NLA SoC: Transition Strips + Strip Adding Operators + Bugfixes

== Transitions ==
Transition strips are now able to be created + evaluated. Transitions allow for interpolation between the endpoints of two adjacent strips in the same track (i.e. two strips which occur in the same track one after the other, but with a gap between them). 

- The current behaviour when only one endpoint affects some setting is non-optimal, since it appears somewhat inconsistently extend/replace values...
- Transform code needs a few fixes still to deal with these


== Strip Adding Operators ==
* New strips referencing Actions can be added using the Shift-A hotkey while in the strips-area. You must have a track selected first though.  
The new strip will get added, starting from the current frame, in the selected track(s) only if there is enough space to do so. Otherwise, the new strip gets added at the top of the stack in a new track.

* New transition strips can be added with the Shift-T hotkey while in the strips area. You must have two adjacent strips selected for this to work.

== New Backend Methods ==
* Recoded the strip/track adding API to be more flexible
* Added a new method for testing whether F-Curve has any modifiers of with certain attributes. Will be used in a later bugfix...

== Bugfixes ==
- Fixed bug with strip-blending which caused the blending modes to be useless.
- NLA buttons now use proper poll callbacks instead of defining checks
- Commented out missing operator in menus, silencing warnings in console
- Removed obsolete/incorrect comments
 

1 files changed, 227 insertions, 2 deletions

diff --git a/source/blender/editors/space_nla/nla_edit.c b/source/blender/editors/space_nla/nla_edit.c
index e8af67aebd1..2996a005177 100644
--- a/source/blender/editors/space_nla/nla_edit.c
+++ b/source/blender/editors/space_nla/nla_edit.c
@@ -48,6 +48,8 @@
 #include "BKE_animsys.h"
 #include "BKE_nla.h"
 #include "BKE_context.h"
+#include "BKE_library.h"
+#include "BKE_main.h"
 #include "BKE_report.h"
 #include "BKE_screen.h"
 #include "BKE_utildefines.h"
@@ -215,6 +217,229 @@ void NLAEDIT_OT_tweakmode_exit (wmOperatorType *ot)
 /* *********************************************** */
 /* NLA Editing Operations */
 
