Index: source/blender/include/BSE_node.h
===================================================================
--- source/blender/include/BSE_node.h	(revision 11762)
+++ source/blender/include/BSE_node.h	(working copy)
@@ -40,6 +40,7 @@
 
 struct SpaceNode;
 struct bNode;
+struct bNodeSocket;
 struct bNodeTree;
 struct Material;
 struct ID;
@@ -78,6 +79,7 @@
 void node_composit_default(struct Scene *scene);
 
 int node_has_hidden_sockets(struct bNode *node);
+float socket_in_visible_category(struct bNodeSocket *currentsock);
 
 struct bNode *node_add_node(struct SpaceNode *snode, int type, float locx, float locy);
 void node_adduplicate(struct SpaceNode *snode);
Index: source/blender/makesdna/DNA_node_types.h
===================================================================
--- source/blender/makesdna/DNA_node_types.h	(revision 11762)
+++ source/blender/makesdna/DNA_node_types.h	(working copy)
@@ -84,6 +84,7 @@
 #define SOCK_VALUE		0
 #define SOCK_VECTOR		1
 #define SOCK_RGBA		2
+#define SOCK_CATEGORY		4
 
 /* sock->flag, first bit is select */
 		/* hidden is user defined, to hide unused */
Index: source/blender/src/editnode.c
===================================================================
--- source/blender/src/editnode.c	(revision 11762)
+++ source/blender/src/editnode.c	(working copy)
@@ -1147,7 +1147,18 @@
 	return 0;
 }
 
+float socket_in_visible_category(bNodeSocket *currentsock)
+{
+	bNodeSocket *sock;
 
+	if(currentsock->type==SOCK_CATEGORY) return 1.0; /* category names are always visible */
+
+	for(sock= currentsock; sock; sock= sock->prev)
+		if(sock->type==SOCK_CATEGORY) return *sock->ns.vec;
+	
+	return 1.0;
+}
+
 static void node_hide_unhide_sockets(SpaceNode *snode, bNode *node)
 {
 	bNodeSocket *sock;
@@ -1591,7 +1602,7 @@
 			
 			if(in_out==SOCK_OUT) {
 				if(find_indicated_socket(snode, &tnode, &tsock, SOCK_IN)) {
-					if(nodeFindLink(snode->edittree, sock, tsock)==NULL) {
+					if(tsock->type!=SOCK_CATEGORY && socket_in_visible_category(tsock) && nodeFindLink(snode->edittree, sock, tsock)==NULL) {
 						if(tnode!=node  && link->tonode!=tnode && link->tosock!= tsock) {
 							link->tonode= tnode;
 							link->tosock= tsock;
@@ -1606,7 +1617,7 @@
 			}
 			else {
 				if(find_indicated_socket(snode, &tnode, &tsock, SOCK_OUT)) {
-					if(nodeFindLink(snode->edittree, sock, tsock)==NULL) {
+					if(tsock->type!=SOCK_CATEGORY && socket_in_visible_category(tsock) && nodeFindLink(snode->edittree, sock, tsock)==NULL) {
 						if(nodeCountSocketLinks(snode->edittree, tsock) < tsock->limit) {
 							if(tnode!=node && link->fromnode!=tnode && link->fromsock!= tsock) {
 								link->fromnode= tnode;
Index: source/blender/src/drawnode.c
===================================================================
--- source/blender/src/drawnode.c	(revision 11762)
+++ source/blender/src/drawnode.c	(working copy)
@@ -1767,6 +1767,8 @@
 		0.15142777,0.52896401,0.82076344,0.97952994,
 	};
 	int a;
+
+	if(type==SOCK_CATEGORY) return; /* don't draw circles for categories */
 	
 	if(select==0) {
 		if(type==-1)
@@ -1979,7 +1981,7 @@
 	
 	/* input sockets */
 	for(nsock= node->inputs.first; nsock; nsock= nsock->next) {
-		if(!(nsock->flag & (SOCK_HIDDEN|SOCK_UNAVAIL))) {
+		if(!(nsock->flag & (SOCK_HIDDEN|SOCK_UNAVAIL)) && (socket_in_visible_category(nsock) || nsock->link)) {
 			nsock->locx= node->locx;
 			nsock->locy= dy - NODE_DYS;
 			dy-= NODE_DY;
@@ -2083,6 +2085,26 @@
 	return TH_NODE;
 }
 
