Problem here is that muted nodes and reroute nodes are supposed to be removed from the execution node tree during the localize function. However, this is function is apparently only used during preview renders and must be considered a hack (is there anything that is not a hack in BI?)
Now the mute/reroute check happens in the node tree exec functions still used by BI and the legacy compositor and texture nodes. It uses the same internal_connect function from nodes to assign input stack indices directly to outputs (which also avoids overhead). Localize function also still does this. Cycles/Tile should also implement muting/reroute in their intermediate node layers by using this function, then it could be removed from localize too.
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.
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…
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.
This branch adds mostly organizational improvements to the node system by renaming the node folders and files. A couple of internal features have been added too.
Detailed information can be found on the wiki page:
http://wiki.blender.org/index.php/User:Phonybone/Particles2010
