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Source/Engine/Streaming/Handlers/ModelsStreamingHandler.cpp

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+// Copyright (c) 2012-2020 Wojciech Figat. All rights reserved.
+
+#include "ModelsStreamingHandler.h"
+#include "Engine/Content/Assets/Model.h"
+
+StreamingQuality ModelsStreamingHandler::CalculateTargetQuality(StreamableResource* resource, DateTime now)
+{
+    ASSERT(resource);
+
+    // TODO: calculate a proper quality levels for models based on render time and streaming enable/disable options
+
+    return MAX_STREAMING_QUALITY;
+}
+
+int32 ModelsStreamingHandler::CalculateResidency(StreamableResource* resource, StreamingQuality quality)
+{
+    ASSERT(resource);
+    auto& model = *(Model*)resource;
+    auto lodCount = model.GetLODsCount();
+
+    if (quality < ZeroTolerance)
+        return 0;
+
+    int32 lods = Math::CeilToInt(quality * lodCount);
+
+    ASSERT(model.IsValidLODIndex(lods - 1));
+    return lods;
+}
+
+int32 ModelsStreamingHandler::CalculateRequestedResidency(StreamableResource* resource, int32 targetResidency)
+{
+    ASSERT(resource);
+    auto& model = *(Model*)resource;
+
+    // Always load only single LOD at once
+    int32 residency = targetResidency;
+    int32 currentResidency = model.GetCurrentResidency();
+    if (currentResidency < targetResidency)
+    {
+        // Up
+        residency = currentResidency + 1;
+    }
+    else if (currentResidency > targetResidency)
+    {
+        // Down
+        residency = currentResidency - 1;
+    }
+
+    return residency;
+}