From 1b00d422461a917623b751b3eb82ad7b522fc273 Mon Sep 17 00:00:00 2001
From: Bastien Montagne <montagne29@wanadoo.fr>
Date: Sat, 11 May 2019 15:43:25 +0200
Subject: [PATCH] Tentative fix for T59850: FBX: wrong alpha in some material
imported by Unity.
Looks like FBX also likes to make a mess with materials' behaviors...
Many thanks to Thomas Chollet (@thomasch) for his help understanding how
Unity handles materials' alpha when importing from FBX.
Hopefully this won't break any other importer... ;)
---
io_scene_fbx/__init__.py | 2 +-
io_scene_fbx/export_fbx_bin.py | 13 ++++++++++++-
2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/io_scene_fbx/__init__.py b/io_scene_fbx/__init__.py
index ac76f4502..693cfe7d8 100644
--- a/io_scene_fbx/__init__.py
+++ b/io_scene_fbx/__init__.py
@@ -21,7 +21,7 @@
bl_info = {
"name": "FBX format",
"author": "Campbell Barton, Bastien Montagne, Jens Restemeier",
- "version": (4, 14, 6),
+ "version": (4, 14, 7),
"blender": (2, 80, 0),
"location": "File > Import-Export",
"description": "FBX IO meshes, UV's, vertex colors, materials, textures, cameras, lamps and actions",
diff --git a/io_scene_fbx/export_fbx_bin.py b/io_scene_fbx/export_fbx_bin.py
index 055aa3e17..59fe34025 100644
--- a/io_scene_fbx/export_fbx_bin.py
+++ b/io_scene_fbx/export_fbx_bin.py
@@ -1257,7 +1257,18 @@ def fbx_data_material_elements(root, ma, scene_data):
# Not in Principled BSDF, so assuming always 0
elem_props_template_set(tmpl, props, "p_color", b"AmbientColor", ambient_color)
elem_props_template_set(tmpl, props, "p_number", b"AmbientFactor", 0.0)
- elem_props_template_set(tmpl, props, "p_color", b"TransparentColor", ma_wrap.base_color)
+ # Sweetness... Looks like we are not the only ones to not know exactly how FBX is supposed to work (see T59850).
+ # According to one of its developers, Unity uses that formula to extract alpha value:
+ #
+ # alpha = 1 - TransparencyFactor
+ # if (alpha == 1 or alpha == 0):
+ # alpha = 1 - TransparentColor.r
+ #
+ # Until further info, let's assume this is correct way to do, hence the following code for TransparentColor.
+ if ma_wrap.transmission < 1.0e-5 or ma_wrap.transmission > (1.0 - 1.0e-5):
+ elem_props_template_set(tmpl, props, "p_color", b"TransparentColor", (ma_wrap.transmission,) * 3)
+ else:
+ elem_props_template_set(tmpl, props, "p_color", b"TransparentColor", ma_wrap.base_color)
elem_props_template_set(tmpl, props, "p_number", b"TransparencyFactor", ma_wrap.transmission)
elem_props_template_set(tmpl, props, "p_number", b"Opacity", 1.0 - ma_wrap.transmission)
elem_props_template_set(tmpl, props, "p_vector_3d", b"NormalMap", (0.0, 0.0, 0.0))
--
GitLab