[Direct3D12] Simplify marshaling for PR #773 (issue #667)

Author: xoofx

Source/SharpDX.Direct3D12/Mapping.xml

@@ -314,7 +314,7 @@
 
     <remove function=".*_Stub"/>
     <remove function=".*_Proxy"/>
-    <remove method="ID3D12RootSignatureDeserializer::GetRootSignatureDesc"/>
+    <map method="ID3D12RootSignatureDeserializer::GetRootSignatureDesc" type="void" property="false" visibility="private"/>
     <map function="D3D12(.+)" name-tmp="$1" />
     <map function="D3D12.*" dll='"d3d12.dll"' group="SharpDX.Direct3D12.D3D12" />
     <map param="D3D12CreateDevice::ppDevice" type="ID3D12Device" attribute="out fast" />

Source/SharpDX.Direct3D12/RootSignatureDescription.cs

@@ -166,6 +166,11 @@ private unsafe Result Serialize(out Blob result, out string errorText)
 
         private unsafe void Deserialize(IntPtr pNativePtr)
         {
+            if(pNativePtr == IntPtr.Zero)
+            {
+                return;
+            }
+
             __Native* pNative = (__Native*)pNativePtr;
 
             if (pNative->ParameterCount > 0)
@@ -184,47 +189,23 @@ private unsafe void Deserialize(IntPtr pNativePtr)
                         if (rangeCount > 0)
                         {
                             ranges = new DescriptorRange[rangeCount];
-                            fixed (DescriptorRange* pCurRange = ranges)
-                            {
-                                DescriptorRange* pSourceDescRange = (DescriptorRange*)rpn[i].Union.DescriptorTable.DescriptorRangesPointer;
-                                DescriptorRange* pSourceDescRangeEnd = pSourceDescRange + rpn[i].Union.DescriptorTable.DescriptorRangeCount;
-                                DescriptorRange* pTargetDescRange = pCurRange;
-                                while (pTargetDescRange < pSourceDescRangeEnd)
-                                {
-                                    *pTargetDescRange = *pSourceDescRange;
-                                    pTargetDescRange++;
-                                    pSourceDescRange++;
-                                }
-
-                            }
+                            Utilities.Read(rpn[i].Union.DescriptorTable.DescriptorRangesPointer, ranges, 0, ranges.Length);
                         }
 
                         Parameters[i] = new RootParameter(rpn[i].ShaderVisibility, ranges);
                     }
                     else
                     {
                         // No need to marshal them when RootParameter don't contain DescriptorTable - simple copy as-is
-                        Parameters[i] = new RootParameter();
-                        Parameters[i].native = *rpn;
+                        Parameters[i] = new RootParameter {native = *rpn};
                     }
                 }
             }
 
             if (pNative->StaticSamplerCount > 0)
             {
                 StaticSamplers = new StaticSamplerDescription[pNative->StaticSamplerCount];
-                fixed (StaticSamplerDescription *pSamplerDesc = StaticSamplers)
-                {
-                    StaticSamplerDescription* pTargetSamplerDesc = pSamplerDesc;
-                    StaticSamplerDescription* pSourceSamplerDesc = (StaticSamplerDescription*) pNative->StaticSamplerPointer;
-                    StaticSamplerDescription* pSourceSamplerDescEnd = pSourceSamplerDesc + pNative->StaticSamplerCount;
-                    while (pSamplerDesc < pSourceSamplerDescEnd)
-                    {
-                        *pTargetSamplerDesc = *pSourceSamplerDesc;
-                        pTargetSamplerDesc++;
-                        pSourceSamplerDesc++;
-                    }
-                }
+                Utilities.Read(pNative->StaticSamplerPointer, StaticSamplers, 0, StaticSamplers.Length);
             }
         }
 

Source/SharpDX.Direct3D12/RootSignatureDeserializer.cs

@@ -17,13 +17,7 @@ public partial class RootSignatureDeserializer
         /// <unmanaged>GetRootSignatureDesc</unmanaged>	
         /// <unmanaged-short>GetRootSignatureDesc</unmanaged-short>	
         /// <unmanaged>const D3D12_ROOT_SIGNATURE_DESC* ID3D12RootSignatureDeserializer::GetRootSignatureDesc()</unmanaged>
-        public SharpDX.Direct3D12.RootSignatureDescription RootSignatureDescription
-        {
-            get { return GetRootSignatureDescription(); }
-        }
-
-        [UnmanagedFunctionPointer(CallingConvention.StdCall)]
-        internal delegate IntPtr GetRootSignatureDescDelegate(IntPtr pThis);
+        public SharpDX.Direct3D12.RootSignatureDescription RootSignatureDescription => GetRootSignatureDescription2();
 
         /// <summary>	
         /// <p> Gets the layout of the root signature. </p>	
@@ -33,15 +27,10 @@ public SharpDX.Direct3D12.RootSignatureDescription RootSignatureDescription
         /// <msdn-id>dn986887</msdn-id>	
         /// <unmanaged>const D3D12_ROOT_SIGNATURE_DESC* ID3D12RootSignatureDeserializer::GetRootSignatureDesc()</unmanaged>	
         /// <unmanaged-short>ID3D12RootSignatureDeserializer::GetRootSignatureDesc</unmanaged-short>	
-        internal SharpDX.Direct3D12.RootSignatureDescription GetRootSignatureDescription()
+        internal SharpDX.Direct3D12.RootSignatureDescription GetRootSignatureDescription2()
         {
-            unsafe
-            {               
-                void* target = ((void**)(*(void**)_nativePointer))[3];
-                GetRootSignatureDescDelegate getRootSignatureDescMethod = Marshal.GetDelegateForFunctionPointer<GetRootSignatureDescDelegate>(new IntPtr(target));
-                IntPtr pDesc = getRootSignatureDescMethod(new IntPtr(_nativePointer));
-                return new RootSignatureDescription(pDesc);
-            }
+            var pDesc = this.GetRootSignatureDescription();
+            return new RootSignatureDescription(pDesc);
         }
     }
 }