The reason is that the per-node updates used for Reroute node type inheritance are not supposed to be looking at connected nodes, they are purely for "local" updates. For this sort of "global" update which requires depth-first search, the update function on the node tree level must be used instead.
1) For inserting into existing groups:
The 'Make Group from selected' (CTRL+g) operator shows a selection popup (like the object parenting operator), with options depending on the type of the active node (last selected):
* "New" -> regular operator, creates new group type with all selected nodes inside.
* "Insert" (only if active node is a group) -> adds all other selected nodes into the group.
Currently still prohibits groups inside groups in general, though would be technically possible as long as no actual recursion occurs (group containing itself).
2) For extracting from an existing group:
New 'Separate from group' operator (p), works similar to separating vertices/edges/faces from mesh. Two modes:
* "Copy" makes a copy of the nodes in the parent tree, but keeps the original group intact.
* "Move" removes selected nodes from the node group and adds them to the parent tree
By holding shift and "cutting" a node link a new reroute helper node can be inserted. This consists of a single socket that can be used to insert additional connection points into a link. This can be used to keep a connection point in the tree when deleting a node, or to control the path of long connections for layout cleanup.
For an detailed user-level description of new features see the following blogpost:
http://code.blender.org/index.php/2012/05/node-editing-tweaks/
TL;DR:
* Frame node gets more usable bounding-box behavior
* Node resizing has helpful mouse cursor indicators and works on all borders
* Node selection/active colors are themeable independently
* Customizable background colors for nodes (useful for frames visual
distinction).
*Add menu is now translated.
*Nodes' title is now translated.
*Nodes' sockets' labels are now translated.
However, about the last point, and unless I’m mistaking, we’ll have to add the "i18n tag" N_() to all sockets' names, in the input/ouput templates declaration, in all nodes' files, as those sockets are collections created at runtime, I think po-generating script has no way to access that from bpy.types... Quite a piece of (borring) work. :/
There are a number of features that use a kind of "internal linking" in nodes:
1. muting
2. delete + reconnect (restore link to/from node after delete)
3. the new detach operator (same as 2, but don't delete the node)
The desired behavior in all cases is the same: find a sensible mapping of inputs-to-outputs of a node. In the case of muting these links are displayed in red on the node itself. For the other operators they are used to relink connections, such that one gets the best possible ongoing link between previous up- and downstream nodes.
Muting previously used a complicated callback system to ensure consistent behavior in the editor as well as execution in compositor, shader cpu/gpu and texture nodes. This has been greatly simplified by moving the muting step into the node tree localization functions. Any muted node is now bypassed using the generalized nodeInternalRelink function and then removed from the local tree. This way the internal execution system doesn't have to deal with muted nodes at all, as if they are non-existent.
The same function is also used by the delete_reconnect and the new links_detach operators (which work directly in the editor node tree). Detaching nodes is currently keymapped as a translation variant (macro operator): pressing ALTKEY + moving node first detaches and then continues with regular transform operator. The default key is ALT+DKEY though, instead ALT+GKEY, since the latter is already used for the ungroup operator.
The structs stored in the anonymous void *default_value in bNodeSocket are now handled completely inside node_socket.c. All allocation/freeing/duplicating for this has been replaced by the appropriate calls to generic API functions (declared in NOD_socket.h).
This will make the default value handling more reliable for future node socket code. Group socket copying and value conversion has also been moved into the generic socket API file.
Instead of generally hiding all unused sockets in collapsed mode, the sockets now have a new explicit flag SOCK_AUTO_HIDDEN, which is only toggled when the hide_toggle operator is called. This way the auto-hidden sockets stay as they are when nodes are duplicated etc. The new flag is necessary to distinguish between manually hidden sockets (via hide_sockets_toggle operator) and automatically hidden sockets and restore the node state when unhiding a node.
Now, compositing, shading and texture nodes have a consistent muting system, with default behaving as previous (for compo), and which can be optionaly customized by each node.
Shader nodes are also GLSL muted.
However, Cycles is currently unaware of muted nodes, will try to address this…
This allows node type init code to have access to the nodetree type object (needed to allow generic muting node initialization). Huge and boring edits...
* Scene.use_shading_nodes property to check if RenderEngine is using new shading
nodes system, and RenderEngine.bl_use_shading_nodes to set this.
* Add mechanism for tagging nodes as being compatible with the old/new system.
This prevents access to non-existent typeinfo during type initialization,
when node types have been removed and such nodes are deleted from older files.
All blenkernel functions now only set the node->update flag instead of directly
calling the update function. All operators, etc. calling blenkernel functions
to modify nodes should make a ntreeUpdate call afterward (they already did that
anyway).
Editor/RNA/renderer/etc. high-level functions still can do immediate updates by
using nodeUpdate and nodeUpdateID (replacing NodeTagChanged/NodeTagIDChanged
respectively). These old functions were previously used only for setting
compositor node needexec flags and clearing cached data, but have become generic
update functions that require type-specific functionality (i.e. a valid typeinfo
struct).
The cause is an unknown node socket type in node groups. Ideally the node system
should handle this better and remove the unknown sockets from groups, but this
is a bit of a risky fix to do now, so instead the shader socket type has been
added, since this is a simple change and the code has been tested well.
The problem was that all outputs got tagged indiscriminately (esp. hidden render layer sockets), leading to full recalculation every time. This was caused by erroneous tagging of bNodeStacks with hasinput/hasoutput flags. This patch restores the old behaviour of tagging all non-static stacks as input values and all outputs that are connected to some input. Only difference is in node groups, where the hasoutput flag is no longer abused for tagging internal buffers, here the is_copy flag is used instead.
