Add check to disable LOD transitions in material layer

CHANGES.md

@@ -2,9 +2,14 @@
 
 ### ? - ?
 
+##### Breaking Changes :mega:
+
+- `UseLodTransitions` has been renamed to `EnableLodTransitions` on `Cesium3DTileset`.
+
 ##### Fixes :wrench:
 
-- Fixed an issue with pixel dithering artifacts that could appear on tilesets.
+- Fixed an issue with flickering pixel artifacts that could appear on tilesets.
+- Fixed an issue with dithering artifacts that would appear on tilesets when using non-temporal anti-aliasing methods for Forward Rendering.
 - Fixed an issue where DynamicPawn could get stuck after interrupting a flight from `UCesiumFlyToComponent`.
 
 ### v2.5.0 - 2024-05-01

Config/Engine.ini

@@ -152,3 +152,8 @@ AspectRatioAxisConstraint=AspectRatio_MaintainXFOV
 +EnumRedirects=(OldName="ECesiumMetadataPackedGpuType", NewName="ECesiumMetadataPackedGpuType_DEPRECATED", ValueChanges=(("None","Unknown_DEPRECATED"),("Uint8","Uint8_DEPRECATED"),("Float","Float_DEPRECATED")))
 
 +FunctionRedirects=(OldName="CesiumFeatureIdTextureBlueprintLibrary.GetTextureCoordinateIndex", NewName="CesiumFeatureIdTextureBlueprintLibrary.GetUnrealUVChannel")
+
++PropertyRedirects=(OldName="Cesium3DTileset.UseLodTransitions", NewName="EnableLodTransitions")
++FunctionRedirects=(OldName="Cesium3DTileset.GetUseLodTransitions", NewName="GetEnableLodTransitions")
++FunctionRedirects=(OldName="Cesium3DTileset.SetUseLodTransitions", NewName="SetEnableLodTransitions")
++PropertyRedirects=(OldName="Cesium3DTileset.SetUseLodTransitions.InUseLodTransitions", NewName="InEnableLodTransitions")

Source/CesiumRuntime/Private/Cesium3DTileset.cpp

@@ -87,7 +87,7 @@ ACesium3DTileset::ACesium3DTileset()
       _beforeMoviePreloadAncestors{PreloadAncestors},
       _beforeMoviePreloadSiblings{PreloadSiblings},
       _beforeMovieLoadingDescendantLimit{LoadingDescendantLimit},
-      _beforeMovieUseLodTransitions{true},
+      _beforeMovieEnableLodTransitions{true},
 
       _tilesetsBeingDestroyed(0) {
 
@@ -272,9 +272,9 @@ void ACesium3DTileset::PostInitProperties() {
   }
 }
 
-void ACesium3DTileset::SetUseLodTransitions(bool InUseLodTransitions) {
-  if (InUseLodTransitions != this->UseLodTransitions) {
-    this->UseLodTransitions = InUseLodTransitions;
+void ACesium3DTileset::SetEnableLodTransitions(bool InEnableLodTransitions) {
+  if (InEnableLodTransitions != this->EnableLodTransitions) {
+    this->EnableLodTransitions = InEnableLodTransitions;
     this->DestroyTileset();
   }
 }
@@ -442,21 +442,21 @@ void ACesium3DTileset::PlayMovieSequencer() {
   this->_beforeMoviePreloadAncestors = this->PreloadAncestors;
   this->_beforeMoviePreloadSiblings = this->PreloadSiblings;
   this->_beforeMovieLoadingDescendantLimit = this->LoadingDescendantLimit;
-  this->_beforeMovieUseLodTransitions = this->UseLodTransitions;
+  this->_beforeMovieEnableLodTransitions = this->EnableLodTransitions;
 
   this->_captureMovieMode = true;
   this->PreloadAncestors = false;
   this->PreloadSiblings = false;
   this->LoadingDescendantLimit = 10000;
-  this->UseLodTransitions = false;
+  this->EnableLodTransitions = false;
 }
 
 void ACesium3DTileset::StopMovieSequencer() {
   this->_captureMovieMode = false;
   this->PreloadAncestors = this->_beforeMoviePreloadAncestors;
   this->PreloadSiblings = this->_beforeMoviePreloadSiblings;
   this->LoadingDescendantLimit = this->_beforeMovieLoadingDescendantLimit;
-  this->UseLodTransitions = this->_beforeMovieUseLodTransitions;
+  this->EnableLodTransitions = this->_beforeMovieEnableLodTransitions;
 }
 