+static void node_draw_category_triangle(uiBlock *block, short xloc, short yloc, float *butpoin, SpaceNode *snode, bNode *node, bNodeSocket *sock)
+{
+	uiBut *bt;	
+
+	uiBlockSetEmboss(block, UI_EMBOSSN);
+
+	if(*butpoin != 1.0) {
+		bt= uiDefIconButBitF(block, TOG, HEADER_NO_PULLDOWN, B_FLIPINFOMENU, ICON_DISCLOSURE_TRI_RIGHT,
+				xloc, yloc, 20, 17,
+				butpoin, 0, 0, 0, 0, "Show category");
+	} else {
+		bt= uiDefIconButBitF(block, TOG, HEADER_NO_PULLDOWN, B_FLIPINFOMENU, ICON_DISCLOSURE_TRI_DOWN,
+				xloc, yloc, 20, 17,
+				butpoin, 0, 0, 0, 0, "Hide category");
+	}
+	uiButSetFunc(bt, node_sync_cb, snode, node);
+	
+	uiBlockSetEmboss(block, UI_EMBOSS);
+}
+
 static void node_draw_basis(ScrArea *sa, SpaceNode *snode, bNode *node)
 {
 	bNodeSocket *sock;
@@ -2192,19 +2214,16 @@
 		glDisable(GL_BLEND);
 	}
 	
-	/* we make buttons for input sockets, if... */
-	if(node->flag & NODE_OPTIONS) {
-		if(node->inputs.first || node->typeinfo->butfunc) {
-			char str[32];
-			
-			/* make unique block name, also used for handling blocks in editnode.c */
-			sprintf(str, "node buttons %p", node);
-			
-			block= uiNewBlock(&sa->uiblocks, str, UI_EMBOSS, UI_HELV, sa->win);
-			uiBlockSetFlag(block, UI_BLOCK_NO_HILITE);
-			if(snode->id)
-				uiSetButLock(snode->id->lib!=NULL, ERROR_LIBDATA_MESSAGE);
-		}
+	if(node->inputs.first || node->typeinfo->butfunc) {
+		char str[32];
+		
+		/* make unique block name, also used for handling blocks in editnode.c */
+		sprintf(str, "node buttons %p", node);
+		
+		block= uiNewBlock(&sa->uiblocks, str, UI_EMBOSS, UI_HELV, sa->win);
+		uiBlockSetFlag(block, UI_BLOCK_NO_HILITE);
+		if(snode->id)
+			uiSetButLock(snode->id->lib!=NULL, ERROR_LIBDATA_MESSAGE);
 	}
 	
 	/* hurmf... another candidate for callback, have to see how this works first */
@@ -2214,42 +2233,62 @@
 	/* socket inputs, buttons */
 	for(sock= node->inputs.first; sock; sock= sock->next) {
 		if(!(sock->flag & (SOCK_HIDDEN|SOCK_UNAVAIL))) {
-			socket_circle_draw(sock->locx, sock->locy, NODE_SOCKSIZE, sock->type, sock->flag & SELECT);
+			if((socket_in_visible_category(sock) || sock->link) && (sock->type!=SOCK_CATEGORY)) socket_circle_draw(sock->locx, sock->locy, NODE_SOCKSIZE, sock->type, sock->flag & SELECT);
 			
-			if(block && sock->link==NULL) {
+			if((node->flag & NODE_OPTIONS) && (sock->link==NULL)) {
 				float *butpoin= sock->ns.vec;
 				
