From 437f800444f2ac47292c2b2dace85a3a15131ec1 Mon Sep 17 00:00:00 2001
From: Patrick Mours <pmours@nvidia.com>
Date: Wed, 9 May 2018 16:32:39 +0200
Subject: [PATCH] Add structure chain constructor which accepts a list of its
 elements (#217)

Add structure chain constructor which accepts a list of its elements
---
 README.md              |  9 +++++++++
 VulkanHppGenerator.cpp | 24 +++++++++++++++++++++++-
 vulkan/vulkan.hpp      | 24 +++++++++++++++++++++++-
 3 files changed, 55 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 46c6794..6dabff4 100644
--- a/README.md
+++ b/README.md
@@ -182,6 +182,15 @@ vk::MemoryAllocateInfo &allocInfo = c.get<vk::MemoryAllocateInfo>();
 vk::ImportMemoryFdInfoKHR &fdInfo = c.get<vk::ImportMemoryFdInfoKHR>();
 ```
 
+Vulkan-Hpp provides a constructor for these chains similar to the CreateInfo objects which accepts a list of all structures part of the chain. The `pNext` field is automatically set to the correct value:
+
+```c++
+vk::StructureChain<vk::MemoryAllocateInfo, vk::MemoryDedicatedAllocateInfo> c = {
+  vk::MemoryAllocateInfo(size, type),
+  vk::MemoryDedicatedAllocateInfo(image)
+};
+```
+
 Sometimes the user has to pass a preallocated structure chain to query information. In those cases the corresponding query functions are variadic templates and do accept a structure chain to construct the return value:
 
 ```
diff --git a/VulkanHppGenerator.cpp b/VulkanHppGenerator.cpp
index 2884d06..362871d 100644
--- a/VulkanHppGenerator.cpp
+++ b/VulkanHppGenerator.cpp
@@ -398,6 +398,11 @@ const std::string structureChainHeader = R"(
       linkAndCopy<StructureElements...>(rhs);
     }
 
+    StructureChain(StructureElements const &... elems)
+    {
+      linkAndCopyElements<StructureElements...>(elems...);
+    }
+
     StructureChain& operator=(StructureChain const &rhs)
     {
       linkAndCopy<StructureElements...>(rhs);
@@ -439,7 +444,24 @@ const std::string structureChainHeader = R"(
       linkAndCopy<Y, Z...>(rhs);
     }
 
-};
+    template<typename X>
+    void linkAndCopyElements(X const &xelem)
+    {
+      static_cast<X&>(*this) = xelem;
+    }
+
+    template<typename X, typename Y, typename ...Z>
+    void linkAndCopyElements(X const &xelem, Y const &yelem, Z const &... zelem)
+    {
+      static_assert(isStructureChainValid<X,Y>::value, "The structure chain is not valid!");
+      X& x = static_cast<X&>(*this);
+      Y& y = static_cast<Y&>(*this);
+      x = xelem;
+      x.pNext = &y;
+      linkAndCopyElements<Y, Z...>(yelem, zelem...);
+    }
+  };
+
 )";
 
 const std::string versionCheckHeader = R"(
diff --git a/vulkan/vulkan.hpp b/vulkan/vulkan.hpp
index 249da81..bf96c05 100644
--- a/vulkan/vulkan.hpp
+++ b/vulkan/vulkan.hpp
@@ -471,6 +471,11 @@ namespace VULKAN_HPP_NAMESPACE
       linkAndCopy<StructureElements...>(rhs);
     }
 
+    StructureChain(StructureElements const &... elems)
+    {
+      linkAndCopyElements<StructureElements...>(elems...);
+    }
+
     StructureChain& operator=(StructureChain const &rhs)
     {
       linkAndCopy<StructureElements...>(rhs);
@@ -512,7 +517,24 @@ namespace VULKAN_HPP_NAMESPACE
       linkAndCopy<Y, Z...>(rhs);
     }
 
-};
+    template<typename X>
+    void linkAndCopyElements(X const &xelem)
+    {
+      static_cast<X&>(*this) = xelem;
+    }
+
+    template<typename X, typename Y, typename ...Z>
+    void linkAndCopyElements(X const &xelem, Y const &yelem, Z const &... zelem)
+    {
+      static_assert(isStructureChainValid<X,Y>::value, "The structure chain is not valid!");
+      X& x = static_cast<X&>(*this);
+      Y& y = static_cast<Y&>(*this);
+      x = xelem;
+      x.pNext = &y;
+      linkAndCopyElements<Y, Z...>(yelem, zelem...);
+    }
+  };
+
   enum class Result
   {
     eSuccess = VK_SUCCESS,