NodeViewPanel.py

# made in response to
# http://blender.stackexchange.com/q/49552/935

bl_info = {
    "version": (1, 0),
    "blender": (2, 75, 0),
    "author": "sambler",
    "name": "testing addon",
    "location": "blender",
    "description": "test showing material nodes in toolshelf" ,
    "warning": "only for testing",
    "category": "test",
}

import bpy

class MaterialNodeViewPanel(bpy.types.Panel):
    """Display material nodes"""
    bl_label = 'Node View Panel'
    bl_idname = 'MAT_PT_nodes'
    bl_space_type = 'VIEW_3D'
    bl_region_type = 'TOOLS'

    def draw(self, context):
        layout = self.layout
        obj = context.object

        if obj.type == 'LAMP':
            # we need obj as a lamp object to get the node_tree property
            obj = bpy.data.lamps[obj.name]
            uses_nodes = obj.use_nodes
            node_tree = obj.node_tree
            outnode_type = 'OUTPUT_LAMP'
        else:
            mat = obj.active_material

            if mat is None:
                layout.row().label(text='No material')
                return

            uses_nodes = mat.use_nodes
            node_tree = obj.active_material.node_tree
            outnode_type = 'OUTPUT_MATERIAL'

        if not uses_nodes:
            layout.row().label(text='Enable nodes in the material properties')
            return

        node = None
        for n in node_tree.nodes:
            if n.type == outnode_type and n.is_active_output:
                node = n
                break
        if node is None:
            layout.row().label(text='No output node found')
        else:
            layout.template_node_view(node_tree, node, node.inputs['Surface'])

def register():
    bpy.utils.register_class(MaterialNodeViewPanel)

def unregister():
    bpy.utils.unregister_class(MaterialNodeViewPanel)

if __name__ == "__main__":
    register()

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