3 files changed, 114 insertions, 5 deletions

diff --git a/source/blender/blenkernel/BKE_nla.h b/source/blender/blenkernel/BKE_nla.h
index 3c3abe11da3..89e5f1af7e1 100644
--- a/source/blender/blenkernel/BKE_nla.h
+++ b/source/blender/blenkernel/BKE_nla.h
@@ -59,9 +59,13 @@ void BKE_nlatrack_set_active(ListBase *tracks, struct NlaTrack *nlt);
 short BKE_nlatrack_has_space(struct NlaTrack *nlt, float start, float end);
 void BKE_nlatrack_sort_strips(struct NlaTrack *nlt);
 
+struct NlaStrip *BKE_nlastrip_find_active(struct NlaTrack *nlt);
 short BKE_nlastrip_within_bounds(struct NlaStrip *strip, float min, float max);
 
 void BKE_nla_action_pushdown(struct AnimData *adt);
 
+short BKE_nla_tweakmode_enter(struct AnimData *adt);
+void BKE_nla_tweakmode_exit(struct AnimData *adt);
+
 #endif
 
diff --git a/source/blender/blenkernel/intern/anim_sys.c b/source/blender/blenkernel/intern/anim_sys.c
index 652f733d553..dbc38d2fc7e 100644
--- a/source/blender/blenkernel/intern/anim_sys.c
+++ b/source/blender/blenkernel/intern/anim_sys.c
@@ -118,6 +118,9 @@ void BKE_free_animdata (ID *id)
 			/* unlink action (don't free, as it's in its own list) */
 			if (adt->action)
 				adt->action->id.us--;
+			/* same goes for the temporarily displaced action */
+			if (adt->tmpact)
+				adt->tmpact->id.us--;
 				
 			/* free nla data */
 			free_nladata(&adt->nla_tracks);
@@ -151,6 +154,7 @@ AnimData *BKE_copy_animdata (AnimData *adt)
 	// XXX review this... it might not be optimal behaviour yet...
 	//id_us_plus((ID *)dadt->action);
 	dadt->action= copy_action(adt->action);
+	dadt->tmpact= copy_action(adt->action);
 	
 	/* duplicate NLA data */
 	copy_nladata(&dadt->nla_tracks, &adt->nla_tracks);
@@ -595,7 +599,7 @@ static float nlastrip_get_frame (NlaStrip *strip, float cframe, short invert)
 	scale = (float)fabs(strip->scale); /* scale must be positive - we've got a special flag for reversing */
 	
 	/* length of referenced action */
-	actlength = strip->actend-strip->actstart;
+	actlength = strip->actend - strip->actstart;
 	if (actlength == 0.0f) actlength = 1.0f;
 	
 	/* length of strip */
@@ -630,11 +634,11 @@ static float nlastrip_get_influence (NlaStrip *strip, float cframe)
 	// the +0.0001 factors are to combat rounding errors
 	if (IS_EQ(strip->blendin, 0)==0 && (cframe <= (strip->start + strip->blendin))) {
 		/* there is some blend-in */
-		return (float)(fabs(cframe - strip->start) + 0.0001) / (strip->blendin);
+		return (float)fabs(cframe - strip->start) / (strip->blendin);
 	}
 	else if (IS_EQ(strip->blendout, 0)==0 && (cframe >= (strip->end - strip->blendout))) {
 		/* there is some blend-out */
-		return (float)(fabs(strip->end - cframe) + 0.0001) / (strip->blendout);
+		return (float)fabs(strip->end - cframe) / (strip->blendout);
 	}
 	else {
 		/* in the middle of the strip, we should be full strength */
@@ -674,8 +678,8 @@ static void nlatrack_ctime_get_strip (ListBase *list, NlaTrack *nlt, short index
 	NlaEvalStrip *nes;
 	short side= 0;
 	
-	/* skip if track is muted */
-	if (nlt->flag & NLATRACK_MUTED) 
+	/* skip if track is muted or disabled */
+	if (nlt->flag & (NLATRACK_MUTED|NLATRACK_DISABLED)) 
 		return;
 	