 void ACesium3DTileset::PauseMovieSequencer() { this->StopMovieSequencer(); }
@@ -1819,7 +1819,7 @@ void ACesium3DTileset::updateTilesetOptionsFromProperties() {
   options.enforceCulledScreenSpaceError = this->EnforceCulledScreenSpaceError;
   options.culledScreenSpaceError =
       static_cast<double>(this->CulledScreenSpaceError);
-  options.enableLodTransitionPeriod = this->UseLodTransitions;
+  options.enableLodTransitionPeriod = this->EnableLodTransitions;
   options.lodTransitionLength = this->LodTransitionLength;
   // options.kickDescendantsWhileFadingIn = false;
 }
@@ -2071,7 +2071,7 @@ void ACesium3DTileset::Tick(float DeltaTime) {
   for (Cesium3DTilesSelection::Tile* pTile : pResult->tilesFadingOut) {
     Cesium3DTilesSelection::TileRenderContent* pRenderContent =
         pTile->getContent().getRenderContent();
-    if (!this->UseLodTransitions ||
+    if (!this->EnableLodTransitions ||
         (pRenderContent &&
          pRenderContent->getLodTransitionFadePercentage() >= 1.0f)) {
       _tilesToHideNextFrame.push_back(pTile);
@@ -2080,7 +2080,7 @@ void ACesium3DTileset::Tick(float DeltaTime) {
 
   showTilesToRender(pResult->tilesToRenderThisFrame);
 
-  if (this->UseLodTransitions) {
+  if (this->EnableLodTransitions) {
     TRACE_CPUPROFILER_EVENT_SCOPE(Cesium::UpdateTileFades)
 
     for (Cesium3DTilesSelection::Tile* pTile :
@@ -2180,7 +2180,7 @@ void ACesium3DTileset::PostEditChangeProperty(
       PropName ==
           GET_MEMBER_NAME_CHECKED(ACesium3DTileset, EnableOcclusionCulling) ||
       PropName ==
-          GET_MEMBER_NAME_CHECKED(ACesium3DTileset, UseLodTransitions) ||
+          GET_MEMBER_NAME_CHECKED(ACesium3DTileset, EnableLodTransitions) ||
       PropName ==
           GET_MEMBER_NAME_CHECKED(ACesium3DTileset, ShowCreditsOnScreen) ||
       PropName == GET_MEMBER_NAME_CHECKED(ACesium3DTileset, Root) ||

Source/CesiumRuntime/Private/CesiumGltfComponent.cpp

@@ -3135,10 +3135,17 @@ static void loadPrimitiveGameThreadPart(
           EMaterialParameterAssociation::LayerParameter,
           0);
 
-      // Initialize fade uniform to fully visible, in case LOD transitions
-      // are off.
       int fadeLayerIndex = pCesiumData->LayerNames.Find("DitherFade");
       if (fadeLayerIndex >= 0) {
+        pMaterial->SetScalarParameterValueByInfo(
+            FMaterialParameterInfo(
+                "EnableLodTransitions",
+                EMaterialParameterAssociation::LayerParameter,
+                fadeLayerIndex),
+            pTilesetActor->GetEnableLodTransitions() ? 1.0f : 0.0f);
+
+        // Initialize fade uniforms to fully visible, in case LOD transitions
+        // are off.
         pMaterial->SetScalarParameterValueByInfo(
             FMaterialParameterInfo(
                 "FadePercentage",
@@ -3147,7 +3154,7 @@ static void loadPrimitiveGameThreadPart(
             1.0f);
         pMaterial->SetScalarParameterValueByInfo(
             FMaterialParameterInfo(
-                "FadingType",
+                "FadeDirection",
                 EMaterialParameterAssociation::LayerParameter,
                 fadeLayerIndex),
             0.0f);

