From c632ec4bacef631b0357dadcdd5d6bacb652c585 Mon Sep 17 00:00:00 2001
From: Egor Yusov <egor.yusov@gmail.com>
Date: Tue, 30 Oct 2018 09:18:54 -0700
Subject: Implemented HLSL vertex shader inputs mapping in Vulkan backend using
 SPV_GOOGLE_hlsl_functionality1 (causes validation layer errors for now)

---
 .../GraphicsEngineVulkan/include/ShaderVkImpl.h    |  2 ++
 Graphics/GraphicsEngineVulkan/src/ShaderVkImpl.cpp | 40 +++++++++++++++++++++-
 2 files changed, 41 insertions(+), 1 deletion(-)

(limited to 'Graphics/GraphicsEngineVulkan')

diff --git a/Graphics/GraphicsEngineVulkan/include/ShaderVkImpl.h b/Graphics/GraphicsEngineVulkan/include/ShaderVkImpl.h
index 144581bf..adcc6a31 100644
--- a/Graphics/GraphicsEngineVulkan/include/ShaderVkImpl.h
+++ b/Graphics/GraphicsEngineVulkan/include/ShaderVkImpl.h
@@ -87,6 +87,8 @@ public:
 #endif
     
 private:
+    void MapHLSLVertexShaderInputs();
+
     // ShaderResources class instance must be referenced through the shared pointer, because 
     // it is referenced by ShaderResourceLayoutVk class instances
     std::shared_ptr<const SPIRVShaderResources> m_pShaderResources;
diff --git a/Graphics/GraphicsEngineVulkan/src/ShaderVkImpl.cpp b/Graphics/GraphicsEngineVulkan/src/ShaderVkImpl.cpp
index 23d2123d..56e32ed1 100644
--- a/Graphics/GraphicsEngineVulkan/src/ShaderVkImpl.cpp
+++ b/Graphics/GraphicsEngineVulkan/src/ShaderVkImpl.cpp
@@ -22,6 +22,7 @@
  */
 
 #include <array>
+#include <cctype>
 #include "pch.h"
 
 #include "ShaderVkImpl.h"
@@ -78,14 +79,51 @@ ShaderVkImpl::ShaderVkImpl(IReferenceCounters* pRefCounters, RenderDeviceVkImpl*
     // Load shader resources
     auto& Allocator = GetRawAllocator();
     auto* pRawMem = ALLOCATE(Allocator, "Allocator for ShaderResources", sizeof(SPIRVShaderResources));
-    auto* pResources = new (pRawMem) SPIRVShaderResources(Allocator, pRenderDeviceVk, m_SPIRV, m_Desc, CreationAttribs.UseCombinedTextureSamplers ? CreationAttribs.CombinedSamplerSuffix : nullptr);
+    bool IsHLSLVertexShader = CreationAttribs.SourceLanguage == SHADER_SOURCE_LANGUAGE_HLSL && m_Desc.ShaderType == SHADER_TYPE_VERTEX;
+    auto* pResources = new (pRawMem) SPIRVShaderResources(Allocator, pRenderDeviceVk, m_SPIRV, m_Desc, CreationAttribs.UseCombinedTextureSamplers ? CreationAttribs.CombinedSamplerSuffix : nullptr, IsHLSLVertexShader);
     m_pShaderResources.reset(pResources, STDDeleterRawMem<SPIRVShaderResources>(Allocator));
+    
+    if (IsHLSLVertexShader)
+    {
+        MapHLSLVertexShaderInputs();
+    }
 
     m_StaticResLayout.InitializeStaticResourceLayout(m_pShaderResources, GetRawAllocator(), m_StaticResCache);
     // m_StaticResLayout only contains static resources, so reference all of them
     m_StaticVarsMgr.Initialize(m_StaticResLayout, GetRawAllocator(), nullptr, 0, m_StaticResCache);
 }
 
+void ShaderVkImpl::MapHLSLVertexShaderInputs()
+{
+    for (Uint32 i = 0; i < m_pShaderResources->GetNumShaderStageInputs(); ++i)
+    {
+        const auto& Input = m_pShaderResources->GetShaderStageInputAttribs(i);
+        const char* s = Input.Semantic;
+        static const char* Prefix = "attrib";
+        const char* p = Prefix;
+        while(*s != 0 && *p != 0 && *p == std::tolower(static_cast<unsigned char>(*s)) )
+        {
+            ++p;
+            ++s;
+        }
+
+        if (*p != 0)
+        {
+            LOG_ERROR_MESSAGE("Unable to map semantic '", Input.Semantic, "' to input location: semantics must have 'ATTRIBx' format.");
+            continue;
+        }
+
+        char* EndPtr = nullptr;
+        auto Location = strtol(s, &EndPtr, 10);
+        if (*EndPtr != 0)
+        {
+            LOG_ERROR_MESSAGE("Unable to map semantic '", Input.Semantic, "' to input location: semantics must have 'ATTRIBx' format.");
+            continue;
+        }
+        m_SPIRV[Input.LocationDecorationOffset] = Location;
+    }
+}
+
 ShaderVkImpl::~ShaderVkImpl()
 {
     m_StaticVarsMgr.Destroy(GetRawAllocator());
-- 
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