From 0951b033a7c81b464231e3202dfb88cc28476c11 Mon Sep 17 00:00:00 2001
From: killian <killiancharrier8@gmail.com>
Date: Tue, 11 Oct 2022 21:14:10 +0200
Subject: [PATCH] Implement Hash for DepthStencilState and DepthBiasState
 (#3092)

* Implement Hash for DepthStencilState and DepthBiasState

* Fix clippy error

* cargo fmt

* Fix Hash implementation

Co-authored-by: char0313 <killia.charrier@etudiant.univ-reims.dr>
---
 CHANGELOG.md          |  1 +
 wgpu-types/src/lib.rs | 21 +++++++++++++++++++--
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 55f93aaf66..28ebf8ef1b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -51,6 +51,7 @@ Bottom level categories:
 
 #### General
 
+- Implement `Hash` for `DepthStencilState` and `DepthBiasState`
 - Add the `"wgsl"` feature, to enable WGSL shaders in `wgpu-core` and `wgpu`. Enabled by default in `wgpu`. By @daxpedda in [#2890](https://github.com/gfx-rs/wgpu/pull/2890).
 - Implement `Clone` for `ShaderSource` and `ShaderModuleDescriptor` in `wgpu`. By @daxpedda in [#3086](https://github.com/gfx-rs/wgpu/pull/3086).
 
diff --git a/wgpu-types/src/lib.rs b/wgpu-types/src/lib.rs
index 369615d1e9..42845642b9 100644
--- a/wgpu-types/src/lib.rs
+++ b/wgpu-types/src/lib.rs
@@ -10,6 +10,7 @@
 
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
+use std::hash::{Hash, Hasher};
 use std::{num::NonZeroU32, ops::Range};
 
 /// Integral type used for buffer offsets.
@@ -3152,7 +3153,7 @@ impl StencilState {
 /// Corresponds to a portion of [WebGPU `GPUDepthStencilState`](
 /// https://gpuweb.github.io/gpuweb/#dictdef-gpudepthstencilstate).
 #[repr(C)]
-#[derive(Clone, Copy, Debug, Default, PartialEq)]
+#[derive(Clone, Copy, Debug, Default)]
 #[cfg_attr(feature = "trace", derive(Serialize))]
 #[cfg_attr(feature = "replay", derive(Deserialize))]
 pub struct DepthBiasState {
@@ -3171,12 +3172,28 @@ impl DepthBiasState {
     }
 }
 
+impl Hash for DepthBiasState {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.constant.hash(state);
+        self.slope_scale.to_bits().hash(state);
+        self.clamp.to_bits().hash(state);
+    }
+}
+
+impl PartialEq for DepthBiasState {
+    fn eq(&self, other: &Self) -> bool {
+        (self.constant == other.constant)
+            && (self.slope_scale.to_bits() == other.slope_scale.to_bits())
+            && (self.clamp.to_bits() == other.clamp.to_bits())
+    }
+}
+
 /// Describes the depth/stencil state in a render pipeline.
 ///
 /// Corresponds to [WebGPU `GPUDepthStencilState`](
 /// https://gpuweb.github.io/gpuweb/#dictdef-gpudepthstencilstate).
 #[repr(C)]
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, Hash, PartialEq)]
 #[cfg_attr(feature = "trace", derive(Serialize))]
 #[cfg_attr(feature = "replay", derive(Deserialize))]
 pub struct DepthStencilState {