From 893c0645802c46eb60b04a87e79a5a4d69e32ea2 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sun, 6 Mar 2022 13:21:28 +0200
Subject: [PATCH] Handle certain shader graph patterns that occur in imported
 glTF files

---
 blender/io_mspgl/export_material.py |  6 +++--
 blender/io_mspgl/export_texture.py  | 34 +++++++++++++++++++++++++----
 blender/io_mspgl/material.py        | 31 +++++++++++++++++++++++++-
 3 files changed, 64 insertions(+), 7 deletions(-)

diff --git a/blender/io_mspgl/export_material.py b/blender/io_mspgl/export_material.py
index 8560984e..b0df347f 100644
--- a/blender/io_mspgl/export_material.py
+++ b/blender/io_mspgl/export_material.py
@@ -75,7 +75,7 @@ class MaterialExporter:
 		for p in textured_props:
 			ctx.next_slice(p.texture.image)
 
-			tex_name = p.texture.image.name+".tex"
+			tex_name = texture_export.get_texture_name(p.texture, p.tex_channels)
 			if tex_name not in resources:
 				resources[tex_name] = texture_export.export_texture(p.texture, p.tex_channels)
 
@@ -121,7 +121,9 @@ class MaterialExporter:
 	def create_property_statement(self, mat_res, prop, resources):
 		from .datafile import Statement
 		if prop.texture:
-			tex_res = resources[prop.texture.image.name+".tex"]
+			from .export_texture import TextureExporter
+			texture_export = TextureExporter()
+			tex_res = resources[texture_export.get_texture_name(prop.texture, prop.tex_channels)]
 			return mat_res.create_reference_statement(prop.tex_keyword, tex_res)
 		elif not prop.keyword:
 			return
diff --git a/blender/io_mspgl/export_texture.py b/blender/io_mspgl/export_texture.py
index 3194edae..2860d461 100644
--- a/blender/io_mspgl/export_texture.py
+++ b/blender/io_mspgl/export_texture.py
@@ -23,11 +23,15 @@ def pixels_to_gray(pixels):
 	for i in range(0, len(pixels), 4):
 		yield int((pixels[i]+pixels[i+1]+pixels[i+2])*255/3)
 
+def pixels_to_single_channel(pixels, channel):
+	for i in range(0, len(pixels), 4):
+		yield int(pixels[i+channel]*255)
+
 class TextureExporter:
 	def export_texture(self, tex_node, channels=['R', 'G', 'B']):
 		image = tex_node.image
 		from .datafile import RawData, Resource, Statement, Token
-		tex_res = Resource(image.name+".tex", "texture")
+		tex_res = Resource(self.get_texture_name(tex_node, channels), "texture")
 
 		tex_res.statements.append(Statement("type", Token("\\2d")))
 
@@ -41,7 +45,20 @@ class TextureExporter:
 		invert_mask = sum(1<<i for i, c in enumerate(channels) if c[0]=='~')
 
 		fn = bpy.path.basename(image.filepath)
-		if not invert_mask and fn:
+		native_channels = None
+		if fn:
+			abs_path = bpy.path.abspath(image.filepath) 
+			if os.path.exists(abs_path):
+				import imbuf
+				native_bpp = imbuf.load(bpy.path.abspath(image.filepath)).planes
+				if native_bpp==32:
+					native_channels = ['R', 'G', 'B', 'A']
+				elif native_bpp==24:
+					native_channels = ['R', 'G', 'B']
+				elif native_bpp==8:
+					native_channels = ['Y']
+
+		if not invert_mask and channels==native_channels:
 			if not tex_node.use_mipmap:
 				tex_res.statements.append(Statement("mipmap_levels", 1))
 			srgb = "_srgb" if colorspace=='sRGB' else ""
@@ -61,17 +78,26 @@ class TextureExporter:
 			if len(channels)==4:
 				texdata = pixels_to_rgba(pixels)
 			elif len(channels)==1:
-				texdata = pixels_to_gray(pixels)
+				if channels[0]=='Y':
+					texdata = pixels_to_gray(pixels)
+				else:
+					texdata = pixels_to_single_channel(pixels, "RGBA".index(channels[0]))
 			elif invert_mask:
 				texdata = pixels_to_rgb_invert(pixels, invert_mask)
 			else:
 				texdata = pixels_to_rgb(pixels)
 
