def map_vertex_color(self,
layer_name: str = 'Col',
active_shading: bool = True):
""" Maps existing vertex color to the base color of the principled bsdf node or a new background color node.
:param layer_name: Name of the vertex color layer. Type: string.
:param active_shading: Whether to keep the principled bsdf shader. If True, the material properties influence light
reflections such as specularity, roughness, etc. alter the object's appearance. Type: bool.
"""
if active_shading:
# create new shader node attribute
attr_node = self.nodes.new(type='ShaderNodeAttribute')
attr_node.attribute_name = layer_name
# connect it to base color of principled bsdf
principled_bsdf = self.get_the_one_node_with_type("BsdfPrincipled")
self.links.new(attr_node.outputs['Color'],
principled_bsdf.inputs['Base Color'])
else:
# create new vertex color shade node
vcol = self.nodes.new(type="ShaderNodeVertexColor")
vcol.layer_name = layer_name
node_connected_to_output, material_output = Utility.get_node_connected_to_the_output_and_unlink_it(
self.blender_obj)
# remove principled bsdf
self.nodes.remove(node_connected_to_output)
background_color_node = self.nodes.new(type="ShaderNodeBackground")
if 'Color' in background_color_node.inputs:
self.links.new(vcol.outputs['Color'],
background_color_node.inputs['Color'])
self.links.new(background_color_node.outputs["Background"],
material_output.inputs["Surface"])
else:
raise Exception(
"Material '{}' has no node connected to the output, "
"which has as a 'Base Color' input.".format(
self.blender_obj.name))
def add_alpha_channel_to_textures(blurry_edges):
"""
Adds transparency to all textures, which contain an .png image as an image input
:param blurry_edges: If True, the edges of the alpha channel might be blurry,
this causes errors if the alpha channel should only be 0 or 1
Be careful, when you replace the original texture with something else (Segmentation, ...),
the necessary texture node gets lost. By copying it into a new material as done in the SegMapRenderer, you
can keep the transparency even for those nodes.
"""
obj_with_mats = [
obj for obj in bpy.context.scene.objects
if hasattr(obj.data, 'materials')
]
visited_materials = set()
# walk over all objects, which have materials
for obj in obj_with_mats:
for slot in obj.material_slots:
material = slot.material
if material is None:
# this can happen if a material slot was created but no material was assigned
continue
if material.name in visited_materials:
# skip a material if it has been used before
continue
visited_materials.add(material.name)
texture_node = None
# check each node of the material
for node in material.node_tree.nodes:
# if it is a texture image node
if 'TexImage' in node.bl_idname:
if '.png' in node.image.name: # contains an alpha channel
texture_node = node
# this material contains an alpha png texture
if texture_node is not None:
nodes = material.node_tree.nodes
links = material.node_tree.links
node_connected_to_the_output, material_output = \
Utility.get_node_connected_to_the_output_and_unlink_it(material)
if node_connected_to_the_output is not None:
mix_node = nodes.new(type='ShaderNodeMixShader')
# avoid blurry edges on the edges important for Normal, SegMapRenderer and others
if blurry_edges:
# add the alpha channel of the image to the mix shader node as a factor
links.new(texture_node.outputs['Alpha'],
mix_node.inputs['Fac'])
else:
# Map all alpha values to 0 or 1 by applying the step function: 1 if x > 0.5 else 0
step_function_node = nodes.new("ShaderNodeMath")
step_function_node.operation = "GREATER_THAN"
links.new(texture_node.outputs['Alpha'],
step_function_node.inputs['Value'])
links.new(step_function_node.outputs['Value'],
mix_node.inputs['Fac'])
links.new(node_connected_to_the_output.outputs[0],
mix_node.inputs[2])
transparent_node = nodes.new(
type='ShaderNodeBsdfTransparent')
links.new(transparent_node.outputs['BSDF'],
mix_node.inputs[1])
# connect to material output
links.new(mix_node.outputs['Shader'],
material_output.inputs['Surface'])
else:
raise Exception(
"Could not find shader node, which is connected to the material output "
"for: {}".format(slot.name))
