From: Mikko Rasa <tdb@tdb.fi>
Date: Fri, 15 Oct 2021 10:48:19 +0000 (+0300)
Subject: Recognize a node graph which gives transparency to unlit materials
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=cdb41a03865c72e69e7829641089fba4c361a56e;p=libs%2Fgl.git

Recognize a node graph which gives transparency to unlit materials
---

diff --git a/blender/io_mspgl/material.py b/blender/io_mspgl/material.py
index eb4c7c24..167751c3 100644
--- a/blender/io_mspgl/material.py
+++ b/blender/io_mspgl/material.py
@@ -39,6 +39,25 @@ def check_invert_green(node_tree, node):
 
 	return get_linked_node_and_socket(node_tree, red.inputs["Image"])
 
+def get_unlit_inputs(node_tree, node):
+	if node.type=='GROUP':
+		return check_group(node_tree, node, get_unlit_inputs)
+	elif node.type=='MIX_SHADER':
+		from .util import get_linked_node_and_socket
+
+		shader1, _ = get_linked_node_and_socket(node_tree, node.inputs[1])
+		shader2, _ = get_linked_node_and_socket(node_tree, node.inputs[2])
+		if shader1.type=='BSDF_TRANSPARENT' and shader2.type=='EMISSION':
+			factor_input = node.inputs["Fac"]
+			factor_from, _ = get_linked_node_and_socket(node_tree, factor_input)
+			color_input = shader2.inputs["Color"]
+			color_from, _ = get_linked_node_and_socket(node_tree, color_input)
+			if factor_from==color_from:
+				return (color_input, factor_input)
+	elif node.type=='EMISSION':
+		return (node.inputs["Color"], None)
+	return (None, None)
+
 class MaterialProperty:
 	def __init__(self, keyword, tex_keyword, value):
 		self.keyword = keyword
@@ -136,12 +155,16 @@ class Material:
 			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':
+		elif surface_node.type=='EMISSION' or surface_node.type=='MIX_SHADER':
+			color_input, alpha_input = get_unlit_inputs(material.node_tree, surface_node)
+			if not color_input:
+				raise Exception("Unsupported configuration for unlit material {}".format(self.name))
+
 			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"])
+			color.set_from_input(material.node_tree, color_input, alpha_input)
 		else:
 			raise Exception("Unsupported surface node type {} on material {}".format(surface_node.type, self.name))