+/* ******************** Add Action-Clip Operator ***************************** */
+/* Add a new Action-Clip strip to the active track (or the active block if no space in the track) */
+
+/* pop up menu allowing user to choose the action to use */
+static int nlaedit_add_actionclip_invoke (bContext *C, wmOperator *op, wmEvent *evt)
+{
+	Main *m= CTX_data_main(C);
+	bAction *act;
+	uiPopupMenu *pup;
+	uiLayout *layout;
+	
+	pup= uiPupMenuBegin(C, "Add Action Clip", 0);
+	layout= uiPupMenuLayout(pup);
+	
+	/* loop through Actions in Main database, adding as items in the menu */
+	for (act= m->action.first; act; act= act->id.next)
+		uiItemStringO(layout, act->id.name+2, 0, "NLAEDIT_OT_add_actionclip", "action", act->id.name);
+	uiItemS(layout);
+	
+	uiPupMenuEnd(C, pup);
+	
+	return OPERATOR_CANCELLED;
+}
+
+/* add the specified action as new strip */
+static int nlaedit_add_actionclip_exec (bContext *C, wmOperator *op)
+{
+	bAnimContext ac;
+	Scene *scene;
+	
+	ListBase anim_data = {NULL, NULL};
+	bAnimListElem *ale;
+	int filter, items;
+	
+	bAction *act = NULL;
+	char actname[22];
+	float cfra;
+	
+	/* get editor data */
+	if (ANIM_animdata_get_context(C, &ac) == 0)
+		return OPERATOR_CANCELLED;
+		
+	scene= ac.scene;
+	cfra= (float)CFRA;
+		
+	/* get action to use */
+	RNA_string_get(op->ptr, "action", actname);
+	act= (bAction *)find_id("AC", actname+2);
+	
+	if (act == NULL) {
+		BKE_report(op->reports, RPT_ERROR, "No valid Action to add.");
+		//printf("Add strip - actname = '%s' \n", actname);
+		return OPERATOR_CANCELLED;
+	}
+	
+	/* get a list of the editable tracks being shown in the NLA
+	 *	- this is limited to active ones for now, but could be expanded to 
+	 */
+	filter= (ANIMFILTER_VISIBLE | ANIMFILTER_ACTIVE | ANIMFILTER_NLATRACKS | ANIMFILTER_FOREDIT);
+	items= ANIM_animdata_filter(&ac, &anim_data, filter, ac.data, ac.datatype);
+	
+	if (items == 0) {
+		BKE_report(op->reports, RPT_ERROR, "No active track(s) to add strip to.");
+		return OPERATOR_CANCELLED;
+	}
+	
+	/* for every active track, try to add strip to free space in track or to the top of the stack if no space */
+	for (ale= anim_data.first; ale; ale= ale->next) {
+		NlaTrack *nlt= (NlaTrack *)ale->data;
+		AnimData *adt= BKE_animdata_from_id(ale->id);
+		NlaStrip *strip= NULL;
+		
+		/* create a new strip, and offset it to start on the current frame */
+		strip= add_nlastrip(act);
+		
+		strip->end 		+= (cfra - strip->start);
+		strip->start	 = cfra;
+		
+		/* firstly try adding strip to our current track, but if that fails, add to a new track */
+		if (BKE_nlatrack_add_strip(nlt, strip) == 0) {
+			/* trying to add to the current failed (no space), 
+			 * so add a new track to the stack, and add to that...
+			 */
+			nlt= add_nlatrack(adt, NULL);
+			BKE_nlatrack_add_strip(nlt, strip);
+		}
+	}
+	
+	/* free temp data */
+	BLI_freelistN(&anim_data);
+	
+	/* set notifier that things have changed */
+	ANIM_animdata_send_notifiers(C, &ac, ANIM_CHANGED_BOTH);
+	WM_event_add_notifier(C, NC_SCENE, NULL);
+	
+	/* done */
+	return OPERATOR_FINISHED;
+}
+
+void NLAEDIT_OT_add_actionclip (wmOperatorType *ot)
+{
+	/* identifiers */
+	ot->name= "Add Action Strip";
+	ot->idname= "NLAEDIT_OT_add_actionclip";
+	ot->description= "Add an Action-Clip strip (i.e. an NLA Strip referencing an Action) to the active track.";
+	
+	/* api callbacks */
+	ot->invoke= nlaedit_add_actionclip_invoke;
+	ot->exec= nlaedit_add_actionclip_exec;
+	ot->poll= nlaop_poll_tweakmode_off;
+	
+	/* flags */
+	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
+	
+	/* props */
+		// TODO: this would be nicer as an ID-pointer...
+	RNA_def_string(ot->srna, "action", "", 21, "Action", "Name of Action to add as a new Action-Clip Strip.");
+}
+
+/* ******************** Add Transition Operator ***************************** */
+/* Add a new transition strip between selected strips */
