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Source/Engine/GraphicsDevice/DirectX/DX12/GPUTimerQueryDX12.cpp

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+// Copyright (c) 2012-2020 Wojciech Figat. All rights reserved.
+
+#if GRAPHICS_API_DIRECTX12
+
+#include "GPUTimerQueryDX12.h"
+#include "GPUContextDX12.h"
+
+GPUTimerQueryDX12::GPUTimerQueryDX12(GPUDeviceDX12* device)
+    : GPUResourceDX12<GPUTimerQuery>(device, String::Empty)
+{
+}
+
+void GPUTimerQueryDX12::OnReleaseGPU()
+{
+    _hasResult = false;
+    _endCalled = false;
+    _timeDelta = 0.0f;
+}
+
+void GPUTimerQueryDX12::Begin()
+{
+    const auto context = _device->GetMainContextDX12();
+    auto& heap = _device->TimestampQueryHeap;
+    heap.EndQuery(context, _begin);
+
+    _hasResult = false;
+    _endCalled = false;
+}
+
+void GPUTimerQueryDX12::End()
+{
+    if (_endCalled)
+        return;
+
+    const auto context = _device->GetMainContextDX12();
+    auto& heap = _device->TimestampQueryHeap;
+    heap.EndQuery(context, _end);
+
+    const auto queue = _device->GetCommandQueue()->GetCommandQueue();
+    VALIDATE_DIRECTX_RESULT(queue->GetTimestampFrequency(&_gpuFrequency));
+
+    _endCalled = true;
+}
+
+bool GPUTimerQueryDX12::HasResult()
+{
+    if (!_endCalled)
+        return false;
+    if (_hasResult)
+        return true;
+
+    auto& heap = _device->TimestampQueryHeap;
+    return heap.IsReady(_end) && heap.IsReady(_begin);
+}
+
+float GPUTimerQueryDX12::GetResult()
+{
+    if (_hasResult)
+    {
+        return _timeDelta;
+    }
+
+    const uint64 timeBegin = *(uint64*)_device->TimestampQueryHeap.ResolveQuery(_begin);
+    const uint64 timeEnd = *(uint64*)_device->TimestampQueryHeap.ResolveQuery(_end);
+
+    // Calculate event duration in milliseconds
+    if (timeEnd > timeBegin)
+    {
+        const uint64 delta = timeEnd - timeBegin;
+        const double frequency = double(_gpuFrequency);
+        _timeDelta = static_cast<float>((delta / frequency) * 1000.0);
+    }
+    else
+    {
+        _timeDelta = 0.0f;
+    }
+
+    _hasResult = true;
+    return _timeDelta;
+}
+
+#endif