Material node trees compliant with basic X3D multitextures are now stored in IFC

src/ifcopenshell-python/ifcopenshell/api/style/add_surface_textures.py

@@ -0,0 +1,92 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2022 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# IfcOpenShell is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+import ifcopenshell
+import ifcopenshell.api
+
+
+class Usecase:
+    def __init__(self, file, **settings):
+        # TODO: This usecase currently depends on Blender's data model
+        self.file = file
+        # Textures is assumed to be a dictionary of texture maps.
+        # The key is the texture map name, and the value is the last texture manipulation in the graph.
+        self.settings = {"textures": None}
+        for key, value in settings.items():
+            self.settings[key] = value
+
+    def execute(self):
+        self.textures = []
+        for texture, node in self.settings["textures"].items():
+            parameters = self.get_default_parameters(texture)
+            self.traverse_node(node, parameters)
+        return list(reversed(self.textures))
+
+    def get_default_parameters(self, texture):
+        return {"mode": "REPLACE", "source": "", "function": "", "rgb": "1 1 1", "alpha": "1", "texture": texture}
+
+    def traverse_node(self, node, parameters):
+        if node.type == "MIX_RGB":
+            if node.blend_type == "MIX":
+                parameters["mode"] = "REPLACE"
+            elif node.blend_type == "ADD":
+                parameters["mode"] = "ADD"
+            elif node.blend_type == "MULTIPLY":
+                parameters["mode"] = "MODULATE"
+
+            if not node.inputs["Fac"].links:
+                if parameters["mode"] == "REPLACE":
+                    parameters["mode"] = "BLEND"
+                parameters["mode"] += "FACTORALPHA"
+                parameters["alpha"] = str(node.inputs["Fac"].default_value)
+
+            if node.inputs["Color1"].links and node.inputs["Color2"].links:
+                self.traverse_node(node.inputs["Color2"].links[0].from_node, parameters)
+                self.traverse_node(
+                    node.inputs["Color1"].links[0].from_node, self.get_default_parameters(parameters["texture"])
+                )
+            elif node.inputs["Color1"].links:
+                parameters["rgb"] = " ".join(map(str, list(node.inputs["Color2"].default_value)[0:3]))
+                parameters["source"] = "FACTOR"
+                self.traverse_node(node.inputs["Color1"].links[0].from_node, parameters)
+            elif node.inputs["Color2"].links:
+                parameters["rgb"] = " ".join(map(str, list(node.inputs["Color1"].default_value)[0:3]))
+                parameters["source"] = "FACTOR"
+                self.traverse_node(node.inputs["Color2"].links[0].from_node, parameters)
+        elif node.type == "VECT_MATH":
+            # TODO Handle 2X, 4X, and signed
+            pass
+        elif node.type == "INVERT":
+            parameters["function"] = "COMPLEMENT" if parameters["function"] == "" else ""
+        elif node.type == "TEX_IMAGE":
+            return self.create_surface_texture(node, parameters)
+        else:
+            # TODO keep traversing backwards
+            pass
+
+    def create_surface_texture(self, node, parameters):
+        self.textures.append(
+            self.file.create_entity(
+                "IfcImageTexture",
+                RepeatS=node.extension == "REPEAT",
+                RepeatT=node.extension == "REPEAT",
+                Mode=parameters["mode"],
+                Parameter=[parameters[p] for p in ["source", "function", "rgb", "alpha", "texture"]],
+                URLReference=node.image.filepath,
+            )
+        )