From cf79810dc93f4f5f52902ca9c7feb8d7c47b6eda Mon Sep 17 00:00:00 2001
From: Joshua Goins <josh@redstrate.com>
Date: Fri, 24 Nov 2023 08:16:03 -0500
Subject: [PATCH] Fix rounding errors

Now model files can be read and written and are (almost) identical!
There's some mysterious padding issues yet to solve, but that's only at
the end of the file.
---
 src/model.rs | 28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/src/model.rs b/src/model.rs
index 07b3509..ffe750f 100755
--- a/src/model.rs
+++ b/src/model.rs
@@ -740,19 +740,19 @@ impl MDL {
         }
 
         Some([
-            round(f32::from(cursor.read_le::<u8>().ok()?) / 255.0),
-            round(f32::from(cursor.read_le::<u8>().ok()?) / 255.0),
-            round(f32::from(cursor.read_le::<u8>().ok()?) / 255.0),
-            round(f32::from(cursor.read_le::<u8>().ok()?) / 255.0)
+            (f32::from(cursor.read_le::<u8>().ok()?) / 255.0),
+            (f32::from(cursor.read_le::<u8>().ok()?) / 255.0),
+            (f32::from(cursor.read_le::<u8>().ok()?) / 255.0),
+            (f32::from(cursor.read_le::<u8>().ok()?) / 255.0)
         ])
     }
 
     fn write_byte_float4<T: BinWriterExt>(cursor: &mut T, vec: &[f32; 4]) -> BinResult<()> {
         cursor.write_le::<[u8; 4]>(&[
-            (vec[0] * 255.0) as u8,
-            (vec[1] * 255.0) as u8,
-            (vec[2] * 255.0) as u8,
-            (vec[3] * 255.0) as u8])
+            (vec[0] * 255.0).round() as u8,
+            (vec[1] * 255.0).round() as u8,
+            (vec[2] * 255.0).round() as u8,
+            (vec[3] * 255.0).round() as u8])
     }
 
     fn read_half4(cursor: &mut Cursor<ByteSpan>) -> Option<[f32; 4]> {
@@ -809,6 +809,14 @@ mod tests {
     use std::io::Cursor;
     use crate::model::MDL;
 
+    macro_rules! assert_delta {
+        ($x:expr, $y:expr, $d:expr) => {
+            for i in 0..4 {
+                if !($x[i] - $y[i] < $d || $y[i] - $x[i] < $d) { panic!(); }
+            }
+        }
+    }
+
     #[test]
     fn byte_float4() {
         let a = [0.0, 1.0, 0.5, 0.25];
@@ -819,7 +827,9 @@ mod tests {
         MDL::write_byte_float4(&mut cursor, &a).unwrap();
 
         let mut read_cursor = Cursor::new(v.as_slice());
-        assert_eq!(MDL::read_byte_float4(&mut read_cursor).unwrap(), a);
+
+        let b = MDL::read_byte_float4(&mut read_cursor).unwrap();
+        assert_delta!(b, a, 0.1);
     }
 
     #[test]