link-gloss.py

import bpy

def get_connected_link(nodes, inputSocket):
    for n in nodes:
        for socket in n.outputs:
            for l in socket.links:
                if l.to_socket == inputSocket:
                    return l
    return None

countfound = 0
for m in bpy.data.materials:
    if m.use_nodes == False:
        continue;

    tree = m.node_tree;
    for n1 in tree.nodes:
        if n1.type != "BSDF_PRINCIPLED":
            continue

        socketBaseColor = n1.inputs[0]
        socketRough = n1.inputs[9]

        link = get_connected_link(tree.nodes, socketRough)
        if link:
            continue

        link = get_connected_link(tree.nodes, socketBaseColor)
        if link is None:
            continue

        node_tex = link.from_node
        if node_tex.type == 'MIX_RGB':
            node_tex = get_connected_link(tree.nodes, node_tex.inputs[1]).from_node

        string = node_tex.image.name
        string = string.replace(".png", "")
        string = string.rsplit("_", 1)[0]

        name_variants = ["GLOSS", "gloss", "G", "g", "glos", "GLOS"]
        for to_append in name_variants:
            name_appended = string + '_' + to_append
            path = '//' + name_appended + '.png'

            tex = None
            try:
                tex = bpy.data.images.load(path)
                print('found texture: ' + name_appended)
                countfound += 1
            except:
                continue

            if tex == None:
                continue

            tex.colorspace_settings.name = 'Non-Color'
            tex.alpha_mode = 'CHANNEL_PACKED'

            node_tex = tree.nodes.new('ShaderNodeTexImage')
            node_tex.location = n1.location
            node_tex.location.x -= 600
            node_tex.image = tex

            node_invert = tree.nodes.new('ShaderNodeInvert')
            node_invert.location = n1.location
            node_invert.location.x -= 300

            tree.links.new(node_tex.outputs[0], node_invert.inputs[1])
            tree.links.new(node_invert.outputs[0], n1.inputs[9])

            break

print(str(countfound) + ' gloss textures found')