text: /***************************************************************************
  # Copyright (c) 2018, NVIDIA CORPORATION. All rights reserved.
  #
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions
  # are met:
  #  * Redistributions of source code must retain the above copyright
  #    notice, this list of conditions and the following disclaimer.
  #  * Redistributions in binary form must reproduce the above copyright
  #    notice, this list of conditions and the following disclaimer in the
  #    documentation and/or other materials provided with the distribution.
  #  * Neither the name of NVIDIA CORPORATION nor the names of its
  #    contributors may be used to endorse or promote products derived
  #    from this software without specific prior written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
  # EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  # PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  # CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  # PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  # PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  # OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  ***************************************************************************/
  #include "stdafx.h"
  #include "Core/API/GpuFence.h"
  #include "Core/API/Device.h"
  
  namespace Falcor
  {
      struct FenceApiData
      {
          HANDLE eventHandle = INVALID_HANDLE_VALUE;
      };
  
      GpuFence::~GpuFence()
      {
          CloseHandle(mpApiData->eventHandle);
          safe_delete(mpApiData);
      }
  
      GpuFence::SharedPtr GpuFence::create()
      {
          SharedPtr pFence = SharedPtr(new GpuFence());
          pFence->mpApiData = new FenceApiData;
          pFence->mpApiData->eventHandle = CreateEvent(nullptr, FALSE, FALSE, nullptr);
          ID3D12Device* pDevice = gpDevice->getApiHandle().GetInterfacePtr();
  
          HRESULT hr = pDevice->CreateFence(pFence->mCpuValue, D3D12_FENCE_FLAG_NONE, IID_PPV_ARGS(&pFence->mApiHandle));
          pFence->mCpuValue++;
          if(FAILED(hr))
          {
              d3dTraceHR("Failed to create a fence object", hr);
              return nullptr;
          }
  
          return pFence;
      }
  
      uint64_t GpuFence::gpuSignal(CommandQueueHandle pQueue)
      {
          d3d_call(pQueue->Signal(mApiHandle, mCpuValue));
          mCpuValue++;
          return mCpuValue - 1;
      }
  
      void GpuFence::syncGpu(CommandQueueHandle pQueue)
      {
          d3d_call(pQueue->Wait(mApiHandle, mCpuValue - 1));
      }
  
      void GpuFence::syncCpu(std::optional<uint64_t> val)
      {
          uint64_t syncVal = val ? val.value() : mCpuValue - 1;
          assert(syncVal <= mCpuValue - 1);
  
          uint64_t gpuVal = getGpuValue();
          if (gpuVal < syncVal)
          {
              d3d_call(mApiHandle->SetEventOnCompletion(syncVal, mpApiData->eventHandle));
              WaitForSingleObject(mpApiData->eventHandle, INFINITE);
          }
      }
  
      uint64_t GpuFence::getGpuValue() const
      {
          return mApiHandle->GetCompletedValue();
      }
  }
  