[Bf-committers] Link custom node trees to datablocks.

[Alexander Romanov]

On 22.10.2015 13:39, Francesc Juhe wrote:
> On 22 Oct 2015, at 10:58, Alexander Romanov <a.romanov at blend4web.com> wrote:
>
>>>>> As for issue, (1) Generalized nodetree editing, I think this could work:
>>>>>
>>>>> - Add a property to SpaceNodeEditor to hold the custom nodetree type.
>>>>> - Add a function registered on NodeTreeType that returns a list of accepted data sources.
>>>> I think, it would looks like:
>>>>
>>>> class MyNodeTree(bpy.types.NodeTree):
>>>>      bl_idname ='MyNodeTree'
>>>>      bl_source_types = {"OBJECT", "WORLD", "MATERIAL”}
>>> I was thinking on a function like the one accepted by EnumProperty that returned items (sequence of string tuples or a function) – sequence of enum items formatted: [(identifier, name, description, icon, number), …]
>>> I think it would be more versatile for custom node trees.
>> I think that the "parent" datablocks types should be defined in blender
>> kernel likeit was doneforAnimData. Thus there is a countable set of
>> types. Each type has general meaning for all custom nodetrees. So it
>> seems that is no need to move this work into scripting.
> But in the end, what is needed to fix the issue is a way to store in SpaceNodeEditor an enum or a value that holds the selected ‘data source’ but there is no real connection between this value and the nodetree returned by NodeTree.get_from_context(), the scripted function that is in fact returning the nodetree that is being edited in the node editor.
>
> Your proposal of using a set of items known to Blender is just limiting the amount of items available to NodeTree.get_from_context() to decide the appropriate nodetree that is returned to the editor.
> Being able to set the items along with NodeTree.get_from_context() is much more versatile.
You are right, here is the collision. Probably, your approach is more 
correct.
>
> What would be the final proposed list of items available to build this enum?
Needed for Blend4Web:
ID_OB, ID_SCE - are the most impotant
ID_LA, ID_CA, ID_MA, ID_SPK - potentially useful This discussion aims to 
provide such list.

>
>>>>> - Add appropriate draw code on space_node.py to draw the data source icons provided by the function and storing it on the SpaceNodeEditor property.
>>>>> - NodeTreeType then uses the property to know the data source selected on the Node Editor.
>>>>>
>>>>> I wanted to try to make a patch for this but haven’t had the time yet, I think this issue is not as difficult as the other.
>>>> if you start before melet me know, please. Iwill also informyou.
>>>>> In the Mitsuba Addon I am reusing SpaceNodeEditor.shader_type to select between world and object data source and works ok.
>>>>>
>>>>>
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>> -- 
>> Alexander Romanov (Blend4Web Team)
>>
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-- 
Alexander Romanov (Blend4Web Team)