-				if(sock->type==SOCK_VALUE) {
-					bt= uiDefButF(block, NUM, B_NODE_EXEC+node->nr, sock->name, 
-						  (short)sock->locx+NODE_DYS, (short)(sock->locy)-9, (short)node->width-NODE_DY, 17, 
-						  butpoin, sock->ns.min, sock->ns.max, 10, 2, "");
-					uiButSetFunc(bt, node_sync_cb, snode, node);
+				if(socket_in_visible_category(sock)) {
+					if(sock->type==SOCK_VALUE) {
+						bt= uiDefButF(block, NUM, B_NODE_EXEC+node->nr, sock->name, 
+							(short)sock->locx+NODE_DYS, (short)(sock->locy)-9, (short)node->width-NODE_DY, 17, 
+							butpoin, sock->ns.min, sock->ns.max, 10, 2, "");
+						uiButSetFunc(bt, node_sync_cb, snode, node);
+					}
+					else if(sock->type==SOCK_VECTOR) {
+						uiDefBlockBut(block, socket_vector_menu, sock, sock->name, 
+							(short)sock->locx+NODE_DYS, (short)sock->locy-9, (short)node->width-NODE_DY, 17, 
+							"");
+					}
+					else if(sock->type==SOCK_RGBA) {
+						short labelw= node->width-NODE_DY-40, width;
+						
+						if(labelw>0) width= 40; else width= node->width-NODE_DY;
+						
+						bt= uiDefButF(block, COL, B_NODE_EXEC+node->nr, "", 
+							(short)(sock->locx+NODE_DYS), (short)sock->locy-8, width, 15, 
+							butpoin, 0, 0, 0, 0, "");
+						uiButSetFunc(bt, node_sync_cb, snode, node);
+						
+						if(labelw>0) uiDefBut(block, LABEL, 0, sock->name, 
+								 (short)(sock->locx+NODE_DYS) + 40, (short)sock->locy-8, labelw, 15, 
+								 NULL, 0, 0, 0, 0, "");
+					}
+					else if(sock->type==SOCK_CATEGORY) {
+						node_draw_category_triangle(block,
+						(short)sock->locx+NODE_DYS,
+						(short)sock->locy-9, butpoin, snode, node, sock);
+
+						uiDefBut(block, LABEL, 0, sock->name,
+						(short)sock->locx+NODE_DYS+NODE_DY, (short)sock->locy-9,
+						(short)node->width-NODE_DY, 17, 0, 0, 0, 0, 0, "");
+					}
 				}
-				else if(sock->type==SOCK_VECTOR) {
-					uiDefBlockBut(block, socket_vector_menu, sock, sock->name, 
-						  (short)sock->locx+NODE_DYS, (short)sock->locy-9, (short)node->width-NODE_DY, 17, 
-						  "");
+			}
+			else {
+				/* exception! uiDefBut won't work in this case so have to use ui_rasterpos_safe instead */
+				if(((node->typeinfo->flag & NODE_OPTIONS) && (socket_in_visible_category(sock) || sock->link)) 
+				     || (node->typeinfo->nclass & NODE_CLASS_OUTPUT)) { 
+					BIF_ThemeColor(TH_TEXT);
+					ui_rasterpos_safe(sock->locx+8.0f, sock->locy-5.0f, snode->aspect);
+					BIF_DrawString(snode->curfont, sock->name, 0);
 				}
-				else if(block && sock->type==SOCK_RGBA) {
-					short labelw= node->width-NODE_DY-40, width;
-					
-					if(labelw>0) width= 40; else width= node->width-NODE_DY;
-					
-					bt= uiDefButF(block, COL, B_NODE_EXEC+node->nr, "", 
-						(short)(sock->locx+NODE_DYS), (short)sock->locy-8, width, 15, 
-						   butpoin, 0, 0, 0, 0, "");
-					uiButSetFunc(bt, node_sync_cb, snode, node);
-					
-					if(labelw>0) uiDefBut(block, LABEL, 0, sock->name, 
-										   (short)(sock->locx+NODE_DYS) + 40, (short)sock->locy-8, labelw, 15, 
-										   NULL, 0, 0, 0, 0, "");
+				else {
+					uiDefBut(block, LABEL, 0, sock->name,
+							(short)sock->locx+NODE_DYS, (short)sock->locy-9,
+							(short)node->width-NODE_DY, 17, 0, 0, 0, 0, 0, "");
 				}
 			}
-			else {
-				BIF_ThemeColor(TH_TEXT);
-				ui_rasterpos_safe(sock->locx+8.0f, sock->locy-5.0f, snode->aspect);
-				BIF_DrawString(snode->curfont, sock->name, 0);
-			}
 		}
 	}
 	
