Set active image node with python

Question

There's any way to change it directly by Python, or there's any way to set by Python what node image is the active to display in viewport (Textured) and bake?

Answer 1

So far as I know, when baking with Cycles, the only way to bake to a texture is to create a texture and click on that node to make it the Active texture. Whatever Texture Node is active is the one which will be baked to. I reported something similar as a bug when Cycles Baking was still new and Brecht wrote back saying

The image texture assignment workflow in Cycles is very different from Blender Internal, that's by design and has been working this way for years. Images are assigned to materials, and the image shown in the image editor is not automatically linked to the UV layer or object you select, that's separate. http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/Texture_Editing

We can argue if this is good or bad, but can't consider it a bug.

Here's an example node setup snippet,

I hope this helps even though it's not a Python related answer.

Answer 2

Here is an example that creates a Texture Image Node for the material Material with Python:

import bpy

node_tree = bpy.data.materials['Material'].node_tree

node = node_tree.nodes.new("ShaderNodeTexImage")
node.select = True
node_tree.nodes.active = node

The new node is selected and made the active node of the node tree.

Answer 3

To expand on CoDEmanX's answer you may also want to create an image for the new node

newimg = bpy.data.images.new('targetImg',1024,1024)
node.image = newimg

And if you want to activate an existing image node for the active object -

matnodes = bpy.context.active_object.material_slots[0].material.node_tree.nodes
imgnodes = [n for n in matnodes if n.type == 'TEX_IMAGE']
for n in imgnodes:
    if n.image.name == 'targetImg':
        n.select = True
        matnodes.active = n

Answer 4

It seems like that as of v2.79 we have to define the Material to use nodes:

mater = bpy.data.materials['Material']
mater.use_nodes = True

node_tree = mater.node_tree

and continue with the suggestions above.