From dafca8032fbdce816686f62b255c058e83ceb659 Mon Sep 17 00:00:00 2001
From: Andrew Hickman <andrew.hickman1@sky.com>
Date: Sat, 3 Oct 2020 20:56:25 +0100
Subject: [PATCH] Fix FloatOrd hash being different for different NaN values
 (#618)

* Fix FloatOrd hash being different for different NaN values

* Fix FloatOrd hashing +0.0 and -0.0 to different values
---
 crates/bevy_core/src/float_ord.rs | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/crates/bevy_core/src/float_ord.rs b/crates/bevy_core/src/float_ord.rs
index 74496b77568db..2958e83857630 100644
--- a/crates/bevy_core/src/float_ord.rs
+++ b/crates/bevy_core/src/float_ord.rs
@@ -40,7 +40,15 @@ impl Eq for FloatOrd {}
 
 impl Hash for FloatOrd {
     fn hash<H: Hasher>(&self, state: &mut H) {
-        state.write(self.0.as_bytes());
+        if self.0.is_nan() {
+            // Ensure all NaN representations hash to the same value
+            state.write(f32::NAN.as_bytes())
+        } else if self.0 == 0.0 {
+            // Ensure both zeroes hash to the same value
+            state.write(0.0f32.as_bytes())
+        } else {
+            state.write(self.0.as_bytes());
+        }
     }
 }