From bd73b9c44df107f3285a6efd477369aecff47409 Mon Sep 17 00:00:00 2001
From: Thomas Barlow <github@mysterymayhem.co.uk>
Date: Sun, 24 Sep 2023 18:34:28 +0100
Subject: [PATCH 1/2] Fix FBX char type being interpreted as bool

Blender has been interpreting the FBX 'C' type as bool, however, it is
actually an 8-bit integer that is separate from the already existing
byte/int8 type. FBX does have 'B' as a bool type, but it seems to be
unused.

FBX Converter displays what it calls "byte" ('Z' type) numerically,
but displays what it calls "int8" ('C' type) with both the numeric value
and the ascii character for that value, which leads me to believe that
this 'C' type should be interpreted as a single `char`. While there
doesn't appear to be many places that the 'C' type is used, it appears
to usually be set to a printable character.

Python doesn't have a `char` type, so the single `char` is read and
written as `bytes` with length equal to 1.

There are no expected changes to the import or export of FBX files with
this patch because the only FBX element that was incorrectly being
exported as a bool is now exported as the '\x01' char, which has the
same raw value as the `True` value that was being exported before.

The main benefit to this patch is that FBX files converted to .json with
fbx2json.py (and optionally back to .fbx with json2fbx.py) will now
maintain any 'C' type values instead of reducing them to True or False.

Additionally, should FBX files using the 'B' bool type be encountered in
the future, they are now supported.
---
 io_scene_fbx/data_types.py     |  3 ++-
 io_scene_fbx/encode_bin.py     |  8 ++++++++
 io_scene_fbx/export_fbx_bin.py | 12 +++++++++---
 io_scene_fbx/fbx2json.py       |  9 ++++++---
 io_scene_fbx/fbx_utils.py      |  4 ++++
 io_scene_fbx/json2fbx.py       |  8 ++++++--
 io_scene_fbx/parse_fbx.py      |  3 ++-
 7 files changed, 37 insertions(+), 10 deletions(-)

diff --git a/io_scene_fbx/data_types.py b/io_scene_fbx/data_types.py
index ac7b32a42..328ba3a9c 100644
--- a/io_scene_fbx/data_types.py
+++ b/io_scene_fbx/data_types.py
@@ -3,7 +3,8 @@
 #
 # SPDX-License-Identifier: GPL-2.0-or-later
 
-BOOL = b'C'[0]
+BOOL = b'B'[0]
+CHAR = b'C'[0]
 INT8 = b'Z'[0]
 INT16 = b'Y'[0]
 INT32 = b'I'[0]
diff --git a/io_scene_fbx/encode_bin.py b/io_scene_fbx/encode_bin.py
index fe2bef09d..030f960cb 100644
--- a/io_scene_fbx/encode_bin.py
+++ b/io_scene_fbx/encode_bin.py
@@ -56,6 +56,14 @@ class FBXElem:
         self.props_type.append(data_types.BOOL)
         self.props.append(data)
 
+    def add_char(self, data):
+        assert(isinstance(data, bytes))
+        assert(len(data) == 1)
+        data = pack('<c', data)
+
+        self.props_type.append(data_types.CHAR)
+        self.props.append(data)
+
     def add_int8(self, data):
         assert(isinstance(data, int))
         data = pack('<b', data)
diff --git a/io_scene_fbx/export_fbx_bin.py b/io_scene_fbx/export_fbx_bin.py
index 15ea7141c..2ff5210a1 100644
--- a/io_scene_fbx/export_fbx_bin.py
+++ b/io_scene_fbx/export_fbx_bin.py
@@ -66,7 +66,7 @@ from .fbx_utils import (
     get_blender_nodetexture_key,
     # FBX element data.
     elem_empty,
-    elem_data_single_bool, elem_data_single_int16, elem_data_single_int32, elem_data_single_int64,
+    elem_data_single_char, elem_data_single_int16, elem_data_single_int32, elem_data_single_int64,
     elem_data_single_float32, elem_data_single_float64,
     elem_data_single_bytes, elem_data_single_string, elem_data_single_string_unicode,
     elem_data_single_bool_array, elem_data_single_int32_array, elem_data_single_int64_array,
@@ -1900,7 +1900,8 @@ def fbx_data_leaf_bone_elements(root, scene_data):
         # object type, etc.
         elem_data_single_int32(model, b"MultiLayer", 0)
         elem_data_single_int32(model, b"MultiTake", 0)
-        elem_data_single_bool(model, b"Shading", True)
+        # Probably the FbxNode.EShadingMode enum. Full description in fbx_data_object_elements.
+        elem_data_single_char(model, b"Shading", b"\x01")
         elem_data_single_string(model, b"Culling", b"CullingOff")
 
         elem_props_template_finalize(tmpl, props)
@@ -1964,7 +1965,12 @@ def fbx_data_object_elements(root, ob_obj, scene_data):
     # object type, etc.
     elem_data_single_int32(model, b"MultiLayer", 0)
     elem_data_single_int32(model, b"MultiTake", 0)
-    elem_data_single_bool(model, b"Shading", True)
+    # This is probably the FbxNode.EShadingMode enum. Not directly used by the FBX SDK, but the SDK guarantees that the
+    # value will be passed through from an imported file to an exported one. Common values are 'Y' and 'T'. 'U' and 'W'
+    # have also been seen in older FBX files. It's not clear which enum member each of these values corresponds to or if
+    # these values are actually application specific. Blender had been exporting this as a `True` bool for a long time
+    # seemingly without issue. The '\x01' char is the same value as `True` in raw bytes.
+    elem_data_single_char(model, b"Shading", b"\x01")
     elem_data_single_string(model, b"Culling", b"CullingOff")
 
     if obj_type == b"Camera":
diff --git a/io_scene_fbx/fbx2json.py b/io_scene_fbx/fbx2json.py
index 487d1884d..8f3d904fe 100755
--- a/io_scene_fbx/fbx2json.py
+++ b/io_scene_fbx/fbx2json.py
@@ -30,7 +30,8 @@ The types are as follows:
 
