[idd] driver: use the frameSize instead of the resource size

As the resource size can be larger then the actual frame data, we
need to track this seperately so that we don't waste cycles copying
data the client will never use.

idd/LGIdd/CFrameBufferResource.cpp

@@ -12,7 +12,10 @@ bool CFrameBufferResource::Init(CSwapChainProcessor * swapChain, uint8_t * base,
 
   // nothing to do if the resource already exists and is large enough
   if (m_base == base && m_size >= size)
+  {
+    m_frameSize = size;
     return true;
+  }
 
   Reset();
 
@@ -87,9 +90,10 @@ bool CFrameBufferResource::Init(CSwapChainProcessor * swapChain, uint8_t * base,
 
   m_res->SetName(resName);
 
-  m_base  = base;
-  m_size  = size;
-  m_valid = true;
+  m_base      = base;
+  m_size      = size;
+  m_frameSize = size;
+  m_valid     = true;
   return true;
 }
 

idd/LGIdd/CFrameBufferResource.h

@@ -16,6 +16,7 @@ class CFrameBufferResource
     bool                   m_valid;
     uint8_t              * m_base;
     size_t                 m_size;
+    size_t                 m_frameSize;
     ComPtr<ID3D12Resource> m_res;
     void                 * m_map;
 
@@ -23,10 +24,11 @@ class CFrameBufferResource
     bool Init(CSwapChainProcessor * swapChain, uint8_t * base, size_t size);
     void Reset();
 
-    bool      IsValid() { return m_valid; }
-    uint8_t * GetBase() { return m_base;  }
-    size_t    GetSize() { return m_size;  }
-    void *    GetMap()  { return m_map;   }
+    bool      IsValid()      { return m_valid;     }
+    uint8_t * GetBase()      { return m_base;      }
+    size_t    GetSize()      { return m_size;      }
+    size_t    GetFrameSize() { return m_frameSize; }
+    void *    GetMap()       { return m_map;       }
 
     ComPtr<ID3D12Resource> Get() { return m_res; }
 };

idd/LGIdd/CSwapChainProcessor.cpp

@@ -217,7 +217,8 @@ void CSwapChainProcessor::SwapChainNewFrame(ComPtr<IDXGIResource> acquiredBuffer
   m_dx12Device->GetCopyQueue().Reset();
 
   if (m_dx12Device->IsIndirectCopy())
-    m_devContext->WriteFrameBuffer(fbRes->GetMap(), 0, fbRes->GetSize(), true);
+    m_devContext->WriteFrameBuffer(
+      fbRes->GetMap(), 0, fbRes->GetFrameSize(), true);
   else
     m_devContext->FinalizeFrameBuffer();
 }