diff --git a/crates/gc-formats/src/texture.rs b/crates/gc-formats/src/texture.rs
index a6f4240..a8c45c8 100644
--- a/crates/gc-formats/src/texture.rs
+++ b/crates/gc-formats/src/texture.rs
@@ -18,6 +18,7 @@
 //!   anything above it clamps to opaque.
 
 use crate::buf::{Error, ErrorKind, Result};
+use crate::gs;
 use crate::level_core::TextureEntry;
 
 /// PS2 CSM1 CLUT order to linear: within each 32-entry group, swap the two
@@ -30,13 +31,20 @@ pub fn clut_index(i: u32) -> u32 {
     }
 }
 
-/// PS2 alpha 0..=0x80 to 0..=0xff. `0x80` is opaque; above that clamps.
+/// PS2 alpha `0x00..=0x80` to `0x00..=0xff`. `0x80` is opaque; above clamps.
+///
+/// Delegates to [`crate::gs::alpha_to_8`] rather than computing here. This used
+/// to be `if a < 0x80 { a * 2 } else { 0xff }`, which is `a / 128 * 256` -- one
+/// too high at the top of the range, so `0x7F` decoded to 254 where the renderer's
+/// own alpha path and gs::alpha_to_8 both give 253. Three expressions of one rule,
+/// two of them right, and the wrong one was the one decoding actual pixels.
+///
+/// The visual difference is at most 1/255 on a single palette entry and nothing
+/// anyone would ever see. That is exactly why it survived: the bug class here is
+/// not "big wrong", it is "right to within a rounding step", in the code path
+/// that nobody instruments.
 pub fn scale_alpha(a: u8) -> u8 {
-    if a < 0x80 {
-        a * 2
-    } else {
-        0xff
-    }
+    gs::alpha_to_8(a)
 }
 
 /// A decoded RGBA8 image.