diff --git a/Src/d3dx12.h b/Src/d3dx12.h
index 6538b82b..cda6e036 100644
--- a/Src/d3dx12.h
+++ b/Src/d3dx12.h
@@ -53,6 +53,71 @@ struct CD3DX12_RECT : public D3D12_RECT
     operator const D3D12_RECT&() const { return *this; }
 };
 
+//------------------------------------------------------------------------------------------------
+struct CD3DX12_VIEWPORT : public D3D12_VIEWPORT
+{
+    CD3DX12_VIEWPORT()
+    {}
+    explicit CD3DX12_VIEWPORT( const D3D12_VIEWPORT& o ) :
+        D3D12_VIEWPORT( o )
+    {}
+    explicit CD3DX12_VIEWPORT(
+        FLOAT topLeftX,
+        FLOAT topLeftY,
+        FLOAT width,
+        FLOAT height,
+        FLOAT minDepth = D3D12_MIN_DEPTH,
+        FLOAT maxDepth = D3D12_MAX_DEPTH )
+    {
+        TopLeftX = topLeftX;
+        TopLeftY = topLeftY;
+        Width = width;
+        Height = height;
+        MinDepth = minDepth;
+        MaxDepth = maxDepth;
+    }
+    explicit CD3DX12_VIEWPORT(
+        _In_ ID3D12Resource* pResource,
+        UINT mipSlice = 0,
+        FLOAT topLeftX = 0.0f,
+        FLOAT topLeftY = 0.0f,
+        FLOAT minDepth = D3D12_MIN_DEPTH,
+        FLOAT maxDepth = D3D12_MAX_DEPTH )
+    {
+        D3D12_RESOURCE_DESC Desc = pResource->GetDesc();
+        const UINT64 SubresourceWidth = Desc.Width >> mipSlice;
+        const UINT64 SubresourceHeight = Desc.Height >> mipSlice;
+        switch (Desc.Dimension)
+        {
+        case D3D12_RESOURCE_DIMENSION_BUFFER:
+            TopLeftX = topLeftX;
+            TopLeftY = 0.0f;
+            Width = Desc.Width - topLeftX;
+            Height = 1.0f;
+            break;
+        case D3D12_RESOURCE_DIMENSION_TEXTURE1D:
+            TopLeftX = topLeftX;
+            TopLeftY = 0.0f;
+            Width = (SubresourceWidth ? SubresourceWidth : 1.0f) - topLeftX;
+            Height = 1.0f;
+            break;
+        case D3D12_RESOURCE_DIMENSION_TEXTURE2D:
+        case D3D12_RESOURCE_DIMENSION_TEXTURE3D:
+            TopLeftX = topLeftX;
+            TopLeftY = topLeftY;
+            Width = (SubresourceWidth ? SubresourceWidth : 1.0f) - topLeftX;
+            Height = (SubresourceHeight ? SubresourceHeight: 1.0f) - topLeftY;
+            break;
+        default: break;
+        }
+
+        MinDepth = minDepth;
+        MaxDepth = maxDepth;
+    }
+    ~CD3DX12_VIEWPORT() {}
+    operator const D3D12_VIEWPORT&() const { return *this; }
+};
+
 //------------------------------------------------------------------------------------------------
 struct CD3DX12_BOX : public D3D12_BOX
 {
@@ -453,13 +518,13 @@ struct CD3DX12_SHADER_BYTECODE : public D3D12_SHADER_BYTECODE
         D3D12_SHADER_BYTECODE(o)
     {}
     CD3DX12_SHADER_BYTECODE(
-        ID3DBlob* pShaderBlob )
+        _In_ ID3DBlob* pShaderBlob )
     {
         pShaderBytecode = pShaderBlob->GetBufferPointer();
         BytecodeLength = pShaderBlob->GetBufferSize();
     }
     CD3DX12_SHADER_BYTECODE(
-        void* _pShaderBytecode,
+        const void* _pShaderBytecode,
         SIZE_T bytecodeLength )
     {
         pShaderBytecode = _pShaderBytecode;
@@ -1938,6 +2003,7 @@ inline HRESULT D3DX12SerializeVersionedRootSignature(
     return E_INVALIDARG;
 }
 
+
 #endif // defined( __cplusplus )
 
 #endif //__D3DX12_H__