[d3d11] Make D3D11 context methods more robust to null pointers

Assetto Corsa tries to do some questionable things when reflections
are disabled in the game options. Refs #648.

src/d3d11/d3d11_context.cpp

@@ -63,10 +63,13 @@ namespace dxvk {
 
 
   void STDMETHODCALLTYPE D3D11DeviceContext::DiscardResource(ID3D11Resource* pResource) {
+    if (!pResource)
+      return;
+
+    // We don't support the Discard API for images
     D3D11_RESOURCE_DIMENSION resType = D3D11_RESOURCE_DIMENSION_UNKNOWN;
     pResource->GetType(&resType);
 
-    // We don't support the Discard API for images
     if (resType == D3D11_RESOURCE_DIMENSION_BUFFER)
       DiscardBuffer(static_cast<D3D11Buffer*>(pResource));
   }
@@ -197,7 +200,7 @@ namespace dxvk {
 
 
   void STDMETHODCALLTYPE D3D11DeviceContext::Begin(ID3D11Asynchronous *pAsync) {
-    if (pAsync == nullptr)
+    if (!pAsync)
       return;
 
     Com<ID3D11Query> query;
@@ -217,7 +220,7 @@ namespace dxvk {
 
 
   void STDMETHODCALLTYPE D3D11DeviceContext::End(ID3D11Asynchronous *pAsync) {
-    if (pAsync == nullptr)
+    if (!pAsync)
       return;
 
     Com<ID3D11Query> query;
@@ -508,6 +511,9 @@ namespace dxvk {
   void STDMETHODCALLTYPE D3D11DeviceContext::CopyResource(
           ID3D11Resource*                   pDstResource,
           ID3D11Resource*                   pSrcResource) {
+    if (!pDstResource || !pSrcResource)
+      return;
+
     D3D11_RESOURCE_DIMENSION dstResourceDim = D3D11_RESOURCE_DIMENSION_UNKNOWN;
     D3D11_RESOURCE_DIMENSION srcResourceDim = D3D11_RESOURCE_DIMENSION_UNKNOWN;
 
@@ -606,6 +612,9 @@ namespace dxvk {
     auto buf = static_cast<D3D11Buffer*>(pDstBuffer);
     auto uav = static_cast<D3D11UnorderedAccessView*>(pSrcView);
 
+    if (!buf || !uav)
+      return;
+
     EmitCs([
       cDstSlice = buf->GetBufferSlice(DstAlignedByteOffset),
       cSrcSlice = uav->GetCounterSlice()
@@ -625,7 +634,7 @@ namespace dxvk {
     const FLOAT                             ColorRGBA[4]) {
     auto rtv = static_cast<D3D11RenderTargetView*>(pRenderTargetView);
 
-    if (rtv == nullptr)
+    if (!rtv)
       return;
 
     const Rc<DxvkImageView> view = rtv->GetImageView();
@@ -653,7 +662,7 @@ namespace dxvk {
     const UINT                              Values[4]) {
     auto uav = static_cast<D3D11UnorderedAccessView*>(pUnorderedAccessView);
 
-    if (uav == nullptr)
+    if (!uav)
       return;
 
     // Gather UAV format info. We'll use this to determine
@@ -746,7 +755,7 @@ namespace dxvk {
     const FLOAT                             Values[4]) {
     auto uav = static_cast<D3D11UnorderedAccessView*>(pUnorderedAccessView);
 
-    if (uav == nullptr)
+    if (!uav)
       return;
 
     VkClearValue clearValue;
@@ -786,7 +795,7 @@ namespace dxvk {
           UINT8                             Stencil) {
     auto dsv = static_cast<D3D11DepthStencilView*>(pDepthStencilView);
 
-    if (dsv == nullptr)
+    if (!dsv)
       return;
 
     // Figure out which aspects to clear based
@@ -966,8 +975,8 @@ namespace dxvk {
 
   void STDMETHODCALLTYPE D3D11DeviceContext::GenerateMips(ID3D11ShaderResourceView* pShaderResourceView) {
     auto view = static_cast<D3D11ShaderResourceView*>(pShaderResourceView);
-      
-    if (view->GetResourceType() == D3D11_RESOURCE_DIMENSION_BUFFER)
+
+    if (!view || view->GetResourceType() == D3D11_RESOURCE_DIMENSION_BUFFER)
       return;
 
     EmitCs([cDstImageView = view->GetImageView()]
@@ -998,6 +1007,9 @@ namespace dxvk {
           UINT                              SrcRowPitch, 
           UINT                              SrcDepthPitch, 
           UINT                              CopyFlags) {
+    if (!pDstResource || !pSrcResource)
+      return;
+
     // We need a different code path for buffers
     D3D11_RESOURCE_DIMENSION resourceType;
     pDstResource->GetType(&resourceType);
@@ -1134,6 +1146,9 @@ namespace dxvk {
           ID3D11Resource*                   pSrcResource,
           UINT                              SrcSubresource,
           DXGI_FORMAT                       Format) {
+    if (!pDstResource || !pSrcResource)
+      return;
+
     D3D11_RESOURCE_DIMENSION dstResourceType;
     D3D11_RESOURCE_DIMENSION srcResourceType;