 * 'Z': - INT8
 * 'Y': - INT16
-* 'C': - BOOL
+* 'B': - BOOL
+* 'C': - CHAR
 * 'I': - INT32
 * 'F': - FLOAT32
 * 'D': - FLOAT64
@@ -109,7 +110,8 @@ def unpack_array(read, array_type, array_stride, array_byteswap):
 read_data_dict = {
     b'Z'[0]: lambda read: unpack(b'<b', read(1))[0],  # 8 bit int
     b'Y'[0]: lambda read: unpack(b'<h', read(2))[0],  # 16 bit int
-    b'C'[0]: lambda read: unpack(b'?', read(1))[0],   # 1 bit bool (yes/no)
+    b'B'[0]: lambda read: unpack(b'?', read(1))[0],   # 1 bit bool (yes/no)
+    b'C'[0]: lambda read: unpack(b'<c', read(1))[0],  # char
     b'I'[0]: lambda read: unpack(b'<i', read(4))[0],  # 32 bit int
     b'F'[0]: lambda read: unpack(b'<f', read(4))[0],  # 32 bit float
     b'D'[0]: lambda read: unpack(b'<d', read(8))[0],  # 64 bit float
@@ -225,7 +227,8 @@ data_types.__dict__.update(
 dict(
 INT8 = b'Z'[0],
 INT16 = b'Y'[0],
-BOOL = b'C'[0],
+BOOL = b'B'[0],
+CHAR = b'C'[0],
 INT32 = b'I'[0],
 FLOAT32 = b'F'[0],
 FLOAT64 = b'D'[0],
diff --git a/io_scene_fbx/fbx_utils.py b/io_scene_fbx/fbx_utils.py
index 6232533b3..f002020ce 100644
--- a/io_scene_fbx/fbx_utils.py
+++ b/io_scene_fbx/fbx_utils.py
@@ -969,6 +969,10 @@ def elem_data_single_bool(elem, name, value):
     return _elem_data_single(elem, name, value, "add_bool")
 
 
+def elem_data_single_char(elem, name, value):
+    return _elem_data_single(elem, name, value, "add_char")
+
+
 def elem_data_single_int8(elem, name, value):
     return _elem_data_single(elem, name, value, "add_int8")
 
diff --git a/io_scene_fbx/json2fbx.py b/io_scene_fbx/json2fbx.py
index 0443cd4ff..19bb09963 100755
--- a/io_scene_fbx/json2fbx.py
+++ b/io_scene_fbx/json2fbx.py
@@ -29,7 +29,8 @@ The types are as follows:
 
 * 'Z': - INT8
 * 'Y': - INT16
-* 'C': - BOOL
+* 'B': - BOOL
+* 'C': - CHAR
 * 'I': - INT32
 * 'F': - FLOAT32
 * 'D': - FLOAT64
@@ -64,8 +65,11 @@ def parse_json_rec(fbx_root, json_node):
 
     e = elem_empty(fbx_root, name.encode())
     for d, dt in zip(data, data_types):
-        if dt == "C":
+        if dt == "B":
             e.add_bool(d)
+        elif dt == "C":
+            d = eval('b"""' + d + '"""')
+            e.add_char(d)
         elif dt == "Z":
             e.add_int8(d)
         elif dt == "Y":
diff --git a/io_scene_fbx/parse_fbx.py b/io_scene_fbx/parse_fbx.py
index 6639be1da..539742ec2 100644
--- a/io_scene_fbx/parse_fbx.py
+++ b/io_scene_fbx/parse_fbx.py
@@ -80,7 +80,8 @@ def unpack_array(read, array_type, array_stride, array_byteswap):
 read_data_dict = {
     b'Z'[0]: lambda read: unpack(b'<b', read(1))[0],  # byte
     b'Y'[0]: lambda read: unpack(b'<h', read(2))[0],  # 16 bit int
-    b'C'[0]: lambda read: unpack(b'?', read(1))[0],   # 1 bit bool (yes/no)
+    b'B'[0]: lambda read: unpack(b'?', read(1))[0],   # 1 bit bool (yes/no)
+    b'C'[0]: lambda read: unpack(b'<c', read(1))[0],  # char
     b'I'[0]: lambda read: unpack(b'<i', read(4))[0],  # 32 bit int
     b'F'[0]: lambda read: unpack(b'<f', read(4))[0],  # 32 bit float
     b'D'[0]: lambda read: unpack(b'<d', read(8))[0],  # 64 bit float
-- 
2.30.2


From 4869899fad6709075b7e548eb3fb2f86f1a4417c Mon Sep 17 00:00:00 2001
From: Thomas Barlow <github@mysterymayhem.co.uk>
Date: Tue, 26 Sep 2023 02:40:53 +0100
Subject: [PATCH 2/2] Increase FBX IO version

---
 io_scene_fbx/__init__.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/io_scene_fbx/__init__.py b/io_scene_fbx/__init__.py
index 19d765fcb..75a4ab720 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, @Mysteryem",
-    "version": (5, 8, 1),
+    "version": (5, 8, 2),
     "blender": (3, 6, 0),
     "location": "File > Import-Export",
     "description": "FBX IO meshes, UVs, vertex colors, materials, textures, cameras, lamps and actions",
-- 
2.30.2