Toggle links tool for Node Editor

This commit adds a new tool, Toggle Links, to the node editor. This tool
allows the user to toggle the status (linked/not linked) between desired
sockets. The tool can be used either by using the f key or the menus.

This functionality is analogue to one found in object editing modes except
for its additional toggle functionality.

To use this tool, the user has to first select an input and an output socket.
Selecting is done by clicking with right mouse button on a socket. After the 
tool has been invoked, the link between those two sockets is toggled. The 
result may vary based on existing linkage.

There can be only one input and one output selected at maximum in a node 
tree. This means that if the user selects a socket while one of the same 
type is already selected, the old one will be deselected.

The tool complements the current way of connecting nodes. One possible use
for it is to use it to review output of nodes by using a viewer node. Just
select wanted input socket of a viewer node, set it visible and use selection 
of an output socket in conjuction with f key to show the output in the viewer
node. Select another output and hit f to see its output and so on.

1 files changed, 111 insertions, 25 deletions

diff --git a/source/blender/src/editnode.c b/source/blender/src/editnode.c
index a14b0ccc389..d035908994c 100644
--- a/source/blender/src/editnode.c
+++ b/source/blender/src/editnode.c
@@ -830,6 +830,23 @@ static void snode_bg_viewmove(SpaceNode *snode)
 	window_set_cursor(win, oldcursor);
 }
 
+static void reset_sel_socket(SpaceNode *snode, int in_out)
+{
+	bNode *node;
+	bNodeSocket *sock;
+	
+	for(node= snode->edittree->nodes.first; node; node= node->next) {
+		if(in_out & SOCK_IN) {
+			for(sock= node->inputs.first; sock; sock= sock->next)
+				if(sock->flag & SOCK_SEL) sock->flag&= ~SOCK_SEL;
+		}
+		if(in_out & SOCK_OUT) {
+			for(sock= node->outputs.first; sock; sock= sock->next)
+				if(sock->flag & SOCK_SEL) sock->flag&= ~SOCK_SEL;
+		}
+	}
+}
+
 /* checks mouse position, and returns found node/socket */
 /* type is SOCK_IN and/or SOCK_OUT */
 static int find_indicated_socket(SpaceNode *snode, bNode **nodep, bNodeSocket **sockp, int in_out)
@@ -1568,6 +1585,33 @@ static void node_insert_convertor(SpaceNode *snode, bNodeLink *link)
 
 #endif
 
+static void node_remove_extra_links(SpaceNode *snode, bNodeSocket *tsock, bNodeLink *link)
+{
+	bNodeLink *tlink;
+	bNodeSocket *sock;
+	
+	if(tsock && nodeCountSocketLinks(snode->edittree, link->tosock) > tsock->limit) {
+		
+		for(tlink= snode->edittree->links.first; tlink; tlink= tlink->next) {
+			if(link!=tlink && tlink->tosock==link->tosock)
+				break;
+		}
+		if(tlink) {
+			/* is there a free input socket with same type? */
+			for(sock= tlink->tonode->inputs.first; sock; sock= sock->next) {
+				if(sock->type==tlink->fromsock->type)
+					if(nodeCountSocketLinks(snode->edittree, sock) < sock->limit)
+						break;
+			}
+			if(sock)
+				tlink->tosock= sock;
+			else {
+				nodeRemLink(snode->edittree, tlink);
+			}
+		}
+	}
+}
+
 /* loop that adds a nodelink, called by function below  */
 /* in_out = starting socket */
 static int node_add_link_drag(SpaceNode *snode, bNode *node, bNodeSocket *sock, int in_out)
@@ -1638,35 +1682,12 @@ static int node_add_link_drag(SpaceNode *snode, bNode *node, bNodeSocket *sock,
 		nodeRemLink(snode->edittree, link);
 	}
 	else {
-		bNodeLink *tlink;
-
 		/* send changed events for original tonode and new */
 		if(link->tonode) 
 			NodeTagChanged(snode->edittree, link->tonode);
 		
