--- a/utils/src/math.rs
+++ b/utils/src/math.rs
@@ -3,6 +3,7 @@
 use const_for::const_for;
 
 /// A 4×4 f32 matrix type.
+#[repr(align(16))]
 pub struct Mat4 {
     inner: [[f32; 4]; 4]
 }
@@ -109,9 +110,13 @@
     }
 
     /// Translate the matrix by a 2D offset.
-    pub const fn translate_2d(&mut self, x: f32, y: f32) {
-        let offset = [x, y, 0.];
-        self.translate(offset);
+    pub const fn translate_2d(&mut self, mut x: f32, mut y: f32) {
+        x *= self.inner[3][0];
+        y *= self.inner[3][1];
+        const_for!(i in 0..4 => {
+            self.inner[0][i] += x;
+            self.inner[1][i] += y;
+        });
     }
 }