+
+/* add the specified action as new strip */
+static int nlaedit_add_transition_exec (bContext *C, wmOperator *op)
+{
+	bAnimContext ac;
+	
+	ListBase anim_data = {NULL, NULL};
+	bAnimListElem *ale;
+	int filter;
+	
+	int done = 0;
+	
+	/* get editor data */
+	if (ANIM_animdata_get_context(C, &ac) == 0)
+		return OPERATOR_CANCELLED;
+	
+	/* get a list of the editable tracks being shown in the NLA */
+	filter= (ANIMFILTER_VISIBLE | ANIMFILTER_NLATRACKS | ANIMFILTER_FOREDIT);
+	ANIM_animdata_filter(&ac, &anim_data, filter, ac.data, ac.datatype);
+	
+	/* for each track, find pairs of strips to add transitions to */
+	for (ale= anim_data.first; ale; ale= ale->next) {
+		NlaTrack *nlt= (NlaTrack *)ale->data;
+		NlaStrip *s1, *s2;
+		
+		/* get initial pair of strips */
+		if ELEM(nlt->strips.first, NULL, nlt->strips.last)
+			continue;
+		s1= nlt->strips.first;
+		s2= s1->next;
+		
+		/* loop over strips */
+		for (; s1 && s2; s1=s2, s2=s2->next) {
+			NlaStrip *strip;
+			
+			/* check if both are selected */
+			if ELEM(0, (s1->flag & NLASTRIP_FLAG_SELECT), (s2->flag & NLASTRIP_FLAG_SELECT))
+				continue;
+			/* check if there's space between the two */
+			if (IS_EQ(s1->end, s2->start))
+				continue;
+				
+			/* allocate new strip */
+			strip= MEM_callocN(sizeof(NlaStrip), "NlaStrip");
+			BLI_insertlinkafter(&nlt->strips, s1, strip);
+			
+			/* set the type */
+			strip->type= NLASTRIP_TYPE_TRANSITION;
+			
+			/* generic settings 
+			 *	- selected flag to highlight this to the user
+			 *	- auto-blends to ensure that blend in/out values are automatically 
+			 *	  determined by overlaps of strips
+			 */
+			strip->flag = NLASTRIP_FLAG_SELECT|NLASTRIP_FLAG_AUTO_BLENDS;
+			
+			/* range is simply defined as the endpoints of the adjacent strips */
+			strip->start 	= s1->end;
+			strip->end 		= s2->start;
+			
+			/* scale and repeat aren't of any use, but shouldn't ever be 0 */
+			strip->scale= 1.0f;
+			strip->repeat = 1.0f;
+			
+			/* make note of this */
+			done++;
+		}
+	}
+	
+	/* free temp data */
+	BLI_freelistN(&anim_data);
+	
+	/* was anything added? */
+	if (done) {
+		/* set notifier that things have changed */
+		ANIM_animdata_send_notifiers(C, &ac, ANIM_CHANGED_BOTH);
+		WM_event_add_notifier(C, NC_SCENE, NULL);
+		
+		/* done */
+		return OPERATOR_FINISHED;
+	}
+	else {
+		BKE_report(op->reports, RPT_ERROR, "Needs at least a pair of adjacent selected strips.");
+		return OPERATOR_CANCELLED;
+	}
+}
+
+void NLAEDIT_OT_add_transition (wmOperatorType *ot)
+{
+	/* identifiers */
+	ot->name= "Add Transition";
+	ot->idname= "NLAEDIT_OT_add_transition";
+	ot->description= "Add a transition strip between two adjacent selected strips.";
+	
+	/* api callbacks */
+	ot->exec= nlaedit_add_transition_exec;
+	ot->poll= nlaop_poll_tweakmode_off;
+	
+	/* flags */
+	ot->flag= OPTYPE_REGISTER|OPTYPE_UNDO;
+}
+
 /* ******************** Delete Strips Operator ***************************** */
 /* Deletes the selected NLA-Strips */
 
@@ -230,7 +455,7 @@ static int nlaedit_delete_exec (bContext *C, wmOperator *op)
 	if (ANIM_animdata_get_context(C, &ac) == 0)
 		return OPERATOR_CANCELLED;
 		
-	/* get a list of the AnimData blocks being shown in the NLA */
+	/* get a list of the editable tracks being shown in the NLA */
 	filter= (ANIMFILTER_VISIBLE | ANIMFILTER_NLATRACKS | ANIMFILTER_FOREDIT);
 	ANIM_animdata_filter(&ac, &anim_data, filter, ac.data, ac.datatype);
 	
@@ -292,7 +517,7 @@ static int nlaedit_split_exec (bContext *C, wmOperator *op)
 	if (ANIM_animdata_get_context(C, &ac) == 0)
 		return OPERATOR_CANCELLED;
 		
-	/* get a list of the AnimData blocks being shown in the NLA */
+	/* get a list of editable tracks being shown in the NLA */
 	filter= (ANIMFILTER_VISIBLE | ANIMFILTER_NLATRACKS | ANIMFILTER_FOREDIT);
 	ANIM_animdata_filter(&ac, &anim_data, filter, ac.data, ac.datatype);