+import os
+
+def get_linked_node_and_socket(node_tree, socket):
+ for l in node_tree.links:
+ if socket==l.to_socket:
+ return (l.from_node, l.from_socket)
+ elif socket==l.from_socket:
+ return (l.to_node, l.to_socket)
+ return (None, None)
+
+def check_group(node_tree, group, func):
+ output = group.node_tree.nodes["Group Output"]
+ from_node, _ = get_linked_node_and_socket(group.node_tree, output.inputs[0])
+ if from_node:
+ from_node, _ = func(group.node_tree, from_node)
+ if from_node and from_node.type=='GROUP_INPUT':
+ return get_linked_node_and_socket(node_tree, group.inputs[0])
+ return (None, None)
+
+def check_invert_green(node_tree, node):
+ if node.type=='GROUP':
+ return check_group(node_tree, node, check_invert_green)
+ elif node.type!='COMBRGB':
+ return (None, None)
+
+ green, g_sock = get_linked_node_and_socket(node_tree, node.inputs["G"])
+ if not green or green.type!='MATH' or green.operation!='SUBTRACT':
+ return (None, None)
+ green, g_sock = get_linked_node_and_socket(node_tree, green.inputs[1])
+
+ red, r_sock = get_linked_node_and_socket(node_tree, node.inputs["R"])
+ blue, b_sock = get_linked_node_and_socket(node_tree, node.inputs["B"])
+ if not red or red.type!='SEPRGB' or blue!=red or green!=red:
+ return (None, None)
+
+ return get_linked_node_and_socket(node_tree, red.inputs["Image"])
+
+class MaterialProperty:
+ def __init__(self, keyword, tex_keyword, value):
+ self.keyword = keyword
+ self.tex_keyword = tex_keyword
+ self.value = value
+ self.texture = None
+ self.tex_usage = None
+ self.invert_green = False
+
+ def set_from_input(self, node_tree, input_socket, alpha_socket=None):
+ if self.keyword:
+ if type(self.value)==tuple:
+ if alpha_socket:
+ self.value = input_socket.default_value[:len(self.value)-1]+(alpha_socket.default_value,)
+ else:
+ self.value = input_socket.default_value[:len(self.value)]
+ else:
+ self.value = input_socket.default_value
+
+ if self.tex_keyword:
+ from_node, _ = get_linked_node_and_socket(node_tree, input_socket)
+ alpha_from = None
+ if from_node:
+ usage = None
+ if from_node.type=='NORMAL_MAP':
+ from_node, _ = get_linked_node_and_socket(node_tree, from_node.inputs["Color"])
+ invert, _ = check_invert_green(node_tree, from_node)
+ if invert:
+ from_node = invert
+ self.invert_green = True
+ usage = 'RGB'
+ elif from_node.type=='RGBTOBW':
+ from_node, _ = get_linked_node_and_socket(node_tree, from_node.inputs["Color"])
+
+ if alpha_socket:
+ alpha_from, _ = get_linked_node_and_socket(node_tree, alpha_socket)
+ if alpha_from and alpha_from!=from_node:
+ raise Exception("Separate textures for color and alpha are not supported")
+
+ if from_node.type=='TEX_IMAGE':
+ self.texture = from_node
+ if usage:
+ self.tex_usage = usage
+ elif alpha_from:
+ self.tex_usage = 'RGBA'
+ elif type(self.value)==tuple:
+ self.tex_usage = 'RGB'
+ else:
+ self.tex_usage = 'GRAY'
+ else:
+ raise Exception("Unsupported property input node type "+from_node.type)
+
+class Material:
+ def __init__(self, material):
+ self.name = material.name
+ self.type = None
+ self.properties = []
+
+ self.render_mode = material.render_mode
+ self.technique = material.technique
+ self.shader = material.shader
+
+ if self.render_mode=='EXTERNAL' and not self.technique:
+ raise Exception("Missing technique with external rendering mode")
+ elif self.render_mode=='CUSTOM' and not self.shader:
+ raise Exception("Missing shader with custom rendering mode")
+
+ out_node = None
+ for n in material.node_tree.nodes:
+ if n.type=='OUTPUT_MATERIAL':
+ out_node = n
+ break
+
+ if not out_node:
+ raise Exception("No material output node found")
+
+ surface_node, _ = get_linked_node_and_socket(material.node_tree, out_node.inputs["Surface"])
+ if not surface_node:
+ if self.render_mode=='BUILTIN':
+ raise Exception("Empty material can't use builtin rendering mode")
+ return
+ elif surface_node.type=='BSDF_PRINCIPLED':
+ self.type = "pbr"
+
+ base_color = self.create_property("base_color", (0.8, 0.8, 0.8, 1.0))
+ metalness = self.create_property("metalness", 0.0)
+ roughness = self.create_property("roughness", 0.5)
+ normal = self.create_property("normal_map")
+ emission = self.create_property("emission", (0.0, 0.0, 0.0))
+
+ base_color.set_from_input(material.node_tree, surface_node.inputs["Base Color"], surface_node.inputs["Alpha"])
+ metalness.set_from_input(material.node_tree, surface_node.inputs["Metallic"])
+ roughness.set_from_input(material.node_tree, surface_node.inputs["Roughness"])
+ normal.set_from_input(material.node_tree, surface_node.inputs["Normal"])
+ emission.set_from_input(material.node_tree, surface_node.inputs["Emission"])
+ elif surface_node.type=='EMISSION':
+ self.type = "unlit"
+
+ color = self.create_property("color", "texture", (1.0, 1.0, 1.0, 1.0))
+
+ color.set_from_input(material.node_tree, surface_node.inputs["Color"])
+ else:
+ raise Exception("Unsupported surface node type "+surface_node.type)
+
+ sampler_settings = None
+ for p in self.properties:
+ if p.texture:
+ settings = (p.texture.default_filter, p.texture.interpolation, p.texture.use_mipmap, p.texture.max_anisotropy)
+ if sampler_settings is None:
+ sampler_settings = settings
+ elif settings!=sampler_settings:
+ raise Exception("Conflicting sampler settings in material textures")
+
+ def create_property(self, *args):
+ prop = None
+ if len(args)==1:
+ prop = MaterialProperty(None, args[0], None)
+ elif len(args)==2:
+ prop = MaterialProperty(args[0], args[0]+"_map", args[1])
+ else:
+ prop = MaterialProperty(*args)
+ self.properties.append(prop)
+ return prop
+
+
+class MaterialAtlas: