[Bf-extensions-cvs] [1cf57247] master: Fix T96076: Work around invalid shininess values in some FBX file.

[Bastien Montagne]

Commit: 1cf57247c7ca13c5dc185baae2201f554f85df50
Author: Bastien Montagne
Date:   Tue Mar 8 18:03:04 2022 +0100
Branches: master
https://developer.blender.org/rBA1cf57247c7ca13c5dc185baae2201f554f85df50

Fix T96076: Work around invalid shininess values in some FBX file.

An exponent should never be negative... but FBX files being FBX files,
just add a 0.0 clamping to that value.

===================================================================

M	io_scene_fbx/__init__.py
M	io_scene_fbx/import_fbx.py

===================================================================

diff --git a/io_scene_fbx/__init__.py b/io_scene_fbx/__init__.py
index 39a7815c..0abafc33 100644
--- a/io_scene_fbx/__init__.py
+++ b/io_scene_fbx/__init__.py
@@ -5,7 +5,7 @@
 bl_info = {
     "name": "FBX format",
     "author": "Campbell Barton, Bastien Montagne, Jens Restemeier",
-    "version": (4, 34, 1),
+    "version": (4, 34, 2),
     "blender": (3, 2, 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/import_fbx.py b/io_scene_fbx/import_fbx.py
index 731ad388..f2726047 100644
--- a/io_scene_fbx/import_fbx.py
+++ b/io_scene_fbx/import_fbx.py
@@ -1431,9 +1431,9 @@ def blen_read_material(fbx_tmpl, fbx_obj, settings):
     # No specular color in Principled BSDF shader, assumed to be either white or take some tint from diffuse one...
     # TODO: add way to handle tint option (guesstimate from spec color + intensity...)?
     ma_wrap.specular = elem_props_get_number(fbx_props, b'SpecularFactor', 0.25) * 2.0
-    # XXX Totally empirical conversion, trying to adapt it
-    #     (from 1.0 - 0.0 Principled BSDF range to 0.0 - 100.0 FBX shininess range)...
-    fbx_shininess = elem_props_get_number(fbx_props, b'Shininess', 20.0)
+    # XXX Totally empirical conversion, trying to adapt it (and protect against invalid negative values, see T96076):
+    #     From [1.0 - 0.0] Principled BSDF range to [0.0 - 100.0] FBX shininess range)...
+    fbx_shininess = max(elem_props_get_number(fbx_props, b'Shininess', 20.0), 0.0)
     ma_wrap.roughness = 1.0 - (sqrt(fbx_shininess) / 10.0)
     # 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: