Blender Python: Normalize materials to Image Texture -> BSDF -> Output

bpy_normalize_image_texture_materials.py

# Script by SuperFromND.
# This was written to partially clean up exported model data from ModNao, a Sega Dreamcast model ripping website.
# License: CC0. Go nuts!

import bpy
for obj in bpy.data.objects:
    if obj.type == 'MESH' and not obj.active_material == None:
        for item in obj.material_slots:
            mat = bpy.data.materials[item.name]
            if mat.use_nodes:
                mat.blend_method = 'CLIP'
                # first pass to just remove anything that's not necessary, i.e. we keep images and material out ONLY
                for node in mat.node_tree.nodes:
                    if (node.type == 'TEX_IMAGE' or node.type == 'OUTPUT_MATERIAL'):
                        # do nothing, but we keep this node
                        pass
                    else:
                        mat.node_tree.nodes.remove(node)
                        
                # second pass to re-assemble the nodes into a normal material
                pbsdf = mat.node_tree.nodes.new("ShaderNodeBsdfPrincipled")
                matoutput = mat.node_tree.nodes.get("Material Output")
                for node in mat.node_tree.nodes:
                    if node.type == 'TEX_IMAGE':
                        links = mat.node_tree.links
                        links.new(node.outputs[0], pbsdf.inputs["Base Color"])
                        links.new(node.outputs[1], pbsdf.inputs["Alpha"])
                        links.new(pbsdf.outputs["BSDF"], matoutput.inputs["Surface"])