Add IsSingleFrame to RenderView for thumbnails/pre-render views drawing without temporal effects and LOD transitions

Source/Editor/Content/Proxy/AssetProxy.cs

@@ -108,6 +108,10 @@ namespace FlaxEditor.Content
             var task = preview.Task;
             task.Enabled = false;
 
+            var view = task.View;
+            view.IsSingleFrame = true; // Disable LOD transitions
+            task.View = view;
+
             var eyeAdaptation = preview.PostFxVolume.EyeAdaptation;
             eyeAdaptation.Mode = EyeAdaptationMode.None;
             eyeAdaptation.OverrideFlags |= EyeAdaptationSettingsOverride.Mode;

Source/Engine/Content/Assets/Model.cpp

@@ -194,7 +194,7 @@ void Model::Draw(const RenderContext& renderContext, const Mesh::DrawInfo& info)
         if (lodIndex == -1)
         {
             // Handling model fade-out transition
-            if (modelFrame == frame && info.DrawState->PrevLOD != -1)
+            if (modelFrame == frame && info.DrawState->PrevLOD != -1 && !renderContext.View.IsSingleFrame)
             {
                 // Check if start transition
                 if (info.DrawState->LODTransition == 255)
@@ -223,8 +223,11 @@ void Model::Draw(const RenderContext& renderContext, const Mesh::DrawInfo& info)
     lodIndex += info.LODBias + renderContext.View.ModelLODBias;
     lodIndex = ClampLODIndex(lodIndex);
 
+    if (renderContext.View.IsSingleFrame)
+    {
+    }
     // Check if it's the new frame and could update the drawing state (note: model instance could be rendered many times per frame to different viewports)
-    if (modelFrame == frame)
+    else if (modelFrame == frame)
     {
         // Check if start transition
         if (info.DrawState->PrevLOD != lodIndex && info.DrawState->LODTransition == 255)
@@ -249,7 +252,7 @@ void Model::Draw(const RenderContext& renderContext, const Mesh::DrawInfo& info)
     }
 
     // Draw
-    if (info.DrawState->PrevLOD == lodIndex)
+    if (info.DrawState->PrevLOD == lodIndex || renderContext.View.IsSingleFrame)
     {
         LODs[lodIndex].Draw(renderContext, info, 0.0f);
     }

Source/Engine/Content/Assets/SkinnedModel.cpp

@@ -30,13 +30,11 @@
 class StreamSkinnedModelLODTask : public ThreadPoolTask
 {
 private:
-
     WeakAssetReference<SkinnedModel> _asset;
     int32 _lodIndex;
     FlaxStorage::LockData _dataLock;
 
 public:
-
     /// <summary>
     /// Init
     /// </summary>
@@ -50,7 +48,6 @@ public:
     }
 
 public:
-
     // [ThreadPoolTask]
     bool HasReference(Object* resource) const override
     {
@@ -58,7 +55,6 @@ public:
     }
 
 protected:
-
     // [ThreadPoolTask]
     bool Run() override
     {
@@ -191,7 +187,7 @@ void SkinnedModel::Draw(RenderContext& renderContext, const SkinnedMesh::DrawInf
         if (lodIndex == -1)
         {
             // Handling model fade-out transition
-            if (modelFrame == frame && info.DrawState->PrevLOD != -1)
+            if (modelFrame == frame && info.DrawState->PrevLOD != -1 && !renderContext.View.IsSingleFrame)
             {
                 // Check if start transition
                 if (info.DrawState->LODTransition == 255)
@@ -220,8 +216,11 @@ void SkinnedModel::Draw(RenderContext& renderContext, const SkinnedMesh::DrawInf
     lodIndex += info.LODBias + renderContext.View.ModelLODBias;
     lodIndex = ClampLODIndex(lodIndex);
 
+    if (renderContext.View.IsSingleFrame)
+    {
+    }
     // Check if it's the new frame and could update the drawing state (note: model instance could be rendered many times per frame to different viewports)
-    if (modelFrame == frame)
+    else if (modelFrame == frame)
     {
         // Check if start transition
         if (info.DrawState->PrevLOD != lodIndex && info.DrawState->LODTransition == 255)
@@ -237,7 +236,7 @@ void SkinnedModel::Draw(RenderContext& renderContext, const SkinnedMesh::DrawInf
             info.DrawState->PrevLOD = lodIndex;
         }
     }
-        // Check if there was a gap between frames in drawing this model instance
+    // Check if there was a gap between frames in drawing this model instance
     else if (modelFrame < frame || info.DrawState->PrevLOD == -1)
     {
         // Reset state
@@ -246,7 +245,7 @@ void SkinnedModel::Draw(RenderContext& renderContext, const SkinnedMesh::DrawInf
     }
 
     // Draw
-    if (info.DrawState->PrevLOD == lodIndex)
+    if (info.DrawState->PrevLOD == lodIndex || renderContext.View.IsSingleFrame)
     {
         LODs[lodIndex].Draw(renderContext, info, 0.0f);
     }

Source/Engine/Graphics/RenderView.h

@@ -97,6 +97,11 @@ public:
     /// </summary>
     API_FIELD() bool IsOfflinePass = false;
 
+    /// <summary>
+    /// Flag used by single-frame rendering passes (eg. thumbnail rendering, model view caching) to reject LOD transitions animations and other temporal draw effects.
+    /// </summary>
+    API_FIELD() bool IsSingleFrame = false;
+
     /// <summary>
     /// The static flags mask used to hide objects that don't have a given static flags. Eg. use StaticFlags::Lightmap to render only objects that can use lightmap.
     /// </summary>

Source/Engine/Renderer/DrawCall.h

@@ -322,13 +322,13 @@ struct TIsPODType<GeometryDrawStateData>
 
 #define GEOMETRY_DRAW_STATE_EVENT_BEGIN(drawState, worldMatrix) \
     const auto frame = Engine::FrameCount; \
-	if (drawState.PrevFrame + 1 < frame) \
+	if (drawState.PrevFrame + 1 < frame && !renderContext.View.IsSingleFrame) \
 	{ \
         drawState.PrevWorld = worldMatrix; \
     }
 
 #define GEOMETRY_DRAW_STATE_EVENT_END(drawState, worldMatrix) \
-	if (drawState.PrevFrame != frame) \
+	if (drawState.PrevFrame != frame && !renderContext.View.IsSingleFrame) \
 	{ \
 		drawState.PrevWorld = worldMatrix; \
 		drawState.PrevFrame = frame; \