From 9165771d5e2a34148f13963e3545ec76f40aeb21 Mon Sep 17 00:00:00 2001
From: REDxEYE <med45c@gmail.com>
Date: Thu, 15 Jun 2023 03:08:04 +0300
Subject: [PATCH] Add BC5U support. Seen in Amnesia: The Bunker

---
 src/PIL/DdsImagePlugin.py | 11 +++++++++--
 src/PIL/ImageFile.py      |  3 +--
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/PIL/DdsImagePlugin.py b/src/PIL/DdsImagePlugin.py
index 6e9e1cada..8c8662499 100644
--- a/src/PIL/DdsImagePlugin.py
+++ b/src/PIL/DdsImagePlugin.py
@@ -254,6 +254,7 @@ class D3DFMT(IntEnum):
     DXT5 = i32(b"DXT5")
     DX10 = i32(b"DX10")
     BC5S = i32(b"BC5S")
+    BC5U = i32(b"BC5U")
     ATI1 = i32(b"ATI1")
     ATI2 = i32(b"ATI2")
     MULTI2_ARGB8 = i32(b"MET1")
@@ -325,7 +326,8 @@ class DdsImageFile(ImageFile.ImageFile):
             try:
                 fourcc = D3DFMT(fourcc_)
             except ValueError:
-                raise NotImplementedError(f"Unimplemented pixel format {repr(fourcc_)}")
+                msg = f"Unimplemented pixel format {repr(fourcc_)}"
+                raise NotImplementedError(msg)
             if fourcc == D3DFMT.DXT1:
                 self.mode = "RGBA"
                 self.pixel_format = "DXT1"
@@ -346,6 +348,10 @@ class DdsImageFile(ImageFile.ImageFile):
                 self.mode = "RGB"
                 self.pixel_format = "BC5S"
                 tile = Image.Tile("bcn", extents, data_offs, (5, self.pixel_format))
+            elif fourcc == D3DFMT.BC5U:
+                self.mode = "RGB"
+                self.pixel_format = "BC5U"
+                tile = Image.Tile("bcn", extents, data_offs, (5, self.pixel_format))
             elif fourcc == D3DFMT.ATI2:
                 self.mode = "RGB"
                 self.pixel_format = "BC5"
@@ -407,7 +413,8 @@ class DdsImageFile(ImageFile.ImageFile):
 
 def _save(im, fp, filename):
     if im.mode not in ("RGB", "RGBA", "L", "LA"):
-        raise OSError(f"cannot write mode {im.mode} as DDS")
+        msg = f"cannot write mode {im.mode} as DDS"
+        raise OSError(msg)
 
     pixel_flags = DDPF.RGB
     if im.mode == "RGB":
diff --git a/src/PIL/ImageFile.py b/src/PIL/ImageFile.py
index 4194a7c35..716b2f06b 100644
--- a/src/PIL/ImageFile.py
+++ b/src/PIL/ImageFile.py
@@ -546,8 +546,7 @@ def _encode_tile(im, fp, tile: List[Image.Tile], bufsize, fh, exc=None):
                     # slight speedup: compress to real file object
                     errcode = encoder.encode_to_file(fh, bufsize)
             if errcode < 0:
-                msg =
-                    f"encoder error {errcode} when writing image file"
+                msg = f"encoder error {errcode} when writing image file"
                 raise OSError(msg) from exc
         finally:
             encoder.cleanup()