 		/* we might need to remove a link */
-		if(in_out==SOCK_OUT) {
-			if(tsock && nodeCountSocketLinks(snode->edittree, link->tosock) > tsock->limit) {
-				
-				for(tlink= snode->edittree->links.first; tlink; tlink= tlink->next) {
-					if(link!=tlink && tlink->tosock==link->tosock)
-						break;
-				}
-				if(tlink) {
-					/* is there a free input socket with same type? */
-					for(tsock= tlink->tonode->inputs.first; tsock; tsock= tsock->next) {
-						if(tsock->type==tlink->fromsock->type)
-							if(nodeCountSocketLinks(snode->edittree, tsock) < tsock->limit)
-								break;
-					}
-					if(tsock)
-						tlink->tosock= tsock;
-					else {
-						nodeRemLink(snode->edittree, tlink);
-					}
-				}					
-			}
-		}
+		if(in_out==SOCK_OUT) node_remove_extra_links(snode, tsock, link);
 	}
 	
 	ntreeSolveOrder(snode->edittree);
@@ -1733,10 +1754,18 @@ static int node_add_link(SpaceNode *snode)
 void node_delete(SpaceNode *snode)
 {
 	bNode *node, *next;
+	bNodeSocket *sock;
 	
 	for(node= snode->edittree->nodes.first; node; node= next) {
 		next= node->next;
 		if(node->flag & SELECT) {
+			/* set selin and selout NULL if the sockets belong to a node to be deleted */
+			for(sock= node->inputs.first; sock; sock= sock->next)
+				if(snode->edittree->selin == sock) snode->edittree->selin= NULL;
+
+			for(sock= node->outputs.first; sock; sock= sock->next)
+				if(snode->edittree->selout == sock) snode->edittree->selout= NULL;
+
 			/* check id user here, nodeFreeNode is called for free dbase too */
 			if(node->id)
 				node->id->us--;
@@ -1826,6 +1855,36 @@ void node_select_linked(SpaceNode *snode, int out)
 	allqueue(REDRAWNODE, 1);
 }
 
+void node_toggle_link(SpaceNode *snode)
+{
+	bNode *fromnode, *tonode;
+	bNodeLink *remlink, *link;
+	bNodeSocket *outsock= snode->edittree->selout;
+	bNodeSocket *insock= snode->edittree->selin;
+
+	if(!insock || !outsock) return;
+
+	remlink= nodeFindLink(snode->edittree, outsock, insock);
+	
+	if(remlink) nodeRemLink(snode->edittree, remlink);
+	else {
+		if(nodeFindNode(snode->edittree, outsock, &fromnode, NULL) &&
+		   nodeFindNode(snode->edittree, insock, &tonode, NULL)) {
+			link= nodeAddLink(snode->edittree, fromnode, outsock, tonode, insock);
+			NodeTagChanged(snode->edittree, tonode);
+			node_remove_extra_links(snode, insock, link);
+		}
+		else return;
+	}
+
+	ntreeSolveOrder(snode->edittree);
+	snode_verify_groups(snode);
+	snode_handle_recalc(snode);
+
+	allqueue(REDRAWNODE, 0);
+	BIF_undo_push("Toggle Link");
+}
+
 static void node_border_link_delete(SpaceNode *snode)
 {
 	rcti rect;
@@ -2091,6 +2150,8 @@ static int node_uiDoBlocks(ScrArea *sa, short event)
 void winqreadnodespace(ScrArea *sa, void *spacedata, BWinEvent *evt)
 {
 	SpaceNode *snode= spacedata;
+	bNode *actnode;
+	bNodeSocket *actsock;
 	unsigned short event= evt->event;
 	short val= evt->val, doredraw=0, fromlib= 0;
 	
@@ -2118,7 +2179,29 @@ void winqreadnodespace(ScrArea *sa, void *spacedata, BWinEvent *evt)
 			break;
 			
 		case RIGHTMOUSE: 
-			if(!node_mouse_select(snode, event)) 
+			if(find_indicated_socket(snode, &actnode, &actsock, SOCK_IN)) {
+				if(actsock->flag & SOCK_SEL) {
+					snode->edittree->selin= NULL;
+					actsock->flag&= ~SOCK_SEL;
+				}
+				else {
+					snode->edittree->selin= actsock;
+					reset_sel_socket(snode, SOCK_IN);
+					actsock->flag|= SOCK_SEL;
+				}
+			}
+			else if(find_indicated_socket(snode, &actnode, &actsock, SOCK_OUT)) {
+				if(actsock->flag & SOCK_SEL) {
+					snode->edittree->selout= NULL;
+					actsock->flag&= ~SOCK_SEL;
+				}
+				else {
+					snode->edittree->selout= actsock;
+					reset_sel_socket(snode, SOCK_OUT);
+					actsock->flag|= SOCK_SEL;
+				}
+			}
+			else if(!node_mouse_select(snode, event)) 
 				toolbox_n();
 
 			break;
@@ -2194,6 +2277,9 @@ void winqreadnodespace(ScrArea *sa, void *spacedata, BWinEvent *evt)
 		case EKEY:
 			snode_handle_recalc(snode);
 			break;
+		case FKEY:
+			node_toggle_link(snode);
+			break;
 		case GKEY:
 			if(fromlib) fromlib= -1;
 			else {