 	/* loop over strips, checking if they fall within the range */
@@ -1104,6 +1108,7 @@ void BKE_animsys_evaluate_animdata (ID *id, AnimData *adt, float ctime, short re
 	 *	- NLA before Active Action, as Active Action behaves as 'tweaking track'
 	 *	  that overrides 'rough' work in NLA
 	 */
+	// TODO: need to double check that this all works correctly
 	if ((recalc & ADT_RECALC_ANIM) || (adt->recalc & ADT_RECALC_ANIM))
  	{
 		/* evaluate NLA data */
diff --git a/source/blender/blenkernel/intern/nla.c b/source/blender/blenkernel/intern/nla.c
index 6235ec58d40..84f98096364 100644
--- a/source/blender/blenkernel/intern/nla.c
+++ b/source/blender/blenkernel/intern/nla.c
@@ -583,4 +583,104 @@ void BKE_nla_action_pushdown (AnimData *adt)
 	}
 }
 
+
+/* Find the active strip + track combo, and set them up as the tweaking track,
+ * and return if successful or not.
+ */
+short BKE_nla_tweakmode_enter (AnimData *adt)
+{
+	NlaTrack *nlt, *activeTrack=NULL;
+	NlaStrip *strip, *activeStrip=NULL;
+	
+	/* verify that data is valid */
+	if ELEM(NULL, adt, adt->nla_tracks.first)
+		return 0;
+		
+	/* if block is already in tweakmode, just leave, but we should report 
+	 * that this block is in tweakmode (as our returncode)
+	 */
+	// FIXME: hopefully the flag is correct!
+	if (adt->flag & ADT_NLA_EDIT_ON)
+		return 1;
+		
+	/* go over the tracks, finding the active one, and its active strip
+	 * 	- if we cannot find both, then there's nothing to do
+	 */
+	for (nlt= adt->nla_tracks.first; nlt; nlt= nlt->next) {
+		/* check if active */
+		if (nlt->flag & NLATRACK_ACTIVE) {
+			/* store reference to this active track */
+			activeTrack= nlt;
+			
+			/* now try to find active strip */
+			activeStrip= BKE_nlastrip_find_active(nlt);
+			break;
+		}	
+	}
+	if ELEM3(NULL, activeTrack, activeStrip, activeStrip->act) {
+		printf("NLA tweakmode enter - neither active requirement found \n");
+		return 0;
+	}
+		
+	/* go over all the tracks up to the active one, tagging each strip that uses the same 
+	 * action as the active strip, but leaving everything else alone
+	 */
+	for (nlt= activeTrack->prev; nlt; nlt= nlt->prev) {
+		for (strip= nlt->strips.first; strip; strip= strip->next) {
+			if (strip->act == activeStrip->act)
+				strip->flag |= NLASTRIP_FLAG_TWEAKUSER;
+			else
+				strip->flag &= ~NLASTRIP_FLAG_TWEAKUSER; // XXX probably don't need to clear this...
+		}
+	}
+	
+	
+	/* go over all the tracks after AND INCLUDING the active one, tagging them as being disabled 
+	 *	- the active track needs to also be tagged, otherwise, it'll overlap with the tweaks going on
+	 */
+	for (nlt= activeTrack; nlt; nlt= nlt->next)
+		nlt->flag |= NLATRACK_DISABLED;
+	
+	/* handle AnimData level changes:
+	 *	- 'real' active action to temp storage (no need to change user-counts)
+	 *	- action of active strip set to be the 'active action'
+	 *	- editing-flag for this AnimData block should also get turned on (for more efficient restoring)
+	 */
+	adt->tmpact= adt->action;
+	adt->action= activeStrip->act;
+	adt->flag |= ADT_NLA_EDIT_ON;
+	
+	/* done! */
+	return 1;
+}
+
+/* Exit tweakmode for this AnimData block */
+void BKE_nla_tweakmode_exit (AnimData *adt)
+{
+	NlaTrack *nlt;
+	
+	/* verify that data is valid */
+	if ELEM(NULL, adt, adt->nla_tracks.first)
+		return;
+		
+	/* hopefully the flag is correct - skip if not on */
+	if ((adt->flag & ADT_NLA_EDIT_ON) == 0)
+		return;
+		
+	// TODO: need to sync the user-strip with the new state of the action!
+		
+	/* for all NLA-tracks, clear the 'disabled' flag */
+	for (nlt= adt->nla_tracks.first; nlt; nlt= nlt->next)
+		nlt->flag &= ~NLATRACK_DISABLED;
+	
+	/* handle AnimData level changes:
+	 *	- 'real' active action is restored from storage
+	 *	- storage pointer gets cleared (to avoid having bad notes hanging around)
+	 *	- editing-flag for this AnimData block should also get turned off
+	 */
+	adt->action= adt->tmpact;
+	adt->tmpact= NULL;
+	adt->flag &= ~ADT_NLA_EDIT_ON;
+}
+
 /* *************************************************** */