) {
+			/* For good measure, make sure that strip actually exists there */
+			if (BLI_findindex(&nlt->strips, adt->actstrip) != -1) {
+				return nlt;
+			}
+			else if (G.debug & G_DEBUG) {
+				printf("%s: Active strip (%p, %s) not in NLA track found (%p, %s)\n",
+				       __func__, 
+				       adt->actstrip, (adt->actstrip) ? adt->actstrip->name : "<None>",
+				       nlt,           nlt->name);
+			}
+		}
+	}
+	
+	/* Not found! */
+	return NULL;
+}
+
 /* Toggle the 'solo' setting for the given NLA-track, making sure that it is the only one
  * that has this status in its AnimData block.
  */