-			data = RawData(image.name+".mdr", bytes(texdata))
+			data = RawData(os.path.splitext(tex_res.name)[0]+".mdr", bytes(texdata))
 			tex_res.statements.append(tex_res.create_reference_statement("external_data", data))
 
 		return tex_res
 
+	def get_texture_name(self, tex_node, channels):
+		image_name = tex_node.image.name
+		if len(channels)==1 and channels[0]!='Y':
+			image_name += "_"+channels[0]
+		return image_name+".tex"
+
 class SamplerExporter:
 	def export_sampler(self, tex_node):
 		from .datafile import Resource, Statement, Token
diff --git a/blender/io_mspgl/material.py b/blender/io_mspgl/material.py
index 84226130..dc6d934b 100644
--- a/blender/io_mspgl/material.py
+++ b/blender/io_mspgl/material.py
@@ -18,7 +18,9 @@ class PropertyNode:
 		self.input = None
 
 		checks = [self.check_group,
+			self.check_scale,
 			self.check_gray,
+			self.check_extract,
 			self.check_normal,
 			self.check_invert_channels,
 			self.check_additive_blend,
@@ -50,11 +52,28 @@ class PropertyNode:
 				self.data = inner.data
 				return self.set_input_from_linked(self.node.inputs[0])
 
+	def check_scale(self):
+		if self.node.type!='MATH':
+			return
+
+		if self.node.operation=='MULTIPLY':
+			for i in range(2):
+				if not self.node.inputs[i].is_linked:
+					self.type = 'SCALE'
+					self.data = self.node.inputs[i].default_value
+					return self.set_input_from_linked(self.node.inputs[1-i])
+
 	def check_gray(self):
 		if self.node.type=='RGBTOBW':
 			self.type = 'GRAY'
 			self.set_input_from_linked(self.node.inputs["Color"])
 
+	def check_extract(self):
+		if self.node.type=='SEPRGB':
+			self.type = 'EXTRACT'
+			self.data = self.socket.name[0]
+			return self.set_input_from_linked(self.node.inputs["Image"])
+
 	def check_normal(self):
 		if self.node.type=='NORMAL_MAP':
 			self.type = 'NORMAL'
@@ -132,6 +151,7 @@ class MaterialProperty:
 		self.value = value
 		self.texture = None
 		self.tex_channels = None
+		self.scale = 1.0
 
 	def set_from_input(self, node_tree, input_socket, alpha_socket=None):
 		if self.keyword:
@@ -157,8 +177,12 @@ class MaterialProperty:
 						channels = ['R', 'G', 'B']
 					elif n.type=='GRAY':
 						channels = ['Y']
+					elif n.type=='EXTRACT':
+						channels = [n.data]
 					elif n.type=='INVERT':
 						channels = ['~'+c if c in n.data else c for c in channels]
+					elif n.type=='SCALE':
+						self.scale = n.data
 					elif n.type=='TEXTURE':
 						self.texture = n.node
 					n = n.input
@@ -168,7 +192,12 @@ class MaterialProperty:
 					if alpha_from and alpha_from!=self.texture:
 						raise Exception("Separate textures for color and alpha are not supported")
 
-				if self.texture:
+				if self.scale==0.0 and self.keyword and type(self.value)!=tuple:
+					self.texture = None
+					self.value = self.scale
+				elif self.scale!=1.0:
+					raise Exception("Unsupported material property scale {}".format(self.scale))
+				elif self.texture:
 					if channels:
 						self.tex_channels = channels
 					elif alpha_from:
-- 
2.43.0