+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)
+
+class MaterialProperty:
+ def __init__(self, value):
+ self.value = value
+ self.texture = None
+ self.tex_usage = None
+
+ def set_from_input(self, node_tree, input_socket, alpha_socket=None):
+ 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)]
+ elif self.value is not None:
+ self.value = input_socket.default_value
+
+ from_node, _ = get_linked_node_and_socket(node_tree, input_socket)
+ alpha_from = None
+ if from_node:
+ if from_node.type=='NORMAL_MAP':
+ 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 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':
+ raise Exception("Unsupported surface node type "+surface_node.type)
+
+ self.type = "pbr"
+
+ base_color = self.properties["base_color"] = MaterialProperty((0.8, 0.8, 0.8, 1.0))
+ metalness = self.properties["metalness"] = MaterialProperty(0.0)
+ roughness = self.properties["roughness"] = MaterialProperty(0.5)
+ normal = self.properties["normal"] = MaterialProperty(None)
+ emission = self.properties["emission"] = MaterialProperty((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"])
+
+ sampler_settings = None
+ for p in self.properties.values():
+ 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")
+
+