From 488780dfd4c7a06ce02963391e33b12d32447208 Mon Sep 17 00:00:00 2001
From: asuessenbach <asuessenbach@nvidia.com>
Date: Mon, 19 Jul 2021 12:12:12 +0200
Subject: [PATCH] Introduce struct hash<vk::Flags<BitType>>

Allows the use of any vk::*Flags type as the key in a std::unordered_map
---
 VulkanHppGenerator.cpp | 12 +++++++++++-
 vulkan/vulkan.hpp      | 10 ++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/VulkanHppGenerator.cpp b/VulkanHppGenerator.cpp
index b805def..94169e9 100644
--- a/VulkanHppGenerator.cpp
+++ b/VulkanHppGenerator.cpp
@@ -409,7 +409,17 @@ std::string VulkanHppGenerator::generateHashStructures() const
 ${hashes}
 )";
 
-  std::string hashes;
+  // start with the hash on Flags<BitType>
+  std::string hashes = R"(
+  template <typename BitType> struct hash<VULKAN_HPP_NAMESPACE::Flags<BitType>>
+  {
+    std::size_t operator()(VULKAN_HPP_NAMESPACE::Flags<BitType> const& flags) const VULKAN_HPP_NOEXCEPT
+    {
+      return std::hash<typename std::underlying_type<BitType>::type>{}(static_cast<typename std::underlying_type<BitType>::type>(flags));
+    }
+  };
+)";
+
   for ( auto const & feature : m_features )
   {
     hashes += generateHashStructures( feature.second.types, feature.first );
diff --git a/vulkan/vulkan.hpp b/vulkan/vulkan.hpp
index 7c130a6..a1164f4 100644
--- a/vulkan/vulkan.hpp
+++ b/vulkan/vulkan.hpp
@@ -13263,6 +13263,16 @@ namespace std
   //=== HASH structures ===
   //=======================
 
+  template <typename BitType>
+  struct hash<VULKAN_HPP_NAMESPACE::Flags<BitType>>
+  {
+    std::size_t operator()( VULKAN_HPP_NAMESPACE::Flags<BitType> const & flags ) const VULKAN_HPP_NOEXCEPT
+    {
+      return std::hash<typename std::underlying_type<BitType>::type>{}(
+        static_cast<typename std::underlying_type<BitType>::type>( flags ) );
+    }
+  };
+
   //=== VK_VERSION_1_0 ===
 
   template <>