[Fix] Invisible spline meshes in instance segmentation (UE4) (#8714)

* Added explicit support for SplineMeshSceneProxy (e.g. PowerPoles) in TaggedComponent, rendering them visible in the instance segmentation.

* Described bug fix in changelog.

CHANGELOG.md

@@ -30,6 +30,7 @@
  * carla.ad subpackages are now directly importable and are not directly importable anymore (e.g. import ad)
  * Fixed segfault in traffic manager when trying to access not available vehicles
  * Fixed invalid comparission in python examples/rss
+ * Fixed invisible spline meshes in instance segmentation
 
 ## CARLA 0.9.15
 

Unreal/CarlaUE4/Plugins/Carla/Source/Carla/Game/TaggedComponent.cpp

@@ -123,7 +123,12 @@ FPrimitiveSceneProxy * UTaggedComponent::CreateSceneProxy(UStaticMeshComponent *
     return NULL;
   }
 
-  return new FTaggedStaticMeshSceneProxy(StaticMeshComponent, true, TaggedMID);
+  USplineMeshComponent* SplineMeshComponent = Cast<USplineMeshComponent>(StaticMeshComponent);
+  if (SplineMeshComponent) {
+    return new FTaggedSplineMeshSceneProxy(SplineMeshComponent, TaggedMID);
+  } else {
+    return new FTaggedStaticMeshSceneProxy(StaticMeshComponent, true, TaggedMID);
+  }
 }
 
 FPrimitiveSceneProxy * UTaggedComponent::CreateSceneProxy(USkeletalMeshComponent * SkeletalMeshComponent)
@@ -242,6 +247,34 @@ FPrimitiveViewRelevance FTaggedStaticMeshSceneProxy::GetViewRelevance(const FSce
   return ViewRelevance;
 }
 
+//
+// FTaggedSplineMeshSceneProxy
+//
+FTaggedSplineMeshSceneProxy::FTaggedSplineMeshSceneProxy(USplineMeshComponent * Component, UMaterialInstance * MaterialInstance) :
+  FSplineMeshSceneProxy(Component)
+{
+  TaggedMaterialInstance = MaterialInstance;
+
+  // Replace materials with tagged material
+  bVerifyUsedMaterials = false;
+
+  for (FLODInfo& LODInfo : LODs) {
+    for (FLODInfo::FSectionInfo& SectionInfo : LODInfo.Sections) {
+      SectionInfo.Material = TaggedMaterialInstance;
+    }
+  }
+}
+
+FPrimitiveViewRelevance FTaggedSplineMeshSceneProxy::GetViewRelevance(const FSceneView * View) const
+{
+  FPrimitiveViewRelevance ViewRelevance = FSplineMeshSceneProxy::GetViewRelevance(View);
+
+  ViewRelevance.bDrawRelevance = ViewRelevance.bDrawRelevance && !View->Family->EngineShowFlags.NotDrawTaggedComponents;
+  ViewRelevance.bShadowRelevance = false;
+
+  return ViewRelevance;
+}
+
 //
 // FTaggedSkeletalMeshSceneProxy
 //

Unreal/CarlaUE4/Plugins/Carla/Source/Carla/Game/TaggedComponent.h

@@ -4,6 +4,7 @@
 #include "Materials/MaterialInstanceDynamic.h"
 #include "Engine/InstancedStaticMesh.h"
 #include "Components/HierarchicalInstancedStaticMeshComponent.h"
+#include "SplineMeshSceneProxy.h"
 #include "Landscape.h"
 #include "LandscapeRender.h"
 #include "LandscapeMaterialInstanceConstant.h"
@@ -59,6 +60,18 @@ private:
   UMaterialInstance * TaggedMaterialInstance;
 };
 
+class FTaggedSplineMeshSceneProxy : public FSplineMeshSceneProxy
+{
+public:
+
+  FTaggedSplineMeshSceneProxy(USplineMeshComponent * Component, UMaterialInstance * MaterialInstance);
+
+  virtual FPrimitiveViewRelevance GetViewRelevance(const FSceneView * View) const override;
+
+private:
+  UMaterialInstance * TaggedMaterialInstance;
+};
+
 class FTaggedSkeletalMeshSceneProxy : public FSkeletalMeshSceneProxy
 {
 public: