From 6f5b2a64e235dce09fd2e6a48e5eb6aedcf7a28e Mon Sep 17 00:00:00 2001
From: Erich Gubler <erichdongubler@gmail.com>
Date: Thu, 14 Dec 2023 10:41:51 -0500
Subject: [PATCH] feat(const_eval): impl. `step`

---
 CHANGELOG.md                        | 1 +
 naga/src/proc/constant_evaluator.rs | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 14776b65a..d6b1ccc53 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -49,6 +49,7 @@ Bottom level categories:
         - `sin`
         - `sinh`
         - `sqrt`
+        - `step`
 
 ## v0.19.0 (2024-01-17)
 
diff --git a/naga/src/proc/constant_evaluator.rs b/naga/src/proc/constant_evaluator.rs
index 1a36a59c4..eefb470b3 100644
--- a/naga/src/proc/constant_evaluator.rs
+++ b/naga/src/proc/constant_evaluator.rs
@@ -859,6 +859,11 @@ impl<'a> ConstantEvaluator<'a> {
             crate::MathFunction::Sqrt => {
                 component_wise_float!(self, span, [arg], |e| { Ok([e.sqrt()]) })
             }
+            crate::MathFunction::Step => {
+                component_wise_float!(self, span, [arg, arg1.unwrap()], |edge, x| {
+                    Ok([if edge <= x { 1.0 } else { 0.0 }])
+                })
+            }
             fun => Err(ConstantEvaluatorError::NotImplemented(format!(
                 "{fun:?} built-in function"
             ))),