@@ -2354,6 +2393,7 @@
 }
 
 /* note; this is used for fake links in groups too */
+/* TODO: fix issue that appears when a category is hidden and cursor is dragged above an item just below category name (has to be last on node) -> node_add_link_drag at editnode.c */
 void node_draw_link(SpaceNode *snode, bNodeLink *link)
 {
 	float vec[4][3];
@@ -2373,9 +2413,9 @@
 	}
 	else {
 		/* going to give issues once... */
-		if(link->tosock->flag & SOCK_UNAVAIL)
+		if((link->tosock->flag & SOCK_UNAVAIL) || (link->tosock->type==SOCK_CATEGORY))
 			return;
-		if(link->fromsock->flag & SOCK_UNAVAIL)
+		if((link->fromsock->flag & SOCK_UNAVAIL) || (link->fromsock->type==SOCK_CATEGORY))
 			return;
 		
 		/* a bit ugly... but thats how we detect the internal group links */
Index: source/blender/nodes/intern/SHD_util.h
===================================================================
--- source/blender/nodes/intern/SHD_util.h	(revision 11762)
+++ source/blender/nodes/intern/SHD_util.h	(working copy)
@@ -101,29 +101,30 @@
 } ShaderCallData;
 
 /* output socket defines */
-#define GEOM_OUT_GLOB	0
-#define GEOM_OUT_LOCAL	1
-#define GEOM_OUT_VIEW	2
-#define GEOM_OUT_ORCO	3
+#define GEOM_OUT_GLOB		0
+#define GEOM_OUT_LOCAL		1
+#define GEOM_OUT_VIEW		2
+#define GEOM_OUT_ORCO		3
 #define GEOM_OUT_UV		4
-#define GEOM_OUT_NORMAL	5
-#define GEOM_OUT_VCOL	6
+#define GEOM_OUT_NORMAL		5
+#define GEOM_OUT_VCOL		6
 #define GEOM_OUT_FRONTBACK	7
 
 
 /* input socket defines */
-#define MAT_IN_COLOR	0
+#define MAT_IN_COLOR		0
 #define MAT_IN_SPEC		1
 #define MAT_IN_REFL		2
-#define MAT_IN_NORMAL	3
-#define MAT_IN_MIR		4
-#define MAT_IN_AMBCOL	5
-#define MAT_IN_AMB		6
-#define MAT_IN_EMIT	7
-#define MAT_IN_SPECTRA	8
-#define MAT_IN_RAY_MIRROR	9
-#define MAT_IN_ALPHA	10
-#define MAT_IN_TRANSLUCENCY	11
+#define MAT_IN_NORMAL		3
+/* 4 is reserved by category */
+#define MAT_IN_MIR		5
+#define MAT_IN_AMBCOL		6
+#define MAT_IN_AMB		7
+#define MAT_IN_EMIT		8
+#define MAT_IN_SPECTRA		9
+#define MAT_IN_RAY_MIRROR	10
+#define MAT_IN_ALPHA		11
+#define MAT_IN_TRANSLUCENCY	12
 
 /* output socket defines */
 #define MAT_OUT_COLOR		0
Index: source/blender/nodes/intern/SHD_nodes/SHD_material.c
===================================================================
--- source/blender/nodes/intern/SHD_nodes/SHD_material.c	(revision 11762)
+++ source/blender/nodes/intern/SHD_nodes/SHD_material.c	(working copy)
@@ -53,6 +53,7 @@
 	{	SOCK_RGBA, 1, "Spec",		0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f},
 	{	SOCK_VALUE, 1, "Refl",		0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f},
 	{	SOCK_VECTOR, 1, "Normal",	0.0f, 0.0f, 0.0f, 1.0f, -1.0f, 1.0f},
+	{	SOCK_CATEGORY, 1, "Extended",	0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f},
 	{	SOCK_RGBA, 1, "Mirror",		0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f},
 	{	SOCK_RGBA, 1, "AmbCol",		0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f},
 	{	SOCK_VALUE, 1, "Ambient",	0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f},
Index: source/blender/nodes/intern/SHD_util.c
===================================================================
--- source/blender/nodes/intern/SHD_util.c	(revision 11762)
+++ source/blender/nodes/intern/SHD_util.c	(working copy)
@@ -55,7 +55,7 @@
 			VECCOPY(in, from);
 		}
 	}
-	else { /* type_in==SOCK_RGBA */
+	else if(type_in==SOCK_RGBA) {
 		if(ns->sockettype==SOCK_RGBA) {
 			QUATCOPY(in, from);
 		}