Source/CesiumRuntime/Public/Cesium3DTileset.h

@@ -425,13 +425,14 @@ class CESIUMRUNTIME_API ACesium3DTileset : public AActor {
    * This will cause more tiles to be loaded, but helps to avoid holes and
    * provides a more consistent mesh, which may be helpful for physics.
    *
-   * Note that this will always be disabled if UseLodTransitions is set to true.
+   * Note that this will always be disabled if Enable Lod Transitions is set to
+   * true.
    */
   UPROPERTY(
       EditAnywhere,
       BlueprintReadWrite,
       Category = "Cesium|Tile Culling",
-      Meta = (EditCondition = "!UseLodTransitions", EditConditionHides))
+      Meta = (EditCondition = "!EnableLodTransitions", EditConditionHides))
   bool EnableFrustumCulling = true;
 
   /**
@@ -442,13 +443,14 @@ class CESIUMRUNTIME_API ACesium3DTileset : public AActor {
    * of the camera above the ground, tiles that are far away (close to
    * the horizon) will be culled when this flag is enabled.
    *
-   * Note that this will always be disabled if UseLodTransitions is set to true.
+   * Note that this will always be disabled if Enable Lod Transitions is set to
+   * true.
    */
   UPROPERTY(
       EditAnywhere,
       BlueprintReadWrite,
       Category = "Cesium|Tile Culling",
-      Meta = (EditCondition = "!UseLodTransitions", EditConditionHides))
+      Meta = (EditCondition = "!EnableLodTransitions", EditConditionHides))
   bool EnableFogCulling = true;
 
   /**
@@ -616,29 +618,34 @@ class CESIUMRUNTIME_API ACesium3DTileset : public AActor {
   FCompletedLoadTrigger OnTilesetLoaded;
 
   /**
-   * Use a dithering effect when transitioning between tiles of different LODs.
+   * Whether to enable a dithering effect when transitioning between tiles of
+   * different LODs.
    *
    * When this is set to true, Frustrum Culling and Fog Culling are always
    * disabled.
+   *
+   * When Forward Rendering is enabled for the project, LOD transitions are
+   * only compatible when used with temporal anti-aliasing methods. Setting this
+   * to true for other methods will result in dithering artifacts.
    */
   UPROPERTY(
       EditAnywhere,
-      BlueprintGetter = GetUseLodTransitions,
-      BlueprintSetter = SetUseLodTransitions,
+      BlueprintGetter = GetEnableLodTransitions,
+      BlueprintSetter = SetEnableLodTransitions,
       Category = "Cesium|Rendering")
-  bool UseLodTransitions = false;
+  bool EnableLodTransitions = false;
 
   /**
-   * How long dithered LOD transitions between different tiles should take, in
+   * How long the LOD transitions between different tiles should take, in
    * seconds.
    *
-   * Only relevant if UseLodTransitions is true.
+   * Only relevant if Enable Lod Transitions is true.
    */
   UPROPERTY(
       EditAnywhere,
       BlueprintReadWrite,
       Category = "Cesium|Rendering",
-      meta = (EditCondition = "UseLodTransitions", EditConditionHides))
+      meta = (EditCondition = "EnableLodTransitions", EditConditionHides))
   float LodTransitionLength = 0.5f;
 
 private:
@@ -904,10 +911,10 @@ class CESIUMRUNTIME_API ACesium3DTileset : public AActor {
   float GetLoadProgress() const { return LoadProgress; }
 
   UFUNCTION(BlueprintGetter, Category = "Cesium")
-  bool GetUseLodTransitions() const { return UseLodTransitions; }
+  bool GetEnableLodTransitions() const { return EnableLodTransitions; }
 
   UFUNCTION(BlueprintSetter, Category = "Cesium")
-  void SetUseLodTransitions(bool InUseLodTransitions);
+  void SetEnableLodTransitions(bool InEnableLodTransitions);
 
   UFUNCTION(BlueprintGetter, Category = "Cesium")
   ETilesetSource GetTilesetSource() const { return TilesetSource; }
@@ -1207,7 +1214,7 @@ class CESIUMRUNTIME_API ACesium3DTileset : public AActor {
   bool _beforeMoviePreloadAncestors;
   bool _beforeMoviePreloadSiblings;
   int32_t _beforeMovieLoadingDescendantLimit;
-  bool _beforeMovieUseLodTransitions;
+  bool _beforeMovieEnableLodTransitions;
 
   bool _scaleUsingDPI;